Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

A0ACF9

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N14231 · BOEING 737-800 · operated by UNITED AIRLINES INC

Hex
A0ACF9
Octal
50126371
Decimal
10,530,041
Country
US
Tail
N14231
Type
B738
No current signal · last broadcast Jul 26, 22:15 UTC
Flights observed
436
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 22:15 UTC

Last known position

Most recent position reported by Mode-S A0ACF9.

Country allocation

The ICAO 24-bit address A0ACF9 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
UAL2192 United Airlines 5 2026-04-20
UAL329 - 4 2026-07-09
UAL275 - 4 2026-06-20
UAL2668 - 4 2026-07-12
UAL2649 United Airlines 4 2026-06-16
UAL2342 - 4 2026-07-04
UAL1712 - 4 2026-07-20
UAL1394 - 4 2026-07-12
UAL1328 United Airlines 4 2026-05-20
UAL1325 - 4 2026-07-12
UAL1310 - 4 2026-06-28
UAL8184 - 3 2026-07-04
UAL644 United Airlines 3 2026-04-20
UAL2635 United Airlines 3 2026-07-24
UAL2318 - 3 2026-07-15
UAL2262 United Airlines 3 2026-07-20
UAL2098 - 3 2026-07-06
UAL2094 United Airlines 3 2026-07-20
UAL2000 United Airlines 3 2026-07-24
UAL1968 - 3 2026-06-13

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL1696 SFO → RNO Jul 26, 21:30 UTCJul 26, 22:15 UTC45m
2026-07-26 UAL2188 DEN → FLL Jul 26, 16:10 UTCJul 26, 19:40 UTC3h 30m
2026-07-26 UAL2188 DEN → FLL Jul 26, 16:08 UTCJul 26, 19:39 UTC3h 31m
2026-07-26 UAL557 SFO → AUS Jul 26, 13:10 UTCJul 26, 14:20 UTC1h 10m
2026-07-26 UAL1417 DEN → RDU Jul 26, 01:35 UTCJul 26, 02:50 UTC1h 15m
2026-07-25 UAL1001 PHX → SFO Jul 25, 20:55 UTCJul 25, 23:25 UTC2h 30m
2026-07-25 UAL2185 MSY → SFO Jul 25, 16:40 UTCJul 25, 19:05 UTC2h 25m
2026-07-25 UAL2185 MSY → SFO Jul 25, 16:41 UTCJul 25, 18:58 UTC2h 17m
2026-07-25 UAL1234 EWR → ORD Jul 25, 13:35 UTCJul 25, 15:00 UTC1h 25m
2026-07-25 UAL1234 EWR → ORD Jul 25, 13:20 UTCJul 25, 15:05 UTC1h 45m
2026-07-25 UAL778 DEN → BZN Jul 25, 02:10 UTCJul 25, 04:05 UTC1h 55m
2026-07-24 UAL1483 LAS → SFO Jul 24, 22:00 UTCJul 25, 00:00 UTC2h 0m
2026-07-24 UAL2000 LGA → IAH Jul 24, 19:45 UTCJul 24, 20:30 UTC45m
2026-07-24 UAL2000 LGA → IAH Jul 24, 19:53 UTCJul 24, 20:25 UTC32m
2026-07-24 UAL2635 IAH → LGA Jul 24, 15:42 UTCJul 24, 17:30 UTC1h 48m
2026-07-24 UAL2635 IAH → LGA Jul 24, 15:40 UTCJul 24, 17:50 UTC2h 10m
2026-07-24 UAL1657 IAH → PHL Jul 24, 12:10 UTCJul 24, 13:45 UTC1h 35m
2026-07-24 UAL1830 SFO → BNA Jul 24, 01:51 UTCJul 24, 03:29 UTC1h 38m
2026-07-24 UAL1830 SFO → BNA Jul 24, 01:50 UTCJul 24, 03:40 UTC1h 50m
2026-07-23 UAL2306 ORD → BOS Jul 23, 22:45 UTCJul 24, 00:30 UTC1h 45m
2026-07-23 UAL1398 COS → ORD Jul 23, 18:15 UTCJul 23, 20:15 UTC2h 0m
2026-07-23 UAL1082 ORD → COS Jul 23, 14:50 UTCJul 23, 16:55 UTC2h 5m
2026-07-23 UAL660 EWR → CHS Jul 23, 10:10 UTCJul 23, 12:00 UTC1h 50m
2026-07-23 UAL660 EWR → CHS Jul 23, 10:14 UTCJul 23, 11:51 UTC1h 37m
2026-07-23 UAL1663 LAS → EWR Jul 23, 00:00 UTCJul 23, 02:55 UTC2h 55m
2026-07-22 UAL527 XPL → IAH Jul 22, 19:00 UTCJul 22, 21:20 UTC2h 20m
2026-07-22 UAL518 IAH → XPL Jul 22, 15:00 UTCJul 22, 17:10 UTC2h 10m
2026-07-21 UAL2228 - Jul 21, 13:50 UTCJul 21, 15:25 UTC1h 35m
2026-07-21 UAL1596 PDX → SFO Jul 21, 03:25 UTCJul 21, 04:15 UTC50m
2026-07-21 UAL1596 PDX → SFO Jul 21, 03:20 UTCJul 21, 04:40 UTC1h 20m
2026-07-21 UAL2395 EWR → PBI Jul 21, 00:05 UTCJul 21, 01:35 UTC1h 30m
2026-07-20 UAL267K SFO → BOI Jul 20, 21:50 UTCJul 20, 23:05 UTC1h 15m
2026-07-20 UAL1712 - Jul 20, 17:10 UTCJul 20, 20:05 UTC2h 55m
2026-07-20 UAL1712 DFW → SFO Jul 20, 16:44 UTCJul 20, 19:58 UTC3h 14m
2026-07-20 UAL539 PHL → SFO Jul 20, 12:45 UTCJul 20, 14:30 UTC1h 45m
2026-07-20 UAL2094 IAH → LGA Jul 20, 05:55 UTCJul 20, 09:00 UTC3h 5m
2026-07-20 UAL2262 LAS → SFO Jul 20, 02:05 UTCJul 20, 03:20 UTC1h 15m
2026-07-20 UAL2019 - Jul 20, 00:00 UTCJul 20, 00:55 UTC55m
2026-07-19 UAL547 IAH → SFO Jul 19, 16:10 UTCJul 19, 21:35 UTC5h 25m
2026-07-19 UAL2096 - Jul 19, 13:20 UTCJul 19, 14:20 UTC1h 0m
2026-07-19 UAL8138 SFO → PSP Jul 19, 03:15 UTCJul 19, 04:05 UTC50m
2026-07-19 UAL741 BZN → LAX Jul 19, 00:00 UTCJul 19, 01:54 UTC1h 54m
2026-07-18 UAL741 - Jul 18, 20:25 UTCJul 19, 01:55 UTC5h 30m
2026-07-18 UAL2487 - Jul 18, 17:25 UTCJul 18, 18:20 UTC55m
2026-07-18 UAL1481 DEN → PHX Jul 18, 14:30 UTCJul 18, 16:20 UTC1h 50m
2026-07-18 UAL1924 SAN → SFO Jul 18, 02:00 UTCJul 18, 03:55 UTC1h 56m
2026-07-17 UAL2232 DEN → YYC Jul 17, 22:10 UTCJul 18, 00:10 UTC2h 0m
2026-07-17 UAL730 COS → DEN Jul 17, 19:47 UTCJul 17, 20:19 UTC32m
2026-07-17 UAL730 COS → DEN Jul 17, 19:40 UTCJul 17, 20:04 UTC25m
2026-07-17 UAL1111 DEN → COS Jul 17, 17:50 UTCJul 17, 18:10 UTC20m

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 N14231 page for operator, model, and routing details .

Mode-S A0ACF9 frequently asked

What is Mode-S code A0ACF9?
A0ACF9 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N14231.
Where is Mode-S A0ACF9 registered?
Mode-S code A0ACF9 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 A0ACF9 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 22:15 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A0ACF9, octal 50126371, decimal 10,530,041.
What flights does A0ACF9 operate?
Mode-S A0ACF9 has broadcast 20 distinct callsigns, including UAL2192, UAL329, UAL275, UAL2668, UAL2649.