Apparatus

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sensors Mode-S transponder

A31A7B

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N29989 · BOEING 787-9 Dreamliner · operated by UNITED AIRLINES INC

Hex
A31A7B
Octal
50615173
Decimal
10,689,147
Country
US
Tail
N29989
Type
B789
No current signal · last broadcast Jul 26, 09:30 UTC
Flights observed
229
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 09:30 UTC

Last known position

Most recent position reported by Mode-S A31A7B.

Country allocation

The ICAO 24-bit address A31A7B 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
UAL821 - 13 2026-06-22
UAL820 - 10 2026-06-22
UAL2222 - 10 2026-07-18
UAL1122 - 10 2026-07-18
UAL761 United Airlines 7 2026-07-23
UAL839 - 6 2026-06-28
UAL713 - 6 2026-06-16
UAL61 - 6 2026-06-16
UAL6 United Airlines 6 2026-07-25
UAL181 United Airlines 6 2026-05-23
UAL178 United Airlines 6 2026-07-22
UAL143 United Airlines 6 2026-07-24
UAL842 - 5 2026-06-28
UAL760 United Airlines 5 2026-07-23
UAL62 United Airlines 5 2026-07-26
UAL60 - 5 2026-06-15
UAL27 United Airlines 5 2026-07-21
UAL262 United Airlines 5 2026-05-27
UAL26 United Airlines 5 2026-07-21
UAL187 - 5 2026-07-16

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL62 IAH → GRU Jul 26, 00:05 UTCJul 26, 09:30 UTC9h 26m
2026-07-25 UAL6 NRT → IAH Jul 25, 08:20 UTCJul 25, 19:50 UTC11h 30m
2026-07-24 UAL143 DEN → NRT Jul 24, 18:00 UTCJul 25, 05:10 UTC11h 10m
2026-07-23 UAL761 MUC → DEN Jul 23, 14:31 UTCJul 24, 01:07 UTC10h 36m
2026-07-23 UAL761 MUC → DEN Jul 23, 14:31 UTCJul 24, 01:02 UTC10h 31m
2026-07-23 UAL760 DEN → MUC Jul 23, 03:05 UTCJul 23, 12:20 UTC9h 15m
2026-07-22 UAL178 KIX → GUM Jul 22, 12:45 UTCJul 22, 23:35 UTC10h 50m
2026-07-22 UAL178 KIX → GUM Jul 22, 12:47 UTCJul 22, 23:57 UTC11h 10m
2026-07-22 UAL177 GUM → KIX Jul 22, 00:20 UTCJul 22, 02:10 UTC1h 50m
2026-07-21 UAL26 LHR → DEN Jul 21, 11:15 UTCJul 21, 20:05 UTC8h 50m
2026-07-21 UAL27 DEN → LHR Jul 21, 00:45 UTCJul 21, 09:00 UTC8h 15m
2026-07-20 UAL26 LHR → DEN Jul 20, 11:05 UTCJul 20, 20:00 UTC8h 55m
2026-07-20 UAL122 IAD → LHR Jul 20, 07:25 UTCJul 20, 07:50 UTC25m
2026-07-20 UAL122 IAD → LHR Jul 20, 01:25 UTCJul 20, 07:20 UTC5h 55m
2026-07-18 UAL2222 CPT → EWR Jul 18, 18:12 UTCJul 19, 08:26 UTC14h 14m
2026-07-18 UAL2222 CPT → EWR Jul 18, 18:12 UTCJul 19, 08:32 UTC14h 20m
2026-07-18 UAL2222 - Jul 18, 17:50 UTCJul 18, 18:10 UTC20m
2026-07-18 UAL1122 - Jul 18, 14:30 UTCJul 18, 14:45 UTC15m
2026-07-18 UAL1122 EWR → CPT Jul 18, 00:56 UTCJul 18, 14:43 UTC13h 47m
2026-07-18 UAL1122 - Jul 18, 01:10 UTCJul 18, 01:45 UTC35m
2026-07-16 UAL187 JNB → EWR Jul 16, 20:19 UTCJul 17, 10:45 UTC14h 26m
2026-07-16 UAL187 - Jul 16, 20:00 UTCJul 16, 20:25 UTC25m
2026-07-16 UAL188 - Jul 16, 02:10 UTCJul 16, 16:15 UTC14h 5m
2026-07-15 UAL3906 - Jul 15, 22:45 UTCJul 15, 23:15 UTC30m
2026-07-15 UAL3906 - Jul 15, 14:05 UTCJul 15, 22:45 UTC8h 40m
2026-07-15 UAL3906 - Jul 15, 13:10 UTCJul 15, 13:15 UTC5m
2026-07-15 UAL3906 GIG → EWR Jul 15, 13:15 UTCJul 15, 22:28 UTC9h 13m
2026-07-03 UAL3940 ORD → GIG Jul 3, 11:33 UTCJul 3, 20:52 UTC9h 19m
2026-07-03 UAL3940 - Jul 3, 11:10 UTCJul 3, 20:50 UTC9h 40m
2026-07-02 UAL908 AMS → ORD Jul 2, 16:15 UTCJul 3, 00:25 UTC8h 10m
2026-07-02 UAL908 AMS → ORD Jul 2, 15:50 UTCJul 3, 00:10 UTC8h 20m
2026-07-02 UAL909 ORD → AMS Jul 2, 05:45 UTCJul 2, 12:45 UTC7h 0m
2026-07-01 UAL3940 ORD → GIG Jul 1, 05:29 UTCJul 1, 07:20 UTC1h 51m
2026-07-01 UAL3940 - Jul 1, 05:10 UTCJul 1, 07:20 UTC2h 10m
2026-06-30 UAL2096 LAX → EWR Jun 30, 15:40 UTCJun 30, 20:05 UTC4h 25m
2026-06-30 UAL2096 LAX → EWR Jun 30, 15:41 UTCJun 30, 20:10 UTC4h 29m
2026-06-28 UAL842 - Jun 28, 23:54 UTCJun 29, 12:49 UTC12h 55m
2026-06-28 UAL839 - Jun 28, 06:40 UTCJun 28, 07:05 UTC25m
2026-06-28 UAL839 LAX → SYD Jun 28, 06:09 UTCJun 28, 21:03 UTC14h 54m
2026-06-27 UAL935 - Jun 27, 12:39 UTCJun 27, 23:04 UTC10h 25m
2026-06-27 UAL923 - Jun 27, 09:15 UTCJun 27, 09:34 UTC20m
2026-06-26 UAL923 - Jun 26, 23:09 UTCJun 27, 02:20 UTC3h 10m
2026-06-26 UAL923 LAX → LHR Jun 26, 22:53 UTCJun 27, 08:58 UTC10h 5m
2026-06-26 UAL153 HKG → LAX Jun 26, 05:19 UTCJun 26, 18:04 UTC12h 45m
2026-06-25 UAL152 LAX → HKG Jun 25, 15:20 UTCJun 25, 15:34 UTC15m
2026-06-25 UAL152 LAX → HKG Jun 25, 12:10 UTCJun 25, 12:25 UTC15m
2026-06-24 UAL152 LAX → HKG Jun 24, 22:25 UTCJun 25, 11:39 UTC13h 15m
2026-06-23 UAL842 SYD → LAX Jun 23, 23:51 UTCJun 24, 12:49 UTC12h 58m
2026-06-23 UAL842 - Jun 23, 23:59 UTCJun 24, 00:55 UTC55m
2026-06-23 UAL839 - Jun 23, 06:34 UTCJun 23, 06:59 UTC25m

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 N29989 page for operator, model, and routing details .

Mode-S A31A7B frequently asked

What is Mode-S code A31A7B?
A31A7B is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N29989.
Where is Mode-S A31A7B registered?
Mode-S code A31A7B 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 A31A7B broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 09:30 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A31A7B, octal 50615173, decimal 10,689,147.
What flights does A31A7B operate?
Mode-S A31A7B has broadcast 20 distinct callsigns, including UAL821, UAL820, UAL2222, UAL1122, UAL761.