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This appendix applies to persons referred to in rule 43.61.
(a) Ensure freedom from entrapped moisture and restrictions.
(b) Ensure the leakage is within the following established tolerances:
(1) For unpressurised aeroplanes:
(i) Method: Evacuate any static pressure system incorporating a static port to a pressure differential of approximately 1 inch of mercury or to a reading, on the altimeter, 1000 feet above the aircraft elevation at the time of the test:
(ii) Tolerance: Without additional pumping for a period of 1 minute, the loss of indicated altitude must not exceed 100 feet on the altimeter:
(2) For pressurised aeroplanes:
(i) Method: Evacuate the static pressure system until a pressure differential equivalent to the maximum cabin differential for which the aeroplane is type certificated is achieved:
(ii) Tolerance: Without additional pumping for a period of 1 minute, the loss of indicated altitude must not exceed 2 percent of the equivalent altitude of the maximum cabin differential pressure or 100 feet, whichever is the greater.
(c) Determine that the static port heater, if installed, is operable.
(d) Ensure that no alterations or deformations of the airframe surface have been made that would affect the relationship between air pressure in the static pressure system and true ambient static air pressure for any flight condition.
(a) Unless otherwise specified each test for performance may be conducted with the instrument subjected to vibration.
(b) When tests are conducted with the temperature substantially different from an ambient temperature of approximately 25 degrees Celsius allowance should be made for the variation from the specified condition.
(c) Altimeter tests must be carried out in accordance with the following:
Scale error:
(1) The altimeter must, with the barometric pressure scale at 1013.25 millibars, be subjected successively to pressures corresponding to the altitude listed in Table 1 up to the maximum normally expected operating altitude of the aircraft in which the altimeter is to be installed:
(2) The reduction in pressure must be made at a rate not exceeding 20 000 feet per minute to within approximately 2000 feet of the test point:
(3) The test point must be approached at a rate compatible with the test equipment:
(4) The altimeter must be kept at the pressure corresponding to each test point for at least 1 minute, but not more than 10 minutes, before a reading is taken:
(5) The error at all test points must not exceed the tolerances listed in Table 1:
Hysteresis:
(6) The hysteresis test must begin not more than 15 minutes after the altimeter's initial exposure to the pressure corresponding to the upper limit of the scale error tests prescribed in paragraph (b)(1)- (5) and the hysteresis test must commence while the altimeter is at this pressure:
(7) Pressure must be increased at a rate simulating a descent in altitude at the rate of 5000 to 20 000 feet per minute until within 3000 feet of the first test point which is 50 % of maximum altitude:
(8) The test point must then be approached at a rate of approximately 3000 feet per minute:
(9) The altimeter must be kept at this pressure for at least 5 minutes, but not more than 15 minutes, before the test reading is taken:
(10) After the reading has been taken, the pressure must be increased further, in the same manner as before, until the pressure corresponding to the second test point which is 40 % of maximum altitude is reached:
(11) The altimeter must be kept at this pressure for at least 1 minute, but not more than 10 minutes, before the test reading is taken:
(12) After the reading has been taken, the pressure must be increased further, in the same manner as before, until atmospheric pressure is reached:
(13) The reading of the altimeter at either of the two test points must not differ by more than the tolerance specified in Table 2 from the reading of the altimeter for the corresponding altitude recorded during the scale error test prescribed in paragraph (b)(1)- (5):
After effect:
(14) Not more than 5 minutes after the completion of the hysteresis test prescribed in paragraph (b)(6)-(13), the reading of the altimeter, corrected for any change in atmospheric pressure, m u s t not differ from the original atmospheric pressure reading by more than the tolerance specified in Table 2:
Friction:
(15) The altimeter must be subjected to a steady rate of decrease of pressure approximating 750 feet per minute.
(16) At each altitude listed in Table 3, the change in reading of the pointers after vibration must not exceed the corresponding tolerance listed in Table 3:
Case leak:
(17) The leakage of the altimeter case, when the pressure within it corresponds to an altitude of 18 000 feet, must not change the altimeter reading by more than the tolerance shown in Table 2 during an interval of 1 minute:
Barometric scale error:
(18) At constant atmospheric pressure, the barometric pressure scale must be set at each of the pressures, falling within its range of adjustment, that are listed in Table 4, and must cause the pointer to indicate the equivalent altitude shown in Table 4 with a tolerance of 25 feet.
(d) Altimeters that are of the air data computer type with associated computing systems, or which incorporate air data correction internally, may be tested in a manner and to specifications developed by the manufacturer.
(a) Each test must be conducted in accordance with paragraph (b).
(b) Measure the automatic pressure altitude at the output of the installed ATC transponder when interrogated on Mode C at a sufficient number of test points, to ensure that the altitude reporting equipment altimeters, and ATC transponders perform their intended functions as installed in the aircraft.
(c) The difference between the automatic reporting output and the altitude displayed at the altimeter must not exceed 125 feet.
Table 1 - Scale error
| Altitude (feet) | Equivalent Pressure (millibars) | Tolerance (± feet) |
|---|---|---|
| -1000 | 1050.406 | 20 |
| 0 | 1013.250 | 20 |
| 500 | 995.075 | 20 |
| 1000 | 977.166 | 20 |
| 1500 | 959.518 | 25 |
| 2000 | 942.129 | 30 |
| 3000 | 908.117 | 30 |
| 4000 | 875.105 | 35 |
| 6000 | 811.996 | 40 |
| 8000 | 752.624 | 60 |
| 10000 | 696.817 | 80 |
| 12000 | 644.408 | 90 |
| 14000 | 595.239 | 100 |
| 16000 | 549.152 | 110 |
| 18000 | 505.998 | 120 |
| 20000 | 465.633 | 130 |
| 22000 | 427.915 | 140 |
| 25000 | 376.009 | 155 |
| 30000 | 300.896 | 180 |
| 35000 | 238.423 | 205 |
| 40000 | 187.539 | 230 |
| 45000 | 147.477 | 255 |
| 50000 | 115.972 | 280 |
Table 2 - Test tolerances
| Test | Tolerance (± feet) |
|---|---|
| Case Leak Test | 100 |
| First test point (50% of maximum altitude) | 75 |
| Second test point (40% of maximum altitude) | 75 |
| After effect test | 30 |
Table 3 - Friction altitude
| Altitude (feet) | Tolerance (± feet) |
|---|---|
| 1000 | 70 |
| 2000 | 70 |
| 3000 | 70 |
| 5000 | 70 |
| 10000 | 80 |
| 15000 | 90 |
| 20000 | 100 |
| 25000 | 120 |
| 30000 | 140 |
| 35000 | 160 |
| 40000 | 180 |
| 50000 | 250 |
Table 4 - Pressure
| Pressure (millibars) | Altitude (feet) |
|---|---|
| 951.55 | -1727 |
| 965.10 | -1340 |
| 982.03 | -863 |
| 998.96 | -392 |
| 1013.25 | 0 |
| 1032.82 | +531 |
| 1046.37 | +893 |
| 1049.41 | +974 |
