Appendix F to Part 43 - ATC Transponder Tests and Inspections
14:1.0.1.3.22.0.283.14.50 : Appendix F
Appendix F to Part 43 - ATC Transponder Tests and Inspections
The ATC transponder tests required by § 91.413 of this chapter
may be conducted using a bench check or portable test equipment and
must meet the requirements prescribed in paragraphs (a) through (j)
of this appendix. If portable test equipment with appropriate
coupling to the aircraft antenna system is used, operate the test
equipment for ATCRBS transponders at a nominal rate of 235
interrogations per second to avoid possible ATCRBS interference.
Operate the test equipment at a nominal rate of 50 Mode S
interrogations per second for Mode S. An additional 3 dB loss is
allowed to compensate for antenna coupling errors during receiver
sensitivity measurements conducted in accordance with paragraph
(c)(1) when using portable test equipment.
(a) Radio Reply Frequency:
(1) For all classes of ATCRBS transponders, interrogate the
transponder and verify that the reply frequency is 1090 ±3
Megahertz (MHz).
(2) For classes 1B, 2B, and 3B Mode S transponders, interrogate
the transponder and verify that the reply frequency is 1090 ±3
MHz.
(3) For classes 1B, 2B, and 3B Mode S transponders that
incorporate the optional 1090 ±1 MHz reply frequency, interrogate
the transponder and verify that the reply frequency is correct.
(4) For classes 1A, 2A, 3A, and 4 Mode S transponders,
interrogate the transponder and verify that the reply frequency is
1090 ±1 MHz.
(b) Suppression: When Classes 1B and 2B ATCRBS Transponders, or
Classes 1B, 2B, and 3B Mode S transponders are interrogated Mode
3/A at an interrogation rate between 230 and 1,000 interrogations
per second; or when Classes 1A and 2A ATCRBS Transponders, or
Classes 1B, 2A, 3A, and 4 Mode S transponders are interrogated at a
rate between 230 and 1,200 Mode 3/A interrogations per second:
(1) Verify that the transponder does not respond to more than 1
percent of ATCRBS interrogations when the amplitude of P2 pulse is
equal to the P1 pulse.
(2) Verify that the transponder replies to at least 90 percent
of ATCRBS interrogations when the amplitude of the P2 pulse is 9 dB
less than the P1 pulse. If the test is conducted with a radiated
test signal, the interrogation rate shall be 235 ±5 interrogations
per second unless a higher rate has been approved for the test
equipment used at that location.
(c) Receiver Sensitivity:
(1) Verify that for any class of ATCRBS Transponder, the
receiver minimum triggering level (MTL) of the system is −73 ±4
dbm, or that for any class of Mode S transponder the receiver MTL
for Mode S format (P6 type) interrogations is −74 ±3 dbm by use of
a test set either:
(i) Connected to the antenna end of the transmission line;
(ii) Connected to the antenna terminal of the transponder with a
correction for transmission line loss; or
(iii) Utilized radiated signal.
(2) Verify that the difference in Mode 3/A and Mode C receiver
sensitivity does not exceed 1 db for either any class of ATCRBS
transponder or any class of Mode S transponder.
(d) Radio Frequency (RF) Peak Output Power:
(1) Verify that the transponder RF output power is within
specifications for the class of transponder. Use the same
conditions as described in (c)(1)(i), (ii), and (iii) above.
(i) For Class 1A and 2A ATCRBS transponders, verify that the
minimum RF peak output power is at least 21.0 dbw (125 watts).
(ii) For Class 1B and 2B ATCRBS Transponders, verify that the
minimum RF peak output power is at least 18.5 dbw (70 watts).
(iii) For Class 1A, 2A, 3A, and 4 and those Class 1B, 2B, and 3B
Mode S transponders that include the optional high RF peak output
power, verify that the minimum RF peak output power is at least
21.0 dbw (125 watts).
(iv) For Classes 1B, 2B, and 3B Mode S transponders, verify that
the minimum RF peak output power is at least 18.5 dbw (70
watts).
(v) For any class of ATCRBS or any class of Mode S transponders,
verify that the maximum RF peak output power does not exceed 27.0
dbw (500 watts).
Note:
The tests in (e) through (j) apply only to Mode S
transponders.
(e) Mode S Diversity Transmission Channel Isolation: For any
class of Mode S transponder that incorporates diversity operation,
verify that the RF peak output power transmitted from the selected
antenna exceeds the power transmitted from the nonselected antenna
by at least 20 db.
(f) Mode S Address: Interrogate the Mode S transponder and
verify that it replies only to its assigned address. Use the
correct address and at least two incorrect addresses. The
interrogations should be made at a nominal rate of 50
interrogations per second.
(g) Mode S Formats: Interrogate the Mode S transponder with
uplink formats (UF) for which it is equipped and verify that the
replies are made in the correct format. Use the surveillance
formats UF = 4 and 5. Verify that the altitude reported in the
replies to UF = 4 are the same as that reported in a valid ATCRBS
Mode C reply. Verify that the identity reported in the replies to
UF = 5 are the same as that reported in a valid ATCRBS Mode 3/A
reply. If the transponder is so equipped, use the communication
formats UF = 20, 21, and 24.
(h) Mode S All-Call Interrogations: Interrogate the Mode S
transponder with the Mode S-only all-call format UF = 11, and the
ATCRBS/Mode S all-call formats (1.6 microsecond P4 pulse) and
verify that the correct address and capability are reported in the
replies (downlink format DF = 11).
(i) ATCRBS-Only All-Call Interrogation: Interrogate the Mode S
transponder with the ATCRBS-only all-call interrogation (0.8
microsecond P4 pulse) and verify that no reply is generated.
(j) Squitter: Verify that the Mode S transponder generates a
correct squitter approximately once per second.
(k) Records: Comply with the provisions of § 43.9 of this
chapter as to content, form, and disposition of the records.
[Amdt. 43-26, 52 FR 3390, Feb. 3, 1987; 52 FR 6651, Mar. 4, 1987,
as amended by Amdt. 43-31, 54 FR 34330, Aug. 18, 1989]