Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

A37FA1

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N32404 · BOEING 737-900 · operated by UNITED AIRLINES INC

Hex
A37FA1
Octal
50677641
Decimal
10,715,041
Country
US
Tail
N32404
Type
B739
No current signal · last broadcast Jul 26, 20:35 UTC
Flights observed
470
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 20:35 UTC

Last known position

Most recent position reported by Mode-S A37FA1.

Country allocation

The ICAO 24-bit address A37FA1 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
UAL2310 United Airlines 16 2026-07-26
UAL1563 United Airlines 16 2026-07-24
UAL1936 United Airlines 14 2026-07-24
UAL2662 United Airlines 13 2026-07-24
UAL1950 - 13 2026-07-09
UAL1872 United Airlines 12 2026-07-24
UAL2124 United Airlines 11 2026-07-25
UAL678 - 10 2026-07-09
UAL2170 - 10 2026-06-22
UAL496 - 9 2026-06-27
UAL2406 United Airlines 9 2026-07-26
UAL2105 - 9 2026-07-21
UAL1361 - 9 2026-06-28
UAL1345 - 9 2026-07-08
UAL1949 United Airlines 8 2026-07-20
UAL1752 - 8 2026-07-08
UAL491 United Airlines 7 2026-07-21
UAL315 United Airlines 7 2026-07-19
UAL2611 United Airlines 7 2026-06-28
UAL2456 United Airlines 7 2026-05-19

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL2406 LAX → SFO Jul 26, 18:25 UTCJul 26, 20:35 UTC2h 10m
2026-07-26 UAL2310 MIA → EWR Jul 26, 14:50 UTCJul 26, 16:40 UTC1h 50m
2026-07-26 UAL1898 DEN → ORD Jul 26, 10:55 UTCJul 26, 13:30 UTC2h 35m
2026-07-25 UAL1795 DEN → CLE Jul 25, 23:45 UTCJul 26, 02:25 UTC2h 40m
2026-07-25 UAL2237 ORD → EWR Jul 25, 19:15 UTCJul 25, 22:10 UTC2h 55m
2026-07-25 UAL2491 SFO → DEN Jul 25, 14:40 UTCJul 25, 17:15 UTC2h 35m
2026-07-25 UAL2124 PDX → SFO Jul 25, 12:15 UTCJul 25, 13:05 UTC50m
2026-07-25 UAL1696 SFO → RNO Jul 25, 01:55 UTCJul 25, 02:35 UTC40m
2026-07-25 UAL1696 SFO → RNO Jul 25, 02:00 UTCJul 25, 02:39 UTC39m
2026-07-24 UAL1872 DEN → AUS Jul 24, 21:25 UTCJul 24, 23:15 UTC1h 50m
2026-07-24 UAL2662 DEN → PDX Jul 24, 17:45 UTCJul 24, 19:45 UTC2h 0m
2026-07-24 UAL1936 SAV → EWR Jul 24, 12:55 UTCJul 24, 15:55 UTC3h 0m
2026-07-24 UAL1936 SAV → EWR Jul 24, 12:59 UTCJul 24, 15:49 UTC2h 50m
2026-07-24 UAL1563 LIH → SFO Jul 24, 02:30 UTCJul 24, 05:10 UTC2h 40m
2026-07-23 UAL2293 JAX → EWR Jul 23, 19:25 UTCJul 23, 23:15 UTC3h 50m
2026-07-23 UAL2293 JAX → EWR Jul 23, 19:20 UTCJul 23, 23:12 UTC3h 52m
2026-07-23 UAL2654 BNA → SFO Jul 23, 13:15 UTCJul 23, 17:15 UTC4h 0m
2026-07-23 UAL2654 BNA → SFO Jul 23, 13:17 UTCJul 23, 17:13 UTC3h 56m
2026-07-23 UAL2840 GUM → SFO Jul 23, 08:25 UTCJul 23, 11:00 UTC2h 35m
2026-07-22 UAL1971 EWR → SAT Jul 22, 19:40 UTCJul 22, 22:15 UTC2h 35m
2026-07-22 UAL1971 EWR → SAT Jul 22, 19:40 UTCJul 22, 22:06 UTC2h 26m
2026-07-22 UAL1493 IAH → DEN Jul 22, 16:10 UTCJul 22, 18:05 UTC1h 55m
2026-07-22 UAL2245 IAH → MCO Jul 22, 12:45 UTCJul 22, 14:50 UTC2h 5m
2026-07-21 UAL2105 - Jul 21, 15:10 UTCJul 21, 15:55 UTC45m
2026-07-21 UAL491 BZN → DEN Jul 21, 12:55 UTCJul 21, 13:45 UTC50m
2026-07-21 UAL780 IAD → LAS Jul 21, 07:35 UTCJul 21, 11:25 UTC3h 50m
2026-07-21 UAL780 IAD → LAS Jul 21, 07:28 UTCJul 21, 11:20 UTC3h 52m
2026-07-21 UAL1420 MCO → EWR Jul 21, 01:35 UTCJul 21, 05:20 UTC3h 45m
2026-07-21 UAL1420 MCO → EWR Jul 21, 01:37 UTCJul 21, 05:14 UTC3h 37m
2026-07-20 UAL1949 ORD → DCA Jul 20, 20:20 UTCJul 20, 23:55 UTC3h 35m
2026-07-20 UAL2773 - Jul 20, 15:50 UTCJul 20, 19:00 UTC3h 10m
2026-07-20 UAL1127 ORD → SFO Jul 20, 12:27 UTCJul 20, 13:41 UTC1h 14m
2026-07-20 UAL1127 ORD → SFO Jul 20, 12:30 UTCJul 20, 13:40 UTC1h 10m
2026-07-20 UAL2304 - Jul 20, 01:30 UTCJul 20, 02:35 UTC1h 5m
2026-07-19 UAL1444 - Jul 19, 21:15 UTCJul 19, 23:40 UTC2h 25m
2026-07-19 UAL315 FLL → IAD Jul 19, 17:20 UTCJul 19, 19:45 UTC2h 25m
2026-07-19 UAL2827 - Jul 19, 14:45 UTCJul 19, 15:30 UTC45m
2026-07-19 UAL2827 SAT → IAH Jul 19, 14:50 UTCJul 19, 15:27 UTC37m
2026-07-19 UAL2250 - Jul 19, 12:35 UTCJul 19, 13:10 UTC35m
2026-07-19 UAL780K IAD → PDX Jul 19, 07:10 UTCJul 19, 10:50 UTC3h 40m
2026-07-19 UAL780K IAD → PDX Jul 19, 07:09 UTCJul 19, 10:47 UTC3h 38m
2026-07-19 UAL1420 MCO → EWR Jul 19, 01:40 UTCJul 19, 05:30 UTC3h 50m
2026-07-18 UAL1872 DEN → AUS Jul 18, 21:40 UTCJul 18, 23:30 UTC1h 50m
2026-07-18 UAL2662 - Jul 18, 18:05 UTCJul 18, 20:05 UTC2h 0m
2026-07-18 UAL2662 IAH → MCO Jul 18, 18:11 UTCJul 18, 20:01 UTC1h 50m
2026-07-18 UAL1936 - Jul 18, 14:00 UTCJul 18, 16:50 UTC2h 50m
2026-07-18 UAL1936 ONT → IAH Jul 18, 13:54 UTCJul 18, 16:44 UTC2h 50m
2026-07-18 UAL1563 - Jul 18, 02:05 UTCJul 18, 04:45 UTC2h 41m
2026-07-18 UAL1563 IAH → ONT Jul 18, 02:04 UTCJul 18, 04:46 UTC2h 42m
2026-07-17 UAL1927 - Jul 17, 20:10 UTCJul 18, 00:04 UTC3h 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 N32404 page for operator, model, and routing details .

Mode-S A37FA1 frequently asked

What is Mode-S code A37FA1?
A37FA1 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N32404.
Where is Mode-S A37FA1 registered?
Mode-S code A37FA1 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 A37FA1 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 20:35 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A37FA1, octal 50677641, decimal 10,715,041.
What flights does A37FA1 operate?
Mode-S A37FA1 has broadcast 20 distinct callsigns, including UAL2310, UAL1563, UAL1936, UAL2662, UAL1950.