Apparatus

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sensors Mode-S transponder

A39FB7

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N33209 · BOEING 737-800 · operated by UNITED AIRLINES INC

Hex
A39FB7
Octal
50717667
Decimal
10,723,255
Country
US
Tail
N33209
Type
B738
No current signal · last broadcast 5h ago
Flights observed
370
Distinct callsigns
20
Country
US
Last broadcast
5h ago

Last known position

Most recent position reported by Mode-S A39FB7.

Country allocation

The ICAO 24-bit address A39FB7 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
UAL565 United Airlines 5 2026-06-03
UAL275 - 5 2026-07-06
UAL2644 - 5 2026-07-10
UAL574 United Airlines 4 2026-05-29
UAL3898 United Airlines 4 2026-06-07
UAL364 - 4 2026-06-17
UAL2745 - 4 2026-07-11
UAL2487 - 4 2026-06-24
UAL1911 - 4 2026-07-06
UAL1799 United Airlines 4 2026-06-01
UAL1733 United Airlines 4 2026-05-19
UAL694 United Airlines 3 2026-06-29
UAL325 - 3 2026-06-25
UAL2865 - 3 2026-06-15
UAL2655 - 3 2026-07-02
UAL2442 - 3 2026-07-04
UAL2287 United Airlines 3 2026-04-20
UAL2144 United Airlines 3 2026-05-18
UAL2142 - 3 2026-07-14
UAL2098 - 3 2026-06-28

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 UAL2142 SFO → SAN Jul 14, 08:23 UTCJul 14, 09:15 UTC52m
2026-07-14 UAL2142 SFO → SAN Jul 14, 08:05 UTCJul 14, 09:15 UTC1h 10m
2026-07-14 UAL1267 LAS → SFO Jul 14, 03:25 UTCJul 14, 04:45 UTC1h 20m
2026-07-14 UAL2338 DEN → LAS Jul 14, 00:45 UTCJul 14, 02:15 UTC1h 30m
2026-07-13 UAL2012 BWI → DEN Jul 13, 20:30 UTCJul 13, 23:35 UTC3h 5m
2026-07-13 UAL1362 DEN → BWI Jul 13, 16:00 UTCJul 13, 19:05 UTC3h 5m
2026-07-13 UAL2185 MFR → DEN Jul 13, 12:00 UTCJul 13, 14:05 UTC2h 5m
2026-07-13 UAL663 DEN → MFR Jul 13, 01:50 UTCJul 13, 03:50 UTC2h 0m
2026-07-12 UAL1191 BUR → DEN Jul 12, 22:45 UTCJul 13, 00:35 UTC1h 50m
2026-07-12 UAL2411 DEN → BUR Jul 12, 01:45 UTCJul 12, 03:35 UTC1h 50m
2026-07-11 UAL1322 - Jul 11, 23:20 UTCJul 12, 00:01 UTC40m
2026-07-11 UAL513 - Jul 11, 19:45 UTCJul 11, 20:25 UTC40m
2026-07-11 UAL513 DEN → BZN Jul 11, 19:49 UTCJul 11, 20:56 UTC1h 7m
2026-07-11 UAL586 SJC → DEN Jul 11, 15:50 UTCJul 11, 18:00 UTC2h 10m
2026-07-11 UAL2745 - Jul 11, 03:01 UTCJul 11, 03:45 UTC45m
2026-07-11 UAL2745 DEN → SJC Jul 11, 02:50 UTCJul 11, 05:00 UTC2h 10m
2026-07-10 UAL2644 PHL → DEN Jul 10, 21:05 UTCJul 11, 01:15 UTC4h 10m
2026-07-10 UAL2644 - Jul 10, 20:25 UTCJul 10, 20:30 UTC5m
2026-07-10 UAL2644 PHL → DEN Jul 10, 20:29 UTCJul 11, 01:22 UTC4h 53m
2026-07-10 UAL1575 DEN → PHL Jul 10, 15:40 UTCJul 10, 19:00 UTC3h 20m
2026-07-10 UAL1234 GEG → DEN Jul 10, 12:25 UTCJul 10, 14:15 UTC1h 50m
2026-07-10 UAL778 DEN → GEG Jul 10, 06:10 UTCJul 10, 08:00 UTC1h 50m
2026-07-10 UAL2644 PHL → DEN Jul 10, 01:15 UTCJul 10, 04:55 UTC3h 40m
2026-07-09 UAL2644 PHL → PHL Jul 9, 22:55 UTCJul 9, 23:10 UTC15m
2026-07-09 UAL1575 DEN → PHL Jul 9, 16:05 UTCJul 9, 19:10 UTC3h 5m
2026-07-09 UAL550 YYC → DEN Jul 9, 12:10 UTCJul 9, 14:00 UTC1h 50m
2026-07-09 UAL720T DEN → YYC Jul 9, 04:15 UTCJul 9, 06:15 UTC2h 0m
2026-07-08 UAL486 - Jul 8, 20:45 UTCJul 9, 00:20 UTC3h 35m
2026-07-08 UAL1790 EWR → MYR Jul 8, 00:25 UTCJul 8, 03:05 UTC2h 40m
2026-07-07 UAL2745 - Jul 7, 19:55 UTCJul 7, 22:50 UTC2h 55m
2026-07-07 UAL2745 GRR → DEN Jul 7, 19:50 UTCJul 7, 22:47 UTC2h 57m
2026-07-07 UAL2637 DEN → GRR Jul 7, 16:10 UTCJul 7, 18:15 UTC2h 5m
2026-07-07 UAL337 - Jul 7, 13:20 UTCJul 7, 14:45 UTC1h 25m
2026-07-07 UAL2432 SFO → LAS Jul 7, 03:05 UTCJul 7, 05:15 UTC2h 10m
2026-07-07 UAL2432 SFO → LAS Jul 7, 03:01 UTCJul 7, 05:12 UTC2h 11m
2026-07-06 UAL1911 - Jul 6, 22:00 UTCJul 7, 00:30 UTC2h 30m
2026-07-06 UAL275 - Jul 6, 20:05 UTCJul 6, 20:20 UTC15m
2026-07-06 UAL275 - Jul 6, 18:00 UTCJul 6, 18:25 UTC25m
2026-07-06 UAL2857 - Jul 6, 00:40 UTCJul 6, 01:30 UTC50m
2026-07-04 UAL1242 - Jul 4, 21:05 UTCJul 4, 21:20 UTC15m
2026-07-04 UAL1487 - Jul 4, 15:20 UTCJul 4, 19:55 UTC4h 35m
2026-07-04 UAL2442 - Jul 4, 11:30 UTCJul 4, 13:25 UTC1h 55m
2026-07-04 UAL2442 CVG → IAH Jul 4, 10:50 UTCJul 4, 13:26 UTC2h 36m
2026-07-04 UAL2069 - Jul 4, 02:00 UTCJul 4, 03:50 UTC1h 50m
2026-07-04 UAL2069 IAH → CVG Jul 4, 02:12 UTCJul 4, 03:54 UTC1h 42m
2026-07-04 UAL1911 - Jul 4, 00:20 UTCJul 4, 00:35 UTC15m
2026-07-03 UAL1911 GUA → IAH Jul 3, 22:01 UTCJul 4, 00:30 UTC2h 29m
2026-07-03 UAL1911 - Jul 3, 22:15 UTCJul 3, 22:25 UTC10m
2026-07-03 UAL275 - Jul 3, 20:00 UTCJul 3, 20:15 UTC15m
2026-07-03 UAL275 - Jul 3, 17:55 UTCJul 3, 18:15 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 N33209 page for operator, model, and routing details .

Mode-S A39FB7 frequently asked

What is Mode-S code A39FB7?
A39FB7 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N33209.
Where is Mode-S A39FB7 registered?
Mode-S code A39FB7 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 A39FB7 broadcasting right now?
No active broadcast right now. Last signal was 5h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A39FB7, octal 50717667, decimal 10,723,255.
What flights does A39FB7 operate?
Mode-S A39FB7 has broadcast 20 distinct callsigns, including UAL565, UAL275, UAL2644, UAL574, UAL3898.