Apparatus

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sensors Mode-S transponder

A31961

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N29907 · BOEING 787-8 Dreamliner · operated by UNITED AIRLINES INC

Hex
A31961
Octal
50614541
Decimal
10,688,865
Country
US
Tail
N29907
Type
B788
Broadcasting now · callsign UAL980 · 36,975 ft
Flights observed
221
Distinct callsigns
20
Country
US
Last broadcast
13d ago

Current position

A31961 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A31961 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
UAL952 United Airlines 21 2026-07-18
UAL980 United Airlines 18 2026-07-25
UAL981 United Airlines 16 2026-07-25
UAL953 United Airlines 15 2026-07-25
UAL770 United Airlines 14 2026-07-24
UAL108 - 11 2026-07-09
UAL612 - 10 2026-06-15
UAL415 United Airlines 10 2026-04-28
UAL613 United Airlines 9 2026-06-15
UAL109 United Airlines 8 2026-07-26
UAL996 - 7 2026-07-03
UAL992 United Airlines 7 2026-07-05
UAL769 United Airlines 7 2026-07-24
UAL991 - 6 2026-07-05
UAL983 - 6 2026-07-01
UAL982 - 6 2026-06-30
UAL908 - 6 2026-07-12
UAL997 - 5 2026-07-04
UAL909 - 5 2026-07-12
UAL202 - 5 2026-06-20

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL109 EDI → EWR Jul 26, 10:25 UTCJul 26, 19:00 UTC8h 35m
2026-07-25 UAL953 ORD → MUC Jul 25, 23:40 UTCJul 26, 07:30 UTC7h 51m
2026-07-25 UAL981 DUB → ORD Jul 25, 10:55 UTCJul 25, 18:20 UTC7h 25m
2026-07-25 UAL981 DUB → ORD Jul 25, 10:53 UTCJul 25, 18:02 UTC7h 9m
2026-07-25 UAL980 ORD → DUB Jul 25, 01:55 UTCJul 25, 08:15 UTC6h 20m
2026-07-25 UAL980 ORD → DUB Jul 25, 01:58 UTCJul 25, 08:19 UTC6h 21m
2026-07-24 UAL770 IAH → EWR Jul 24, 22:25 UTCJul 24, 22:30 UTC5m
2026-07-24 UAL770 IAH → EWR Jul 24, 13:40 UTCJul 24, 22:15 UTC8h 35m
2026-07-24 UAL770 IAH → EWR Jul 24, 13:46 UTCJul 24, 22:08 UTC8h 22m
2026-07-24 UAL769 BDL → ORD Jul 24, 03:15 UTCJul 24, 11:25 UTC8h 10m
2026-07-23 UAL981 DUB → ORD Jul 23, 11:10 UTCJul 23, 18:35 UTC7h 25m
2026-07-23 UAL980 ORD → DUB Jul 23, 01:55 UTCJul 23, 04:15 UTC2h 20m
2026-07-23 UAL980 ORD → DUB Jul 23, 01:58 UTCJul 23, 08:26 UTC6h 28m
2026-07-22 UAL981 DUB → ORD Jul 22, 11:15 UTCJul 22, 18:05 UTC6h 50m
2026-07-22 UAL980 ORD → DUB Jul 22, 02:05 UTCJul 22, 03:30 UTC1h 25m
2026-07-22 UAL980 ORD → DUB Jul 22, 02:13 UTCJul 22, 08:36 UTC6h 23m
2026-07-19 UAL981 DUB → ORD Jul 19, 11:00 UTCJul 19, 18:05 UTC7h 5m
2026-07-19 UAL980 ORD → DUB Jul 19, 01:58 UTCJul 19, 08:22 UTC6h 24m
2026-07-19 UAL980 ORD → DUB Jul 19, 01:40 UTCJul 19, 02:15 UTC35m
2026-07-18 UAL952 MUC → ORD Jul 18, 09:55 UTCJul 18, 18:50 UTC8h 55m
2026-07-17 UAL953 ORD → MUC Jul 17, 23:25 UTCJul 18, 07:20 UTC7h 56m
2026-07-17 UAL981 DUB → ORD Jul 17, 12:10 UTCJul 17, 19:15 UTC7h 5m
2026-07-17 UAL980 ORD → DUB Jul 17, 03:05 UTCJul 17, 09:50 UTC6h 45m
2026-07-16 UAL952 - Jul 16, 09:55 UTCJul 16, 18:25 UTC8h 30m
2026-07-15 UAL953 - Jul 15, 23:25 UTCJul 16, 07:25 UTC8h 0m
2026-07-15 UAL981 - Jul 15, 10:55 UTCJul 15, 17:55 UTC7h 0m
2026-07-15 UAL980 - Jul 15, 01:45 UTCJul 15, 03:00 UTC1h 15m
2026-07-15 UAL980 ORD → DUB Jul 15, 01:58 UTCJul 15, 08:26 UTC6h 28m
2026-07-14 UAL770 BCN → ORD Jul 14, 13:25 UTCJul 14, 22:00 UTC8h 35m
2026-07-14 UAL769 - Jul 14, 03:10 UTCJul 14, 11:20 UTC8h 10m
2026-07-13 UAL981 - Jul 13, 10:45 UTCJul 13, 16:15 UTC5h 30m
2026-07-13 UAL981 DUB → ORD Jul 13, 10:53 UTCJul 13, 17:37 UTC6h 44m
2026-07-13 UAL980 - Jul 13, 01:35 UTCJul 13, 08:20 UTC6h 45m
2026-07-12 UAL908 - Jul 12, 10:15 UTCJul 12, 18:10 UTC7h 55m
2026-07-12 UAL909 ORD → AMS Jul 12, 00:27 UTCJul 12, 07:25 UTC6h 58m
2026-07-12 UAL909 - Jul 12, 00:05 UTCJul 12, 02:01 UTC1h 55m
2026-07-11 UAL981 DUB → ORD Jul 11, 11:10 UTCJul 11, 18:15 UTC7h 5m
2026-07-11 UAL981 DUB → ORD Jul 11, 10:53 UTCJul 11, 17:56 UTC7h 3m
2026-07-11 UAL980 - Jul 11, 01:50 UTCJul 11, 08:20 UTC6h 30m
2026-07-11 UAL980 ORD → DUB Jul 11, 01:58 UTCJul 11, 08:17 UTC6h 19m
2026-07-10 UAL952 MUC → ORD Jul 10, 09:50 UTCJul 10, 18:35 UTC8h 45m
2026-07-09 UAL108 IAD → MUC Jul 9, 22:20 UTCJul 10, 06:10 UTC7h 50m
2026-07-05 UAL991 BCN → IAD Jul 5, 12:20 UTCJul 5, 20:15 UTC7h 55m
2026-07-05 UAL992 IAD → BCN Jul 5, 01:51 UTCJul 5, 10:16 UTC8h 25m
2026-07-05 UAL992 IAD → BCN Jul 5, 02:45 UTCJul 5, 10:15 UTC7h 30m
2026-07-04 UAL997 - Jul 4, 10:15 UTCJul 4, 18:30 UTC8h 15m
2026-07-04 UAL997 - Jul 4, 03:25 UTCJul 4, 18:30 UTC15h 5m
2026-07-03 UAL996 IAD → ACC Jul 3, 23:31 UTCJul 4, 08:59 UTC9h 28m
2026-07-03 UAL996D IAD → ACC Jul 3, 20:41 UTCJul 4, 06:21 UTC9h 40m
2026-07-03 UAL996D - Jul 3, 20:45 UTCJul 4, 04:40 UTC7h 55m

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 N29907 page for operator, model, and routing details .

Mode-S A31961 frequently asked

What is Mode-S code A31961?
A31961 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N29907.
Where is Mode-S A31961 registered?
Mode-S code A31961 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 A31961 broadcasting right now?
Yes. Mode-S A31961 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A31961, octal 50614541, decimal 10,688,865.
What flights does A31961 operate?
Mode-S A31961 has broadcast 20 distinct callsigns, including UAL952, UAL980, UAL981, UAL953, UAL770.