Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

A704F9

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N551UW · AIRBUS A-321 · operated by UMB BANK N A TRUSTEE

Hex
A704F9
Octal
51602371
Decimal
10,945,785
Country
US
Tail
N551UW
Type
A321
No current signal · last broadcast 3h ago
Flights observed
318
Distinct callsigns
20
Country
US
Last broadcast
3h ago

Last known position

Most recent position reported by Mode-S A704F9.

Country allocation

The ICAO 24-bit address A704F9 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
AAL863 - 4 2026-07-06
AAL402 - 4 2026-07-09
AAL2947 American Airlines 4 2026-06-07
AAL2762 American Airlines 4 2026-06-15
AAL1276 American Airlines 4 2026-06-07
AAL777 American Airlines 3 2026-07-07
AAL727 American Airlines 3 2026-05-23
AAL707 American Airlines 3 2026-06-04
AAL3195 American Airlines 3 2026-05-16
AAL2759 - 3 2026-06-26
AAL2670 - 3 2026-06-27
AAL2635 American Airlines 3 2026-05-14
AAL2517 American Airlines 3 2026-05-12
AAL2466 American Airlines 3 2026-06-02
AAL2461 - 3 2026-07-13
AAL2458 American Airlines 3 2026-05-19
AAL2434 - 3 2026-07-13
AAL2387 - 3 2026-06-18
AAL2367 American Airlines 3 2026-06-16
AAL2362 American Airlines 3 2026-05-21

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 AAL3176 - Jul 14, 00:45 UTCJul 14, 03:00 UTC2h 15m
2026-07-13 AAL338 PHX → ORD Jul 13, 19:50 UTCJul 13, 22:55 UTC3h 5m
2026-07-13 AAL2461 SAN → PHX Jul 13, 17:21 UTCJul 13, 18:16 UTC55m
2026-07-13 AAL2461 - Jul 13, 17:25 UTCJul 13, 18:15 UTC50m
2026-07-13 AAL2461 - Jul 13, 14:45 UTCJul 13, 15:45 UTC1h 0m
2026-07-13 AAL2434 ORD → PHX Jul 13, 10:25 UTCJul 13, 13:20 UTC2h 55m
2026-07-13 AAL2434 ORD → PHX Jul 13, 10:23 UTCJul 13, 13:19 UTC2h 56m
2026-07-13 AAL2323 - Jul 13, 03:40 UTCJul 13, 06:30 UTC2h 50m
2026-07-12 AAL1576 - Jul 12, 23:45 UTCJul 13, 02:25 UTC2h 40m
2026-07-12 AAL2945 - Jul 12, 19:50 UTCJul 12, 22:15 UTC2h 25m
2026-07-12 AAL2945 MIA → LGA Jul 12, 19:49 UTCJul 12, 22:15 UTC2h 26m
2026-07-12 AAL899 DFW → MIA Jul 12, 15:55 UTCJul 12, 18:20 UTC2h 25m
2026-07-12 AAL899 DFW → MIA Jul 12, 15:52 UTCJul 12, 18:19 UTC2h 27m
2026-07-12 AAL2558 FLL → DFW Jul 12, 11:10 UTCJul 12, 13:45 UTC2h 35m
2026-07-12 AAL2946 DFW → FLL Jul 12, 00:10 UTCJul 12, 02:35 UTC2h 25m
2026-07-11 AAL2320 - Jul 11, 21:00 UTCJul 11, 22:30 UTC1h 30m
2026-07-11 AAL2320 PNS → DFW Jul 11, 20:56 UTCJul 11, 22:30 UTC1h 34m
2026-07-11 AAL2320 DFW → PNS Jul 11, 18:20 UTCJul 11, 19:40 UTC1h 20m
2026-07-11 AAL2216 - Jul 11, 13:45 UTCJul 11, 16:55 UTC3h 10m
2026-07-11 AAL1483 PSQ → PDX Jul 11, 01:45 UTCJul 11, 07:00 UTC5h 15m
2026-07-11 AAL1483 PHL → PHL Jul 11, 01:35 UTCJul 11, 01:40 UTC5m
2026-07-10 AAL1075 PHL → PHL Jul 10, 15:40 UTCJul 10, 23:20 UTC7h 40m
2026-07-10 AAL794 - Jul 10, 11:15 UTCJul 10, 13:25 UTC2h 10m
2026-07-10 AAL794 FLL → PHL Jul 10, 11:12 UTCJul 10, 13:22 UTC2h 10m
2026-07-10 AAL2946 DFW → FLL Jul 10, 01:45 UTCJul 10, 04:05 UTC2h 20m
2026-07-09 AAL402 - Jul 9, 20:55 UTCJul 10, 00:10 UTC3h 15m
2026-07-09 AAL402 PHL → PHL Jul 9, 19:00 UTCJul 9, 19:05 UTC5m
2026-07-09 AAL402 PHL → PHL Jul 9, 18:20 UTCJul 9, 18:25 UTC5m
2026-07-09 AAL402 DFW → PHL Jul 9, 14:45 UTCJul 9, 17:45 UTC3h 0m
2026-07-09 AAL2928 AUS → DFW Jul 9, 12:05 UTCJul 9, 12:45 UTC40m
2026-07-08 AAL972 DFW → AUS Jul 8, 22:40 UTCJul 8, 23:10 UTC30m
2026-07-08 AAL2081 MCO → DFW Jul 8, 18:45 UTCJul 8, 21:05 UTC2h 20m
2026-07-08 AAL2081 DFW → MCO Jul 8, 15:10 UTCJul 8, 17:20 UTC2h 10m
2026-07-07 AAL777 ORD → BOS Jul 7, 21:20 UTCJul 7, 23:40 UTC2h 20m
2026-07-07 AAL777 ORD → BOS Jul 7, 21:18 UTCJul 7, 23:34 UTC2h 16m
2026-07-07 AAL777 ORD → BOS Jul 7, 17:40 UTCJul 7, 19:55 UTC2h 15m
2026-07-07 AAL1692 PHL → DFW Jul 7, 12:35 UTCJul 7, 15:40 UTC3h 5m
2026-07-07 AAL2285 PDX → PHL Jul 7, 05:45 UTCJul 7, 10:25 UTC4h 40m
2026-07-06 AAL3064 CLT → PDX Jul 6, 23:10 UTCJul 7, 04:10 UTC5h 0m
2026-07-06 AAL3064 CLT → PDX Jul 6, 23:09 UTCJul 7, 04:10 UTC5h 1m
2026-07-06 AAL863 - Jul 6, 14:05 UTCJul 6, 20:45 UTC6h 40m
2026-07-06 AAL3182 - Jul 6, 10:30 UTCJul 6, 12:00 UTC1h 30m
2026-07-06 AAL2763 - Jul 6, 01:55 UTCJul 6, 03:30 UTC1h 35m
2026-07-05 AAL2082 - Jul 5, 23:00 UTCJul 6, 00:15 UTC1h 15m
2026-07-05 AAL2082 MCO → CLT Jul 5, 22:55 UTCJul 6, 00:15 UTC1h 20m
2026-07-05 AAL2082 - Jul 5, 20:20 UTCJul 5, 21:45 UTC1h 25m
2026-07-05 AAL1651 - Jul 5, 14:25 UTCJul 5, 18:30 UTC4h 5m
2026-07-04 AAL2477 - Jul 4, 18:00 UTCJul 4, 18:50 UTC50m
2026-07-04 AAL2315 BOS → PHX Jul 4, 11:20 UTCJul 4, 16:15 UTC4h 55m
2026-07-04 AAL2315 BOS → PHX Jul 4, 10:45 UTCJul 4, 10:50 UTC5m

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 N551UW page for operator, model, and routing details .

Mode-S A704F9 frequently asked

What is Mode-S code A704F9?
A704F9 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N551UW.
Where is Mode-S A704F9 registered?
Mode-S code A704F9 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 A704F9 broadcasting right now?
No active broadcast right now. Last signal was 3h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A704F9, octal 51602371, decimal 10,945,785.
What flights does A704F9 operate?
Mode-S A704F9 has broadcast 20 distinct callsigns, including AAL863, AAL402, AAL2947, AAL2762, AAL1276.