Civil Aviation Order 108.34 Instrument 2007 (Cth)

I, WILLIAM BRUCE BYRON, Director of Aviation Safety, on behalf of CASA, make this instrument under regulation 82 of the Civil Aviation Regulations 1988.

[Signed Bruce Byron]

Bruce Byron
Director of Aviation Safety and
   Chief Executive Officer

17 December 2007

Civil Aviation Order 108.34 Instrument 2007

1          Name of instrument

This instrument is the Civil Aviation Order 108.34 Instrument 2007.

2          Commencement

This instrument commences on the day after it is registered.

3          New Civil Aviation Order 108.34

Civil Aviation Order 108.34 is repealed and a new Civil Aviation Order 108.34 substituted as set out in Schedule 1.

Schedule 1          Civil Aviation Order 108.34

Specification — airborne radio systems

1          Application

1.1     This Civil Aviation Order specifies installation and performance requirements for airborne radio systems installed under regulation 82 of the Civil Aviation Regulations 1988.

Note 1   Subregulations 174A (1B) and 177 (1B) of the Civil Aviation Regulations 1988 contain directions issued by the Director under regulation 82 of the Civil Aviation Regulations 1988 with respect to radio equipment required for aircraft navigation under Instrument Flight Rules and for communication with the aeronautical mobile radio service.

Note 2   Civil Aviation Order 100.37 prescribes requirements and procedures to be followed in obtaining approval of airborne radio installations.

1.2     Except where indicated in this Order, or otherwise agreed to by the Director, the specifications of this Order are also applicable to airborne radio systems installed for purposes other than compliance with regulation 82 of the Civil Aviation Regulations 1988.

2          Definitions

In this Order:

arborne radio system means an integral part of an aircraft which provides a communication or radio navigation function.

approved radio equipment means radio equipment approved by the Director for use in airborne radio systems required to be installed under a direction issued by the Director under regulation 82 of the Civil Aviation Regulations 1988.

I.F.R. aircraft means an aircraft which is approved to operate under Instrument Flight Rules.

limited I.F.R. aircraft means an aircraft which is approved to operate under limited Instrument Flight Rules.

night V.M.C. aircraft means an aircraft which is approved to operate at night under visual meteorological conditions.

V.F.R. aircraft means an aircraft other than I.F.R., limited I.F.R., or night V.M.C. aircraft, which is approved to operate under Visual Flight Rules.

3          Equipment standards

All radio equipment forming part of a radio system fitted under a requirement of AIP Gen must be of types approved by the Director for their specific functions.

4          Equipment environment

4.1     Radio equipment, components and wiring must be protected wherever their location would otherwise expose them to the possibility of accidental damage by luggage, freight, persons or detrimental fluids.

4.2     Radio equipment must be mounted and located in such a manner that, under normal operating conditions, it will not be subjected to vibration amplitudes or temperature ranges outside the limits specified by the approval given by the Director.

Note   Since the service life and reliability of electronic equipment is materially affected by extremes of temperature, account should be taken of this at an early stage of an installation design. Adequate ventilation, either natural or forced, should be provided when equipment may be required to operate in a high temperature environment.

4.3     All radio equipment must be so installed that normal movement of a unit on its mounting will not result in contact with other radio equipment, instruments or portions of the aircraft structure.

4.4     All radio equipment and inter-wiring must be so installed and secured that:

(a)   they do not cause interference with, or limit the free, proper and full operation of flight controls, relays, switches, actuators or similar devices under the most adverse positioning or placement of equipment or wiring; and

(b)   the temperature attained by a coaxial cable must not exceed the maximum operating temperature given in the manufacturer’s specification for the cable; and

Note   As a guide, conventional coaxial cable should be located no closer than 0.15 metres to object, the surface temperature of which is likely to exceed 70°C.

(c)   magnetic compass deviation due to the installation and operation of the equipment does not exceed the permissible limits specified in Civil Aviation Order 108.6; and

(d)   they do not cause deleterious interference with the functioning of other radio or electronic systems fitted to the aircraft.

4.5     Permanent stowage must be provided for all microphones and headsets so that at least 38 cm separation will exist between any direct reading magnetic compass and the stowed microphone or headset.

5          Controls and indicators

5.1     The controls and indicators of all airborne radio systems must be readily accessible and visible from the normal seated position of the appropriate crew member(s).

5.2     Indicators must be so positioned as to avoid significant parallax error when viewed from the appropriate crew position(s).

5.3     The lighting of radio control panels and radio navigation instruments in I.F.R., limited I.F.R. and night V.M.C. aircraft must comply with the requirements specified for instrument illumination and intensity control contained in Appendix IV of Civil Aviation Order 20.18.

6          Identification and marking

6.1     All components not forming part of a standard item of radio equipment including switches, relays, protective devices, controls, indicators and indicator lamps, must be plainly identified by the affixing of permanent labels.

6.2     Components which form parts of dual radio systems must be identified so as to clearly indicate the system to which they belong.

6.3     All cable connectors which are capable of being cross connected to an incorrect position in an installation must be labelled or otherwise marked to indicate the correct connection.

6.4     All marking and labelling must be in English or be recognised abbreviations.

7          Bonding

7.1     All fixed items of equipment which make up an airborne radio system must be permanently and effectively bonded to the airframe or aircraft bonding system.

Note 1   Since the main purpose of bonding of radio systems is to achieve a low RF impedance path, the DC resistance value is not necessarily significant. However, practice indicates that if a DC resistance value of 0.006 ohms or less is achieved, a satisfactory RF impedance path will usually result.

Note 2   Where direct connection of the faying surfaces is not possible the recognised method of bonding consists of a tinned copper strip of adequate cross section and the shortest possible length. Means should be taken to ensure that mechanically bonded connections will remain effective under service conditions.

8          Supply of electrical power to airborne radio systems

Note   Prior to the installation of a radio system(s), it should be established that the aircraft electrical power supply would still be capable of supplying the most onerous combination of electrical loads. This may be determined by means of an electrical load analysis.

8.1     Electrical cables used in an airborne radio system must comply with a cable specification accepted by an aircraft manufacturer for use in aircraft or with a specification otherwise approved by, or acceptable to, the Director.

Note   Cable looms which are manufactured and supplied by the radio equipment manufacturer for specific radio equipment may be deemed to be approved by the Director unless otherwise indicated.

8.2     Other cables of an airborne radio system, e.g. sense aerial cables, must comply with such special requirements as may be specified by the relevant radio equipment manufacturer.

8.3     With the equipment mounted in position, bonded and operating, the voltage measured at the input terminal of the equipment must not be less than the minimum voltage specified by the equipment manufacturer. Where a manufacturer does not specify a minimum voltage, the voltage at the input terminal of the equipment must be within 2% of the voltage at the radio supply busbar. Transmitter circuits must be checked under key-down conditions.

8.4     Unless the Director otherwise agrees, there must be a facility readily available to the flight crew for removing power separately from each radio system. The removal of a fuse is not an acceptable facility for this purpose.

Note 1   Provision of a radio system ON-OFF switch or a manual retrippable type circuit breaker is an acceptable facility.

Note 2   Radio equipment which houses more than 1 radio system in the 1 package (e. g. VHF COM. AND VHF NAV — AUDIO and MARKER), all of which are controlled by a common power switch and which have 1 connection only to the aircraft power supply, is deemed to meet the intention of the foregoing requirement.

8.5     Wherever equipment design permits, each airborne radio system must have its own current overload protective device and no other component or equipment not being part of the particular radio system must also receive its power via such device.

8.6     The interwiring between any airborne radio system must be so designed and arranged that a fault in the interconnecting wire or connected equipment will not cause the interwiring wire to become a smoke or fire risk.

Note   Where wire gauge changes are made in the interwiring between equipment, it may be necessary in order to meet the foregoing requirement to install a protective device compatible with the lesser wire gauge and inserted at a point as close to the current source as design permits.

8.7     The rating and system identification of all fuses and circuit breakers installed in radio systems must be plainly and permanently marked.

8.8     For each type of fuse which is capable of being replaced in flight, suitable stowage must be provided for spare fuses. The number of spare fuses for which provision is made must not be less than 20% of the number of each rating in service.

8.9     The operation of a protective device must not isolate from the airframe those parts of the radio circuit which are normally at airframe potential. In installations in which neither the positive nor negative supply lead is at airframe potential, protective devices must be fitted in both supply leads.

8.10     No radio equipment must rely entirely on a bonding strap to provide the return circuit for primary power.

8.11     Where an inverter or transformer-rectifier constitutes the source of power for 2 communication or 2 radio navigation systems, it must be possible to switch to an alternative source of power.

8.12     For I.F.R. aircraft of maximum take-off weight greater than 5 700 kg, at least 1 radio communication system and at least 1 radio navigation system must be connected to the highest priority electrical power source which is capable of providing sufficient power for the connected radio systems.

Note   Normally, for Australian internal operations, this requirement will be met with 1 VHF communication system and with 1 ADF or VHF navigation system connected, depending on the facility most used on the aircraft’s normal operating routes.

9          Antenna systems

9.1     All antenna systems must be designed and installed in such a manner as to avoid deleterious mutual interference between radio systems. Information on the radiation characteristics of an antenna system and/or the insertion loss in the feed system must be supplied when requested by the Director.

9.2     Antennas and their component parts must be so positioned and installed as to present the least possible hazard to the aircraft in the event of their breakage.

9.3     A tensioning device, or a weak link fitted in the aft end of the antenna, must be incorporated in all fixed wire antennas.

9.4     Fixed wire antennas must be physically independent of one another.

9.5     Trailing antenna wires must use a drogue in preference to weights. Where the use of a drogue is impractical, a series of small weights assembled in accordance with an approved drawing must be used.

9.6     Remotely controlled antenna winches must be so installed or protected that spilling of the wire from the drum cannot cause interference with the aircraft control system.

9.7     A spark gap capsule, if fitted as a separate item, must be placed as close as practicable to the lead-in insulator.

9.8     The lead within the aircraft between an HF coupler and the antenna must be as short as practicable, and must be adequately supported and spaced from the aircraft structure, control cables and wiring.

Note   In order to obtain maximum radiation efficiency and cause a minimum of RF interference to other aircraft systems, the coupler should, if possible, be positioned so that the lead to the antenna is less than 150 mm long.

9.9     Coaxial cables must not have an attenuation or mismatch into the antenna causing a loss in excess of 3 db unless special provision is made for such loss in the equipment.

9.10     All antennas, unless installed under a protective cover, must either be connected to airframe by a DC path or be fitted with a static leak.

Note   Receivers which embody such a DC path and are connected for long periods to such antennas constitute the required static leak.

9.11     The design of an antenna system in which 2 or more receivers are connected to a single antenna must be such that the failure or disconnection of 1 receiver will not have a deleterious effect on the other receiver(s) and the insertion loss of coupling devices will not preclude normal performance by each connected receiver.

10        Audio systems

10.1     An aircraft audio system which uses an audio amplifier for its operation must be capable, in the event of a failure of the audio amplifier, of providing continued reception, and, where installed, crew member inter-communication.

Note   An audio amplifier constituting part of a receiver, and having auxiliary audio inputs connected to other radio systems, is regarded as an audio system for the purpose of this Order.

10.2     Where, to achieve compliance with paragraph 10.1, the audio system design provides for a headset output, a headset must be installed.

Note   The provision of a headset outlet and the carriage of a headset is recommended for all aircraft.

10.3     The power rating of the aircraft’s speaker must be adequate for the purpose, and the speaker must be installed so as to provide efficient operation.

10.4     The maximum audio power available at the input to any speaker must not exceed the maximum power handling capability of the speaker.

Note   Where the power handling capability of a speaker is inadequate, it is preferable, if practicable, to install an additional parallel connected speaker rather than to limit the audio output by other means.

10.5     The design of the audio system must permit adjustment to be made so as to minimise acoustic feed-back when microphones are operated in the correct manner.

10.6     The audio output circuits of a receiver must be loaded within the limits specified by the relevant equipment manufacturer, or otherwise approved by the Director, and in such a manner that the output level of 1 receiver is not varied appreciably by the selection of other receivers.

10.7     The level of residual noise in the audio system must be substantially below normal audio signal levels and must not cause annoyance by virtue of its level or nature.

Note   The Director may determine that a test of residual noise is warranted and will then specify test requirements appropriate to the particular installation.

10.8     Installations comprising more than 1 communication system and/or more than 1 radio navigation system must employ audio on/off switching for each system, unless in the case of navigation systems it can be shown that no ambiguity will occur in the identification of those radio systems which are common to a single audio switch.

10.9     The audio signal from a marker system in which a single indicator lamp is actuated must not be fully muted during operation of the aircraft’s VHF transceiver(s).

11        Voice communications systems — performance and testing

11.1     The operation of voice communication systems must not adversely affect the presentation of essential data used in instrument let-down, approach and landing systems.

11.2     It must be established that the operation of other systems within the aircraft does not cause a level of interference in the audio transducers sufficient to affect the readability and range of received signals on any frequency within the VHF band, or on any discrete frequency used for HF communication.

11.3     The performance of any system used in communications with the aeronautical mobile service must be evaluated prior to certification of its installation in the aircraft and at such other times as may be required by the Director.

Note 1   An evaluation may be carried out with the aircraft stationary and whilst taxiing, by communicating with an aeronautical ground station or another aircraft. Evaluation of HF communication systems should be conducted on all available active frequencies.

Note 2   Where there is doubt about the performance of a system, the Director may require communication tests to be performed in flight as described in Appendix I.

12        ADF systems — performance and testing

12.1     Quadrantal error corrections

All ADF navigation systems must be checked and corrected as far as possible for quadrantal error.

Note   In the case of V.F.R. and night V.M.C. aircraft only, where the ADF equipment has no means of applying quadrantal error correction or where the error exceeds the capability of the correcting mechanism, the errors may be placarded adjacent to the indicator.

12.2     ADF residual errors

After the application of corrections for quadrantal errors, the residual errors given in the following table, applicable to the particular operational classification, must not be exceeded.

Operational   Checks required at   Maximum

classification   permissible

errors

V.F.R.   0° and 180°   ±   6°

night V.M.C.   0° and 180°   ±   6°

Max quadrantal error points   ±   10°

limited I.F.R.   0° and ± 15°, 180° and ± 15°   ±   5°

Any other bearing   ±   7°

I.F.R.   0° and ± 15°, 180° and ± 15°   ±   5°

Any other bearing   ±   6°

12.3     Level of interference

The level of interference from any combination of aircraft systems normally operated in flight must not be sufficient to cause a significant deflection of the ADF direction indicator when the aircraft is flown at the published effective range of a serviceable NDB or locator, and must not degrade the readability of the station identification.

Note   Effective coverage for NDBs and locators is provided in Aeronautical Information Publication — En Route Supplement (ERS).

12.4     Interaction of dual installations

The operation of any 1 ADF system of a dual installation must not have a deleterious effect on the other, nor must a defect in 1 system contribute to malfunctioning of the other irrespective of the operational rating given to the equipment.

12.5     Indicator oscillations

In the case of I.F.R., limited I.F.R. and night V.M.C. aircraft, the ADF indicator must not oscillate more than ± 5 degrees when the aircraft is flown at the published operational range of a serviceable NDB or locator, and in atmospheric conditions known to be satisfactory.

12.6     System reversals

In the case of I.F.R., limited I.F.R. and night V.M.C. aircraft, the ADF system must give 1 reversal of the bearing pointer only, within a circular area centred on the ground station and having a radius which is equal to the height of the aircraft above the station.  Partial reversals which lead or lag the main reversal, are permissible.

12.7     Testing

The checks specified in this subsection must be performed when so required under the terms of Civil Aviation Order 100.37.

13        VHF navigation (CW) systems — performance and testing

13.1     ILS systems

ILS instrumentation must be so arranged that localiser and glideslope information displayed simultaneously on any 1 indicator always relate to the same Instrument Landing System.

13.2     For all VOR, VAR, Localiser, Glideslope systems

The level of interference from any combination of aircraft systems which are normally operated in flight, and are not of an intermittent or short-term nature, must not be sufficient to cause a significant deflection of the flight path indicator when the flag is concealed and must not degrade the readability of the station identification. The level of interference from any source, intermittent or otherwise, must not be of such magnitude as to cause the flag to indicate usuability in the absence of a usable signal.

13.3     For VOR, VAR, Localiser and Glideslope systems installed in night V.M.C. and V.F.R. aircraft

Note   A simulator may be used for checking items (a) to (e).

(a)   sense of indication for a flight path deviation must be correct; and

(b)   “TO-FROM” sense indications must be correct; and

(c)   “OFF” flag operation must be correct; and

(d)   operation of audio filters, where applicable, must be correct; and

(e)   audio output, where applicable, must be adequate.

13.4     For VOR systems installed in I.F.R. and limited I.F.R. aircraft

Note 1   A simulator may be used for checking items (a) to (e).

Note 2   Sensitivities referred to in this paragraph, and in paragraphs 13.5 and 13.6 are related to a “standard” 5 dot-0-5 dot, 150 microamperes-0-150 microamperes indicator. Proportional deflections apply to other than “standard” indicators.

(a)   the deviation indicator must centre when the Omni Bearing Selector (OBS) is within 3 degrees of the selected radial. Tests should be made on a representative number of radials; and

(b)   the deflection sensitivity must be such that a 5 dot left and a 5 dot right deflection (or its equivalent) must be obtained when the OBS is varied 10 degrees ± 2 degrees from the on-course setting, and the indications must be of the correct sense; and

(c)   where installed, the Radio Magnetic Indicator (RMI) reading must be within 4 degrees of the selected radial; and

(d)   the TO-FROM indicator must continue to show TO or FROM as originally selected when the OBS is rotated by ± 45 degrees from the selected radial; and

(e)   the flag must remain concealed during all of the foregoing tests but, when the signal input level is reduced so as to cause the deviation indicator deflection to fall by 2 dots (or equivalent), the flag must be at least partly visible; and

(f)    the TO-FROM indicator must show the correct sense and change from 1 position to the other when passing over the station; and

Note   As a guide, the TO-FROM indicator can be expected to give erratic behaviour for the following times at a ground speed of 150 knots.

Height (ft) above VOR 

Time in seconds 

2 000

5 000

10 000

5

12

22

The fluctuation of the TO-FROM indicator will normally be about half the period of the deviator indicator fluctuation.

(g)   reliable bearing information must be obtained at a distance of not less than 80% of the effective radio horizon for the VOR transmitter at the altitude being flown when the aircraft has a relative bearing of 0 and 180 degrees to the station.

Note   Reliable bearing information means that the flag should be fully concealed and the deviation indicator showing a steady deviation either, left or right.

13.5     For VAR and Localiser systems installed in I.F.R. and limited I.F.R. aircraft

Note   A simulator may be used for checking items (a) to (c).

(a)   the deviation indicator must centre within ± ½ dot (± 15 microamperes) when the tone ratio is 0 db. (ddm = 0); and

Note   The centering tolerances stated apply to ILS systems approved for Category 1 operations. Future requirements for Category 2 and Category 3 operations will be promulgated as required.

(b)   the sensitivity must be such that the deviation indicator deflection is 3 dots ± 1 dot (60 to 120 microamperes) or equivalent for both left and right deflections when using a signal with 4 db. tone ratios (ddm = 0.091) and the deflection must be in the correct sense; and

(c)   the flag must remain concealed during the above tests, but when the signal input level is reduced so as to cause the deviation indicator deflection to fall by 2 dots (or equivalent), the flag must at least be partly visible; and

(d)   at a distance of not less than 20 nautical miles from the localiser, and at a left or right displacement of not less than 25 degrees from the extended centre line of the runway, the flag must be concealed (or equivalent) and the deviation indicator must remain steady at maximum deflection in the proper sense. The localiser identification must be clearly indentifiable.

13.6     For Glideslope systems installed in I.F.R. and limited I.F.R. aircraft

Note 1   Glideslope systems which have not been approved for I.F.R. operations will be endorsed in the aircraft flight manual as “Not approved for operational use”.

Note 2   A simulator may be used for checking items (a) to (c) below.

(a)   the deviation indicator must centre within less than ½ (± 12 microamperes) when the tone ratio is 0 db. (ddm = 0); and

(b)   the sensitivity must be such that the deviation indicator deflection is 4.3 dots ± .7 dot (110 to 150 microamperes) or equivalent for both up and down deflections when using a signal with 3.3 db tone ratios or 2.7 dots ± .3 dot (68 to 93 microamperes) or equivalent when using a 2 db tone ratio, and the deflection must be in the correct sense; and

(c)   the flag must remain concealed during the foregoing tests, but when the signal input level is reduced so as to cause the deviation indicator deflection to fall by 2 dots (or equivalent), the flag must at least be partly visible;

(d)   reliable flight path and deviation information must be obtained at least 15 nautical miles from the end of the runway and along the runway centre line and at positions below and above the glide path; and

Note   Reliable flight path information means that the flag should be fully concealed and the deviation indicator show an unfluctuating deviation.

(e)   the deviation indicator must show a centered position within less than ½ dot (± 12 microamperes) or equivalent when the aircraft is at the published approach altitude over a locator or marker beacon.

13.7     For Marker systems installed in I.F.R. and limited I.F.R. aircraft

Note   Marker systems which have not been approved for I.F.R. operations will be endorsed in the aircraft flight manual as “Not approved for operational use”.

(a)   while executing a normal ILS approach and with the marker sensitivity switch set to the “HI” sensitivity position, the marker lights must remain illuminated for the following length of time:

Outer Marker   12 seconds ± 4 seconds

Middle Marker   6 seconds ± 2 seconds

Inner Marker (where installed)   3 seconds ± 1 second

and the appropriate audio tone must be clearly audible and at an audio level acceptable by comparison with other radio system audio levels; and

Note   The foregoing times are based on a ground speed of 96 knots and proportional adjustment should be made for other ground speeds.

(b)   while executing a normal ILS approach and with the marker sensitivity switch set to the “LO” sensitivity position, marker lights must be illuminated for 50% to 80% of the time obtained in the “HI” position.

13.8     Testing

(1)     The flight and simulator checks specified in paragraphs 13.2 to 13.7 must be performed when so required under the terms of Civil Aviation Order 100.37.

(2)     When so required by the Director, additional flight testing of VHF navigation systems must be performed as specified in Appendix II.

14        DME systems — performance and testing

Note 1   Tests for 1000 MHz DME systems may be based on the requirements of this subsection, but acceptability of the test results will be subject to individual assessment by the Director.

Note 2   A simulator or equipment self-test facility may be used for checking items (a) to (c) of paragraph 14.1.

14.1     For all DME systems

(a)   the DME system must lock-on to the correct selected channel and must indicate the correct distance within the limits of tolerance specified by the manufacturer of the equipment; and

(b)   audio output must be adequate; and

(c)   the flag alarm or equivalent device must indicate the correct operational condition of the equipment.

14.2     For DME systems installed in I.F.R. and limited I.F.R. aircraft

(a)   frequency, accuracy and VSWR must comply with the relevant equipment manufacturer’s specifications, or as otherwise agreed by the Director; and

(b)   the interrogator-responder must remain locked on to the beacon at a distance of not less than 80% of the effective radio horizon for the beacon at the bearing and altitude flown; and

(c)   at the reciprocal of this course, final lock-on must occur at not less than 80% of the effective radio horizon for the beacon at the bearing and altitude being flown; and

(d)   when the aircraft is banked in orbit at an angle of 25 degrees for both left and right hand orbits at 70% of the effective radio horizon, the extent of any drop out or code distortion which may occur must be within limits agreed by the Director; and

(e)   the manoeuvre described in subparagraph (d) above must be repeated with landing gear and flaps down at a distance of approximately 50% of effective radio horizon when the DME aerial is mounted on the underside of the aircraft. No drop-out or code break-up must occur; and

(f)    when performing “over-the-top” tests, commencing at a distance of not less than 10 nautical miles from a beacon and between 4 000 feet and 6 000 feet altitude, the distance indicator must decrease and increase steadily. Drop out must not occur more than 1.5 nautical miles from the true “over-the-top” position; and

(g)   when performing “over-the-top” tests with landing gear and flaps extended, commencing at a distance of not less than 7 nautical miles from a beacon and at an altitude of approximately 2 000 feet, the distance indicator must decrease, then increase steadily. Drop out must not occur more than 1.0 nautical mile before or after the true “over-the-top” position; and

(h)   operation for 10 seconds or more of any radio transmitter in the aircraft must not cause a drop-out when the DME has locked on to a distance ground station.

14.3     Testing

(1)     The flight and simulator checks specified in paragraphs 14.1 and 14.2 must be performed when so required under the terms of Civil Aviation Order 100.37.

(2)     When so required by the Director, additional flight testing of DME systems must be performed as specified in Appendix II.

15        Weather radar systems — performance and testing

15.1     For all weather radar systems

(a)   no objectional interference must be observed on the radar indicator from any other system(s) normally operated in flight; and

(b)   the indicated bearings of objects shown on the display must be within ± 10 degrees of their actual relative bearings.

15.2     For weather radar systems installed in accordance with requirements of AIP Gen 1.5

Note 1   Antenna stabilisation, when provided, must eliminate loss or blurring of the display when the aircraft is manoeuvred within the ranges of pitch and roll for which antenna stabilisation is designed.

Note 2   Echoes should be observable at distances of at least 80% of the maximum range for which the equipment is calibrated.

15.3     Testing

The flight and simulator checks specified in paragraphs 15.1 and 15.2 must be performed when so required under the terms of Civil Aviation Order 100.37.

16        ATC transponders — performance and testing

16.1     The level of interference from all aircraft systems normally operated in flight must not be sufficient to initiate a response from an ATC transponder.

16.2     Operation of the transponder system must be verified using:

(a)   a simulator; or

(b)   a local beacon; or

(c)   the transponder self-test facility.

Note   Use Code Number 0101 for this purpose.

16.3     When so required by the Director, flight testing of a transponder system must be performed as specified in Appendix III.

Appendix I

Test in flight for VHF communication systems

1     Conduct the flight at the normal cruising altitude, having regard for Air Traffic Control requirements.

2     Establish the maximum distance over which communication between the aircraft and a selected ground station can be achieved, when flying away from and towards the ground station, i.e. at relative bearings of 180 and 0 degrees.

3     At or near the maximum distance, determine if the level of interference on all used channels, due to other aircraft systems, causes any reduction of range or readability of received signals.

Note   The VHF range which should be achieved (effective radio horizon) may be determined from the nomogram given as Appendix IV.

4     At a range of not less than 80% of the effective radio horizon, execute both left and right orbits about a fixed point, level the aircraft every 10 degrees and determine those sectors where:

(a)   communication is maintained; and

(b)   communication is not maintained.

For those sectors where communication is not maintained, establish:

(a)   the angular width of each sector; and

(b)   that the distance at which communication is maintained is not less than 65% of the effective radio horizon.

5     At a range of not less than 60% of the effective radio horizon, establish that communication can be maintained when flying towards and away from the ground station in the following conditions:

(a)   at all attitudes used in normal climb and descent; and

(b)   at all banked attitudes used in cruising flight.

Appendix II

Tests in flight for VHF navigation systems VOR, VAR and DME

1     Conduct the flight at the normal cruising altitude, having regard for Air Traffic Control requirements.

2     Establish the maximum distances at which reliable bearing or distance information is obtained when flying away from and towards the ground station (relative bearing of 180 and 0 degrees) are not less than 80% of the effective radio horizon.

3     At or near the maximum distance, determine if the ground station is clearly identifiable.

4     Determine if interference on unused localiser channels, due to other aircraft systems causes a localiser needle deflection of more than 1 dot (or equivalent).

5     At a distance of not less than 70% of the effective radio horizon, execute both left and right orbits about a fixed point, level the aircraft every 10 degrees and determine those sectors where:

(a)   a reliable signal is received; and

(b)   a reliable signal is not received.

For those sectors where:

(a)   a reliable signal is received, establish:

that it is received over angular sectors of ± 30 degrees fore and aft, relative to the aircraft centre line; or

(b)   a reliable signal is not received, establish:

(i)the angular width of each sector; and

(ii)that the distance at which a reliable signal is received is not less than 60% of the effective radio horizon.

6     At a distance of not less than 55% of the effective radio horizon, establish that a reliable signal can be received flying towards and away from the ground station in the following conditions:

(a)   at all banked attitudes used in cruising flight; and

(b)   at all attitudes used in normal climb and descent.

Note   The range which should be achieved (effective radio horizon) may be determined from the nomogram given as Appendix IV.

Appendix III

Tests in flight for transponder systems

1     Conduct the flight at normal cruising altitude, having regard for Air Traffic Control requirements.

2     Establish that the maximum distances at which a reliable response is obtained by ATC, when flying away from and towards the ground interrogator (relative bearings 180 and 0 degrees) is not less than 75% of the effective radio horizon.

3     At a distance of not less than 65% of the effective radio horizon, execute orbits about, or overfly a fixed point, level the aircraft every 10 degrees and determine those sectors where:

(a)   a reliable response is received; and

(b)   a reliable response is not received.

For those sectors where:

(a)   a reliable response is received establish that it is received over angular sectors of ± 30 degrees fore and aft, relative to the aircraft centreline; or

(b)   a reliable response is not received, establish:

(i)  the angular width of each sector; and

(ii)  that the distance at which a reliable response is received is not less than 50% of the effective radio horizon.

4     At a distance of not less than 50% of the effective radio horizon, establish that a reliable response can be obtained flying towards and away from the ground interrogator in the following conditions:

(a)   at all banked attitudes used in cruising flight; and

(b)   at all attitudes used in normal climb and descent.

Note   The range which should be achieved (effective radio horizon) may be determined from the nomogram given at Appendix IV.

Appendix IV

Nomogram for effective radio horizon

Example shown:

Height of ground station — 200 feet

Height of aircraft — 7 000 feet

Effective radio horizon — 120 nautical miles.