Apparatus

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sensors Mode-S transponder

A31A96

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N29991 · BOEING 787-9 Dreamliner · operated by UNITED AIRLINES INC

Hex
A31A96
Octal
50615226
Decimal
10,689,174
Country
US
Tail
N29991
Type
B789
No current signal · last broadcast Jul 26, 19:15 UTC
Flights observed
226
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 19:15 UTC

Last known position

Most recent position reported by Mode-S A31A96.

Country allocation

The ICAO 24-bit address A31A96 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
UAL153 United Airlines 12 2026-05-16
UAL152 United Airlines 12 2026-05-15
UAL178 - 11 2026-07-18
UAL177 - 10 2026-07-18
UAL182 - 9 2026-07-16
UAL263 - 8 2026-07-19
UAL262 United Airlines 8 2026-07-19
UAL761 - 7 2026-07-20
UAL181 United Airlines 7 2026-07-17
UAL143 - 7 2026-07-21
UAL771 United Airlines 6 2026-07-26
UAL29 United Airlines 6 2026-05-25
UAL28 United Airlines 6 2026-05-26
UAL821 United Airlines 5 2026-07-25
UAL142 - 5 2026-07-15
UAL863 United Airlines 4 2026-05-18
UAL772 United Airlines 4 2026-05-14
UAL760 United Airlines 4 2026-07-20
UAL7 - 4 2026-06-17
UAL61 United Airlines 4 2026-05-25

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL771 BNA → ORD Jul 26, 07:00 UTCJul 26, 19:15 UTC12h 15m
2026-07-25 UAL821 SFO → MEX Jul 25, 16:30 UTCJul 26, 03:30 UTC11h 0m
2026-07-25 UAL821 SFO → MEX Jul 25, 14:25 UTCJul 25, 14:40 UTC15m
2026-07-25 UAL821 SFO → MEX Jul 25, 12:05 UTCJul 25, 12:10 UTC5m
2026-07-25 UAL821 SFO → MEX Jul 25, 09:35 UTCJul 25, 10:10 UTC35m
2026-07-25 UAL821 SFO → MEX Jul 25, 09:35 UTCJul 25, 12:07 UTC2h 32m
2026-07-25 UAL820 MEX → SFO Jul 25, 00:13 UTCJul 25, 02:21 UTC2h 8m
2026-07-25 UAL820 MEX → SFO Jul 25, 00:10 UTCJul 25, 00:25 UTC15m
2026-07-24 UAL820 MEX → SFO Jul 24, 07:45 UTCJul 24, 22:10 UTC14h 25m
2026-07-23 UAL199 PVG → LAX Jul 23, 06:25 UTCJul 24, 00:10 UTC17h 45m
2026-07-22 UAL198 LAX → PVG Jul 22, 20:50 UTCJul 23, 14:55 UTC18h 5m
2026-07-22 UAL33 NRT → LAX Jul 22, 12:25 UTCJul 22, 17:40 UTC5h 15m
2026-07-21 UAL143 DEN → NRT Jul 21, 18:04 UTCJul 22, 05:06 UTC11h 2m
2026-07-21 UAL143 - Jul 21, 18:05 UTCJul 21, 20:25 UTC2h 20m
2026-07-20 UAL761 - Jul 20, 14:55 UTCJul 21, 01:05 UTC10h 9m
2026-07-20 UAL761 MUC → DEN Jul 20, 14:46 UTCJul 21, 00:55 UTC10h 9m
2026-07-20 UAL760 DEN → MUC Jul 20, 02:50 UTCJul 20, 12:25 UTC9h 35m
2026-07-19 UAL263 LHR → DEN Jul 19, 14:14 UTCJul 19, 23:09 UTC8h 55m
2026-07-19 UAL263 LHR → DEN Jul 19, 14:20 UTCJul 19, 23:10 UTC8h 50m
2026-07-19 UAL262 DEN → LHR Jul 19, 03:40 UTCJul 19, 12:05 UTC8h 25m
2026-07-18 UAL178 - Jul 18, 15:10 UTCJul 19, 01:25 UTC10h 15m
2026-07-18 UAL177 - Jul 18, 00:39 UTCJul 18, 02:35 UTC1h 55m
2026-07-18 UAL177 DEN → FCO Jul 18, 00:13 UTCJul 18, 10:24 UTC10h 11m
2026-07-17 UAL181 FRA → DEN Jul 17, 10:15 UTCJul 17, 19:40 UTC9h 25m
2026-07-16 UAL182 - Jul 16, 22:40 UTCJul 17, 07:40 UTC9h 0m
2026-07-16 UAL181 FRA → DEN Jul 16, 09:55 UTCJul 16, 19:20 UTC9h 25m
2026-07-15 UAL182 - Jul 15, 22:30 UTCJul 16, 07:20 UTC8h 50m
2026-07-15 UAL142 - Jul 15, 08:05 UTCJul 15, 18:20 UTC10h 15m
2026-07-14 UAL143 DEN → NRT Jul 14, 18:08 UTCJul 15, 05:18 UTC11h 10m
2026-07-14 UAL143 - Jul 14, 18:20 UTCJul 15, 05:20 UTC10h 59m
2026-07-13 UAL761 - Jul 13, 14:50 UTCJul 13, 16:45 UTC1h 55m
2026-07-13 UAL761 MUC → DEN Jul 13, 14:31 UTCJul 14, 00:40 UTC10h 9m
2026-07-13 UAL761 MUC → DEN Jul 13, 14:31 UTCJul 14, 00:39 UTC10h 8m
2026-07-13 UAL760 DEN → MUC Jul 13, 03:01 UTCJul 13, 12:10 UTC9h 10m
2026-07-12 UAL263 LHR → DEN Jul 12, 14:10 UTCJul 12, 23:10 UTC9h 0m
2026-07-12 UAL262 DEN → LHR Jul 12, 02:45 UTCJul 12, 11:06 UTC8h 21m
2026-07-12 UAL262 DEN → LHR Jul 12, 02:45 UTCJul 12, 11:20 UTC8h 35m
2026-07-11 UAL178 - Jul 11, 13:25 UTCJul 11, 23:50 UTC10h 25m
2026-07-11 UAL177 DEN → FCO Jul 11, 00:55 UTCJul 11, 11:00 UTC10h 5m
2026-07-10 UAL26 LHR → DEN Jul 10, 11:05 UTCJul 10, 19:55 UTC8h 50m
2026-07-10 UAL27 DEN → LHR Jul 10, 00:10 UTCJul 10, 08:40 UTC8h 30m
2026-07-09 UAL181 FRA → DEN Jul 9, 10:05 UTCJul 9, 19:30 UTC9h 25m
2026-07-08 UAL182 DEN → FRA Jul 8, 22:18 UTCJul 9, 07:43 UTC9h 25m
2026-07-08 UAL182 - Jul 8, 23:05 UTCJul 8, 23:30 UTC25m
2026-07-08 UAL142 - Jul 8, 08:20 UTCJul 8, 17:30 UTC9h 10m
2026-07-08 UAL142 NRT → DEN Jul 8, 08:15 UTCJul 8, 18:19 UTC10h 4m
2026-07-07 UAL143 DEN → NRT Jul 7, 18:40 UTCJul 8, 05:55 UTC11h 15m
2026-07-06 UAL178 KIX → GUM Jul 6, 12:45 UTCJul 7, 00:15 UTC11h 30m
2026-07-06 UAL177 DEN → FCO Jul 6, 00:50 UTCJul 6, 10:30 UTC9h 40m
2026-07-05 UAL263 - Jul 5, 14:05 UTCJul 5, 22:55 UTC8h 50m

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 N29991 page for operator, model, and routing details .

Mode-S A31A96 frequently asked

What is Mode-S code A31A96?
A31A96 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N29991.
Where is Mode-S A31A96 registered?
Mode-S code A31A96 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 A31A96 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 19:15 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A31A96, octal 50615226, decimal 10,689,174.
What flights does A31A96 operate?
Mode-S A31A96 has broadcast 20 distinct callsigns, including UAL153, UAL152, UAL178, UAL177, UAL182.