Apparatus

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sensors Mode-S transponder

A55D31

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N445AA · AIRBUS A-321neo · operated by AMERICAN AIRLINES INC

Hex
A55D31
Octal
51256461
Decimal
10,837,297
Country
US
Tail
N445AA
Type
A21N
Transponder active on ground
Flights observed
448
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 22:15 UTC

Last known position

Most recent position reported by Mode-S A55D31.

Country allocation

The ICAO 24-bit address A55D31 falls within the block assigned to United States (US) by ICAO Annex 10, Volume III. Every aircraft registered in United States receives a permanent address from this block at the time of registration; the address stays with the airframe even if the aircraft is re-registered to a different operator within the country.

Callsign history 20 distinct

Callsign Airline Flights Last seen
AAL675 - 9 2026-07-03
AAL2585 American Airlines 7 2026-07-25
AAL144 - 7 2026-07-05
AAL3328 American Airlines 5 2026-06-12
AAL3258 American Airlines 5 2026-05-28
AAL2517 American Airlines 5 2026-07-26
AAL2045 American Airlines 5 2026-07-07
AAL1928 - 5 2026-07-08
AAL1524 American Airlines 5 2026-05-28
AAL692 - 4 2026-07-04
AAL3272 American Airlines 4 2026-04-17
AAL3245 American Airlines 4 2026-05-14
AAL3016 - 4 2026-06-21
AAL2888 American Airlines 4 2026-04-16
AAL2838 American Airlines 4 2026-04-23
AAL2793 - 4 2026-04-13
AAL266 American Airlines 4 2026-05-27
AAL246 American Airlines 4 2026-05-19
AAL2277 American Airlines 4 2026-05-08
AAL1580 - 4 2026-07-12

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 AAL2517 LAX → DFW Jul 26, 22:05 UTCJul 26, 22:15 UTC10m
2026-07-26 AAL2517 LAX → DFW Jul 26, 17:10 UTCJul 26, 21:00 UTC3h 50m
2026-07-26 AAL422 DCA → MIA Jul 26, 12:50 UTCJul 26, 14:55 UTC2h 5m
2026-07-25 AAL667 SEA → DFW Jul 25, 22:45 UTCJul 26, 00:50 UTC2h 5m
2026-07-25 AAL1332 DEN → PHX Jul 25, 19:29 UTCJul 25, 20:47 UTC1h 18m
2026-07-25 AAL1332 DEN → PHX Jul 25, 17:00 UTCJul 25, 20:50 UTC3h 50m
2026-07-25 AAL2184 PHL → MIA Jul 25, 12:25 UTCJul 25, 15:00 UTC2h 35m
2026-07-25 AAL2585 SFO → PHX Jul 25, 06:25 UTCJul 25, 10:25 UTC4h 0m
2026-07-25 AAL2923 BOS → LAX Jul 25, 01:30 UTCJul 25, 05:10 UTC3h 40m
2026-07-24 AAL2923 BOS → LAX Jul 24, 20:35 UTCJul 25, 00:05 UTC3h 30m
2026-07-24 AAL2032 PHL → RSW Jul 24, 00:10 UTCJul 24, 01:10 UTC1h 0m
2026-07-23 AAL2031 CLT → LGA Jul 23, 17:40 UTCJul 23, 22:45 UTC5h 5m
2026-07-23 AAL1228 DFW → CLE Jul 23, 12:05 UTCJul 23, 14:05 UTC2h 0m
2026-07-23 AAL1118 DFW → BNA Jul 23, 06:15 UTCJul 23, 10:40 UTC4h 25m
2026-07-22 AAL162 HNL → LAX Jul 22, 22:50 UTCJul 23, 03:35 UTC4h 45m
2026-07-22 AAL31 - Jul 22, 15:20 UTCJul 22, 20:50 UTC5h 30m
2026-07-22 AAL31 LAX → HNL Jul 22, 15:15 UTCJul 22, 20:45 UTC5h 30m
2026-07-21 AAL2160 CUN → LAX Jul 21, 22:28 UTCJul 22, 02:47 UTC4h 19m
2026-07-21 AAL2160 CUN → LAX Jul 21, 22:30 UTCJul 22, 00:15 UTC1h 45m
2026-07-21 AAL2801 LAX → CUN Jul 21, 16:30 UTCJul 21, 21:00 UTC4h 30m
2026-07-21 AAL2801 LAX → CUN Jul 21, 16:26 UTCJul 21, 20:55 UTC4h 29m
2026-07-21 AAL286 PHL → STL Jul 21, 09:10 UTCJul 21, 13:55 UTC4h 45m
2026-07-21 AAL510 PHL → SAN Jul 21, 01:25 UTCJul 21, 06:45 UTC5h 20m
2026-07-20 AAL2031 CLT → LGA Jul 20, 17:35 UTCJul 20, 22:25 UTC4h 50m
2026-07-20 AAL2499 CLT → PHL Jul 20, 14:05 UTCJul 20, 16:10 UTC2h 5m
2026-07-20 AAL2090 MSY → DFW Jul 20, 11:45 UTCJul 20, 12:25 UTC40m
2026-07-20 AAL2090 MSY → DFW Jul 20, 11:45 UTCJul 20, 12:21 UTC36m
2026-07-20 AAL918 - Jul 20, 03:40 UTCJul 20, 04:15 UTC35m
2026-07-20 AAL918 LIM → MIA Jul 20, 03:21 UTCJul 20, 08:43 UTC5h 22m
2026-07-20 AAL918 LIM → MIA Jul 20, 03:21 UTCJul 20, 08:40 UTC5h 19m
2026-07-19 AAL1307 - Jul 19, 22:05 UTCJul 19, 22:15 UTC10m
2026-07-19 AAL1307 - Jul 19, 20:15 UTCJul 19, 20:35 UTC20m
2026-07-19 AAL1307 MIA → LIM Jul 19, 20:13 UTCJul 20, 01:37 UTC5h 24m
2026-07-19 AAL1558 - Jul 19, 12:00 UTCJul 19, 17:00 UTC5h 0m
2026-07-19 AAL385 BOS → DFW Jul 19, 04:11 UTCJul 19, 09:21 UTC5h 10m
2026-07-18 AAL1562 - Jul 18, 23:05 UTCJul 19, 02:15 UTC3h 10m
2026-07-18 AAL1562 BOS → MIA Jul 18, 23:04 UTCJul 19, 02:14 UTC3h 10m
2026-07-18 AAL1564 DFW → SAT Jul 18, 16:10 UTCJul 18, 20:50 UTC4h 40m
2026-07-18 AAL694 - Jul 18, 12:45 UTCJul 18, 14:00 UTC1h 15m
2026-07-18 AAL694 - Jul 18, 08:35 UTCJul 18, 08:50 UTC15m
2026-07-18 AAL297 LAX → HNL Jul 18, 01:34 UTCJul 18, 06:50 UTC5h 16m
2026-07-17 AAL2368 - Jul 17, 22:15 UTCJul 17, 23:10 UTC55m
2026-07-17 AAL2655 - Jul 17, 20:10 UTCJul 17, 21:00 UTC50m
2026-07-17 AAL2655 - Jul 17, 17:44 UTCJul 17, 18:44 UTC1h 0m
2026-07-17 AAL428 - Jul 17, 11:20 UTCJul 17, 15:44 UTC4h 25m
2026-07-17 AAL428 PHL → PHL Jul 17, 10:30 UTCJul 17, 10:50 UTC20m
2026-07-17 - PHL → PHL Jul 17, 09:45 UTCJul 17, 09:50 UTC5m
2026-07-17 AAL2189 - Jul 17, 04:14 UTCJul 17, 05:20 UTC1h 5m
2026-07-16 AAL2529 CLT → SEA Jul 16, 21:46 UTCJul 17, 02:14 UTC4h 28m
2026-07-16 AAL2529 - Jul 16, 21:50 UTCJul 17, 02:15 UTC4h 25m

About Mode-S

A Mode-S transponder code (also called an "ICAO 24-bit address" or "hex code") is a 6-character hexadecimal identifier permanently assigned to an aircraft when it's first registered. Unlike callsigns (which change with each flight) or registrations (which can change if an aircraft is sold internationally), the Mode-S address stays with the airframe for the life of the aircraft in that country.

Every ADS-B transmission from an aircraft includes its Mode-S address, making it the most reliable way to identify a specific airframe. Flight-tracking services like Apparatus use the Mode-S address as the primary key for tying position broadcasts, callsigns, and ownership records together.

Prefer a tail-number view? See the N445AA page for operator, model, and routing details .

Mode-S A55D31 frequently asked

What is Mode-S code A55D31?
A55D31 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N445AA.
Where is Mode-S A55D31 registered?
Mode-S code A55D31 is allocated to United States (US). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is A55D31 broadcasting right now?
Mode-S A55D31 is currently broadcasting from the ground.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A55D31, octal 51256461, decimal 10,837,297.
What flights does A55D31 operate?
Mode-S A55D31 has broadcast 20 distinct callsigns, including AAL675, AAL2585, AAL144, AAL3328, AAL3258.