U.S. Departmentof TransportationFederal AviationAdministration

Advisory Circular

1

Initiated by: AFS-340

DATE: 5/24/95

AC NO: 90-89A

AMATEUR-BUILT AIRCRAFT AND ULTRALIGHT

FLIGHT TESTING HANDBOOK

U.S. Departmentof TransportationFederal AviationAdministration

Advisory Circular

i

Subject: AMATEUR-BUILT AIRCRAFT Date: 5/24/95 AC No: 90-89A& ULTRALIGHT FLIGHT Initiated by: AFS-340 Change:TESTING HANDBOOK

1. PURPOSE. This advisory circular (AC) setsforth suggestions and safety related recommenda-tions to assist amateur and ultralight builders indeveloping individualized aircraft flight test plans.2. CANCELLATION. AC 90-89, Amateur-Built Aircraft Flight Testing Handbook, datedSeptember 18, 1989, is cancelled.3. RELATED READING MATERIAL. A listof selected reading material on amateur-built/ultralight flight testing and first flight experiencemay be found in appendix 3.4. BACKGROUND.

a. The Federal Aviation Administration(FAA), the Experimental Aircraft Association(EAA), and the United States Ultralight Association(USUA) are concerned and committed to improvingthe safety record of amateur-built and ultralight air-craft.

b. The FAA Administrator, T. Allen McArtor,and EAA President, Paul H. Poberezny, signed aMemorandum of Agreement on August 1, 1988,which addressed the need for educational and safetyprograms to assist amateur-builders in test flyingtheir aircraft. In accordance with that agreement, thisAC provides guidelines for flight testing amateur-built aircraft.

c. As part of the FAAs continuing efforts toimprove the safety record of all types of general avia-tion aircraft, this AC has been revised to includeflight testing recommendations for canard-type andultralight aircraft.

5. DEFINITIONS. The following terms aredefined for use in this AC.

a. Amateur-built aircraft means an aircraftissued an Experimental Airworthiness Certificateunder the provisions of Federal Aviation Regulations(FAR) 21.191 (g).

b. The term ultralight means a vehicle thatmeets the requirements of FAR 103.1.

c. The term ultralight in this AC also meansa two-place training vehicle of 496 pounds or less,operating under an EAA or USUA exemption toFAR Part 103.

d. For the purpose of this AC, both an ama-teur-built aircraft and a ultralight vehicle will bereferred to as an aircraft.6. DISCUSSION.

a. This ACs purpose is the following:(1) To make amateur-built/ultralight air-

craft pilots aware that test flying an aircraft is a criti-cal undertaking, which should be approached withthorough planning, skill, and common sense.

(2) To provide recommendations andsuggestions that can be combined with other sourceson test flying (e.g., the aircraft plan/kit manufactur-ers flight testing instructions, other flight testingdata). This will assist the amateur/ultralight ownerto develop a detailed flight test plan, tailored for theiraircraft and resources.

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AC 90-89A 5/24/95

b. The flight test plan is the heart of all profes-sional flight testing. The plan should account forevery hour spent in the flight test phase and shouldbe adhered to with the same respect for the unknownthat all successful test pilots share. The time allottedfor each phase of a personalized flight test plan mayvary, and each phase may have more events orchecks than suggested in this AC. The goals, how-ever, should be the same.

c. The two goals for an amateur builder/ultralight owner should be as follows:

(1) At the end of the aircrafts flight testphase, the aircraft will have been adequately testedand found airworthy and safe to operate within itsestablished operational envelope.

(2) Incorporation of the flight test oper-ational and performance data into the aircrafts flightmanual so the pilot can reference the data prior toeach flight.

7. REQUEST FOR INFORMATION.a. This AC is designed as a reference docu-

ment to assist in preparing a flight test plan for anamateur-built or ultralight aircraft.

(1) The suggestions and recommendationsin chapters 1 through 6 are for conventionally-designed aircraft with an air-cooled, 4-cycle, recip-rocating engine that develops less than 200 horse-power with a fixed pitch propeller.

(2) Chapter 7 deals with flight testing rec-ommendations for canard aircraft.

(3) Chapters 8 through 10 address flighttesting considerations for ultralight vehicles underFAR Part 103 and two-seat ultralight training

vehicles of less than 496 pounds empty weightoperating under an exemption to FAR Part 103.

b. Because of the large number of existingamateur-built/ultralight aircraft designs and newdesigns being introduced each year, the FAA encour-ages public participation in updating this document.Send comments, suggestions, or information aboutthis AC to the following address:

U.S. Department of TransportationFederal Aviation AdministrationFlight Standards Service (AFS-340)800 Independence Ave, SW.Washington, DC 20591c. Suggestions also may be sent to AFS-340

by FAX (202) 267-5115.d. After a review, appropriate comments,

suggestions, and information may be included in thenext revision of this AC.8. TO OBTAIN COPIES OF THIS AC. OrderAC 90-89A from:

U.S. Department of TransportationProperty Use and StorageSection, M-45.3Washington, DC 20590.

William J. WhiteDeputy Director, Flight Standards Service

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5/24/95 AC 90-89A

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CONTENTSPage

CHAPTER 1. PREPARATIONSection 1. Homework ............................................................................................................................... 1Section 2. Airport Selection ..................................................................................................................... 2

Figure 1 - Runway Length Chart ................................................................................................. 3Section 3. Emergency Plans and Equipment ........................................................................................... 4Section 4. Test Pilot ................................................................................................................................. 6Section 5. Medical Facts For Pilots ......................................................................................................... 7Section 6. Transporting The Aircraft To the Airport .............................................................................. 9Section 7. Assembly and Airworthiness Inspection ................................................................................ 10Section 8. Weight and Balance ................................................................................................................ 14

Figure 2 - Empty Weight CG ....................................................................................................... 15Figure 3 - Take Off CG ................................................................................................................ 16Figure 4 - Additional Equipment Added ...................................................................................... 17

Section 9. Paperwork ................................................................................................................................ 18Section 10. Powerplant Tests ..................................................................................................................... 19Section 11. Additional Engine Tests ......................................................................................................... 22Section 12. Propeller Inspection ................................................................................................................ 25

Figure 5 - Propeller Tracking ....................................................................................................... 26CHAPTER 2. TAXI TESTSSection 1. Low Speed Taxi Tests ............................................................................................................ 29Section 2. High Speed Taxi Tests ........................................................................................................... 30CHAPTER 3. THE FIRST FLIGHTSection 1. General .................................................................................................................................... 33Section 2. The Role of the Chase Plane .................................................................................................. 34Section 3. Emergency Procedures ............................................................................................................ 35Section 4. First Flight ............................................................................................................................... 36Section 5. First Flight Procedures ............................................................................................................ 37CHAPTER 4. THE FIRST 10 HOURSSection 1. The Second Flight ................................................................................................................... 41Section 2. The Third Flight ...................................................................................................................... 41Section 3. Hours 4 through 10 ................................................................................................................. 41CHAPTER 5. EXPANDING THE ENVELOPESection 1. General .................................................................................................................................... 45Section 2. Hours 11 through 20 ............................................................................................................... 45

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Figure 6 - Climb Airspeed and Altitude Graph ........................................................................... 47Figure 7 - Best Rate of Climb Speed Graph ............................................................................... 48

Section 3. Hours 21 through 35: Stability and Control Checks ............................................................. 49Figure 8 - Static Stability .............................................................................................................. 49Figure 9 - Time ............................................................................................................................. 50

Section 4. A Word or Two About Flutter ............................................................................................... 52

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CONTENTSContinuedPage

Section 5. Spins ........................................................................................................................................ 54Section 6. Accelerated Stalls .................................................................................................................... 56CHAPTER 6. PUTTING IT ALL TOGETHER: 36 HOURS TO ?Section 1. Maximum Gross Weight Tests ............................................................................................... 57Section 2. Service Ceiling Tests .............................................................................................................. 58Section 3. Navigation, Fuel Consumption, and Night Flying ................................................................. 59CHAPTER 7. THOUGHTS ON TESTING CANARD TYPE AMATEUR-BUILT AIRCRAFTSection 1. Canards .................................................................................................................................... 63CHAPTER 8. ULTRALIGHT AIRFRAME INSPECTIONSection 1. Differences .............................................................................................................................. 67Section 2. The Test Pilot .......................................................................................................................... 68Section 3. Pre-flight Airframe Inspection ................................................................................................ 68CHAPTER 9. ULTRALIGHT ENGINE/FUEL SYSTEM INSPECTIONSection 1. Engine Inspection .................................................................................................................... 71Section 2. Fuel Systems ........................................................................................................................... 72CHAPTER 10. ULTRALIGHT TEST FLYING RECOMMENDATIONSSection 1. Three Recommendations ......................................................................................................... 75Section 2. Airport Selection ..................................................................................................................... 75Section 3. Taxiing ..................................................................................................................................... 76Section 4. First Flight Differences ........................................................................................................... 76Section 5. Emergency Procedures ............................................................................................................ 77Appendix 1. Sample Checklist for a Condition Inspection .................................................................(7 pages) ........................................................................................................................................................ 1Appendix 2. Addresses for Accident/Incident Information .................................................................(1 page) .......................................................................................................................................................... 1Appendix 3. Additional References on Flight Testing .........................................................................(4 pages) ........................................................................................................................................................ 1

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CHAPTER 1. PREPARATIONThe Laws of Aerodynamics are unforgiving and the ground is hard. Michael Collins (1987)

SECTION 1. HOMEWORKIf you have no plan--you have no goal. Harold Little, Aircraft Manufacturer (1994)

1. OBJECTIVE. A planned approach to flighttesting.

a. The most important task for an amateur-builder is to develop a comprehensive FLIGHTTEST PLAN. This PLAN should be individually tai-lored to define the aircrafts specific level ofperformance. It is therefore important that the entire

flight test plan be developed and completedBEFORE the aircrafts first flight.

b. The objective of a FLIGHT TEST PLANis to determine the aircrafts controllability through-out all the maneuvers and to detect any hazardousoperating characteristics or design features. This datashould be used in developing a FLIGHT MANUALthat specifies the aircrafts performance and definesits operating envelope.

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SECTION 2. AIRPORT SELECTIONAn airport should be chosen with the same care and consideration as getting a second doctors opinion.

Fred Wimberly, EAA Flight Test Advisor (1994)

1. OBJECTIVE. To select an airport to test flythe aircraft.

a. The airport should have one runwayaligned into the prevailing wind with no obstructionson the approach or departure end. Hard surface run-ways should be in good repair and well maintainedto avoid foreign object damage (FOD) to the propel-ler and landing gear. Grass fields should be levelwith good drainage. Avoid airports in densely popu-lated or developed areas and those with high ratesof air traffic. The runway should have the propermarkings with a windsock or other wind directionindicator nearby.

b. To determine an appropriate runway, usethe chart in figure 1 (sea-level elevation), or the fol-lowing rule-of-thumb:

c. The ideal runway at sea-level elevationshould be at least 4,000 feet long and 100 feet wide.For each 1,000 feet increase in field elevation, add500 feet to the runway length. If testing a highperformance aircraft, the airports runway at sea-level should be more than 6,000 feet long and 150feet wide to allow a wider margin of safety. Otherconsiderations, such as power to weight ratio, wingdesign, and density altitude, also should be factoredinto the equation for picking the best runway forthe initial flight testing.

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Take-off Distance in FeetFIGURE 1. Runway Length Chart

d. Identify emergency landing fields locatedwithin gliding distance from anywhere in the airportpattern altitude. Since engine failures are second onlyto pilot error as the major cause of amateur-builtaircraft accidents, preparations for this type of emer-gency should be a mandatory part of the FLIGHTTEST PLAN.

e. It is advisable to perform flight tests froman airport with an active unicom or tower, even ifthe aircraft does not have an electrical system oris not equipped with a radio. Even at an uncontrolledfield, a communications base should be improvised.For both situations, a hand held radio with aviationfrequencies and a headset with a mike and a push-to-talk switch on the stick/yoke is recommended.Good radio communications improves the overalllevel of safety and reduces cockpit workload.

f. The FAA recommends airport selection cri-teria include the availability of hangar space andramp areas. These facilities will provide protectionfrom inclement weather and vandalism while the air-craft is being tested, maintained, and inspected.

g. The airport should have a telephone andfire fighting equipment, the latter being in compli-ance with relevant municipal codes (e.g., fire codes).

h. Explain the Flight Test Program andEMERGENCY PLANS to the airport manager orowner. They may be able to assist the amateur-builder in obtaining temporary hangar space, provid-ing ground/air communications, and supplying emer-gency equipment for use during the flight test.

45/24/95AC 90-89A

SECTION 3. EMERGENCY PLANS AND EQUIPMENTThe object of the game, gentlemen, is not to cheat death: the object is not to let him play. Patrick

Poteen, Sgt. U.S. Army

1. OBJECTIVE. To develop a FLIGHT TESTPLAN which contain two sets of emergency plans;one for IN-FLIGHT emergencies and another forGROUND emergencies.

a. The IN-FLIGHT emergency plan shouldaddress the following:

(1) Complete engine failure or partial fail-ure, especially after take off

(2) Flight control problems and severe out-of-rig conditions

(3) Fire in the engine compartment orcockpit

b. The GROUND EMERGENCY plan shouldbe developed to train the ground crew and/or theairport fire department crash crew on the following:

(1) The airplane canopy or cabin doorlatching mechanism

(2) The pilots shoulder harness/seat beltrelease procedure

(3) The location and operation of the fuelshut-off valve

(4) The master switch and magneto/igni-tion switch location and OFF position

(5) Engine cowling removal procedures togain access to the battery location or for fire fighting

(6) The battery location and disconnectprocedures

(7) Fire extinguisher application and use(8) How to secure the ballistic parachute

system

c. Ground Crew. Every test of an amateur-built aircraft should be supported by a minimumground crew of two experienced individuals. Theground crews function is two-fold:

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(1) To ensure that the aircraft is in air-worthy condition for safe operation

(2) To provide assistance to the test pilotin an emergency

d. The Airport.(1) If the airport does not have a fire rescue

unit, it is suggested the ground crew have a fourwheel drive vehicle equipped with a portable radio,first aid kit, metal-cutting tools, and a fire extin-guisher. A minimum of one person should be trainedin first-aid.

(2) If the airport provides a fire rescue unit,the test pilot should ensure the rescue unit and theground crew are trained and competent in performingground emergency functions as identified in theFLIGHT TEST PLAN.

(3) Suggestion. For a small donation,some local volunteer fire and rescue companies willprovide the amateur-builder with a standby crew dur-ing the initial critical portions of the flight test phase.

e. Hospital Location. The ground crew shouldknow the location and telephone numbers of the hos-pitals and fire rescue squads in the vicinity of theairport AND the flight test area. If the test pilot isallergic to specific medications, or has a rare bloodtype, a medical alert bracelet or card should be car-ried or worn to alert medical personnel of the condi-tion.

f. Fire Extinguisher. Fire extinguishersshould be available to the ground crew, and a fireextinguisher should be securely mounted in the cock-pit within easy reach of the test pilot. A fire axe,or other tool capable of cutting through the canopy,also should be positioned in the cockpit.

g. Fire Protection. There is always danger ofa flash fire during test flights. To prevent burns, thepilot should wear an aviation/motorcycle helmet,NOMEX coveralls/gloves and smoke goggles. IfNOMEX clothing is not available, cotton or woolclothing will offer some protection from heat andflames. Pilots should never wear nylon or poly-ester clothing because synthetic materials meltwhen exposed to heat and will stick to the skin.

h. Pilot Protection. A modern aviation/motor-cycle helmet, a properly installed shoulder harness,a well designed seat, a clean cockpit design free of

protruding components/sharp edges, NOMEX cloth-ing, smoke goggles, and a memorized emergencyplan ensure safety during flight testing.

i. Parachute. The decision to wear a parachutedepends on the type of aircraft being tested. Someaircraft have forward hinged canopies that are notequipped with quick release pins or have pusherpropellers which increase the chance of injury to thepilot while exiting the aircraft. Other aircraft designsmay pose no exit problems. If the decision is madeto wear a parachute, check that it has been recentlypacked (within 120 days) by a qualified parachuterigger. Ensure that the chute has not been exposedto rain/moisture and when worn, does not interferewith cockpit management. The test pilot should bethoroughly trained on how to exit the aircraft anddeploy the parachute.

j. Ballistic Chutes. Ballistic chutes are the lat-est development in dealing with in-flight emer-gencies. A ballistic chute is attached to the aircraftand when activated, lowers the whole aircraft andthe pilot to the ground at the rate of descent ofapproximately 20 feet per second.

(1) Deployment Scenarios:(i) structural failure

(ii) mid-air collision(iii) stall/spin(iv) loss of control/icing(v) engine failure over bad terrain

(vi) pilot incapacitation(2) Installation Considerations: The

builder should consider the following when installinga ballistic chute:

(i) Matching the chute with the air-crafts size, weight, and Vne speed (check with thechute manufacturer)

(ii) How the chute will be positionedand mounted

(iii) The chutes effect on the air-crafts weight and balance before deployment andaircrafts touchdown attitude after deployment

(iv) Compatibility of the openingloads and the aircrafts structural design limits

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(v) The routing of the bridle andharness

(vi) The routing of the activatinghousing

(vii) The placement of the activatinghandle in the cockpit

(viii) Incorporation of chute deploy-ment procedures in the in-flight emergency plan andemergency check list

(ix) The deployment time, fromactivation to full chute opening

(3) If a ballistic chute is installed, thebuilder should add the appropriate ballistic chuteinspection items to the aircrafts pre-flight inspec-tion check list. The builder also should add theballistic chute manufacturers repack/refitting sched-ule and maintenance inspections to the flight manualand the conditional annual inspection check list.

SECTION 4. TEST PILOT

We are looking for a few good Men and Women! Marine Corps advertisement (1991)

1. OBJECTIVE. To select a qualified individualto be the test pilot.2. GENERAL. The test pilot should be com-petent in an aircraft of similar configuration, size,weight, and performance as the aircraft to be tested.If the aircrafts builder is the test pilot, the costsinvolved in maintaining pilot competence should bebudgeted with the same level of commitment andpriority that is assigned to plans and materials tocomplete the project.3. TEST PILOT REQUIREMENTS.

a. A test pilot should meet the following mini-mum qualifications:

(1) Physically fit: Test flying an aircraft isa stressful and strenuous task

(2) No alcohol or drugs in the last 24 hours(3) Rated, current, and competent in the

same category and class as the aircraft being tested(4) Current medical and biennial or flight

review as appropriate, or a current USUA certifi-cation and flight review

b. Suggested Test Pilot Flight Time Require-ments. The following suggested number of flighthours are only an indication of pilot skill, not anindicator of pilot competence. Each test pilot mustassess if their level of competence is adequate orif additional flight training is necessary. If an individ-ual determines they are not qualified to flight test

an unproven aircraft, someone who is qualified mustbe found.

(1) 100 hours solo time before flight test-ing a kit plane or an aircraft built from a time-provenset of plans

(2) 200 hours solo time before flight test-ing for a one of a kind or a high performanceaircraft

(3) A minimum of 50 recent takeoffs andlandings in a conventional (tail wheel aircraft) if theaircraft to be tested is a tail dragger

c. The test pilot should:(1) Be familiar with the airport and the

emergency fields in the area(2) Talk with and, if possible, fly with a

pilot in the same kind of aircraft to be tested(3) Take additional instruction in similar

type certificated aircraft. For example, if the aircraftto be tested is a tail dragger, a Bellanca Citabriaor Super Cub is appropriate for training. For testingan aircraft with a short wing span, the GrummanAmerican Yankee or Globe Swift is suitable fortraining.

(4) Be considered competent when theyhave demonstrated a high level of skill in all plannedflight test maneuvers in an aircraft with performancecharacteristics similar to the test aircraft

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(5) Study the ground and in-flight emer-gency procedures developed for the aircraft and prac-tice them in aircraft with similar flight characteristics

(6) Have logged a minimum of 1 hour oftraining in recovery from unusual attitudes within45 days of the first test flight

(7) If appropriate, have logged a minimumof 10 tail wheel take-off and landings within the past30 days

(8) Study the performance characteristicsof the aircraft to be tested. Refer to the designersor kit manufacturers instructions, articles written bybuilders of the same make and model aircraft, andstudy actual or video tape demonstrations of the air-craft.

(9) Review the FAA/National Transpor-tation Safety Board (NTSB)/EAA accident reportsfor the same make and model aircraft to be awareof problems the aircraft has experienced during pre-vious operations (see appendix 2 for the address).

(10) Memorize the cockpit flight controls,switches, valves, and instruments. A thoroughknowledge of the cockpit will result in controlledand coordinated mental and physical reactions duringemergencies.

NOTE: The EAA has developed a FlightAdvisor Program which offers builders/pilots assistance in performing a self evalua-tion of the flight test program and/or selec-tion of the test pilot. To obtain additionalinformation, contact a local EAA Chapteror EAA Headquarters, (414) 426-4800.

SECTION 5. MEDICAL FACTS FOR PILOTSIf the pilot is unairworthy, so is the airplane! Bill Chana, Aeronautical Engineer

1. OBJECTIVE. To identify some of the wellknown medical causes for aircraft accidents and tostress the importance of a personal pre-flight check-list in addition to an aircraft pre-flight checklist.

a. Alcohol. FAR Part 91, General Operatingand Flight Rules, 91.17 requires that 8 hoursmust elapse from the last drink to the first flight.Test flying an aircraft, however, places additionalmental and physical demands on the pilot. The FAAstrongly recommends a minimum of 24 hoursbetween the last drink and the test flight. This isbecause small amounts of alcohol in the blood streamcan affect judgement, reaction time, and decrease apilots tolerance to hypoxia.

b. Anesthetics. Local and dental anesthetic canaffect a pilots performance in many adverse ways.It is recommended that a minimum of 48 hourselapse from the time of anesthesia to the time thepilot climbs into the cockpit.

c. Blood Donations. Do not fly for 3 weeksafter donating blood. The body needs approximatelythree weeks for a complete physiological recovery.Although the physical affects may not be noticeableat sea level, they will become apparent when flyingat higher altitudes.

d. Carbon Monoxide (CO). CO is a colorless,odorless, tasteless gas that is always present inengine exhaust fumes. Carbon monoxide preventsoxygen absorption by the blood, and exposure to thegas creates vision problems, headaches, disorienta-tion, and blurred thinking (see chapter 1, section 7,paragraph 3 (g) for testing the aircraft for COcontamination).

e. Drugs. Similar to alcohol, drugs will reduceor impair judgement and affect reflexes and hand/eye coordination. It is a given that the use/abuse ofillegal drugs is dangerous and against the law.Prescription drugs and over-the-counter remedies,however, also may be dangerous when combinedwith flying. The FAA recommends all pilots whomust take medication consult with an Aviation Medi-cal Examiner (AME) to understand the medicationsaffects on their ability to think and react while inthe cockpit.

f. Ear and Sinus Pain.(1) Ear and sinus pain is usually caused

by the eardrum or sinuses failing to equalize the airpressure during a descent. The blocked ears andsinuses can be caused by a head cold. The pain canbe considerable and is most noticeable during

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descents. For ear blockages try yawning, swallowing,or chewing gum which may give some relief. TheValsalva procedure can be effective: pinch the nose,close the mouth, and try to force air through thenostrils.

(2) If ear blockage occurs during flight, tryclimbing back to a higher altitude (lower air pres-sure) until the pain lessens. Then begin a gradualrate of descent, allowing the ears and sinuses timeto adapt to the increasing pressure.

(3) After landing, nasal sprays will givesome sinus pain relief. To relieve ear pain, try wet-ting paper towels with hot water, put the towels inthe bottom of a plastic or dixie cup and then holdthe cups over the ears. The warmth will help easethe inflamed tissues and reduce the pain. If paincontinues, see a doctor.

NOTE: The best way to avoid this problemis not to fly with a head cold, upper res-piratory infection, or nasal allergic condi-tion. Be advised that some nasal and oraldecongestants could be ineffective at altitudeand have side effects such as drowsiness thatcan significantly impair pilot performance.Again, consult with an Aviation MedicalExaminer to understand the affects of medi-cation before flying.

g. Fatigue. Fly only when healthy, fit, andalert. Mental and physical fatigue will generally slowdown a pilots reaction time, affect decision making,and attention span. Lack of sleep is the most common

cause of fatigue, but family and business problemscan create mental fatigue which can have the sameeffects on the pilot as lack of sleep.

h. Flicker Vertigo. Light, when flashing at afrequency between 4 to 29 cycles per second, cancause a dangerous physiological condition in somepeople called flicker vertigo. These conditions rangefrom nausea and dizziness to unconsciousness, oreven reactions similar to an epileptic fit. When head-ing into the sun, a propeller cutting the light mayproduce this flashing effect. Avoid flicker vertigo,especially when the engine is throttled back for land-ing. To alleviate this when the propeller is causingthe problem, frequently change engine revolutionsper minute (rpm). When flying at night and the rotat-ing beacon is creating flicker vertigo, turn it off.

i. Underwater Diving. Never fly immediatelyafter SCUBA diving. Always allow 24 hours toelapse before flying as a pilot or a passenger in orderto give the body sufficient time to rid itself of exces-sive nitrogen absorbed during diving.

j. Stress. Stress from the pressures of a joband everyday living can impair a pilots perform-ance, often in subtle ways. A test pilot may furtherincrease the stress level by setting unreasonable testflying schedules in order to meet an arbitrary bedone by date. Stress also may impair judgement,inducing the pilot to take unwarranted risks, suchas flying into deteriorating weather conditions or fly-ing when fatigued to meet a self imposed deadline.

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SECTION 6. TRANSPORTING THE AIRCRAFT TO THE AIRPORTBest laid plans of mice and men are often stuck in traffic. Ben Owen, EAA Executive Director (1994)

1. OBJECTIVE. To reduce damaging the air-craft in transit. The following suggestions may pre-vent this from happening:

a. Use a truck or flat bed truck/trailer largeenough to accommodate the aircraft and the addi-tional support equipment.

b. If the aircraft wings are removable, buildpadded jigs, cradles, or fixtures to hold and supportthem during the trip to the airport.

c. Secure the fixtures to the truck/trailer, thensecure the wings to the fixture.

d. Use two or more ropes at each tie downpoint.

e. Use heavy moving pads used for householdmoves to protect wings and fuselage. Most rent-a-truck firms offer them for rental.

f. During the planning stage, obtainapplicable permits and follow the local ordinancesfor transporting an oversized load. Ask the localpolice if they can provide an escort to the airport.

g. Brief the moving crew thoroughly beforeloading and unloading the aircraft.

h. Ensure the designated driver has recentexperience driving a truck/trailer and is familiar withthe roads to the airport.

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SECTION 7. ASSEMBLY AND AIRWORTHINESS INSPECTIONComplacency is one of the major causes of accidents, no matter how well things are going, something

can go wrong Art Scholl

1. OBJECTIVE. To determine the airworthinessof the aircraft and its systems.2. GENERAL.

a. If the aircraft must be reassembled afterbeing moved to the airport -- take time to do socarefully. This is a critical event because mistakescan easily be made due to the builders preoccupationwith the impending first flight of the aircraft. Oneof the most common and deadly mistakes is toreverse the rigging on the ailerons. To prevent errorsin reassembling the aircraft, follow the designersor kit manufacturers instructions, or use a writtencheck list specifically designed as part of theFLIGHT TEST PLAN. At the completion of eachmajor operation, have another expert check the work.

b. When the aircraft is reassembled, performa pre-flight fitness inspection. This inspectionshould be similar in scope and detail to an annualinspection. The fitness inspection should be accom-

plished even if the aircraft has just been issued aspecial airworthiness certificate by the FAA. Evenif a builder was 99 percent perfect and performed10,000 tasks building the aircraft, there would stillbe a hundred items that would need to be found andcorrected before the first flight.3. FITNESS INSPECTION - AIRFRAME.The following additional safety check list items maynot be applicable to all amateur-built make andmodel aircraft, but are presented for considerationand review:

a. Control stick/wheel: The control stick/wheel should have a free and smooth operationthroughout its full range of travel. There should beno binding or contact with the sides of the fuselage,seat, or instrument panel. There should be no free-play (slack) in the controls, nor should the controlsbe tight as to have stick-slip movement.

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b. Rudder pedals: Move the rudder pedalsthrough the full range of travel. The pedal movementshould be smooth with no binding. The test pilotshould ensure that their shoes will not catch onexposed metal lines, fixtures, or electrical wire har-ness.

c. Brakes: Hand and/or toe brake pressureshould be firm with no tendency to bleed down orlock up. Spongy brakes that must be pumped up,or show a drop in the level of brake fluid in thereservoir after a few brake applications, indicate abrake fluid or air leak in the system.

d. Main landing gear: Ensure that the gearattach points, shimmy dampener, bungees, wheels,brakes, and wheel fairings are airworthy. Ifapplicable, check that the tail wheel pivot point iscentered and vertical in relation to the longitudinalaxis of the aircraft. It is critical that the main landinggear alignment toe in/toe out is zero or matches thespecifications for fuselage/landing gear alignmentcalled out in the plans. Even one landing gear wheelout of alignment can cause a ground loop.

e. Control surfaces: Perform rigging checks toensure that control input for ailerons, rudder, ele-vators, and trim tabs results in the correct amountof travel and direction of the control movement andthat contact with the stops is made. Also ensure thatthe flaps, if installed, have the proper travel, operateas a single unit, and cannot be extended beyond themaximum extended position. It is important to ensurethat the control cable tension is correct by checkingit with a calibrated tensiometer and confirming thatall the attachment hardware is secured and safety-wired.

(1) If the cable tension is less than thespecifications require, the in flight air loads dur-ing flight will prevent full travel of the control, evenif the control has the right amount of deflection andhits all the stops in the cockpit/wing/tail when testedon the ground. With low cable tension, the desiredcontrol movement input will be absorbed by the slackin the cables.

(2) While checking cable tension, makesure there is no free play in the flight controlhinges and rod ends. Free play and loose cable ten-sion combined with control mass imbalance sets thestage for the onset of control surface flutter. Donot, however, rig the controls at too high a cable

tension. This will cause high wear rate on the pulleysand prevent good control feel, especially at low air-speeds.

f. Instrument panel: All the instrumentsshould be properly secured in the panel and havepreliminary markings on them. Airspeed indicatorand engine tachometer should be marked with theEXPECTED performance range markings. Oiltemperature and oil pressure must have the enginemanufacturers recommended operating rangemarked. If the markings are on the instrument glassface, paint a white slippage mark on both the glassand on the instrument case to alert the pilot in casethe glass/range marks have moved. Attach a tem-porary placard to the instrument panel with theexpected stall, climb, and glide speeds. It is a handyreference in times of emergency.

g. Behind the instrument panel: Very fewamateur-built aircraft of the same make and modelhave the same instrument panel design. Each ama-teur-builder should inspect this area to ensure thatall line connections are tight, that nothing interfereswith control travel, and there are no loose wires orfuel, oil, or hydraulic leaks.

h. Carbon Monoxide: Carbon Monoxide leaksalso can be performed. Wait until night or put theaircraft in a dark hangar. Climb into the cockpit andhave a friend shine a bright flood light close to thefire-wall. If light leaks into the cockpit, carbon mon-oxide can seep in. Mark it and seal it.

i. Engine and propeller controls: All controlsshould be visually inspected, positive in operation,and securely mounted. The friction lock on both con-trols should be checked for operation. Each controlshould have full movement with at least a 14 inchof cushion at the full travel position. The controlcables should be firmly attached to the fuselage alongeach 24 inches of their runs to prevent whippingof the cable and loss of cable movement at the otherend. Control cables with ball sockets should havelarge area washers on either end of the bolt connec-tion. This will ensure the control will remain con-nected, even if the ball socket fails and drops out.

j. Static system: The best procedure to checkthe altimeter for leaks and accuracy is to have theentire static system checked in accordance with FARPart 43, appendix E, at an FAA-approved repair sta-tion.

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4. FIELD CHECK. Two people are needed toaccomplish the following field check that will enablean amateur-builder to detect if the aircraftsinstrument system is leaking: (Note: This field checkis not an accuracy check.)

a. Airspeed check: Slip a long rubber hoseover the pitot mast (surgical tubing is recommended).As one person reads the airspeed, the other shouldvery slowly roll up the other end of the tubing. Thiswill apply pressure to the instrument. When the air-speed indicator needle reaches the aircrafts approxi-mate recommended cruise speed, pinch the hose shut,and hold that reading. The airspeed needle shouldremain steady for a minute if the system is sound.A fast drop off will indicate a leak in the instrument,fittings, lines, or the test hose attachment. NEVERforce air in the pitot tube or orally apply suctionon a static vent. This will cause damage to theinstruments.

b. Altimeter/vertical speed check.(1) To check the static side, apply low suc-

tion at the end of the static vent port. The easiestway to gain access to the static system is to removethe static line at the static port. If there are two staticports, tape the unused port closed. Next, get two feetof surgical tubing, seal one end, and tightly roll itup. Attach the open end to the static line and slowlyunroll the tubing. This will apply a suction, or lowpressure, to the static system.

(2) The altimeter should start to show anincrease in altitude. The vertical speed indicator alsoshould indicate a rate of climb. The airspeed mayshow a small positive indication. When the altimeterreads approximately 2,000 feet, stop and pinch offthe tube. There will be some initial decrease in alti-tude and the vertical speed will read zero. The altim-eter should then hold the indicated altitude for atleast a minute. If altitude is lost, check for leaks.

(3) IMPORTANT: The above airspeed andaltimeter field checks should not be considered theequivalent of airspeed or static system accuracy testsas certified by a certificated repair station, but acheck of the system for possible leaks. These checksdo not take into consideration the pitot tube and staticports located on the airframe. The FAA recommendsthe builder not deviate from the designers originalplans when installing the pitot and static system.

c. Fuel system: Since 1983, more than 70 per-cent of the engine failures in amateur-built aircraftwere caused by fuel system problems. Many timesthe direct cause of engine failure was dirt and debrisin the fuel tank and lines left behind during the manu-facturing process.

(1) Before the aircrafts fuel tanks arefilled, the amateur-builder should vacuum any manu-facturing debris from each tank and wipe them downwith a tack cloth (available from a paint supplystore). Next, the system should be flushed with avia-tion grade gasoline several times in order to removeany small or hard to reach debris from the tanksand lines. The fuel filter/gasolator screen/carburetorfinger screen should also be cleaned. The amountof time spent sanitizing the fuel system will pro-vide big safety dividends for the life of the aircraft.

(2) When filling the tanks, place the air-craft in the straight and level cruise position. Addfuel in measured amounts to calibrate the fuel tankindicators. While allowing the aircraft to sit for ashort time to observe for possible leaks, inspect thefuel tank vents to see if they are open and clear.Check that the fuel tank caps seal properly. If thereare no leaks and the fuel system has an electric boostpump, pressurize the system and again check forleaks. The fuel selector, vents and fuel drains shouldbe properly marked and tested for proper operation.

NOTE: Many amateur-built aircraft take 5to 8 years to build. During that time, manyrubber-based oil and fuel lines and cork gas-kets that were installed early in the buildingprocess may have age hardened, cracked,and/or turned brittle. The builder shouldcarefully inspect these components andreplace as necessary to prevent a prematureengine failure.

d. Hydraulic system: The hydraulic systemshould function dependably and positively in accord-ance with the designers intent. Retractable landinggear should be rigorously cycled on the ground,using both the normal and emergency landing gearextension system.

e. Safety belt and shoulder harness: Theseitems should be checked for condition and properinstallation. A review of amateur-built aircraftaccidents has disclosed a significant number ofaccidents in which the seat belt mounting hard points

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5/24/95 AC 90-89A

failed. Each seat belt and shoulder harness mountinghard point should be built to the designers specifica-tions to ensure that it will hold the harness and pilotin the aircraft at the ultimate design G load speci-fication, both positive and negative, for the aircraft.

f. Avionics and electrical checks: Test the avi-onics systems. Perform an operational check toensure the radio(s) transmit and receive on all fre-quencies. Inspect circuit breakers/fuses, micro-phones, and antennas for security and operation. Testthe ELT for proper operation and battery life. Elec-trical systems can be checked for operation of lights,instruments, and basic nav/comm performance.Other electrical systems, such as generator/alternatoroutput can be checked during the engine run-ins, taxi,and flight tests. Check the battery and the batterycompartment for security and if applicable, ensure

that the battery is properly vented to the outside ofthe aircraft. Check the condition of the engine toairframe bonding (grounding) wire. Ensure that allelectrical instruments operate properly.

g. Cowling and panel checks: Ensure that allinspection panels are in place, the cowling is secured,and cowl flap operation is satisfactory. Inspect thepropeller spinner and its backing plate for cracks.

h. Canopy/door locks checks: Ensure the can-opy or doors on the aircraft work as advertised. Dou-ble check the canopy or door lock(s) so the canopyand doors will not open in flight and disturb theairflow over the wings and stall the aircraft. If acanopy jettison system is installed, check for properoperation when the aircraft on the ground and whenit is on jacks. (Jacks will simulate flight loads onthe aircraft.)

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SECTION 8. WEIGHT AND BALANCENever argue with your spouse or a mathematician Phil Larsh, Accident Prevention Counselor,

Colfax IN (1994)

1. OBJECTIVE. To discuss the importance ofdeveloping an accurate weight and balance calcula-tions for both test and recreational flights. Additionalinformation on weight and balance can be found inAC 91-23A, Pilots Weight and Balance Handbook.

a. A good weight and balance calculation isthe keystone of flight testing. Accurately determiningthe aircrafts take-off weight and ensuring that thecenter of gravity (CG) is within the aircrafts design

for each flight is critical to conducting a safe flighttest.

b. An aircraft should be level when weighed,spanwise and fore and aft in accordance with themanufacturers instructions, and should be in thelevel flight position. It is highly recommended thatthe weighing be done in an enclosed area, using threecalibrated scales. Bathroom scales are not rec-ommended because they are not always accurate.

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ITEMS WEIGHT (LBS) ARM (INCHES) MOMENT (IN-LBS)

Left Wheel

Right Wheel

Tail Wheel

TOTALS

101

99

42

242

60

60

180

80.8

6060

5940

7560

19560

TOTAL MOMENT = Empty weight CG or 19560 = 80.8TOTAL WEIGHT 242

FIGURE 2. EMPTY WEIGHT CG

2. DETERMINING EMPTY WEIGHT CG.a. The sample airplane for determining empty

weight is a single seater, which the kit manufactur-ers design empty weight of 253 pounds and a grossweight limit of 500 pounds. The datum line is locatedat the nose of the aircraft and the CG range isbetween 69 to 74 inches from the datum.

b. To work a CG problem, figure the EMPTYWEIGHT CG first. On a piece of paper draw fourblocks. Title each block from left to right as shownin figure 3.

(1) Under the block titled item, verticallylist left wheel, right wheel, and nose/tailwheel.

(2) Place a calibrated scale under eachwheel and record the weight on each gear, in pounds,

in the weight block along side the appropriate wheel.This process is done with an empty fuel tank.

(3) Measure in inches the distance from thedatum line, or imaginary point identified by themanufacturer (e.g., nose of the aircraft), to the centerline (C/L) of the three wheels. Record the distanceof each wheel and place it in the moment arm blockbeside the appropriate wheel (see figure 2).

(4) Multiply the number of inches (arm)by the weight on each wheel to get the moment (inch-pounds) for each wheel. Add the weight on the threegears and the three moments in inch pounds anddivide the total weight into the total moment. Thesum is the EMPTY WEIGHT CENTER OFGRAVITY in inches. In the sample case, the emptyweight CG is 80.8.

NOTE: All calculations should be carriedout to two decimal places.

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ITEMS WEIGHT (LBS) ARM (INCHES) MOMENT (IN-LBS)

A/C

Pilot

Fuel

TOTALS

242

170

30

442

80.8

65

70

74

19560

11050

2100

32710

TOTAL MOMENT = Takeoff CG or 32710 = 74TOTAL WEIGHT 442

FIGURE 3. TAKE-OFF CG

3. DETERMINING TAKE-OFF WEIGHT CG.a. Since the aircrafts empty weight and empty

weight CG are fixed numbers, the only way an air-crafts CG can be changed is by adding weight inother locations.

b. For example, in figure 3, the aircraftsempty weight has been written in the appropriateblocks. The pilot weighs 170 pounds and fuel (5 gal-lons) weighs 30 pounds.

c. Again, all measurements are made from thedatum to the center line of the object that has beenadded. Weight multiplied by inches from the datumequals moment. Add the weights and moments tofind the take-off CG for that particular flight.

d. Loaded in this configuration, the aircraftis within the CG flight envelope and is safe to fly.

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ITEMS WEIGHT (LBS) ARM (INCHES) MOMENT (IN-LBS)

A/C

S/B

Pilot

Strobe

Fuel

Fuel

TOTALS

242

15

170

1.5

30

1.5

460

80.8

75

65

179

70

55

74.3

19560

1125

11050

268.5

2100

82.5

34186

TOTAL MOMENT = Alteration Takeoff Weight CG or 34186 = 74.3TOTAL WEIGHT 460

FIGURE 4. ADDITIONAL EQUIPMENT ADDED

4. ADDING ADDITIONAL EQUIPMENT.a. During flight testing, a strobe battery and

hand held radio are added. The battery/battery boxweight is 15 pounds and the location is 75 inchesaft of the datum; the strobe assembly weight is 1.5pounds and is located 179 inches aft of the datum;the radios weight is 1.5 pounds and is located 55inches aft of the datum (see figure 4).

b. In the sample problem, the previous figuresfor take-off weight and moment are still accurate,hence those numbers have been listed in the appro-priate blocks.

(1) Add the battery, strobe, and radio num-bers in the appropriate locations and calculate thetotals. At 465 pounds, the aircraft is still 35 poundsunder its design gross weight limit of 500 poundsbut is out of balance because the CG has moved.3 inches further aft (74.3 inches) than the allowablerear CG limit of 74 inches.

(2) Since the aircraft is out of balance withan aft CG, it is no longer 100 percent stable in pitchand would be dangerous to fly. In most cases, itis not the amount of weight added to the aircraftthat can cause a major safety problem but its loca-tion.

(3) To bring this aircraft back into the safeCG range, the battery would have to be moved 9inches forward (66 inches from the datum line).Another alternative is to install 8 pounds of ballastin the nose (20 inches from the datum).

(4) If the sample aircraft exceeded thedesigners gross weight limit (e.g., 300 pound pilot)instead of the CG limit, its climb, stall, and perform-ance capability would be poor and the possibilityfor in-flight structural failure would be high.

NOTE: In the sample weight and balance,positive numbers were chosen by placing thedatum line on the nose of the aircraft. Somemanufacturers prefer to use a datum locatedsomewhere between the aircrafts nose andthe leading edge of the wing.

(5) This kind of datum will set up a systemof positive arms (items located aft of the datum) andnegative arms (items located forward of the datum).

(6) When working a weight and balanceproblem with negative and positive moments, sub-tract the sum of all negative moments from the sumof all positive moments to reach a total momentfor the aircraft.

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SECTION 9. PAPERWORKIt is harder to write a lie in a logbook than tell one, because your eyes see it and your fingers feel

it. Bob Moorman, Ultralight Instructor (1994)

1. OBJECTIVE. To have the proper documenta-tion and paperwork to conduct the flight test.

a. Weight and Balance: The weight and bal-ance for the aircraft should be carefully done. Thegross weight and CG range should be determinedprior to every flight.

b. Airworthiness/Registration/OperatingLimitations/Placards/Weight and Balance: Must beon board, or the aircraft is not legal to be operated.

c. Checklists: In addition to the assembly/air-worthiness checklist previously discussed in section7, the builder should prepare the following check-lists: preflight; take-off/cruise; before starting;descent/before landing; starting the engine; afterlanding; before takeoff; securing the aircraft; andemergency procedures. A checklist to cover theabove procedures may seem a tedious task, but itwill only be the size of a 5x8 card -- similar to achecklist for a Cessna 150 or a Piper PA-28-140.

NOTE: The amateur-builder should antici-pate several revisions to the checklists.

d. Flight Manual: It is imperative a flightmanual describing the anticipated performance of theaircraft be written by the aircraft builder/kit manufac-turer. The manual will be revised several times dur-ing the flight test phase until it accurately reportsthe aircrafts performance.

e. Maintenance Records (logbooks): Opera-tors of amateur-built aircraft are required to onlyrecord the yearly condition inspections in accordancewith the aircrafts operating limitations. The FAArecommends, however, that every amateur-built air-craft/ultralight owner record in the aircraftslogbooks all inspections and maintenance performed.This will create an aircrafts maintenance history andwill be invaluable in spotting trends.

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5/24/95 AC 90-89A

SECTION 10. POWERPLANT TESTSDont short-change the engine tests or you wont be around to give your grandkids a ride. Dick Koehler,

A&P Instructor (1994)

1. OBJECTIVE. To ensure that the engine hasbeen properly run-in and is safe to operate in allrpm ranges.

a. An engine pre-oil and cold compression testcan be conducted as follows:

(1) Remove the rocker-box covers and onespark plug from each cylinder.

(2) Using an external oil pump, or by rotat-ing the propeller in the direction of rotation, pumpa substantial supply of oil up from the sump intothe rocker arms.

(3) When the engine is pre-oiled, run acold compression test of each cylinder.

(4) The results will serve only as an initialbench mark for comparing other compression teststaken after the engine has been run-up to operatingtemperature.

b. New/newly overhauled engine run-in proce-dures:

(1) Most amateur-builders start with a newor newly overhauled engine and proceed to run itin on the airframe. This practice is followed dueto lack of access to a test cell or a special clubpropeller that is specifically designed to aid in enginecooling during run-in. There are pros and cons tousing an airframe to run in an engine, but the bestadvice has always been to follow the engine manu-facturers instructions. These instructions are foundeither in the manufacturers overhaul manuals, serv-ice bulletins, or service letters. Following the manu-facturers instructions is especially important if theengine has chrome cylinders which require specialrun-in procedures.

(2) Also, before running-up the engine, becertain that it has the proper grade oil in the sump.Some new and newly overhauled engines are shippedwith a special preservative oil to prevent corrosion.

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5/24/95AC 90-89A

Drain this out and reservice the engine with the cor-rect oil before starting.

c. Used engine run-in procedures: Some ama-teur-builders install a used engine from a flyable air-craft. The same checks and adjustments used on anew or newly overhauled engine should be con-ducted. New and used engines require specialattention to engine cylinder baffling to ensure cyl-inder cooling is within the engine manufacturerscylinder head temperature specifications.

d. Pre run-in checks:(1) Before beginning the powerplant tests,

inspect the engine and propeller carefully. All fueland oil line connections should be tight. Check thetorque on the engine mount attaching bolts. Be cer-tain that there are no tools, hardware, or rags layingbetween the cylinders or under the magnetos.

(2) Check for the proper amount of oil inthe engine and that the dip stick gives an accuratereading of the oil quantity. Be advised that someengines were mounted on an angle in type certifi-cated aircraft. These engines have a special part num-ber oil dip stick, which corrects for the differentangle of oil in the crankcase. The same engine,mounted level in a amateur-built aircraft with theoriginal dip stick, will not show the correct oil quan-tity.

e. Test and Support Equipment:(1) A cylinder head temperature gauge

(CHT) is needed to ensure that all cylinders arereceiving the proper flow of cooling air.

(2) On the newer aircraft engines, the cyl-inders are drilled and tapped to accept a bayonettype of CHT thermocouple probes. For older engines,the thermocouple is designed like a spark plugwasher and fits under a spark plug. It can be installedin any cylinder, either under the top or bottom sparkplug.

(3) Each type of CHT design can havemultiple thermocouples which are connected to aselector switch in the cockpit. The pilot then selectsthe cylinder he wants to monitor. This also is anexcellent troubleshooting tool for identifying fouledplugs and bad ignition leads.

(4) If there is only one CHT thermocouple,attach it to the rearmost cylinder on the right side

of the engine (as viewed from the cockpit) and run-up the engine. Run the same test on the oppositerearmost cylinder to be certain the hottest runningcylinder was selected. Calibrated oil pressure and oiltemperature gauges also are needed to test theaccuracy of the engine instruments installed in theaircraft.

(5) The following support equipment isneeded: 50 feet or more of tie-down rope, tie-downstakes, two chocks for each wheel, fire extinguisher,assorted hand tools, safety-wire, cotter-pins, ear andeye protection, grease pencils, logbooks, clip board,pen and paper, a watch to time the tests, rags, andmanufacturers instructions.

f. Safety Precautions: Before the first enginerun, ensure the aircraft is tied down, brakes on, andthe wheels are chocked. The builder and flight testteam should wear ear and eye protection. All flighttest participants should be checked out on fire extin-guisher use and operation. During engine runs, donot allow anyone to stand beside the engine, or in-line or close to the propeller. Making minor adjust-ments to a running engine, such as idle and mixturesettings, is a very dangerous procedure and shouldbe done with great care by experienced individuals.

g. The First Engine Run:(1) The first start of the engine is always

a critical operation. The engine should be pre-oiledin accordance with the manufacturers instructions.For aircraft using other than FAA-approved oil pres-sure and temperature gauges, the FAA recommendsattaching an external calibrated oil temperature andpressure gauge to the 4 cycle engine in order to cali-brate the engine instruments. After priming theengine and completing the starting engine checklistitems, the first concern is to get an oil pressure read-ing within the first 20 to 30 seconds. If there is nooil pressure reading -- shut down.

(2) There are three common problems thatwould cause low or fluctuating oil pressure.

(i) Air in the oil pressure gauge line:This is easily fixed by loosening the line connectionnear the oil pressure gauge and squirting oil intothe line until full. Another option is to use a pre-oiler to provide the pressure and carefully bleed theair out of the line near the oil gauge by looseningthe B-nut that connects the oil line to the gauge.

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5/24/95 AC 90-89A

(ii) A misadjusted oil pressure reliefvalve: Cleaning the pressure relief ball, checking forthe proper number of washers, correcting spring ten-sion, and re-adjusting the setting could solve theproblem.

(iii) An internal problem within theengine (most likely the oil pump): An engine teardown would be required.

(3) With good oil pressure/temperaturereadings and the engine running smoothly, ensurethat the engine oil pressure and temperature gaugesin the cockpit match the calibrated oil pressure andtemperature gauges, which were attached to the air-craft for the first run. Do not overlook this test. Itis critical to determine the accuracy of the cockpitengine gauges not only for the ground engine run-in period, but for in-flight engine cooling tests.

(4) Work through the engine manufactur-ers run-in schedule. The majority of the enginemanufacturers recommend a series of engine runsfrom low rpm to maximum rpm. Each run usuallyincorporates a 200 rpm increase and lasts no longerthan 10 minutes. The secret to a successful enginerun is not to let the engine temperatures exceedmanufactures limits during engine runs.

NOTE: Engines with chrome cylinders orchrome rings require different high powerrun-in programs. Follow the manufacturersrun-in instructions to ensure the engine willperform satisfactorily over its lifetime.

h. Engine Cool Down: After a ground-run, thecooling off period takes approximately an hour. Thisis because a newly overhauled engine needs timefor the internal parts (e.g., rings, cylinders, valves,bearings, and gear faces) to expand and contract sev-eral times to obtain a smooth surface that retainsits memory. This is a lengthy process even whendone right, but it is important not to skip any ofthe recommended runs to save time. To do so isto risk increasing oil consumption and reducing over-all engine performance, reliability, and engine lifespan -- which could be costly in the long-term.

i. Record the engine run-in data: During theengine run, monitor the cylinder head temperatures,oil temperature, and oil pressure. Record the readingsand adjustments for future reference. If the cylinderhead temperatures are rising close to the red line,reduce power and stop the test. Some causes of highcylinder head temperatures include using spark plugswith the improper heat range; cylinder head tempera-ture gauges installed on the wrong cylinder; missingor badly designed cylinder head cooling baffles; par-tially plugged fuel nozzles (applicable to fuelinjected engines); fuel lines of improper internaldiameter (creates lean mixtures); engine improperlytimed either mechanically and/or electrically; and thecarburetor fuel mixture set excessively lean.

j. After shut-down:(1) After each engine run, check for fuel

and oil leaks, loose connections, and hot spots oncylinders (burnt paint). The FAA recommends drain-ing the oil and removing the oil screen/filter withinthe first 2 hours of running the engine. Check thescreen/filter for ferrous metal with a magnet. Washand inspect the screen/filter for non-ferrous metallike brass, bronze, or aluminum.

(2) A very small quantity of metal in thescreen is not uncommon in a new or newly over-hauled engine. It is part of the painful process ofrunning-in. If subsequent oil screen checks(2 hours apart) show the engine is making metal,this indicates a problem inside the engine and a teardown inspection is required.

(3) It also is recommended all fuel sumps,filters, and gasolators be checked for debris aftereach engine run. Special attention should be givento the fuel system by the builder who constructedfuel tanks out of composite or fiberglass materials.Composite and fiberglass strands can be very fine,making visual detection difficult. Frequent cleaningof the fuel filters and screens early in the flight test-ing phase will avoid a gradual build up of loosecomposite fibers, which would reduce or stop theflow of fuel to the engine.

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5/24/95AC 90-89A

SECTION 11. ADDITIONAL ENGINE TESTSAlways go with the best fix not the cheapest fix. Bill Deeth, Master Mechanic (1994)

1. OBJECTIVE. To determine if the engine sup-ply of fuel is adequate at all angles of attack.

a. Mixture and Idle Speed Check: Aftercompleting the initial engine run-in tests, checkthe idle speed and mixture settings. To determineif the mixture setting is correct, perform the follow-ing:

(1) Warm up the engine until all readingsare normal

(2) Adjust the engine rpm to the rec-ommended idle rpm

(3) Slowly pull the mixture control backto idle cut-off

(4) Just before the engine quits, the enginerpm should rise about 50 rpm if the mixture is prop-erly adjusted. If the rpm drops off without anyincrease in rpm, the idle mixture is set too lean. Ifthe rpm increases more than 50 rpm, the idle mixtureis set too rich.

NOTE: Some amateur-builders, after prop-erly setting the idle mixture/rpm to themanufacturers specification, increase theengine idle rpm by 100 rpm for the first 10+ hours of flight testing. This is to ensurethat the engine will not quit when the throt-tle is pulled back too rapidly, or when poweris reduced on the final approach to landing.

b. Magneto Check:(1) The magneto checks should be smooth

and the difference between both magnetos rpm dropsshould average about 50 rpm. The builder alsoshould perform a HOT MAG check, to ensureagainst the engine, on its own, deciding when andwhere to start. To perform a hot mag check, runup the aircraft until the engine is warm. At idle rpmturn the magneto switch off; the engine should stoprunning. If the engine continues to run, one or bothof the magnetos is hot (not grounded).

(2) The usual causes for a hot magneto area broken P lead coming out of the magneto ora bad magneto switch. THIS IS AN IMMEDIATE

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5/24/95 AC 90-89A

THREAT TO THE PERSONAL SAFETY OF ANY-ONE NEAR THE AIRPLANE AND MUST BEREPAIRED AT ONCE.

c. Cold Cylinder Check:(1) If the engine is running rough and the

builder determines it may be an ignition problem,perform the following check:

(i) Run the engine on the bad mag-neto for about 30 seconds at 1200 rpm. Withoutswitching the mag switch back to both, shut offthe engine.

(ii) One of the test crew shouldquickly use a grease pencil to mark an area of theexhaust stacks approximately an inch from the flangethat attaches the stacks to the cylinders.

(iii) Check the marks on the stacks. Ifone or more of the exhaust stacks with a grease markhas NOT been burned to a grayish-white color andthe mark on the stack still retains most of the originalcolor of the grease pencil, the cold cylinder hasbeen identified.

(2) Probable causes of the cold cylinderproblem are defective spark plugs, ignition leads, ora cracked distributor in one of the magnetos. Todetect if the spark plugs are bad, switch both plugsto another cylinder. If the grease pencil proves theproblem moved to the new cylinder, the spark plugsare bad. If the problem remains with the originalcylinder, the ignition lead or magneto is bad.

d. Carburetor Heat:(1) It is strongly recommended that all

amateur-builders install a carburetor heat system thatcomplies with the engine manufacturers rec-ommendation. If no recommendation is available, theFAA suggests a carburetor heat system for a sea-level engine and a conventional venturi should bedesigned so that it will provide a 90 degrees Fincrease in the venturi at 75 percent power. For alti-tude engines using a conventional venturi carburetor,120 degrees F increase in venturi temperature at 75percent power will prevent or eliminate icing.Remember: Too little carburetor heat will have noeffect on carburetor icing, and too much carburetorheat will cause a overly rich mixture which willreduce power and may shut down the engine.

(2) During the engine tests, make numer-ous checks of the carburetor heat system. To avoidoverly rich mixtures from oversized carburetor heatducts, ensure that the carburetor heat duct is the samesize as the inlet of the carburetor.

(3) Be certain there is a positive reductionin rpm each time carb heat is applied. If thereis no reduction, or the rpm drop is less than expected,check the carb heat control in the cockpit and onthe carb heat air box for full travel. Also check forair leaks in the SCAT TUBE that connects theheat muff to the carburetor air box.

e. Fuel Flow and Unusable Fuel Check: Thisis a field test to ensure the aircraft engine will getenough fuel to run properly, even if the aircraft isin a steep climb or stall attitude.

(1) First, place the aircrafts nose at anangle 5 degrees above the highest anticipated climbangle. The easiest and safest way to do this witha conventional gear aircraft is to dig a hole and placethe aircrafts tail in it. For a nose gear aircraft, builda ramp to raise the nose gear to the proper angle.

(2) Make sure the aircraft is tied-down andchocked. With minimum fuel in the tanks, disconnectthe fuel line to carburetor. The fuel flow with a grav-ity flow system should be 150 percent of the fuelconsumption of the engine at full throttle. With afuel system that is pressurized, the fuel flow shouldbe at least 125 percent. When the fuel stops flowing,the remaining fuel is the unusable fuel quantity.

(3) Since the fuel consumption of mostmodern engines is approximately .55 pounds perbrake horsepower per hour for a 100 horsepowerengine, the test fuel flow should be 82.5 pounds (13.7gallons) per hour for gravity feed, or 68.75 pounds(11.5 gallons) per hour for a pressurized system. Thepounds per hour divided by 60 equals 1.4 poundsand 1.15 pounds per minute fuel rate respectively.

NOTE: Formula for fuel flow rate gravityfeed is .55 x engine horsepower x 1.50 =pounds of fuel per hour divided by 60 toget pounds per minute, divided by 6 to getgallons per minute. For a pressurized sys-tem, substitute 1.25 for 1.50 to determinefuel flow rate.

f. Changing Fuel Flow or Pressure: If theaircrafts fuel flow rate is less than planned, there

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is a volume or pressure problem. An increase in thefuel flow volume may necessitate installation oflarger fuel line fittings on the fuel tanks, fuel selector,and carburetor in addition to larger internal diameterfuel lines. To increase fuel pressure, install an elec-trically driven or engine driven mechanical fuelpump prior to the first flight.

g. Compression Check: When the engine run-in procedures have been completed, perform an addi-tional differential compression check on the engineand record the findings. If a cylinder has less than60/80 reading on the differential test gauges on ahot engine, that cylinder is suspect. Have someonehold the propeller at the weak cylinders top dead

center and with compressed air still being applied,LISTEN. If air is heard coming out of the exhaustpipe, the exhaust valve is not seating properly. Ifair is heard coming out of the air cleaner/carb heatair box, the intake valve is bad. When the oil dipstick is removed and air rushes out, the piston ringsare the problem.

h. Last Check: Drain the oil and replace theoil filter, if applicable. Check the oil and screensfor metal, visually inspect the engine, and do a run-up in preparation for the taxi tests. Do not fly theaircraft if anything is wrong, no matter how smallor how insignificant. The sky, like the sea, is anunforgiving and uncompromising environment.

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SECTION 12. PROPELLER INSPECTIONA tough decision is what a man makes when he cannot form a committee to share the blame George

Lutz, Col. U.S. Air Force, Retired (1994)

1. OBJECTIVE. To help the amateur-builder/ultralight aircraft owner develop an inspection pro-gram to maintain his/her propeller.

a. There are three kinds of propeller designs:metal, wood, and composite.

(1) Because of weight considerations,metal propellers are used more on amateur-built air-craft than ultralight aircraft. This makes wood andcomposite propellers the overwhelming choice forultralight aircraft.

(2) Wood propellers are light, reliable, andinexpensive but require frequent inspections.

(3) Composite carbon-graphite materialprops are more expensive than wood, but are strongerand require less maintenance.

b. All types of propellers have one thing incommon: they are constantly under high levels ofvibration, torque, thrust, bending loads, and rota-tional stress. Even small nicks in the leading edge

of the blade can very quickly lead to a crack, fol-lowed by blade separation. Propeller tip failure anda subsequent violent, out of balance situation cancause the propeller, engine, and its mounts to bepulled from the airframe in less than 5 seconds.

c. It is essential that the make and modelpropeller is carefully chosen. Always follow themanufacturers recommendations.

d. Exercise caution if experimenting with dif-ferent makes and models propellers. A propeller withthe wrong size and pitch will give a poor rate ofclimb, cruise, or could cause the engine to over-rev.

2. RECOMMENDATIONS FOR ALLPROPELLERS.

a. Never use a propeller for a tow bar whenmoving the aircraft.

b. Never stand in front of or in-line of a rotat-ing propeller.

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c. Never PROP an engine on uneven orwet/snow covered ground.

d. Always inspect the propeller before andafter a flight.

e. When working on a propeller, make surethe ignition is off first.

f. Always maintain the propeller to manufac-turers instructions.

g. To avoid nicks and cuts, do not performrun-ups near gravel/loose stones.

h. Apply a coat of automotive wax once amonth to protect the finish and keep out moisture.

i. Assume a propeller is unairworthy if it hassuffered any kind of impact or ground strike.

j. After any repair or repainting, or if vibra-tion or roughness is noted, re-balance the propeller.

k. Propeller blades should be balanced within1 gram of each other to avoid over stressing the gearreduction system and propeller shaft.

l. Check the bolt torque on all newly installedpropellers every hour of operation for the first 10hours and once every 5 hours thereafter.

m. After torquing the propeller, track theblades.

FIGURE 5 - Propeller Tracking

3. PROPELLER TRACKING CHECK.a. Ensuring good powerplant operation first

starts with a properly installed propeller. Eachpropeller should be checked for proper tracking(blades rotating in the same plane of rotation). Thefollowing procedure is simple and takes less than30 minutes:

(1) Chock the aircraft so it cannot bemoved. Remove one sparkplug from each cyl-

inder. This will make the propeller easier and saferto turn.

(2) Rotate the blade so it is pointingstraight down.

(3) Place a solid object (e.g., a heavywooden block that is at least a couple inches higheroff the ground than the distance between the propel-ler tip and the ground) next to the propeller tip soit just touches.

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(4) Rotate the propeller slowly to see if thenext blade tracks through the same point (touchesthe block, see figure 2). Each blade should be within116 from one another.

b. If the propeller is out of track, it may bedue to one or more propeller blades that are bent,a bent propeller flange, or propeller mounting boltsthat are over or under torqued. An out-of-trackpropeller will cause vibration and stress to the engineand airframe and may cause premature propeller fail-ure.

4. METAL PROPELLER INSPECTION Per-haps the two biggest problems affecting the air-worthiness of metal propellers are corrosion andnicks on the leading edge.

a. Identifying Corrosion.(1) Surface corrosion can occur on the sur-

face of metal blades due to a chemical or electro-chemical action. The oxidation product usuallyappears on the surface of the metal as a white pow-der.

(2) Pitting corrosion causes small cavitiesor pits extending into the metal surface. This is anadvanced form of corrosion, appearing as small darkholes that usually form under decals or blade over-lays.

(3) Inter-granular corrosion, rare and dif-ficult to detect in propellers, is the most dangerousform of corrosion. It attacks the boundary layers ofthe metal, creating patches of lifted metal and white/gray exfoliation on the surface of the propeller. Itis sometimes found in propellers that had a groundstrike and have been straightened.

(4) If any of these signs of corrosion arefound, do NOT fly the aircraft. Refer to the manufac-turers maintenance manual for corrosion limits andrepairs or AC 43.4, Corrosion Control for Air-craft, and AC 20-37D, Aircraft, Metal PropellerMaintenance, for additional maintenance informa-tion and corrective actions.

b. Nicks and Metal Blades.(1) Nicks in the leading and trailing edge

of a metal blade are usually V-shaped. They arecaused by high speed impact between the propellerand a stone or piece of gravel. Properly trainedindividuals can dress out the crack if the nick

is not too wide and/or deep. Before each nick isdressed out, each nick and surrounding area shouldbe inspected with a 10-power magnifying glass forcracks. If an area looks suspicious, inspect the areaagain using the propeller manufacturers approveddye penetrant or fluorescent penetrant method.

(2) If the nick is left unattended, the highpropeller operational stresses will be concentrated atthe bottom of the nicks V and, in time, will generatea crack. The crack can migrate across the blade untilthe blade fails, producing a massive imbalancebetween the propeller and the engine, ultimatelycausing structural failure. Cracks in metal bladesCANNOT be repaired. A cracked propeller must bemarked unserviceable and discarded.

c. Warning. Metal propellers are matched/tuned to the engine and airframe resonant frequencyby being manufactured with a particular diameter tominimize vibration. DO NOT SHORTEN METALBLADES for any reason unless the manufacturerspecifically permits this major alteration.5. PROPELLER INSPECTION.

a. Wood propellers should be inspected beforeand immediately after a flight. Inspect to ensure thefollowing:

(1) The drain holes are open on metaledged blade tips

(2) The metal/composite leading edge issecured and serviceable

(3) The blades, hub, and leading edge haveno scars or bruises

(4) The mounting bolt torque and safetywire or cotter pins are secure

(5) There are no cracks on the propellerspinner (if applicable), and the safety wire is secure

(6) There are no small cracks in the protec-tive coating on the propeller, which are caused byUV radiation

(7) The charring around the mating surfaceof the prop and the engine flange -- both indicationsof a loose propeller

b. A word about torque: A new, woodenpropeller should have the mounting bolts checked

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for proper torque within the first hour of flight andevery hour for 10 operational hours thereafter.

(1) After 10 hours, check the bolt torqueevery 5 hours thereafter. The mounting bolt torquealso should be checked prior to flight if the aircrafthas been in storage for a long period of time (3 to6 months).

(2) If the bolts need to be torqued, it issuggested all the bolts be loosened for an hour toallow the wood to relax. Finger tighten the boltsuntil snug and tighten the attaching bolts in smallincrements, moving diagonally across the bolt circle.It is good practice to check the propeller track (seechapter 1, section 7) as the bolts are torqued down.The torqued bolts should be safety wired in pairs.

(3) If nylon/fiber insert type nuts are used,they should be changed every time the propeller boltsare re-torqued. They should never be used with abolt with a cotter key hole in the threaded areabecause the sharp edges around the hole will cutthe nylon/fiber insert and reduce the fastenerseffectiveness. All self-locking nuts should have atleast two bolt threads visible pass the nylon/fiberinsert after torquing.

(4) If any of the following damage isfound, a wood propeller should be removed fromthe aircraft and sent back to the manufacturer forrepair. If the propeller cannot be saved, it shouldbe marked unserviceable.

(i) Any cracks in the blades or hub(ii) Deep cuts across the wood grain

(iii) Blade track that exceeds 116limits after attempts to repair

(iv) Any warpage or obvious defect(v) Extreme wear (leading edge

erosion, bolt hole elongation)(vi) Any separation between

lamination

NOTE: When parking the aircraft, alwaysleave the wood propeller in the horizontalposition. This position will allow the woodto absorb small amounts of moisture evenlyacross its entire span rather than con-centrating the moisture (weight) in the lowblade and creating a vibration problem.

6. COMPOSITE PROPELLERSINSPECTION.

a. There are generally two types of compositepropellers: thermo-plastic injection molded propellerand the carbon/graphite fiber composite propeller.

(1) The thermo-plastic injection moldedpropeller is a low cost, thin bladed propeller usedon engines of 80 horsepower or less. Propellerinspection is straight forward, by examining theblades and hub for cracks and nicks. If a crack isfound, do not fly until the propeller is replaced. Smallnicks of 316 of an inch or less can be dressed outand filled using a two-part epoxy.

(2) Carbon/graphite composite propellersare primarily used on engines of 40 horsepower andmore. One should inspect for small hair line cracksin the gel coat. These spider cracks are usuallycaused by vibration generated by a mismatch of theengine and propeller combination. If a crack in thebase material of the propeller other than the gel coatis found, do not fly until the manufacturer inspectsthe propeller.

(i) Nicks of 12 inch or less in theleading or trailing edges of carbon/graphite propel-lers can be dressed out and filled using a two-partepoxy. But if the nick has severed the fiberglass rov-ing (looks like a fiberglass wire bundle) that runshub to tip on the leading and trailing edge, do notfly. The propeller has been severely damaged andmust be sent back to the factory for inspection andrepair.

(ii) Before making even small repairson a composite propeller, check with the manufac-turer first. Larger nicks must go back to the factoryfor inspection and repair.

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CHAPTER 2. TAXI TESTSSECTION 1. LOW SPEED TAXI TESTS

Yelling Clear the Prop! before you start an aircraft is the first of a series of well planned,choreographed steps to make you a professional. Jack Crawford, Pilot, Mechanic, Airport Operator

(1994)

1. OBJECTIVES. The objectives of the taxitests are fourfold:

a. To ensure that the aircraft tracks straightand there is adequate directional control at 20 percentbelow the anticipated take-off speed.

b. To determine if the aircrafts engine coolingand the brake system are adequate.

c. To predict the flight trim of the aircraft andits handling characteristics during take off and land-ings.

d. To allow the pilot to become proficient withthe handling and braking characteristics of the air-craft.

NOTE: All taxi tests, low and high speed,should be made as if it were the first flight.The pilot should be wearing the properclothing, seat belt/shoulder harness and hel-met and be mentally and physically pre-pared for the possibility of flight.

2. TAXI TESTS.a. Prior to beginning taxi tests in a conven-

tional (tail dragger) aircraft, the tail should be raiseduntil the aircraft is in the approximate take-off posi-tion. The pilot should spend an hour or more in thecockpit to become accustomed to the aircrafts take-off position. This small but important aspect of train-ing will help the pilot avoid overreacting to an unex-pected deck angle on the first flight.

NOTE: All taxi tests should always be mon-itored by a minimum of one other memberof the flight test team, who will watch forevidence of fire/smoke or other problems notvisible to the pilot.

b. The taxi tests should begin with a taxi speedno faster than a man can walk. The pilot should spendthis time getting acquainted with the aircrafts lowspeed handling characteristics by practicing 90, 180,and 360 degree turns and braking action. The pilotshould also remember that monitoring the oil pres-sure, oil temperature, cylinder head temperature, andmaintaining them within limits is a critical functionthat must not be overlooked.

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NOTE: The builder should be aware thatsome aircraft brake manufacturers havespecific brake lining conditioning proce-dures (break-in) for metallic and non-asbes-tos organic linings. Proper brake liningconditioning should be completed beforestarting the low and high speed taxi tests.If not properly conditioned, the brake liningwill wear quickly and give poor brakingaction at higher speeds.

c. The pilot should check the flightinstruments for operation each time the aircraft is

taxied out. The compass should match the magneticheading of the runway or taxi way the aircraft ison. When making a turn (e.g., right hand turn), theturn coordinator/turn and bank should indicate a righthand turn but the ball should skid to the left. Thevertical speed indicator should read zero and theartificial horizon should indicate level.

d. After each taxi run, inspect the aircraft foroil and brake fluid leaks. No leak should be consid-ered a minor problem. Every leak must be repairedand the system serviced prior to the next taxi test.

SECTION 2. HIGH SPEED TAXI TESTSFirst get use to the fact that you are now 30 feet wide and you steer with your feet. Wayne Nutsch

1. OBJECTIVE. To determine the aircraftshigh speed handling and braking parameters.

a. Propeller rotation will determine which rud-der pedal is pressed to compensate for the asymmet-rical thrust of the propeller blades. For example,when viewed from the cockpit, a Volkswagen auto-motive engine mounted in a tractor configuration willrotate the propeller counter-clockwise. In this case,the pilot must use the left rudder pedal for high speedtaxi and take-off.

b. As with every part of the flight testing pro-gram, the high sp