Nta Booklet

8/4/2019 Nta Booklet

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Operations at non-

towered aerodromes

d,Be heard, be seen, be safe:

carry & use your radio



The inormation contained in this booklet was correct at the time o

publishing, and is subject to change without notice. CASA makes no

representation as to its accuracy. This booklet has been prepared by

CASA Saety Promotion or inormation purposes only.

Plan your route thoroughly, and carry current charts and documents.

Always check ERSA, NOTAMs, and the weather, BEFORE you y.

© 2010 Civil Aviation Saety Authority 1004.1262



Contents

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1 Limitations o see-and-avoid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2 New circuit procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

3 Radio rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Bibliography. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Contacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21





IntroductionFrom 3 June 2010, you will have to carry and use a radio

i you are ying at or in the vicinity o a certifed, registeredor military aerodrome that is non-towered. Some circuit

procedures will change or all non-towered aerodromes.

The changes are aimed at reducing the risk o mid-air

collisions by maximising separation at aerodromes without

air trafc control services. They are enshrined in amendments

to Civil Aviation Regulation 166 and supporting Civil Aviation

Advisory Publications, CAAPs 166-1(0) and 166-2(0).Certifed aerodromes have runways capable o handling aircrat

with more than 30 passengers or 3,400kg o cargo. They are used

by regular public transport, charter and GA aircrat. Registered

aerodromes have lower minimum operating standards than certifed

aerodromes. Military aerodromes are controlled by the Australian

Deence Force, and, as in the past, you need permission to land.

By defnition, non-towered aerodromes are in uncontrolled, Class Gairspace. When air trafc control is not operating, towered aerodromes

come under the rules o non-towered aerodromes regardless o which

airspace they are normally in.

CASA might at times ‘designate’ uncertifed and non-registered aerodromes

at which carriage o radio will also be required. We will publish the names o

designated aerodromes in the En-route Supplement Australia (ERSA) and/or

NOTAMS.

The rule changes coincide with the replacement o general aviation airport

procedures (GAAP) with Class D airspace. They come amid mounting evidence

or limits to the see-and-avoid principle. Many accidents and incidents could have

been prevented by the carriage and use o radio. Radio communication heightens

situational awareness. It enhances visual scans by telling you where to look or other

aircrat. Experts estimate that you are eight times more likely to see a threat aircrat i

you use a radio.

2 3





This ‘alerted see-and-avoid’ philosophy

underlies the rule changes, and will

be supported by an extensive auditingand surveillance campaign. It comes as

trafc at many non-towered aerodromes

increases, with the Dash 8 and even

Boeing 737 aircrat o regular public

transport sharing the circuit with the

Cessna 172s and ultralights o general

aviation. The wide range in the types and

perormance o aircrat converging on

aerodromes, and in the experience o the

pilots ying them, heightens the risk o

mid-air collisions.

Another problem is a practice that is the

worst-kept secret in aviation—sneaking

into aerodromes unannounced in order

to evade landing ees. The practice ails

rational cost-beneft analysis, given thatlives are at stake and landing ees, trivial.

This booklet should be read in conjunction

with CAAP 166-1(0) and CAAP 166-2(0),

which outline the rule changes and advise

on a code o conduct and good airmanship

practices at non-towered aerodromes.

It covers: the limitations o the see-and-avoid principle. It also outlines the

new circuit and radio communications

procedures, and gives hints on ways to

enhance the saety o everyone operating

at non-towered aerodromes.

4 5





1 Limitations of see and avoid

6 7

Although mid-air collisions are rare, horrorstories o near misses abound. In one

incident, in NSW in 2009, an aeroplane

came within 150m o a helicopter.

Such incidents could have been avoided

had pilots been using radios to hone visual

scans or trafc.

On 20 May 1988, the worst didoccur. A Cessna 172 collided with a

Piper Tomahawk in the circuit area o

Coolangatta aerodrome in Queensland,

killing our people, according to the ATSB.

The accident, which happened in

conditions o good visibility, underlined the

shortcomings o visual scans, and provided

the impetus or the ATSB report Limitations of the see-and-avoid principle .

Private pilots on VFR ights spend

about hal their time scanning or trafc,

according to research cited in the report.

Airline pilots possibly devote less time to

scans.

Ergonomic, physiological, behaviouraland environmental actors limit the

eectiveness o visual scans, however,

regardless o how long you spend on them.

‘Most cockpit windscreen confgurations

severely limit the view available to the

pilot,’ the report says.

Window posts, windscreen bug splatter,sunvisors, wings and ront seat occupants,

obscure the view.

‘Window posts, windscreen crazing anddirt can act as ocal traps and cause the

pilot to involuntarily ocus at a very short

distance ...,’ the report adds. ‘Direct glare

rom the sun and veiling glare reected

rom windscreens can eectively mask

some areas o the view.’

And scans are typically unsystematic,

with attention ocused on the view romthe centre o the windscreen. A thorough,

systematic search ‘is not a solution as in

most cases it would take an impractical

amount o time’, the report says.

Compounding these problems are

physiological actors.

One is the blindspot in the eye, where theoptic nerve exits the eyeball.

Yet another problem is ‘empty feld

myopia’. ‘In the absence o visual cues,

the eyes ocus at a resting distance o

around hal a metre,’ the report says. ‘An

object which is smaller than the eye’s

acuity threshold is unlikely to be detectedand even less likely to be identifed as an

approaching aircrat.’

Peripheral vision is aected by increased

workload, atigue and stress as i busy

pilots are ‘unknowingly wearing blinkers’.

Meanwhile, moving objects are easier

to see than stationary ones, but, in mostcases, ‘an aircrat on a collision course

appears as a stationary target in the pilot’s

visual feld’.



Another physiological limitation is the time

it takes the eye to ocus as our muscles

move to alter the shape o the lens. Itprobably takes the average pilot several

seconds to shit their ocus to a distant

object, and the process can be aected

by atigue.

Poor contrast is another problem, with

aircrat ading into the background. It is

also difcult to pick out an aircrat against

a complex background o sky and terrain.

‘An approaching aircrat in many cases

presents a very small visual angle until a

short time beore impact,’ the report adds.

Even i a pilot does see an approaching

aircrat, there ‘is no guarantee that evasive

action will be successul’.

‘It takes a signifcant amount o time to

recognise and respond to a collision threat

and an inappropriate evasive manoeuvre

may serve to increase rather than

decrease the chance o a collision.

‘Because o its many limitations, the see-

and-avoid concept should not be expected

to ulfl a signifcant role in uture air trafcsystems,’ the report concludes.

Despite the change in emphasis in the

revised rules, you should maximise

the eectiveness o scans. Clean your

windscreen, and ree up time or scanning

when it is most needed by managing your

ight to minimise cockpit workload on

approach and landing.

Use a rigorous scanning technique. In

variations on the widely used ‘block’

method, the pilot successively fxes onthe centres o blocks o 10 to 15 degrees

across the horizon and 10 degrees above

and below it, according to the Air Saety

Foundation.

The ‘side-to-side’ block scan starts at one

side o the aircrat and steps block-by-

block to the other. The ront-to-side scan

starts at the centre, working out to oneside beore returning to the centre and

covering the other side.

The technique has limitations, however,

and you should check or overtaking

aircrat every ew scans, the ASF says.

Meanwhile, radio will sharpen your ability

to spot aeroplanes closing in on you.



1 2 3 4 5 6 7 8

Side-to-side scanning methodStart at the left of your visual area and make a methodical sweep to the

right, pausing in each block of viewing to focus your eyes. At the end of the

scan, return to the panel.

Front-to-side scanning methodStart at the centre block of your visual eld (centre of front windshield);

move to the left, focusing in each block then swing quickly back to the

centre block after reaching the last block on the left and repeat the

performance to the right.

Figure 1 Block system scanSource: AOPA Air Saety Foundation

8 9



On 7 July 2009, an aeroplane came within 150m o a Kawasaki

helicopter on approach to Moree aerodrome in NSW. The aircrat

was at the same level as the helicopter at the time o the incident.

It had not made a broadcast on the CTAF requency.

Communication breakdown

During the climb rom Wollongong aerodrome on 21 January 2001, the

pilot o a Cessna 206 heard engine noise and looked up to see a Cessna

172 pass less than 10t above. The pilot o the C-206 reported that

he had made the appropriate radio broadcasts on the CTAF requency.

However, the C-206 was at the CTAF boundary, and the pilot o the

C-172 was operating on the area requency. The pilot o the C-206 noted

that both pilots heard the other aircrat pass beore seeing each other.

As the pilot o a Beechcrat KingAir was joining crosswind leg or runway

06L at Jandakot Aerodrome, Western Australia on 9 November 2001, a

Cessna 172 passed rom let to right between 10 and 15m in ront. The

pilot o the KingAir had no time or evasive action but widened the circuit,

and tried to make radio contact with the aircrat. The crew o the KingAir

had not heard any transmissions on the MBZ requency rom the Cessna.

The C-172 departed to the south and the KingAir made an uneventul

landing. CASA was advised o this occurrence.



Several radio calls made on the MBZ by two inbound aircrat ailed to

elicit a response rom a VFR Cessna 172 departing Williamtown Airport

in NSW on 25 November 2001. The Cessna started its takeo roll as

an inbound Beech 1900 was joining crosswind. The pilot o the Beech

carried out an avoidance manoeuvre to join mid-crosswind. Another

regional aircrat was on fnal when the departing Cessna passed

behind and approximately 600t above.

The pilot o a Cessna 172 was conducting dual training circuits o runway 28

at Archerfeld aerodrome in Queensland on 7 May 2002 under MBZ procedures

as the tower closed. On the student’s ourth circuit turning downwind, a Beech

36 (Bonanza) passed nearby rom right to let. The Cessna had not heard any

inbound transmission or circuit joining call rom the Bonanza. The instructortook over the controls and descended to about 800t to let the Bonanza y

across and above. The Bonanza joined downwind at 1,000t without giving way

to trafc already in the circuit. When asked i he had seen the Cessna, the pilot

said, ‘not until the last minute’.

While passing 1,400t on climb on upwind with a simulated

engine ailure rom Broome Aerodrome, Western Australia,

on 23 July 2003, a Cessna 402 crew saw a Cessna 210

descending about 300t above and 50 metres in ront. TheC-210 pilot’s previous transmissions o the aircrat’s position

and intentions had been inaccurate.

Source: ATSB 10 11



2 New circuit procedures

Check the En-route Supplement Australia(ERSA) to see i aerodromes you intend

using are certifed, registered or military,

and thereore subject to the new rules that

require radio carriage and use.

The usual let circuit pattern is retained in

the revised CAR 166 rules unless stated

otherwise in ERSA or by NOTAM.

The standard circuit heights and spacings

that were introduced as part o the NAS2C

airspace reorms in 2005 have been

retained or the dierent aircrat types in

order to maximise segregation.

radio carriage MANDATORY

at all CERT, REG, MIL aerodromes

radio carriage NOT MANDATORY

at UNCR aerodromes unless

required by the aerodrome operator

or designated by CASA.

FOR ILLUSTRATIVE PURPOSES ONLY

Figure 2 How mandatory radio carriage is depicted in ERSA

However, the treatment o aircratperormance parameters has been

tweaked. High perormance aircrat—jets,

and many turboprops with a standard

circuit speed above about 150kt should y

at 1500t above the aerodrome.

Medium perormance aircrat, such as

most piston-engined GA aircrat with

circuit speeds between 55kt and 150kt,should y at 1000t.

Low perormance aircrat—some sport

aircrat such as microlights and gyroplanes

with a circuit speed under 55kt—should

y a standard circuit height o 500t.



12 13



Joining the circuit on base leg is allowed

but not recommended. You must assess

the trafc levels and suitability beoreyou join as you must give way to other

trafc and join without conict. You should

broadcast your intentions, know the wind

speed and direction, and the circuit pattern

in use.

The circuit Ater take-o, during the climbout, make

the turn onto crosswind at a height that

allows you to arrive on downwind at the

circuit height. You should not be less than

500t above the aerodrome.

High perormance turbo-props and jets y

a wider circuit at 1,500t whereas medium

and low perormance aircrat ying a

1,000t and 500t circuit respectively will

y a tighter circuit.

Departing the circuitDepart the circuit area by extending one o

the our standard circuit legs. Only whenyou are well outside the circuit area, and

no trafc conict exists, can you make a

turn opposite to the circuit direction. This

would normally be at least 3nm rom the

circuit, but it could be less or aircrat with

high climb perormance.

Joining the circuitI you are unamiliar with an aerodrome’s

layout, circuit direction or conditions,overy or circle it at least 500t above the

circuit altitude. Where high perormance

aircrat could be operating, this will usually

be at 2,000t above the aerodrome

elevation. Once you have determined the

circuit direction you can descend on the

non-active (dead) side o the circuit.

Low perormance aircrat such as

ultralights, and some rotorcrat with a

maximum speed o about 55kt should

overy midfeld at 500t above the

aerodrome.

We recommend you join the circuit on

downwind leg, either rom an extension

o the downwind leg, a 45 degree angleabout halway down downwind, or rom a

shortened crosswind leg which takes you

over the runway.

Straight in approaches are allowed but not

recommended. They require you to assess

the trafc levels and suitability to ensure

that you do not conict with other circuittrafc and that no reciprocal runway is in

use. You must know the wind direction and

speed, and be established on fnal by 3nm.

Broadcast your intentions.

eight th

ind at t

e less t

d jets y

medium

ill



Joining circuit

on a base leg

Arriving at not less

than 500ft above

circuit height

Joining at 45º

Arriving at not

less than 500ft

above circuit

height

Joining circuit

at crosswind

Joining for straight

in approach not

less than 3nm

D e s c e n d

t o

c i r c u i t h e i g h t

D o wn wi n d l e

g

F i n a l

Crosswind leg

Base leg

Joining circuit on

a downwind leg

Recommended circuit join

Figure 3 Aerodrome trafc circuit showing arrivals and joining

ning at 45

than 500ft abo

circuit height

14 15





3 Radio rules

When at or near a non-towered aerodrome, check that your radio is on thecorrect requency, and listen to the broadcasts. Under CAR 166 C, you must

make a radio broadcast whenever it is reasonably necessary to avoid a

collision or the risk o a collision.

For minimum compliance, you should broadcast your intentions:

beore or during taxiing

immediately beore entering a runway, whether

active or not

inbound 10nm or earlier rom the aerodrome

immediately beore joining the circuit

on a straight-in approach, on fnal, by 3nm rom

the threshold

on a base-join approach, beore joining on basewhen ying near, but not intending to land at, a

non-towered aerodrome, where the pilot intends to

y through the vicinity but not land.

But use your radio more often if needed.

16 17



When making radio calls state the name

o the aerodrome, your aircrat’s type,

call sign and position, and your intention.Repeat the name o the aerodrome. Use

standard phraseology and don’t chat.

I you are ying VFR, identiy yoursel i

you hear an IFR pilot intending to make an

instrument approach. I you are ying IFR,

report your position and intentions in plain

English, not as IFR approach points, which

VFR pilots might not know.

As needed, make other broadcasts such

as:

turning: downwind base and fnal

clear o runway.

The collision avoidance systems TCAS and

ACAS are other methods o alerted see-

and-avoid. I you are ying a GA aircratand have a transponder, turn it on so that

RPT aircrat equipped with TCAS and

ACAS know where you are.



18 19



Bibliography

CAAP 166-1(0) Operations in the vicinity of non-towered (non-controlled) aerodromes ,

CASA, 2010

CAAP 166-2(0) Pilots’ responsibility for collision avoidance in the vicinity of non-

towered (non-controlled) aerodromes using ‘see-and-avoid’ , CASA, 2010

Limitations of the see-and-avoid principle , ATSB, 1991

Operations at non-towered aerodromes (DVD), CASA Aviation Saety Promotion, 2010

Look out! Situational awareness , (DVD) CASA Aviation Saety Promotion, 2009

AOPA Air Saety Foundation, ‘Collision avoidance strategies and tactics’, Safety

Advisor , Operations and Profciency No. 4 http://www.aopa.org/as/publications/

sa15.pd



CASA contacts

PHONE: 131 757

EMAIL: [email protected]

WEB: www.casa.gov.au/nta/

CASA GPO Box 2005 Canberra ACT 2601

20 21



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