Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

A2B810

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N27421 · BOEING 737-900 · operated by UNITED AIRLINES INC

Hex
A2B810
Octal
50534020
Decimal
10,663,952
Country
US
Tail
N27421
Type
B739
No current signal · last broadcast Jul 26, 21:45 UTC
Flights observed
422
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 21:45 UTC

Last known position

Most recent position reported by Mode-S A2B810.

Country allocation

The ICAO 24-bit address A2B810 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
UAL1417 - 5 2026-07-01
UAL677 - 4 2026-06-19
UAL457 - 4 2026-06-20
UAL2659 United Airlines 4 2026-04-30
UAL2058 - 4 2026-07-21
UAL1834 United Airlines 4 2026-07-21
UAL1715 United Airlines 4 2026-05-02
UAL1458 United Airlines 4 2026-05-17
UAL1010 United Airlines 4 2026-07-21
UAL644 United Airlines 3 2026-06-11
UAL587 United Airlines 3 2026-05-17
UAL519 United Airlines 3 2026-04-27
UAL444 United Airlines 3 2026-07-23
UAL357 - 3 2026-07-13
UAL2776 United Airlines 3 2026-06-09
UAL2674 United Airlines 3 2026-04-17
UAL2631 United Airlines 3 2026-04-30
UAL2370 United Airlines 3 2026-05-17
UAL2344 - 3 2026-07-09
UAL2158 United Airlines 3 2026-05-01

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL1623 EWR → AUS Jul 26, 20:05 UTCJul 26, 21:45 UTC1h 40m
2026-07-26 UAL1623 EWR → AUS Jul 26, 17:35 UTCJul 26, 18:00 UTC25m
2026-07-26 UAL2167 ORD → CVG Jul 26, 12:15 UTCJul 26, 15:25 UTC3h 10m
2026-07-26 UAL1961 LAS → IAD Jul 26, 00:15 UTCJul 26, 03:15 UTC3h 0m
2026-07-26 UAL1961 LAS → IAD Jul 26, 00:02 UTCJul 26, 03:12 UTC3h 10m
2026-07-25 UAL1248 SFO → ORD Jul 25, 17:55 UTCJul 25, 21:55 UTC4h 0m
2026-07-25 UAL2816 HKG → ORD Jul 25, 13:50 UTCJul 25, 15:45 UTC1h 55m
2026-07-25 UAL2419 MFR → SFO Jul 25, 03:20 UTCJul 25, 05:10 UTC1h 50m
2026-07-24 UAL682 EWR → SFO Jul 24, 23:40 UTCJul 25, 01:50 UTC2h 10m
2026-07-24 UAL682 EWR → SFO Jul 24, 23:22 UTCJul 25, 01:31 UTC2h 9m
2026-07-24 UAL2163 EWR → MYR Jul 24, 17:00 UTCJul 24, 21:45 UTC4h 45m
2026-07-24 UAL2766 HKG → ORD Jul 24, 03:10 UTCJul 24, 04:30 UTC1h 20m
2026-07-23 UAL2040 PHL → IAH Jul 23, 22:35 UTCJul 24, 01:05 UTC2h 30m
2026-07-23 UAL2040 PHL → IAH Jul 23, 21:56 UTCJul 24, 00:35 UTC2h 39m
2026-07-23 UAL1392 EWR → CLT Jul 23, 19:25 UTCJul 23, 20:30 UTC1h 5m
2026-07-23 UAL2826 - Jul 23, 16:20 UTCJul 23, 18:10 UTC1h 50m
2026-07-23 UAL2084 ORD → SFO Jul 23, 13:30 UTCJul 23, 15:05 UTC1h 35m
2026-07-23 UAL2084 ORD → SFO Jul 23, 13:18 UTCJul 23, 15:04 UTC1h 46m
2026-07-23 UAL635 EWR → MSY Jul 23, 10:15 UTCJul 23, 11:25 UTC1h 10m
2026-07-23 UAL635 EWR → MSY Jul 23, 10:14 UTCJul 23, 11:16 UTC1h 2m
2026-07-23 UAL444 BNA → IAD Jul 23, 02:55 UTCJul 23, 03:45 UTC50m
2026-07-22 UAL444 BNA → IAD Jul 22, 20:35 UTCJul 23, 00:55 UTC4h 20m
2026-07-22 UAL2177 PDX → ORD Jul 22, 18:00 UTCJul 22, 19:20 UTC1h 20m
2026-07-22 UAL2177 PDX → ORD Jul 22, 17:56 UTCJul 22, 19:13 UTC1h 17m
2026-07-22 UAL2356 BUR → SFO Jul 22, 14:40 UTCJul 22, 15:40 UTC1h 0m
2026-07-22 UAL2242 ORD → SFO Jul 22, 01:42 UTCJul 22, 04:40 UTC2h 58m
2026-07-22 UAL2242 ORD → SFO Jul 22, 01:25 UTCJul 22, 04:45 UTC3h 20m
2026-07-21 UAL1010 OMA → SFO Jul 21, 20:50 UTCJul 21, 23:30 UTC2h 40m
2026-07-21 UAL1010 OMA → SFO Jul 21, 20:44 UTCJul 21, 23:07 UTC2h 23m
2026-07-21 UAL1834 DFW → EWR Jul 21, 17:15 UTCJul 21, 19:20 UTC2h 5m
2026-07-21 UAL1834 DFW → EWR Jul 21, 13:25 UTCJul 21, 15:45 UTC2h 20m
2026-07-21 UAL2058 - Jul 21, 00:50 UTCJul 21, 01:35 UTC45m
2026-07-21 UAL2058 EWR → BOS Jul 21, 00:53 UTCJul 21, 01:33 UTC40m
2026-07-20 UAL1051 CUN → EWR Jul 20, 18:30 UTCJul 20, 22:00 UTC3h 30m
2026-07-20 UAL1018 - Jul 20, 15:00 UTCJul 20, 16:45 UTC1h 45m
2026-07-20 UAL2419 MFR → SFO Jul 20, 03:05 UTCJul 20, 05:00 UTC1h 55m
2026-07-19 UAL624 PHX → DEN Jul 19, 23:35 UTCJul 20, 01:00 UTC1h 25m
2026-07-19 UAL455 ORD → MSN Jul 19, 19:00 UTCJul 19, 21:55 UTC2h 55m
2026-07-19 UAL1334 - Jul 19, 16:00 UTCJul 19, 17:15 UTC1h 15m
2026-07-19 UAL2247 SFO → IAD Jul 19, 13:00 UTCJul 19, 14:00 UTC1h 0m
2026-07-18 UAL1778 EWR → SAT Jul 18, 10:30 UTCJul 18, 11:55 UTC1h 25m
2026-07-18 UAL1568 ORD → SFO Jul 18, 01:30 UTCJul 18, 02:35 UTC1h 5m
2026-07-17 UAL2179 LGA → ORD Jul 17, 21:20 UTCJul 17, 23:39 UTC2h 20m
2026-07-17 UAL1850 - Jul 17, 15:49 UTCJul 17, 17:35 UTC1h 45m
2026-07-17 UAL2420 RSW → IAH Jul 17, 11:35 UTCJul 17, 13:55 UTC2h 20m
2026-07-17 UAL2420 RSW → IAH Jul 17, 11:41 UTCJul 17, 13:30 UTC1h 49m
2026-07-17 UAL1761 ORD → MSY Jul 17, 01:49 UTCJul 17, 03:34 UTC1h 45m
2026-07-17 UAL1761 - Jul 17, 01:45 UTCJul 17, 03:30 UTC1h 45m
2026-07-16 UAL1010 TPA → ORD Jul 16, 20:49 UTCJul 16, 23:29 UTC2h 40m
2026-07-16 UAL1010 DEN → TPA Jul 16, 16:00 UTCJul 16, 19:10 UTC3h 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 N27421 page for operator, model, and routing details .

Mode-S A2B810 frequently asked

What is Mode-S code A2B810?
A2B810 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N27421.
Where is Mode-S A2B810 registered?
Mode-S code A2B810 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 A2B810 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 21:45 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A2B810, octal 50534020, decimal 10,663,952.
What flights does A2B810 operate?
Mode-S A2B810 has broadcast 20 distinct callsigns, including UAL1417, UAL677, UAL457, UAL2659, UAL2058.