211 ground to APU power, from APU to engine generators, and during cross-tie switching in all possible combinations.
(b) Verify that simultaneous transmission of ACARS data and VHF voice communication is satisfactory and is free of interference between the two independent VHF systems, considering frequency and VHF antenna isolation. Exercise all possible switching combinations.
(c) If the selective calling system (SELCAL) can be initiated by the ground station via the ACARS data link, demonstrate performance of that function by observing that the cockpit aural and visual indications are proper.
(d) If the flight management system (FMS) data base or operational program can be accessed in flight by ACARS, exercise all interface functions to demonstrate performance of the intended function.
(e) ACARS should not cause interfer ence with the operation of any of the airplane’s radio/navigation systems. Particular attention should also be devoted to noninterference with flight guidance takeoff and approach functions, particularly autoland, since these are likely flight regimes for ACARS transmissions.
(5) SELCAL . Verify performance of intended function of the SELCAL by receipt of VHF and HF (if appropriate) calls from ground stations.
(6) Satellite Communications (SATCOM) . [Reserved]
(7) Portable Battery-Powered Megaphones .
(a) Conduct hearing range and intelligibility tests on the airplane to demonstrate that the amplified speech is heard and clearly understood throughout the interior cabin region served by the megaphones, with the engines off and with all significant conditions associated with an accident (including the presence of passengers and the normally-attendant confusion din) appropriately simulated.
(b) Verify that the megaphone reliably performs its intended function and is designed:
1 For ease of handling, and use, with one hand;
2 With sufficient acoustical feedback suppression; and
3 With a volume control.
c. Procedures - Navigation .
(1) Very High Frequency Omnidirectional Range (VOR) Systems .
(a) These flight tests may be reduced if adequate antenna radiation pattern studies have been made and these studies show the patterns to be without significant holes (with the airplane configurations used in flight, i.e., flaps, landing gear, etc.). Particular note should be made in recognition that certain propeller r.p.m. settings may cause modulation of the course deviation indication (prop-modulation). This information should be presented in the AFM.
1 The airborne VOR system should operate normally with warning flags out of view at all headings of the airplane (wings level) throughout the airspace within 160 NM of the VOR facility (for airplanes to be operated above 18,000 ft.), from the radio line-of-sight altitude to within 90 percent of the maximum altitude for which the airplane is certified or the maximum operating altitude.
2 The accuracy determination should be made such that the indicated reciprocal agrees within 2 degrees. The test should be conducted over at least two known points on the ground such that data are obtained in each quadrant. Data should correlate with the ground calibration and in no case should the absolute error exceed ±6 degrees. There should be no excessive fluctuation in the course deviation indications.
(b) En route Reception. Fly from a VOR facility rated for high altitude along a radial at an altitude of 35,000 ft. (or to within 90 percent of the airplane maximum certificated altitude or the maximum operating altitude) to a range of 160 NM (80 NM for airplanes not to be operated above 18,000 ft.). The VOR warning flag should not come into view, nor should there be deterioration of the station identification signal. The course width should be 20 degrees ±5 degrees (10 degrees either side at the selected radial). If practical, perform an en route segment on a Doppler VOR station to verify the compatibility of the airborne unit. Large errors have been found when incompatibility exists.
(c) Long Range Reception. Perform a right and/or left 360 degree turn at a bankangle of at least 10 degrees, at an altitude just above the radio line-of-sight, and at a distance of at least 160 NM (80 NM for airplanes to be operated below 18,000 ft.) from the VOR facility.
Signal dropout should not occur as evidenced by the malfunction indicator appearance.
Dropouts that are relieved by a reduction of bank angle at the same relative heading to the station are satisfactory. The VOR identification should be satisfactory during the left and right turns.
Skidding turns may be used to minimize turn radius.
(d) High Angle Reception. Repeat the turns described in paragraph (c) above, but at a distance of 50 to 70 NM (20 to 30 NM for airplanes not to be operated above 18,000 ft.)
from the VOR facility and at an altitude of at least 35,000 ft. (or to within 90 percent of the maximum certificated altitude of the airplane or the maximum operating altitude).
(e) En route Station Passage. Verify that the TO-FROM indicator correctly changes as the airplane passes through the cone of confusion above a VOR facility.
(f) VOR Approach. Conduct VOR approach(es) with gear and flaps down. The facility should be 12-15 NM behind the airplane with the approach conducted after a 30 degree
213 radial change over the station. Use sufficient maneuvering in the approach to assure the signal reception is maintained during beam tracking.
(g) EMC should be evaluated with all systems operating in flight, to verify by observation that no adverse effects are present in the required flight systems.
(h) Identifier. The audio identifier should be checked, as should the decoded ident, if equipped with a digital bus.
(i) Station tuning. Evaluate various methods of station tuning, including automatic and manually through a FMS. Also, a check for proper indications for loss of signal or receiver failure should be done.
(2) Localizer Systems .
(a) These flight tests may be reduced if adequate antenna radiation pattern studies have been made, and those studies show the patterns to be without significant holes. A significant hole is one that is greater than 10 decibels (dB) from the average within 30 degrees horizontally and 15 degrees vertically of the nose of the airplane.
1 The signal input to the receiver, presented by the antenna system, should be of sufficient strength to keep the malfunction indicator out of view when the airplane is in the approach configuration (landing gear extended-approach flaps) and at least 25 NM from the station. This signal should be received for 360 degrees of airplane heading at all bank angles up to 10 degrees left or right, at all normal pitch attitudes, and an altitude of approximately 2,000 ft.
2 Satisfactory results should also be obtained at bank angles up to 30 degrees, when the airplane heading is within 60 degrees of the inbound localizer course. Results should be satisfactory with bank angles up to 15 degrees on headings from 60 degrees to 90 degrees of the localizer inbound course, and up to 10 degrees bank angle on headings from 90 degrees to 180 degrees from the localizer inbound course.
3 The deviation indicator should properly direct the airplane back to course when the airplane is right or left of course.
4 The station identification signal should be of adequate strength and sufficiently free from interference to provide positive station identification, and voice signals should be intelligible with all electrical equipment operating and pulse equipment transmitting.
(b) Localizer Intercept. In the approach configuration and at a distance of at least 25 NM from the localizer facility, fly toward the localizer front course, inbound, at an angle of at least 50 degrees. Perform this maneuver from both left and right of the localizer beam. No flags should appear during the time the deviation indicator moves from full deflection to on-course.
(c) Localizer Tracking. While flying the localizer inbound and not more than 5 miles before reaching the outer marker, change the heading of the airplane to obtain full needle
214 deflection; then fly the airplane to establish localizer on-course operation. The localizer deviation indicators should direct the airplane to the localizer on-course. Perform this maneuver with both a left and a right needle deflection. Continue tracking the localizer until over the transmitter. Acceptable front course and back course approaches should be conducted to 200 ft.
or less above the threshold.
(d) Electromagnetic Compatibility (EMC). With all systems operating in flight, verify by observation that no adverse effects are present in the required flight systems.
(3) Glideslope Systems .
(a) These flight tests may be reduced if adequate antenna radiation pattern studies have been made, and those studies show the patterns to be without significant holes. A significant hole is one that is greater than 10 db from the average within 30 degrees horizontally and 15 degrees vertically of the nose of the airplane.
1 The signal input to the receiver should be of sufficient strength to keep the warning flags out of view at all distances up to 10 NM from the final approach fix. This performance should be demonstrated at all airplane headings between 30 degrees right and left of the localizer course. The deviation indicator should properly direct the airplane back to the glideslope path when the airplane is above or below the path.
2 Interference with the navigation operation should not occur with all airplane equipment operating and all pulse equipment transmitting. There should be no interference with other equipment as a result of glideslope operation.
(b) Glideslope Interception. Fly the localizer course inbound, at the altitude at which the glideslope beam intercepts the final approach fix, and at least 10 NM from the fix.
The glideslope deviation indicator should be centered (± 25 percent of full scale) at the final approach fix. There should be no flags from the time the needle leaves the full scale fly-up position until it reaches the full scale fly-down position.
(c) Glideslope Tracking. While tracking the glideslope, maneuver the airplane through normal pitch and roll attitudes. The glideslope deviation indicator should show proper operation with no flags. Acceptable approaches to 100 ft. or less above the threshold should be conducted.
(d) EMC should be evaluated with all systems operating in flight to verify by observation that no adverse effects are present in the required flight systems.
(4) Marker Beacon System .
(a) In low sensitivity, the marker beacon annunciator light should be illuminated for a distance of 2,000 to 3,000 ft. when flying at an altitude of 1,000 ft. on the localizer centerline in all flap and gear configurations.
215 NOTE: An acceptable test to determine dist ances of 2,000 to 3,000 ft. is to fly at a ground speed listed in Table I and time the marker beacon light duration.
Table I
Altitude = 1,000 ft. above ground level (AGL)
Ground Speed (Knots) Light Time (Seconds)
2,000 ft. 3,000 ft.
90 13 20 110 11 16 130 9 14 150 8 12
For ground speeds other than the values in Table 1,the following formulas may be used:
Upper limit 1775Ground Speed in Knots (secs.)
Lower limit 1183Ground Speed in Knots (secs.)
(b) If a high/low sensitivity feature is installed and selected, the marker beacon annunciator light and audio will remain on longer than when in low sensitivity.
(c) The audio signal should be of ad equate strength and sufficiently free from interference to provide positive identification.
(d) As an alternative procedure, cross the outer marker at normal ILS approach altitudes and determine adequate marker aural and visual indication.
(e) Illumination should be adequate in bright sunlight and at night.
(f) EMC should be evaluated with all systems operating in flight to verify by observation that no adverse effects are present in the required flight systems.
(5) Automatic Direction Finder (ADF) System .
(a) Receiving Function. Determine that, when flying toward or away from a station with all required electrical and radio equipment in operation, the average bearing pointer indications are such that they present a usable bearing at the below-listed distances, during daylight hours (between one hour after local sunrise and one hour before local sunset) and when atmospheric disturbances are at a minimum. The amplitude of pointer oscillation is relatively unimportant, provided a valid direction to the station can be determined. At the distances shown
216 below, the tone audio identification of the station to which the receiver is tuned should be intelligible.
(b) General Information.
Classification of LF/MF Radio Beacons in U.S. National Service
C l a s s Power (watts)
Comlo under 25 MH under 50 H 50-1999 HH 2000 or more
Facility Range Compass Locators 15 Nautical miles Transmitters <50 watts 25 Nautical miles Transmitters 100-200 watts 50 Nautical miles Transmitters 200-400 watts 60 Nautical miles Transmitters over 400 watts 75 Nautical miles
NOTE: In areas where the known service range is less than the above distances, the actual shorter range may be used. It is advisable to ascertain the operating status of the facility to be used, prior to flight testing.
(c) Pointer Reversal. While flying the airplane directly over a properly operating ground-based station, note the airplane’s altitude and measure the complete pointer reversal time by using a stopwatch. Using the airplane’s true ground speed and the airplane’s altitude, determine that the pointer reversal occurred within a circular area centered over the station, having a radius equal to the altitude being flown. Partial reversals that lead or lag the main reversal are permissible.
(d) Bearing Accuracy. Using a properly operating directional gyro, and a ground checkpoint whose location is known with respect to the ground-based station to which the ADF is tuned, fly the airplane over the ground checkpoint at a minimum of six airplane headings (relative to the station to which the ADF is tuned), including headings of 0 degrees, 180 degrees, and headings 15 degrees each side thereof. Determine that the compensated or otherwise corrected ADF bearing indication is not in error by more than ±5 degrees at any of the six headings. Repeat the foregoing procedure but fly at a minimum of six headings relative to the ground based station, including 45 degrees, 90 degrees, 135 degrees, 225 degrees, 270 degrees, and 315 degrees. In this case, the compensated or otherwise corrected bearing indication should not be in error by more than ±10 degrees at any of these six headings.
217 NOTE: The distance between the ground checkpoint and the ground-based station used should be at least one-half of the service range of that station.
(e) Indicator Response. With the ADF indicating station dead ahead, switch to a station having a relative bearing of 175 degrees. The indicator should indicate within ±3 degrees of the bearing in not more than 10 seconds.
(f) Antenna Mutual Interaction. If the ADF installation being tested is dual, check for coupling between the antennas by using the following procedures.
1 With #1 ADF receiver tuned to a station near the low end of the ADF band, tune the #2 receiver slowly throughout the frequency range of all bands and determine whether the #1 ADF indicator is adversely affected.
2 Repeat 1 with the #1 ADF receiver tuned to a station near the high end of the ADF band.
(g) EMC should be evaluated with all systems operating in flight, to verify by observation that no adverse effects are present in the required flight systems.
(h) Precipitation Static. The effect of precipitation static should be considered.
This type of static is normally found in areas of high cirrus clouds, dry snow, dust storms, etc.
(6) Distance Measuring Equipment (DME) .
(a) Airplanes to be operated above 18,000 ft. The DME system should continue to track without dropouts when the airplane is maneuvered throughout the airspace within 160 NM of the VORTAC station and at altitudes above radio line-of-sight up to the maximum altitude for which the airplane is certificated. This tracking standard should be met with the airplane:
1 In cruise configuration.
2 At bank angles up to 10 degrees (skidding turns may be used to minimize turn radius).
3 Climbing and descending at normal maximum climb and descent attitudes.
4 Orbiting a DME facility.
5 Providing clearly intelligible (visual/aural) identification of the DME facility.
(b) Airplanes to be operated at altitudes below 18,000 ft. The DME system should perform as specified in paragraph (a) above, except that the maximum distance from the DME facility need not exceed 80 NM.
(c) Climb and Maximum Distance. Determine that there is no mutual interference between the DME system and other equipment aboard the airplane. Beginning at a distance of at least 10 NM from a DME facility and at an altitude of 2,000 ft. above the DME facility, fly the airplane on a heading so it will pass over the facility. At a distance of 5 to 10 NM beyond the DME facility, operate the airplane at its normal maximum climb attitude, up to an altitude of 35,000 ft. or to within 90 percent of the maximum certificated altitude, maintaining the airplane on a station radial (within 5 degrees). The DME should continue to track with no unlocks to a range of 160 NM (80 NM for airplanes not to be operated at altitudes above 18,000 ft.).
(d) Long Range Reception. Perform two 360 degree turns, one to the right and one to the left, at a bank angle of 8 to 10 degrees at not less than 160 NM (80 NM for airplanes not to be operated above 18,000 ft.) from the DME facility. A single turn will be sufficient if the antenna installation is symmetrical. There should be no more than one unlock, not to exceed one search cycle (maximum 35 seconds) in any five miles of radial flight. Tests may be conducted up to a maximum certificated altitude.
(e) High Angle Reception. Repeat the flight pattern and observations of paragraph (d) above at a distance of 50-70 NM (20 to 30 NM for airplanes not to be operated above 18,000 ft.) from the DME facility and at an altitude of at least 35,000 ft. (or to within 90 percent of the maximum altitude for which the airplane is certificated or the maximum operating altitude).
(f) Penetration. From an altitude of at least 35,000 ft. (or the airplane maximum altitude, if lower), perform a letdown directly toward the ground station using normal maximum rate of descent procedures to a DME facility, so as to reach an altitude of 5,000 ft. above the DME facility 5 to 10 NM before reaching the DME facility. The DME should continue to track during the maneuver with no unlocks.
(g) Orbiting. At an altitude of 2,000 ft. above the terrain, at holding pattern speeds appropriate for the type of airplane and with the landing gear extended, fly at least 15 degree sectors of left and right 35 NM orbital patterns around the DME facility. The DME should continue to track with no more than one unlock, not to exceed one search cycle, in any 5 miles of orbited flight.
(h) Approach. Make a normal approach to a field with a DME. The DME should track without an unlock (station passage excepted).
(i) EMC should be evaluated with all systems operating in flight to verify by prior observation that no adverse effects are present in the required flight systems.
(7) Transponder Equipment .
(a) The air traffic control (ATC) transponder system should furnish a strong and stable return signal to the interrogating radar facility when the airplane is flown in straight and level flight throughout the airspace within 160 NM of the radar station, from radio line-of-sight to within 90 percent of the maximum altitude for which the airplane is certificated or to the maximum operating altitude. Airplanes to be operated at altitudes not exceeding 18,000 ft.
should meet the above requirements to only 80 NM.
(b) When the airplane is flown in the following maneuvers within the airspace described above, the dropout time should not exceed 36 seconds:
1 In turns at bank angles up to 10 degrees (skidding turns may be used to minimize turn radius).
2 Climbing and descending at typical climb and descent attitudes.
(c) Climb and Distance Coverage.
1 Beginning at a distance of at least 10 NM from, and at an altitude of 2,000 ft. above that of the radar facility, and using a transponder code assigned by the air route traffic control center (ARTCC), fly on a heading that will pass the airplane over the facility.
Operate the airplane at its normal maximum climb attitude up to within 90 percent of the maximum altitude for which the airplane is certificated, or to a maximum operating altitude, maintaining the airplane at a heading within five degrees from the radar facility. After reaching the maximum altitude for which the airplane is certificated, fly level at the maximum altitude to 160 NM (or 80 NM for airplanes to be operated below 18,000 ft.) from the radar facility.
2 Communicate with the ground radar personnel for evidence of transponder dropout. During the flight, check the “ident” mode of the ATC transponder to assure that it is performing its intended function. Determine that the transponder system does not interfere with other systems aboard the airplane and that other equipment does not interfere with the operation of the transponder system. There should be no dropouts, that is, when there is no return for two or more sweeps. If ring-around, spoking, or clutter appears on the ground radar scope, the airplane should switch to “low” sensitivity to reduce the interference. Uncontrollable ringing that hinders use of the ground radar should be considered unsatisfactory.
(d) Long Range Reception. At 90 percent of maximum certificated altitude, perform two 360 degree turns, one to the right and one to the left, at bank angles of 8 degrees and 10 degrees with the flight pattern at least 160 NM (or 80 NM for airplanes to be operated below 18,000 ft.) from the radar facility. During these turns, the radar display should be monitored and there should be no signal dropouts (two or more sweeps). (Airspeed adjustments may be made to reduce turn radius.)
(e) High Angle Reception. Repeat the flight pattern and observations of paragraph (d), above, at a distance of 50 to 70 NM from the radar facility and at an altitude of at least 35,000 ft. or within 90 percent of the maximum altitude for which the airplane is certificated or the maximum operating altitude. There should be no dropout (two or more
220 sweeps). Switch the transponder to a code not selected by the ground controller. The airplane secondary return should disappear from the scope. The controller should then change his control box to a common system and a single slash should appear on the scope at the airplane’s position.
If a problem surfaces, a placard so noting should be required.
(f) High Altitude Cruise. Fly the airplane within 90 percent of its maximum certificated altitude or its maximum operating altitude beginning at a point 160 NM (or 80 NM for airplanes to be operated below 18,000 ft.) from the radar facility on a course that will pass over the radar facility. There should be no transponder dropouts (two or more sweeps) or “ringaround,” except when station passage occurs or when known site features produce anomalies.
(g) Holding and Orbiting Patterns.
1 At an altitude of 2,000 feet or minimum obstruction clearance altitude (whichever is greater) above the radar antenna, and at holding pattern speeds, flaps and gear extended, fly one each standard rate 360 degree turn, right and left, at a distance of approximately 10 NM from the air route surveillance radar (ARSR) or airport surveillance radar (ASR) facility. There should be no signal dropout (two or more sweeps).
2 At an altitude of 2,000 feet or minimum obstruction clearance altitude (whichever is greater) above the radar antenna and at holding pattern speeds appropriate for the type of airplane, fly a 45 degree segment of a 10 NM orbit centered on the radar facility with gear and flaps extended. There should be no signal dropout (two or more sweeps).
(h) Surveillance Approach. From an a ltitude of 35,000 feet or within 90 percent of the maximum certificated altitude of the airplane or the maximum operating altitude, whichever is less, perform a letdown and approach to a runway of an airport served by ASR having an air traffic control radar beacon system (ATCRBS) facility. Alternately, a simulated approach and letdown may be made along a path parallel to, but separated three to four miles from, a vertical plane through the location of an ARSR facility. The approach should be made at the maximum normal rate of descent and in the normal approach and landing configuration for the airplane, and should continue down to an altitude of 200 feet or less above the ground radar antenna elevation. Not more than one dropout should occur for any 10 sweeps during final approach; if ring-around occurs, the flightcrew should reduce the sensitivity and the ring-around should cease.
(i) Altitude Reporting. Conduct a functional test of the altitude encoder (transponder Mode C) by comparison with ATC-displayed altitudes. Verify correspondence at several altitudes between ATC readings and the captain’s altimeter, when set at or corrected to
29.92 inches of mercury.
NOTE: Throughout all tests, verify self-test function and radar interrogation reply light.
(j) EMC should be evaluated with all systems operating in flight to verify by observation that no adverse effects are present in the required flight systems.
(8) Weather Radar System .
(a) Warm-up Period (if applicable.) All tests should be conducted after the manufacturer’s specified warm-up period.
(b) Display. Check that the scope trace and sweep display move smoothly and are without gaps or objectionable variations in intensity. For color displays, verify appropriate colors and color contrast.
(c) Range Capabilities. While maintaining level flight at 90 percent of maximum approved altitude of the airplane, set the radar controls so that large radar-identifiable objects such as mountains, lakes, rivers, coastlines, storm fronts, turbulence, etc., are displayed on the radar scope. Objects should be displayed at the maximum range specified by the manufacturer.
Maneuver the airplane and adjust the radar controls so that tests may be conducted for the range requirements. The radar should be capable of displaying line-of-sight known prominent targets.
(d) Beam Tilting and Structural Clearance.
1 With the airplane maintained in level flight, adjust the radar controls so that large radar-identifiable targets appear on the radar scope when the antenna tilt control is adjusted for zero degrees. Maneuver the airplane so that an appropriate target appears at the dead ahead (0 degrees) bearing position. Slowly change the tilt control through an appropriate range and observe that the radar scope presentation does not change erratically, which might indicate structural interference between the radome and antenna. This interference should not occur throughout the operational speed envelope of the airplane.
2 Bearing Accuracy. Fly under conditions that allow visual identification of a target, such as an island, a river, or a lake, at a range within the range of the radar. When flying toward the target, select a course from the reference point to the target and determine the error in the displayed bearing to the target on all range settings. Change the heading of the airplane in increments of 10 degrees to ±30 degrees maximum and verify the error does not exceed ±5 degrees maximum in the displayed bearing to the target.
(e) Stability. While observing a target return on the radar indicator, turn off the stabilizing function and put the airplane through pitch and roll movements. Observe the blurring of the display. Turn the stabilizing mechanism on and repeat the roll and pitch movements.
Evaluate the effectiveness of the stabilizing function in maintaining a sharp display.
(f) Contour Display (Iso Echo).
1 If heavy cloud formations or rainstorms are reported within a reasonable distance from the test base, select the contour display mode. The radar should differentiate between heavy and light precipitation.
222 2 In the absence of the above weather conditions, determine the effectiveness of the contour display function by switching from normal to contour display while observing large objects of varying brightness on the indicator. The brightest object should become the darkest when switching from normal to contour mode.
(g) Antenna Stability When Installed. While in level flight at 10,000 feet or higher, adjust the tilt approximately 2-3 degrees above the point where ground return was eliminated. Put the airplane through down pitch, then roll movements. No ground return should be present.
NOTE: Roll right and left approximately 15 degrees; pitch nose down approximately 10 degrees.
(h) Ground Mapping. Fly over areas containing large, easily identifiable landmarks such as rivers, towns, islands, coastlines, etc. Compare the form of these objects on the indicator with their actual shape as visually observed from the cockpit.
(i) Mutual Interference. Determine that no objectionable interference is present on the radar indicator from any electrical or radio/navigational equipment, when operating, and that the radar installation does not interfere with the operation of any other equipment.
Particular attention should be devoted to radar effect on electronic display systems and on localizer, glideslope, and ADF signals during approach to landing.
(j) EMC should be evaluated with all systems operating in flight to verify by observation that no adverse effects are present in the required flight systems.
(9) Inertial Navigation System (INS) .
(a) AC 25-4, “Inertial Navigation System,” dated February 16, 1966, contains the basic criteria for the engineering evaluation of an inertial navigation system and offers acceptable means of compliance with the applicable regulations that contain mandatory requirements in an objective form. The engineering evaluation of an INS should also include awareness of AC 121-13, Change 2 “Self-Contained Navigation Systems (Long Range),” dated December 21, 1970, which presents criteria to be met before an operator can obtain operational approval. For flights up to 10 hours, the radial error should not exceed 2 nautical miles per hour of operation on a 95 percent statistical basis. For flights longer than 10 hours, the error should not exceed ±20 NM cross-track or ±25 NM along-track error. A two nautical mile radial error is represented by a circle, having a radius of two nautical miles, centered on the selected destination point. For airplanes intended for air carrier operation, reference should be made to appendix G to part 121 of the CFR.
(b) The INS equipment supplier, through the applicant, will generally provide system reliability data sufficient so that additional testing for equipment reliability demonstration will not be required. Assuming adequate cooling is available for the installation, the data can be considered independent of which type of airplane was used for derivation.