Apparatus

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sensors Mode-S transponder

A1F622

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N2251U · BOEING 777-300ER · operated by UNITED AIRLINES INC

Hex
A1F622
Octal
50373042
Decimal
10,614,306
Country
US
Tail
N2251U
Type
B77W
Broadcasting now · callsign UAL857 · 36,000 ft
Flights observed
210
Distinct callsigns
20
Country
US
Last broadcast
1h ago

Current position

A1F622 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A1F622 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
UAL862 - 16 2026-07-13
UAL810 - 12 2026-06-28
UAL809 - 12 2026-06-30
UAL951 United Airlines 10 2026-06-05
UAL877 - 9 2026-07-12
UAL190 United Airlines 9 2026-05-30
UAL989 United Airlines 8 2026-06-05
UAL950 United Airlines 8 2026-06-04
UAL43 United Airlines 8 2026-06-06
UAL988 United Airlines 7 2026-06-04
UAL878 - 7 2026-06-14
UAL872 - 7 2026-06-19
UAL857 - 7 2026-07-13
UAL435 - 7 2026-06-13
UAL42 United Airlines 7 2026-06-02
UAL189 United Airlines 7 2026-05-29
UAL1175 United Airlines 6 2026-06-10
UAL871 - 5 2026-06-17
UAL79 - 5 2026-06-29
UAL869 - 4 2026-06-13

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-13 UAL857 - Jul 13, 21:00 UTCJul 14, 06:30 UTC9h 30m
2026-07-13 UAL862 HKG → SFO Jul 13, 04:11 UTCJul 13, 16:53 UTC12h 42m
2026-07-13 UAL862 - Jul 13, 04:30 UTCJul 13, 16:30 UTC12h 0m
2026-07-12 UAL877 SFO → HKG Jul 12, 07:40 UTCJul 12, 21:05 UTC13h 25m
2026-07-10 UAL3852 - Jul 10, 19:15 UTCJul 11, 08:25 UTC13h 11m
2026-06-30 UAL809 - Jun 30, 21:50 UTCJul 1, 10:35 UTC12h 45m
2026-06-30 UAL838 - Jun 30, 08:30 UTCJun 30, 17:05 UTC8h 35m
2026-06-29 UAL79 - Jun 29, 16:15 UTCJun 30, 05:05 UTC12h 51m
2026-06-29 UAL2416 SFO → EWR Jun 29, 07:44 UTCJun 29, 12:14 UTC4h 30m
2026-06-28 UAL810 MNL → SFO Jun 28, 13:41 UTCJun 29, 01:14 UTC11h 33m
2026-06-28 UAL810 MNL → SFO Jun 28, 13:40 UTCJun 29, 01:20 UTC11h 40m
2026-06-27 UAL809 SFO → MNL Jun 27, 21:40 UTCJun 28, 10:44 UTC13h 5m
2026-06-27 UAL862 - Jun 27, 05:55 UTCJun 27, 17:59 UTC12h 5m
2026-06-27 UAL862 - Jun 27, 05:10 UTCJun 27, 05:25 UTC15m
2026-06-26 UAL877 - Jun 26, 07:45 UTCJun 26, 21:10 UTC13h 25m
2026-06-24 UAL810 MNL → SFO Jun 24, 13:44 UTCJun 25, 01:44 UTC12h 0m
2026-06-23 UAL809 - Jun 23, 21:45 UTCJun 24, 10:55 UTC13h 10m
2026-06-23 UAL1960 - Jun 23, 11:29 UTCJun 23, 16:59 UTC5h 30m
2026-06-22 UAL78 NRT → EWR Jun 22, 08:54 UTCJun 22, 21:25 UTC12h 30m
2026-06-22 UAL78 NRT → EWR Jun 22, 08:51 UTCJun 22, 21:22 UTC12h 31m
2026-06-21 UAL79 EWR → NRT Jun 21, 16:19 UTCJun 22, 04:54 UTC12h 35m
2026-06-21 UAL79 EWR → NRT Jun 21, 16:12 UTCJun 22, 04:52 UTC12h 40m
2026-06-21 UAL2416 SFO → EWR Jun 21, 07:40 UTCJun 21, 12:35 UTC4h 55m
2026-06-20 UAL810 - Jun 20, 14:50 UTCJun 21, 03:19 UTC12h 30m
2026-06-20 UAL810 MNL → SFO Jun 20, 15:01 UTCJun 21, 03:12 UTC12h 11m
2026-06-19 UAL809 SFO → MNL Jun 19, 21:59 UTCJun 20, 10:59 UTC13h 0m
2026-06-19 UAL872 - Jun 19, 03:55 UTCJun 19, 13:14 UTC9h 20m
2026-06-19 UAL872 - Jun 19, 02:04 UTCJun 19, 02:19 UTC15m
2026-06-17 UAL871 - Jun 17, 22:15 UTCJun 18, 10:40 UTC12h 25m
2026-06-17 UAL1960 - Jun 17, 11:25 UTCJun 17, 16:40 UTC5h 15m
2026-06-16 UAL78 NRT → EWR Jun 16, 08:44 UTCJun 16, 15:50 UTC7h 5m
2026-06-16 UAL78 NRT → EWR Jun 16, 08:51 UTCJun 16, 20:39 UTC11h 48m
2026-06-15 UAL79 - Jun 15, 16:09 UTCJun 15, 23:09 UTC7h 0m
2026-06-15 UAL79 EWR → NRT Jun 15, 16:02 UTCJun 16, 05:31 UTC13h 29m
2026-06-15 UAL2416 - Jun 15, 07:45 UTCJun 15, 12:15 UTC4h 30m
2026-06-14 UAL878 HKG → SFO Jun 14, 14:51 UTCJun 15, 03:11 UTC12h 20m
2026-06-14 UAL878 HKG → SFO Jun 14, 14:45 UTCJun 15, 03:00 UTC12h 14m
2026-06-13 UAL869 - Jun 13, 21:20 UTCJun 14, 11:20 UTC14h 1m
2026-06-13 UAL1960 MCO → ORD Jun 13, 11:20 UTCJun 13, 16:45 UTC5h 25m
2026-06-13 UAL435 - Jun 13, 02:00 UTCJun 13, 03:00 UTC1h 0m
2026-06-12 UAL435 - Jun 12, 18:01 UTCJun 12, 23:25 UTC5h 25m
2026-06-12 UAL1346 - Jun 12, 08:15 UTCJun 12, 12:45 UTC4h 30m
2026-06-12 UAL200 GUM → HNL Jun 12, 04:15 UTCJun 12, 04:35 UTC20m
2026-06-11 UAL201 HNL → GUM Jun 11, 01:20 UTCJun 11, 01:45 UTC25m
2026-06-10 UAL1175 SFO → HNL Jun 10, 21:15 UTCJun 10, 21:30 UTC15m
2026-06-10 UAL1175 SFO → HNL Jun 10, 16:45 UTCJun 10, 17:10 UTC25m
2026-06-10 UAL872 TPE → SFO Jun 10, 03:55 UTCJun 10, 04:30 UTC35m
2026-06-10 UAL872 TPE → SFO Jun 10, 02:35 UTCJun 10, 02:50 UTC15m
2026-06-10 UAL872 TPE → SFO Jun 10, 02:23 UTCJun 10, 13:14 UTC10h 51m
2026-06-08 UAL871 SFO → TPE Jun 8, 22:25 UTCJun 9, 11:25 UTC13h 0m

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 N2251U page for operator, model, and routing details .

Mode-S A1F622 frequently asked

What is Mode-S code A1F622?
A1F622 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N2251U.
Where is Mode-S A1F622 registered?
Mode-S code A1F622 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 A1F622 broadcasting right now?
Yes. Mode-S A1F622 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A1F622, octal 50373042, decimal 10,614,306.
What flights does A1F622 operate?
Mode-S A1F622 has broadcast 20 distinct callsigns, including UAL862, UAL810, UAL809, UAL951, UAL877.