Apparatus

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sensors Mode-S transponder

A12B31

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N17458 · operated by UNITED AIRLINES INC

Hex
A12B31
Octal
50225461
Decimal
10,562,353
Country
US
Tail
N17458
No current signal · last broadcast Jul 26, 20:20 UTC
Flights observed
128
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 20:20 UTC

Last known position

Most recent position reported by Mode-S A12B31.

Country allocation

The ICAO 24-bit address A12B31 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
UAL1691 - 4 2026-07-23
BOE123 - 4 2026-05-28
UAL2377 - 3 2026-07-16
UAL1826 United Airlines 3 2026-07-26
UAL1650 - 3 2026-06-29
UAL8150 - 2 2026-06-30
UAL8120 - 2 2026-07-14
UAL700 United Airlines 2 2026-07-25
UAL654 - 2 2026-07-16
UAL641 United Airlines 2 2026-07-24
UAL601 United Airlines 2 2026-07-23
UAL4214 United Airlines 2 2026-06-24
UAL3882 - 2 2026-06-25
UAL2629 United Airlines 2 2026-07-23
UAL2460 - 2 2026-07-16
UAL2428 - 2 2026-07-08
UAL2398 United Airlines 2 2026-07-24
UAL2380 - 2 2026-07-05
UAL2372 - 2 2026-07-15
UAL2305 United Airlines 2 2026-07-25

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL1715 DEN → EWR Jul 26, 18:20 UTCJul 26, 20:10 UTC1h 50m
2026-07-26 UAL1826 SFO → DEN Jul 26, 10:54 UTCJul 26, 15:40 UTC4h 46m
2026-07-26 UAL1826 SFO → DEN Jul 26, 10:50 UTCJul 26, 14:15 UTC3h 25m
2026-07-25 UAL700 BOS → EWR Jul 25, 23:05 UTCJul 26, 02:10 UTC3h 5m
2026-07-25 UAL700 BOS → EWR Jul 25, 22:35 UTCJul 26, 02:05 UTC3h 30m
2026-07-25 UAL2038 TPA → EWR Jul 25, 17:15 UTCJul 25, 20:20 UTC3h 5m
2026-07-25 UAL2642 IAH → PHX Jul 25, 12:45 UTCJul 25, 15:35 UTC2h 50m
2026-07-25 UAL2305 RSW → ORD Jul 25, 00:00 UTCJul 25, 03:30 UTC3h 30m
2026-07-25 UAL2305 RSW → ORD Jul 25, 00:06 UTCJul 25, 03:32 UTC3h 26m
2026-07-24 UAL1074 MCO → EWR Jul 24, 16:05 UTCJul 24, 21:50 UTC5h 45m
2026-07-24 UAL641 IAD → BOS Jul 24, 12:53 UTCJul 24, 14:15 UTC1h 22m
2026-07-24 UAL641 IAD → BOS Jul 24, 13:10 UTCJul 24, 14:15 UTC1h 5m
2026-07-24 UAL1252 EWR → MIA Jul 24, 10:05 UTCJul 24, 10:50 UTC45m
2026-07-24 UAL2398 IAD → EWR Jul 24, 00:55 UTCJul 24, 02:10 UTC1h 15m
2026-07-23 UAL2629 LGA → IAH Jul 23, 20:35 UTCJul 23, 22:45 UTC2h 10m
2026-07-23 UAL2206 IAD → MCO Jul 23, 16:55 UTCJul 23, 18:55 UTC2h 0m
2026-07-23 UAL1691 EWR → IAD Jul 23, 14:27 UTCJul 23, 15:14 UTC47m
2026-07-23 UAL1691 EWR → IAD Jul 23, 14:30 UTCJul 23, 15:15 UTC45m
2026-07-23 UAL601 BOS → EWR Jul 23, 11:25 UTCJul 23, 12:25 UTC1h 0m
2026-07-23 UAL2398 IAD → EWR Jul 23, 00:30 UTCJul 23, 01:35 UTC1h 5m
2026-07-22 UAL2629 LGA → IAH Jul 22, 20:40 UTCJul 22, 22:45 UTC2h 5m
2026-07-22 UAL2206 IAD → MCO Jul 22, 17:20 UTCJul 22, 19:10 UTC1h 50m
2026-07-22 UAL1691 - Jul 22, 14:45 UTCJul 22, 15:35 UTC50m
2026-07-22 UAL1691 EWR → IAD Jul 22, 14:45 UTCJul 22, 15:28 UTC43m
2026-07-22 UAL601 BOS → EWR Jul 22, 12:10 UTCJul 22, 13:10 UTC1h 0m
2026-07-20 UAL1611 - Jul 20, 23:00 UTCJul 21, 00:05 UTC1h 5m
2026-07-20 UAL2174 BNA → EWR Jul 20, 18:35 UTCJul 20, 20:30 UTC1h 55m
2026-07-20 UAL1616 EWR → BNA Jul 20, 15:30 UTCJul 20, 17:05 UTC1h 35m
2026-07-20 UAL2468 - Jul 20, 13:10 UTCJul 20, 14:10 UTC1h 0m
2026-07-19 UAL744 - Jul 19, 23:45 UTCJul 20, 02:10 UTC2h 25m
2026-07-19 UAL2690 LAS → IAH Jul 19, 19:05 UTCJul 19, 22:15 UTC3h 10m
2026-07-19 UAL2394 BOS → EWR Jul 19, 15:20 UTCJul 19, 16:10 UTC50m
2026-07-19 UAL1110 EWR → BOS Jul 19, 13:05 UTCJul 19, 13:45 UTC40m
2026-07-17 UAL2100 SAV → EWR Jul 17, 22:45 UTCJul 18, 03:15 UTC4h 31m
2026-07-17 UAL1289 EWR → SEA Jul 17, 15:15 UTCJul 17, 20:29 UTC5h 15m
2026-07-17 UAL1437 CMH → ORD Jul 17, 11:04 UTCJul 17, 13:35 UTC2h 30m
2026-07-17 UAL2474 - Jul 17, 03:34 UTCJul 17, 04:14 UTC40m
2026-07-16 UAL2377 - Jul 16, 22:35 UTCJul 17, 01:35 UTC3h 0m
2026-07-16 UAL2460 - Jul 16, 18:00 UTCJul 16, 20:55 UTC2h 55m
2026-07-16 UAL654 - Jul 16, 12:55 UTCJul 16, 16:05 UTC3h 10m
2026-07-15 UAL1103 - Jul 15, 21:20 UTCJul 16, 02:15 UTC4h 55m
2026-07-15 UAL1798 - Jul 15, 19:25 UTCJul 15, 19:40 UTC15m
2026-07-15 UAL1798 - Jul 15, 14:25 UTCJul 15, 14:55 UTC30m
2026-07-15 UAL2372 - Jul 15, 03:20 UTCJul 15, 04:00 UTC40m
2026-07-14 UAL2372 - Jul 14, 23:10 UTCJul 14, 23:20 UTC10m
2026-07-14 UAL2373 - Jul 14, 16:15 UTCJul 14, 16:40 UTC25m
2026-07-14 UAL2127 - Jul 14, 13:15 UTCJul 14, 14:15 UTC1h 0m
2026-07-14 UAL8120 PHX → SFO Jul 14, 07:40 UTCJul 14, 09:10 UTC1h 30m
2026-07-14 UAL2347 SFO → PHX Jul 14, 04:55 UTCJul 14, 06:35 UTC1h 40m
2026-07-14 UAL1572 - Jul 14, 01:30 UTCJul 14, 02:10 UTC40m

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 N17458 page for operator, model, and routing details .

Mode-S A12B31 frequently asked

What is Mode-S code A12B31?
A12B31 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N17458.
Where is Mode-S A12B31 registered?
Mode-S code A12B31 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 A12B31 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 20:20 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A12B31, octal 50225461, decimal 10,562,353.
What flights does A12B31 operate?
Mode-S A12B31 has broadcast 20 distinct callsigns, including UAL1691, BOE123, UAL2377, UAL1826, UAL1650.