Civil Aviation Order 103.28 Instrument 2007 (Cth)
I, WILLIAM BRUCE BYRON, Director of Aviation Safety, on behalf of CASA, make this instrument under subregulation 21A (1) 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 103.28 Instrument 2007
1 Name of instrument
This instrument is the Civil Aviation Order 103.28 Instrument 2007.
2 Commencement
This instrument commences on the day after it is registered.
3 New Civil Aviation Order 103.28
Civil Aviation Order 103.28 is repealed and a new Civil Aviation Order 103.28 substituted as set out in Schedule 1.
Schedule 1 Civil Aviation Order 103.28
Equipment standards — localiser/VAR navigation receiving equipment
This Order is to be read in conjunction with Civil Aviation Order 103.21.
1 Application
1.1 This Civil Aviation Order specifies standards for airborne ILS localiser and VAR navigation receiving equipment operating within the frequency range from 108 to 112 MHz.
1.2 These standards apply to the approval of equipment for use in Australian registered aircraft for the purpose of providing information for the navigation of the aircraft.
Note Special requirements for ILS localiser receiving equipment intended for use in Category II and Category III “all weather” landing minima are not covered by this Equipment Standard.
2 Design requirements
2.1 The receiving and indicating functions of the equipment must be designed for comparability with the Standards and Recommended Practices for ILS localisers specified by the International Civil Aviation Organization current at the time of approval application.
Note Compatibility with Australian Visual-Aural Ranges (VAR) is achieved by compliance with this requirement.
2.2 The frequency range and number of channels must be adequate for the intended operational purpose of the equipment.
Note Australian ILS localiser and VAR channels are allocated from odd tenth megahertz frequencies within the range 108.1 to 111.9 MHz.
2.3 Not more than 2 controls must be used for frequency selection and tuning. These controls must switch into operation preset frequency determining circuits.
Note Continuously tunable receivers will not be approved.
2.4 Means to verify the quality of the received signal and, as far as practicable, the correct functioning of the equipment, must be provided. For equipment with an I or L rating, an alarm device complying with the requirements of paragraph 4.9 must be provided.
Note 1 The alarm function may be combined with a VOR TO/FROM indicator providing that such combination meets all applicable requirements mentioned in this Equipment Standard.
Note 2 The alarm device should, as far as practicable, be capable of warning of malfunctions in the filters or tone selecting and comparing circuits.
2.5 The filters or selective circuits in the 90 and 150 Hz tone comparator circuits must, as far as practicable, reject noise and other frequencies.
2.6 For equipment with an I or L rating, the indicator dial markings and alarm device indicator must be visible from any point within the frustum of a cone, the side of which makes an angle of 30 degrees with the perpendicular to the dial and the small diameter of which is the indicator window.
2.7 The course deviation indicator pointer must be capable of detecting at least 13 mm from its centred position. For cross-pointer ILS type indicators, and indicators with similar markings, but without a glideslope deviation pointer, the deflection must be measured along the line corresponding to the centred position of a glideslope deviation pointer.
2.8 The performance of the equipment in its navigation functions must not be degraded by the operation of squelch circuits. The effect of squelch circuits must be confined to the muting of audio output.
2.9 Navigation functions must not be affected by the operation of mutual gain controls.
2.10 Audio level controls must be connected in such a manner that variation of the controls will not cause a significant change in audio output level of other equipment with which its audio output may be paralleled.
2.11 The manufacturer must state the load requirements for instrument and indicator output circuits.
2.12 The operation of instrument and indicator circuits must not be affected when the audio output load impedance is varied within limits stated by the manufacturer.
2.13 Controls not intended for use during flight must not be readily accessible to the flight crew.
2.14 All indicators, controls and test points must be clearly marked or readily identifiable as follows:
(a) indicators and controls for in-flight operation must be marked in English symbols;
(b) indicators, controls and test points for maintenance adjustments to installed equipment must be marked in English or recognised technical symbols;
(c) controls and test points used only during maintenance at the test bench must be identifiable by means of suitable markings or other means of providing unambiguous identification, e.g. overlays, photographs.
2.15 The equipment must be designed so that any possibility of incorrect mating of connectors is minimised. Plugs and sockets without positive means to prevent incorrect mating must be suitably marked or readily identifiable with their function or suitable circuit reference.
2.16 The equipment must be so designed that the possibility of electric shock to passengers or crew is negligible.
2.17 The equipment must be so constructed that normal methods of mounting and the application of vibration and shock under the most severe conditions likely to be encountered by the equipment will not cause detuning or other malfunctions to occur or otherwise damage the equipment.
2.18 The equipment must be designed so that the rating of each component, with appropriate derating, is not exceeding in any localised component environment which may occur during operation of the equipment in any overall environment implied by its classification.
2.19 The attachment of components and the restraint of plug-in components, adjustments and tuning devices must be adequate to ensure their security and permanence of adjustment under the vibration conditions within which the equipment may be operated.
2.20 The performance characteristics of the equipment must be unaffected by operation of panel and indicator lamps incorporated in the equipment.
Note It is recommended that lamps be fitted with a dimming device or provision made for their connection into a suitable dimming circuit.
3 Conditions of test
3.1 Compliance with this Civil Aviation Order must be substantiated by tests conducted on 1 or more sets of equipment to the extent appropriate to the desired classification.
Note 1 The Director may allow some departure from certain individual requirements provided that, in his opinion, overall performance is consistent with the intended purpose of the equipment and generally satisfactory throughout the range of environmental conditions mentioned in this Order.
Note 2 The Director may require additional tests to be conducted if particular designs or performance characteristics appear to warrant special assessment.
3.2 During, and subsequent to the application of, the specified test, the equipment must not exhibit evidence of any condition which would be detrimental to its continued satisfactory performance.
3.3 Unless otherwise specified or required, tests must be conducted under room ambient conditions.
Note Room ambient conditions should be:
atmospheric pressure — 810 to 1050 mb or 24 to 31 inches Hg;
air temperature — + 10 op 40°C;
relative humidity — less than 85%.
3.4 Unless otherwise specified or required, the equipment must be operated at normal rated power supply voltage and frequency. Variations up to ± 2% of voltage and ± 2% of frequency will be accepted.
Note 1 Normal rated voltages and frequencies are those specified by the manufacturer for continuous or stated duty cycle operation of the equipment. Usual ratings would be 13.75 or 27.5 volts for DC and 115 volts at 400 Hz for AC operated equipment.
Note 2 For equipment designed to operate on a variable frequency AC supply, the terms “selected test frequency” and “critical test frequency” should be used and noted in the test reports.
3.5 The input signal level must be interpreted as the “open circuit” voltage (EMF) of the signal source. The signal source output impedance must comprise a resistance within 10% and reactance of not more than 10% of the characteristic impedance of the transmission line for which the receiver is designed. The input signal levels mentioned in this Equipment Standard are for receivers designed for a transmission line having a nominal characteristic impedance of 52 ohms. In the case of a receiver designed for a transmission line having a normal characteristic impedance other than 52 ohms, the input signal levels must be computed according to the following equation:
E2 =
where:
E2 is the input signal level to be used for a receiver designed for a transmission line having a nominal characteristic impedance other than 52 ohms;
E1 is the applicable input signal level;
R2 is the nominal characteristic impedance of the transmission line for which the receiver is designed.
3.6 Where a voltage level at radio frequency (other than an input signal level) is specified, it must be interpreted as the voltage actually occurring between the points stated, or the point and equipment frame, as appropriate.
3.7 Unless otherwise agreed by the Director, equipment covered by these Equipment Standards must be capable of continuous operation.
3.8 Accepted test procedures must be used for the conduct of the performance tests required by these Equipment Standards. Unless otherwise agreed by the Director, the same procedures must be used for the conduct of similar tests under environmental, low voltage and normal test conditions.
Note Suggested test procedures are contained in Appendix 2.
3.9 Evidence that test equipment is properly calibrated and checked must be made available at the Director’s request.
3.10 Minor modifications to correct, deficiencies noted as a result of the tests may be made at any stage of the tests providing that such tests as the Director considers necessary are repeated.
Note Results of repeated tests should be identifiable with the specific modification.
4 Minimum performance requirements under normal test conditions
Note 1 Statistical summation of centring errors due to a number of variable conditions is required in determining compliance of rating I equipment with paragraph 4.1. The results of several tests from section 6 of this Equipment Standard are required for the calculation. The test program may, therefore, be conducted in a sequence convenient to this requirement.
Note 2 In conformity with similar practices adopted in the UK and the USA, the Centering accuracy of rating I equipment (which may be used for ILS and localiser approaches under the appropriate meteorological minima) has been granted according to its suitability for the approach characteristics of different aircraft and operating criteria.
Note 3 Standard test signals and the more significant terms and abbreviations used in this Equipment Standard are defined in Appendix 1.
4.1 Centering accuracy
4.1.1 The equipment must produce an on-course indication within the deviation limits specified in Table 1 when it is subjected to each of the applicable variable conditions in Table 2 while a standard localiser centring signal at a level of 1 000 microvolts (unless otherwise specified) is applied to the receiver input.
Table 1
On-course deviation limits
Operational rating
I
V
Centering accuracy grade A B C Deviation limits expressed as a percentage of standard deflection 33 23 16 50
4.1.2 Additionally, for rating I equipment, the root-sum-square of the maximum “left” deviations and the root-sum-square of the maximum “right” deviations due to the applicable conditions marked (X) in Table 2, with a standard localiser centring signal at a level of 1 000 microvolts (unless otherwise specified), must not exceed the limits in Table 1.
Table 2
Course accuracy test — variable conditions Operational rating applicability I V 1 Variation of RF signal level from 50 to 10 000 microvolts (X) X 2 Variation of RF carrier frequency above and below the assigned channel frequency by 6 kHz plus the magnitude of the maximum departure of the received centre frequency from the assigned channel frequency under any environmental conditions implied by the equipment classification (X) X 3 Where a 10 000 microvolt undesired signal modulated 30% at 150 Hz is added to a desired standard localiser centring signal, and:
(a) the desired signal level is varied from 200 to 10 000 microvolts; and
(b) the frequency of the undesired signal is varied from 108.1 to 111.9 MHz, excluding the band within 100 kHz of the selected channel frequency and any frequency which produces a 90 or 150 Hz beat note from the receiver; and
(c) the modulation on the undesired signal is not phase-locked with the modulation of the desired signal
(X) Z 4 Simultaneous variation of the modulating tone frequencies from 98.5% to 101.5% of 90 and 150 Hz (X) Z 5 Simultaneous variation of the percentage modulation of the 90 and 150 Hz tones from 18% to 22% of each tone (X) Z 6 Variation of the phase relationship of the 90 and 150 Hz tones from the correct phasing by ± 12° of the common 30 Hz subharmonic (X) Z 7 Variation over the frequency range 350 to 2 500 Hz of an audio signal which additionally modulates the carrier 30% X Z 8 Variation of all primary power input voltages from 90% to 110% normal rated, or any greater range for which the equipment is designed (X) X 9 Variation of primary power input frequency (if applicable) over the range for which the equipment is designed (X) X 10 During the altitude test (X) X 11 During the high temperature test — (X)(T) X X 12 During the temperature variation test — (X)(T) X 13 During the low temperature test — (X)(T) X X 14 After the humidity test (X) 15 During the vibration test (X) 16 During the repetitive voltage transient test (X) 17 During the conducted audio frequency susceptibility test (S) X Z 18 During the audio frequency magnetic field susceptibility test (S) X Z 19 During the conducted and radiated radio frequency susceptibility test (S) X Z
Note Symbols used in Table 2 have the following significance:
X means that the test is required for determination of compliance with paragraph 4.1 (a);
(X) means that the test is required for determination of compliance with paragraphs 4.1 (a) and (b);
(T) as these conditions are not independent of each other, the maximum errors to be used in the statistical analysis are the maximum “left” and “right” errors occurring in the group of tests;
(Z) although the application of conditions 3, 4 and 5 is not specified for equipment with V rating, a similar standard is desirable.
4.2 Deflection sensitivity
When the equipment has been initially adjusted to produce standard deflection with a standard localiser deviation signal at a level of 1 000 microvolts and the level is then varied over the range from 50 to 10 000 microvolts, the deviation must not vary more than:
± 20% ± 33% of standard deflection for ratings I V
4.3 Deflection balance
As the 90 and 150 Hz tone predominance of a standard localiser deviation signal at a level of 1 000 microvolts is reversed, the opposite deviations obtained must differ in magnitude by not more than:
5% 25% of standard deflection for ratings I V
4.4 Deflection linearity — electrical
This requirement applies only to equipment for which an I rating is required.
4.4.1 As the DDM of a standard localiser test signal is increased from zero to 0.155, the output current must be within 10% of being proportional to the DDM, or within 5% of standard deflection of being proportional to the DDM, whichever is greater.
4.4.2 Additionally, as the DDM is increased from 0.155 to 0.4, the output current must not decrease.
4.4.3 This requirement must be met throughout the range of signal levels from 50 to 10 000 microvolts and for both “left” and “right” deflections.
Note 1 It is desirable that linearity of the output current be maintained within the above limits as the DDM is increased to 0.18 if the equipment may be required to supply signals to an auto-pilot.
Note 2 A similar standard is desirable for all equipment, especially if the electrical output is intended for possible connection to an auto-pilot.
4.5 Deflection response — electrical outputs
When the DDM of a standard localiser test signal is abruptly changed from zero to any value less than 0.155, the output current must reach 67% of its ultimate value within 0.6 second.
Note Provision should be made for subsequent adjustment of response to suit operational conditions.
4.6 Deflection range — indicators
The course deviation pointer must visibly deflect at least ¾ inch along its scale when the DDM is changed from zero to 0.093 and the RF signal input level is 1 000 microvolts.
Note 1 This requirement applies to both left and right deflection (i.e. 150 and 90 Hz tones predominating in turn).
Note 2 Refer also to paragraph 2.7.
4.7 Deflection linearity — indicators
This requirement applies only to equipment for which an I rating is desired.
4.7.1 As the DDM of a standard localiser test signal is increased from zero to 0.093, the deflection must be within 10% of being proportional to the DDM, or within 5% of standard deflection of being proportional to the DDM, whichever is greater.
4.7.2 Additionally, as the DDM is increased beyond that producing full-scale deflection to a value of 0.4, the indicator deflection must be not less than full scale.
4.7.3 This requirement must be met throughout the range of signal levels from 50 to 10 000 microvolts and for both “left” and “right” defections.
Note A similar standard is desirable for all equipment.
4.8 Deflection response and damping — indicators
This requirement applies only to equipment for which an I rating is desired.
When the DDM of a standard localiser test signal is abruptly changed from zero to any value less than 0.155, the indicator pointer must reach 67% of its ultimate deflection in from 0.5 to 2 seconds and the overshoot must not exceed 5%.
Note 1 The manufacturer may choose to provide all or any part of the damping within the equipment or provide for externally connected damping capacitors, etc.
Note 2 A similar standard is desired for all equipment.
4.9 Alarm device
This requirement applies to all equipment for which an I rating is desired (see paragraph 2.4):
(a) the alarm device must be fully visible or otherwise indicate system failure:
(i) in the absence of an RF signal; and
(ii) when an unmodulated RF carrier at the selected frequency is applied to the receiver input and its level varied from zero to 20 000 microvolts; and
(iii) when an RF carrier at the selected frequency and modulated 30% by audio signal varied over the range 300 to 3 000 Hz is applied to the receiver input; and
(b) the alarm device must at least begin to appear or otherwise indicate system degradation:
(i) when the percentage modulation of both tones is reduced to 10%; and
(ii) when either tone is removed from a standard localiser centring signal and its level varied over the range 30 to 20 000 microvolts; and
(iii) when only 50%, or less, of standard deflection is produced by a standard localiser deviation signal due to variation of its RF carrier level; and
(c) the alarm device must not be visible and must not otherwise indicate unsatisfactory operation of a properly functioning system when the level of a standard localiser test signal is varied over the range from not more than 15 microvolts (rating I) to 10 000 microvolts.
4.10 Selectivity
4.10.1 The level of an input signal, modulated 30% at 1 000 Hz, required to produce constant output must not vary more than 6 dB when its frequency is varied above and below the assigned channel frequency by 10 kHz plus the magnitude of the maximum departure of received centre frequency from the assigned channel frequency under any combination of environmental conditions implied by the equipment classification.
4.10.2 When the level of an input signal, modulated 30% at 1 000 Hz, is increased by 60 dB (rating I) or 40 dB (rating V), the amount by which the input frequency must be changed to restore a selected output must be not more than 90 kHz.
4.11 Spurious responses
This requirement applies to equipment for which an I rating is desired.
When the frequency of an unwanted signal modulated 30% at 150 Hz, at a level of 20 000 microvolts, is varied over the range 190 kHz to 1 200 MHz, excluding the band 108 to 112 MHz, and applied to the receiver simultaneously with a standard localiser centring signal at a level of 200 microvolts (i.e. 40 dB relative levels), deviation indications due to spurious responses must not exceed:
16% 23% 33% of standard deflection for rating I grade C B A
4.12 RF sensitivity
(a) The level of a standard localiser deviation signal required to produce at least 60% of standard deflection, with erratic movement of the deviation indicator pointer either side of its mean position not exceeding 5% of standard deflection must not exceed:
15 30 microvolts for ratings I V
(b) The level of a standard localiser audio signal required to produce an audio output with a signal-plus-noise to noise ratio of 6 dB must not exceed:
15 30 microvolts for ratings I V
4.13 Audio AGC
The audio output must not vary more than:
6 12 microvolts for ratings I V
as the level of an RF signal modulated 30% at 1 000 Hz is varied from 6 dB above the RF sensitivity level to 10 000 microvolts.
4.14 Audio output
With an RF input signal modulated 30% at 1 000 Hz, the audio output capability must be not less than the rated output power published by the manufacturer. This requirement must be met over the input signal level range from the RF sensitivity level mentioned in paragraph 4.12 (b) to 10 000 microvolts.
Note To ensure satisfactory performance in a wide variety of installations, an audio output capability not less than 50 milliwatts for the headset output circuit and 3 watts for the speaker output circuit (if provided) is recommended.
4.15 Distortion
With an RF input signal modulated 30% by an audio frequency varied over the range 350 to 2 500 Hz and the audio output set to produce rated output at 1 000 Hz, the total harmonic distortion must not exceed 25%. This requirement must be met as the input signal level is varied over the range from 100 to 10 000 microvolts.
4.16 Audio frequency response
The overall audio frequency response must be such as to produce clearly intelligible reception of any normal human speaking voice and attenuation of those frequencies which may detract from, or not significantly contribute to, intelligibility.
4.17 Audio output regulation
The manufacturer must declare the effect of variation of audio load impedance on audio output power or voltage.
Note Although no specific values of acceptability are set down for this requirement, the information is necessary to the design and approval of aircraft audio installations. The information should cover load impedance variations from 0.25 to 2 RL for headphone circuits and 0.5 RL for speaker circuits.
4.18 Manual gain control
The manual gain control must be capable of varying the audio output of the receiver by at least 24 dB with any level of standard localiser audio signal from 20 to 10 000 microvolts applied to the receiver input.
4.19 Spurious emissions
Note 1 Equipment which complies with the requirements for either Category A or Category B equipment specified in RTCA DO-160 or later amendment will be taken to comply with this paragraph.
Note 2 The emission of spurious radio frequency energy of a transient nature resulting from the manual operation of switches, but not including emissions from circuits operating as a result of that manual operation, may exceed the limits mentioned in this paragraph if its duration does not exceed 1 second.
4.19.1 Emissions from antenna
The power of any spurious emission present at the antenna terminal on any discrete frequency between 190 kHz and 1 200 MHz must not exceed 1 nanowatt (for rating I) or 20 nanowatts (for rating V).
4.19.2 Emissions from interwiring
This requirement applies only to equipment for which an I rating is desired.
Unwanted radio frequency energy on any cable must be of such level, or must be contained in such manner, that the level of signals on discrete frequencies from 190 kHz to 1 200 MHz induced in another cable run with it does not exceed 1 000 microvolts. (Refer to Appendix 2 for suggested test procedure.)
Note Although this requirement does not apply to receivers with V rating, a similar standard is desirable. Particular attention should be given to minimising spurious emissions within the frequency ranges from 190 kHz to 20 MHz to 108 to 136 MHz in order to provide reasonable assurance that mutual interference limits, mentioned in other Civil Aviation Orders, can be met. Transistorised inverters in power supply circuits are frequently responsible for unacceptable emissions.
4.20 Channel selection time
The maximum time for the equipment to change from 1 channel to any other must not exceed 10 seconds.
4.21 RF input impedance
This requirement applies to equipment for which an I rating is required.
Over the frequency range for which the receiver is designed, the VSWR produced on the antenna transmission line by the receiver must not exceed 3:1.
4.22 Operation of mechanical devices
Mechanical devices must perform their intended function. Marginal operation must be avoided.
4.23 Variation of primary power frequency
The equipment must comply with this Equipment Standard when the primary power frequency is varied throughout the range for which the equipment has been designed. For equipment designed to operate from a nominally constant frequency supply, it must be assumed that the frequency will vary by at least ± 5%.
4.24 Application of conducted voltage transients
This requirement applies only to equipment for which an I rating is desired.
Note 1 Although specified for I rating equipment only, it is desired that this requirement be applied, where practicable, to all equipment especially that which incorporates solid state devices susceptible to damage by voltage transients.
Note 2 This requirement is expressed in this interim form pending further investigation of the magnitude and effects of aircraft electrical system voltage transients.
4.24.1 Intermittent transients
After application of intermittent transients as specified in RTCA DO-160 or later amendment, the equipment must not exhibit evidence of damage and must continue to function without degradation.
4.24.2 Repetitive transients
When the equipment is subjected to repetitive transients test specified in RTCA DO-160 or later amendment, the requirements of paragraph 4.1 of this Order must be met.
4.25 Conducted and radiated interference susceptibility
These requirements apply only to equipment for which an I rating is desired.
Note Although these requirements do not apply to equipment with V rating, a similar standard is desirable, especially for the former, in order to provide reasonable assurance that mutual interference limits, mentioned in other Civil Aviation Orders, can be met.
4.25.1 Conducted audio frequencies
The requirements of paragraph 4.1 must be met when the equipment is subjected to the test mentioned in RTCA DO-160 or later amendment.
4.25.2 Audio frequency magnetic fields
The requirements of paragraph 4.1 must be met when the equipment is subjected to the test specified in RTCA DO-160 or later amendment.
4.25.3 Radio frequencies conducted and radiated
The requirements of paragraph 4.1 must be met when the equipment is subjected to the tests specified in RTCA DO-160 or later amendment.
5 Minimum performance requirements at low primary voltage
5.1 When all primary power input voltages are simultaneously reduced to 80% of normal rated for DC and 90% of normal rated for AC supplies:
(a) deflection sensitivity must meet the requirements of paragraph 4.2 over the input signal level range from 100 to 10 000 microvolts; and
(b) RF sensitivity must be not more than 6 dB (for rating I) below that mentioned in paragraph 4.12; and
(c) the maximum time for the equipment to change from 1 channel to any other must not exceed 10 seconds; and
(d) mechanical devices must perform their intended functions.
6 Minimum performance requirements under environmental test conditions
Note Environmental test procedures are mentioned in Civil Aviation Order 103.21.
6.1 Altitude test
When the equipment is subjected to this test:
(a) there must be no evidence of arcing, burning or other deleterious effect; and
(b) the requirements of paragraphs 4.1 (Centering accuracy) and 4.2 (Deflection sensitivity) must be met.
6.2 Depressurisation test
6.2.1 When the equipment is subjected to this test, it must continue to function as intended. Some degradation of performance may be permitted.
6.2.2 There must be no evidence of any condition occurring as a result of this test which may cause complete failure of the equipment.
6.3 Short time operating high temperature test
When the equipment is subjected to this test:
(a) there must be no evidence of overheating of any component or exudation of grease or other compounds; and
(b) the equipment must continue to function as intended. Some degradation of performance is permitted.
6.4 High temperature test
When the equipment is subjected to this test:
(a) there must be no evidence of overheating of any component or exudation of grease or other compounds; and
(b) the requirements of paragraphs 4.1 (Centering accuracy), 4.2 (Deflection sensitivity) and 4.12 (RF sensitivity) must be met.
6.5 Temperature variation test
When the equipment is subjected to this test the requirements of paragraphs 4.1 (Centering accuracy), 4.2 (Deflection sensitivity) and 4.12 (RF sensitivity) must be met.
6.6 Low temperature test
When the equipment is subjected to this test:
(a) the requirements of paragraphs 4.1 (Centering accuracy), 4.2 (Deflection sensitivity), 4.20 (Channel selection time) and 4.22 (Operation of mechanical devices) must be met; and
(b) RF sensitivity must not be more than 6 dB below that mentioned in paragraph 4.12; and
(c) audio output capability must be not more than 3 dB below that mentioned in paragraph 4.14.
6.7 Humidity test
6.7.1 After the equipment has been subjected to this test, and immediately following the 15 minute warm-up period:
(a) the requirements of paragraphs 4.1 (Centering accuracy) and 4.2 (Deflection sensitivity) must be met; and
(b) RF sensitivity, for the conditions mentioned in paragraph 4.12, must be 50 microvolts or better.
6.7.2 Within 4 hours from the time primary power is applied, the requirements of paragraphs 4.1 (Centering accuracy), 4.2 (Deflection sensitivity), 4.12 (RF sensitivity), 4.20 (Channel selection time) and 4.22 (Operation of mechanical devices) must be met.
6.8 Resonance search
When the equipment is subjected to the resonance search, there must be no evidence of excessive flexure of the chassis or mounting and components must not develop independent movement which would be likely to result in failure of the component or its attachment to the equipment.
6.9 Anti-vibration mounting attenuation test
When the equipment is subjected to this test:
(a) the mountings must not attain their limit of displacement in any direction; and
(b) magnification of vibration amplitude must be confined to frequencies below 20 Hz.
6.10 Vibration test
When the equipment is subjected to this test:
(a) there must be no evidence of detuning, upset of adjustments or other malfunctions; and
(b) the requirements of paragraphs 4.1 (Centering accuracy), 4.2 (Deflection sensitivity) and 4.12 (RF sensitivity) must be met.
6.11 Acceleration test
After the equipment has been subjected to this test, there must be no evidence of it breaking free from its mountings.
Appendix 1
Definitions
1 Standard test signals
Standard localiser test signals must have the characteristics mentioned below. It is permissible to use any type of signal generator which produces signals within the specified tolerances.
RTCA DO-52, Calibration procedures for signal generators used in the testing of VOR and ILS receivers, describes acceptable procedures for calibrating and checking several types of ILS signal generator.
2 Standard localiser test signal
An RF carrier amplitude modulated simultaneously by 90 and 150 Hz tones so that the sum of their respective modulation percentages is 40 ± 2%.
The tones must:
(a) be derived from a common signal source and must be phase-locked so that their voltage waveforms simultaneously pass through zero in the same direction; and
(b) be within ± 0.3% of the nominal frequencies; and
(c) each have a total harmonic content not exceeding 3%.
3 Standard localiser centring signal
A standard localiser test signal in which the difference in depth of modulation of the 90 and 150 Hz tones is less than 0.002.
4 Standard localiser deviation signal
A standard localiser test signal in which the difference in depth of modulation of the 90 and 150 Hz tones is 0.093 ± 0.002.
5 Standard localiser audio signal
A standard localiser deviation signal to which is added a 1 000 Hz tone amplitude modulating the carrier 30%.
6 Standard deflection
(a) In the case of indicators in which the deflection from centre to full-scale is linear, standard deflection must be 60% of full-scale deflection.
(b) In the case of indicators in which the centre to full-scale deflection is non‑linear beyond that deflection which is obtained when the difference in depth of modulation of the 90 and 150 Hz tones is 0.093, standard deflection must be at least 9.5 mm.
(c) In the case of an electrical output from the equipment, standard deflection must be the current obtained when the difference in depth of modulation of the 90 and 150 Hz tones is 0.093; when the equipment is adjusted to produce standard deflection and the input signal is a standard localiser deviation signal at a level of 1 000 microvolts.
7 Difference in depth of modulation (DDM)
Difference in depth of modulation is the percentage modulation depth of the larger signal minus the percentage modulation depth of the smaller signal divided by 100, i.e.:
DDM = .
Appendix 2
Test procedures
1 It is recognised that compliance with sonic of the minimum performance requirements mentioned in this Civil Aviation Order might be determined using alternative test procedures. However, paragraph 3.8 states that “accepted” test procedures are to be used and the Director may require a full description of the procedures actually used should there be any doubt as to the validity of the results of any test.
2 Procedures suitable for the conduct of most of the tests mentioned in this Civil Aviation Order are contained in RTCA DO-195 or later amendment. In some instances, suitable procedures may be determined from the wording of the requirement.
3 For the convenience of manufacturers who do not have ready access to RTCA DO‑195 or later amendment, or certain of the test equipment mentioned in it, the following information on acceptable test procedures may be useful.
3.1 Simultaneous application of 2 signals to the receiver input
Test 3, Table 2, paragraph 4.1 and paragraph 4.11 require the simultaneous application of 2 signals to the receiver input. It is important that the 2 signal generators and the receiver be properly interconnected and terminated for these tests. The preferred procedure for these tests is as follows:
Connect 2 signal generators via a suitable “T” pad to the receiver input. The pad must provide suitable termination and isolation for the signal generators and receiver. One signal generator will supply the “desired” signal, the other the “undesired” or “interfering” signal.
When both signal generators and the receiver are designed for a nominal 52 ohm RF termination, the “T” pad should be as shown by Figure 1.
“T” pad
Figure 1
“T” pad for 52 ohm equipment
When using the “T” pad, the RF signal levels mentioned are the “open circuit” levels at the output of the “T” pad with the receiver disconnected.
3.2 Spurious emissions (paragraph 4.19 refers)
3.2.1 Emissions from antenna
Connect a suitable tunable receiver — such as a field intensity receiver — to the antenna terminal of the receiver under test. Ensure that correct impedance matching is achieved. The receiver under test may be set to approximately 110 MHz.
Tune the tunable receiver across the specified frequency range and note the presence and level of signal indications.
A signal generator in place of the receiver under test may be used to determine the levels of noted signals and these converted to power by calculation.
3.2.2 Emissions from interwiring
The test conditions should simulate a typical installation in an aircraft.
Mount the equipment by its normal means, approximately centrally, on a copper, brass or aluminium groundplane measuring at least 0.76 metre wide and having an area of at least 1.1 square metres.
This test should preferably be conducted in a screened room with the groundplane connected to the room shielding by low reactance paths from at least both ends of the groundplane.
Where the length of interconnecting cables is not specified by the manufacturer, these should be at least 1.52 metres long and arranged as in a typical installation. Cables should be raised about 50 mm above the groundplane to reduce shunt capacitance effects. Only those cables so specified by the manufacturer in wiring diagrams applicable to the equipment may be screened.
Bonding straps across vibration isolators, etc should be fitted where these would be used in a normal installation. Bonding must not be used in any place where it would not normally be used in an installation.
Tie in with each bundle of cables in the simulated installation an 18 or 20 gauge insulated cable, unterminated at both ends. Connect a suitable tunable receiver, such as a field intensity receiver, to this “pick-up” cable.
Tune the tunable receiver across the specified frequency range and note the presence and level of signal indications. A signal generator may then be used to determine the levels of noted signals.
Appendix 3
Course accuracy calculation
The root-sum-square of entering errors, as required in paragraph 4.1, may be calculated as follows:
(a) Tabulate, as in Columns 2 and 4 of the following table, the maximum “left” and “right” deviations due to each of the variable conditions in Table 1, paragraph 4.1. Note, however, that the temperature tests are grouped to determine the maximum errors resulting from any temperature condition.
(b) Calculate the square of each maximum error and enter in Columns 3 and 5.
(c) Add Column 3 and calculate the square root of the sum. Do likewise for Column 5.
The results in the following example would qualify the equipment for rating I, grade C.
If the equipment incorporates a course deviation indicator, a similar tabulation and calculation will be required in respect of it.
The figures have no significance and serve only as an example of the method.
Example
Maximum centring errors
No. Variable condition Left
error
mAError2 Right error
mAError2 1 2 3 4 5 1 RF signal level 3 9 2 4 2 RF carrier frequency 1 1 5 25 3 Cross modulation (Note 1) 4 16 4 16 4 90/150 Hz frequency 2 4 2 4 5 90/150 Hz modulation depth 2 4 1 1 6 90/150 Hz phase 1 1 0 0 7 Audio frequency 7 Note 2 4 Note 2 8 Primary power voltage 1 1 2 4 9 Primary power frequency NA - NA - 10 Altitude 3 9 0 0 11 High temperature 8 64 10 100 12 Temperature variation 8 64 10 100 13 Low temperature 8 64 10 100 14 Vibration 7 49 6 36 15 Repetitive voltage transient 0 0 2 4 16 Conducted audio frequencies 14 Note 2 3 Note 2 17 Audio frequency magnetic field 9 Note 2 2 Note 2 18 Conducted and radiated RF 7 Note 2 11 Note 2 Sum of squares 158 194 Root of sum of squares 12.6 13.9
Note 1 If the cross-modulation test is conducted with an interfering signal modulated 90 or 150 Hz only, assume that an opposite error of equal magnitude would result if the other sensor were used. If the test is conducted with the interfering signal modulated 150 and 90 Hz in turn, enter the appropriate results in Columns 2 and 4.
Note 2 Omitted due to small probability of occurrence during normal operations.
A more thorough, statistical procedure for determination of localiser receiver course accuracy is described in RTCA DO-195 or later amendment and may be used in lieu of the above, if preferred.
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