Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

A31A77

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N29985 · BOEING 787-9 Dreamliner · operated by WILMINGTON TRUST CO TRUSTEE

Hex
A31A77
Octal
50615167
Decimal
10,689,143
Country
US
Tail
N29985
Type
B789
Broadcasting now · callsign UAL263 · 35,975 ft
Flights observed
183
Distinct callsigns
20
Country
US
Last broadcast
3h ago

Current position

A31A77 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A31A77 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 United Airlines 8 2026-05-26
UAL820 United Airlines 8 2026-05-26
UAL761 United Airlines 7 2026-06-17
UAL152 United Airlines 7 2026-06-28
UAL142 - 7 2026-07-11
UAL870 United Airlines 6 2026-06-05
UAL863 United Airlines 6 2026-06-04
UAL760 - 6 2026-06-17
UAL178 - 6 2026-07-13
UAL177 - 6 2026-07-13
UAL772 - 5 2026-06-27
UAL713 United Airlines 5 2026-06-05
UAL60 United Airlines 5 2026-04-19
UAL28 United Airlines 5 2026-04-17
UAL27 - 5 2026-07-12
UAL26 - 5 2026-07-12
UAL153 United Airlines 5 2026-06-29
UAL771 - 4 2026-06-26
UAL7 - 4 2026-07-10
UAL262 - 4 2026-07-14

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 UAL262 DEN → LHR Jul 14, 02:45 UTCJul 14, 11:05 UTC8h 20m
2026-07-13 UAL178 - Jul 13, 12:55 UTCJul 13, 23:50 UTC10h 55m
2026-07-13 UAL177 - Jul 13, 00:01 UTCJul 13, 10:00 UTC10h 0m
2026-07-12 UAL26 - Jul 12, 11:01 UTCJul 12, 11:45 UTC45m
2026-07-12 UAL26 LHR → DEN Jul 12, 10:50 UTCJul 12, 19:57 UTC9h 7m
2026-07-12 UAL27 DEN → LHR Jul 12, 00:18 UTCJul 12, 08:20 UTC8h 2m
2026-07-12 UAL27 - Jul 12, 00:01 UTCJul 12, 07:45 UTC7h 45m
2026-07-11 UAL142 - Jul 11, 07:50 UTCJul 11, 18:20 UTC10h 30m
2026-07-10 UAL7 - Jul 10, 15:50 UTCJul 10, 19:10 UTC3h 20m
2026-07-10 UAL7 IAH → NRT Jul 10, 16:02 UTCJul 11, 04:49 UTC12h 47m
2026-07-10 UAL63 - Jul 10, 01:25 UTCJul 10, 10:50 UTC9h 25m
2026-07-09 UAL62 - Jul 9, 00:00 UTCJul 9, 09:20 UTC9h 20m
2026-07-08 UAL6 - Jul 8, 08:15 UTCJul 8, 19:35 UTC11h 20m
2026-07-08 UAL6 NRT → IAH Jul 8, 08:26 UTCJul 8, 19:35 UTC11h 9m
2026-07-07 UAL32 - Jul 7, 18:05 UTCJul 8, 04:50 UTC10h 45m
2026-07-06 UAL935 - Jul 6, 12:25 UTCJul 6, 22:55 UTC10h 30m
2026-07-06 UAL948 SFO → LHR Jul 6, 00:10 UTCJul 6, 09:55 UTC9h 45m
2026-07-05 UAL1757 - Jul 5, 04:15 UTCJul 5, 09:05 UTC4h 50m
2026-07-03 UAL2023 CPT → IAD Jul 3, 18:00 UTCJul 4, 09:00 UTC15h 0m
2026-07-02 UAL1011 IAD → CPT Jul 2, 22:45 UTCJul 3, 12:35 UTC13h 50m
2026-07-02 UAL1849 MCO → EWR Jul 2, 16:00 UTCJul 2, 20:30 UTC4h 30m
2026-07-01 UAL1227 EWR → SFO Jul 1, 18:10 UTCJul 1, 23:30 UTC5h 20m
2026-07-01 UAL123 - Jul 1, 06:55 UTCJul 1, 13:50 UTC6h 55m
2026-06-30 UAL122 EWR → LHR Jun 30, 14:09 UTCJun 30, 20:02 UTC5h 53m
2026-06-30 UAL122 - Jun 30, 13:55 UTCJun 30, 19:45 UTC5h 50m
2026-06-29 UAL1855 - Jun 29, 20:40 UTCJun 30, 01:19 UTC4h 40m
2026-06-29 UAL153 HKG → LAX Jun 29, 05:00 UTCJun 29, 18:10 UTC13h 10m
2026-06-29 UAL153 HKG → LAX Jun 29, 00:19 UTCJun 29, 02:25 UTC2h 6m
2026-06-28 UAL152 LAX → HKG Jun 28, 13:25 UTCJun 28, 13:45 UTC20m
2026-06-28 UAL152 LAX → HKG Jun 28, 12:49 UTCJun 28, 15:31 UTC2h 42m
2026-06-27 UAL152 LAX → HKG Jun 27, 20:09 UTCJun 28, 10:10 UTC14h 0m
2026-06-27 UAL772 - Jun 27, 05:04 UTCJun 27, 06:44 UTC1h 40m
2026-06-27 UAL772 PEK → LAX Jun 27, 04:29 UTCJun 27, 15:22 UTC10h 53m
2026-06-26 UAL771 - Jun 26, 07:10 UTCJun 26, 17:44 UTC10h 35m
2026-06-26 UAL771 LAX → PEK Jun 26, 06:54 UTCJun 26, 20:41 UTC13h 47m
2026-06-25 UAL935 - Jun 25, 12:50 UTCJun 25, 22:59 UTC10h 10m
2026-06-24 UAL923 - Jun 24, 22:55 UTCJun 25, 08:55 UTC10h 0m
2026-06-24 UAL153 HKG → LAX Jun 24, 05:08 UTCJun 24, 17:09 UTC12h 1m
2026-06-24 UAL153 HKG → LAX Jun 24, 04:55 UTCJun 24, 05:29 UTC35m
2026-06-24 UAL153 HKG → LAX Jun 24, 02:05 UTCJun 24, 02:24 UTC20m
2026-06-23 UAL152 LAX → HKG Jun 23, 13:15 UTCJun 23, 13:29 UTC15m
2026-06-23 UAL152 LAX → HKG Jun 23, 13:19 UTCJun 23, 15:15 UTC1h 56m
2026-06-23 UAL152 LAX → HKG Jun 23, 10:04 UTCJun 23, 10:19 UTC15m
2026-06-22 UAL152 LAX → HKG Jun 22, 20:04 UTCJun 23, 09:29 UTC13h 25m
2026-06-20 UAL199 PVG → LAX Jun 20, 12:41 UTCJun 21, 00:38 UTC11h 57m
2026-06-20 UAL198 - Jun 20, 06:19 UTCJun 21, 00:45 UTC18h 25m
2026-06-19 UAL198 - Jun 19, 20:40 UTCJun 20, 08:14 UTC11h 35m
2026-06-19 UAL33 - Jun 19, 08:04 UTCJun 19, 17:49 UTC9h 45m
2026-06-18 UAL143 DEN → NRT Jun 18, 18:10 UTCJun 19, 05:30 UTC11h 19m
2026-06-17 UAL761 MUC → DEN Jun 17, 14:35 UTCJun 18, 00:45 UTC10h 10m

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 N29985 page for operator, model, and routing details .

Mode-S A31A77 frequently asked

What is Mode-S code A31A77?
A31A77 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N29985.
Where is Mode-S A31A77 registered?
Mode-S code A31A77 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 A31A77 broadcasting right now?
Yes. Mode-S A31A77 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A31A77, octal 50615167, decimal 10,689,143.
What flights does A31A77 operate?
Mode-S A31A77 has broadcast 20 distinct callsigns, including UAL821, UAL820, UAL761, UAL152, UAL142.