Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

A39BFA

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N33103 · BOEING 757-200 · operated by WELLS FARGO TRUST CO NA TRUSTEE

Hex
A39BFA
Octal
50715772
Decimal
10,722,298
Country
US
Tail
N33103
Type
B752
No current signal · last broadcast Jul 26, 19:40 UTC
Flights observed
221
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 19:40 UTC

Last known position

Most recent position reported by Mode-S A39BFA.

Country allocation

The ICAO 24-bit address A39BFA 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
UAL1759 United Airlines 7 2026-05-29
UAL1758 United Airlines 7 2026-05-29
UAL887 - 6 2026-07-16
UAL351 - 6 2026-07-15
UAL2679 - 6 2026-07-16
UAL2307 United Airlines 6 2026-05-27
UAL145 United Airlines 6 2026-06-03
UAL743 United Airlines 5 2026-04-20
UAL2641 United Airlines 5 2026-06-03
UAL2127 - 5 2026-07-10
UAL2115 United Airlines 5 2026-07-20
UAL144 United Airlines 5 2026-06-03
UAL886 - 4 2026-07-15
UAL648 United Airlines 4 2026-04-27
UAL350 - 4 2026-07-14
UAL274 United Airlines 4 2026-07-25
UAL2359 United Airlines 4 2026-04-14
UAL2191 United Airlines 4 2026-04-15
UAL1700 - 4 2026-07-16
UAL36 United Airlines 3 2026-05-16

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL229 BZN → SFO Jul 26, 12:00 UTCJul 26, 19:30 UTC7h 30m
2026-07-26 UAL229 BZN → SFO Jul 26, 11:40 UTCJul 26, 11:45 UTC5m
2026-07-26 UAL317 IAH → PHL Jul 26, 03:40 UTCJul 26, 09:55 UTC6h 16m
2026-07-25 UAL274 RDU → EWR Jul 25, 18:45 UTCJul 25, 23:35 UTC4h 50m
2026-07-25 UAL1095 MYR → EWR Jul 25, 10:40 UTCJul 25, 16:25 UTC5h 45m
2026-07-24 UAL336T SFO → SAN Jul 24, 18:30 UTCJul 24, 23:00 UTC4h 30m
2026-07-24 UAL1095 MYR → EWR Jul 24, 10:45 UTCJul 24, 16:00 UTC5h 15m
2026-07-21 UAL228 IAD → DUB Jul 21, 03:05 UTCJul 21, 04:30 UTC1h 25m
2026-07-20 UAL336J SFO → IAD Jul 20, 18:10 UTCJul 20, 22:45 UTC4h 35m
2026-07-20 UAL2115 MIA → EWR Jul 20, 10:25 UTCJul 20, 15:40 UTC5h 15m
2026-07-20 UAL1283 DEN → EWR Jul 20, 03:35 UTCJul 20, 06:30 UTC2h 55m
2026-07-20 UAL1283 DEN → EWR Jul 20, 03:35 UTCJul 20, 06:40 UTC3h 5m
2026-07-19 UAL663 DEN → ABQ Jul 19, 20:10 UTCJul 19, 23:40 UTC3h 30m
2026-07-18 UAL271 - Jul 18, 13:50 UTCJul 18, 14:20 UTC30m
2026-07-18 UAL271 SNN → EWR Jul 18, 13:42 UTCJul 18, 20:14 UTC6h 32m
2026-07-18 UAL271 SNN → EWR Jul 18, 13:42 UTCJul 18, 20:15 UTC6h 33m
2026-07-18 UAL270 - Jul 18, 05:10 UTCJul 18, 11:00 UTC5h 50m
2026-07-17 UAL274 RDU → EWR Jul 17, 18:50 UTCJul 18, 00:00 UTC5h 10m
2026-07-17 UAL2115 EWR → SFO Jul 17, 10:15 UTCJul 17, 15:40 UTC5h 25m
2026-07-16 UAL1700 - Jul 16, 23:25 UTCJul 17, 04:14 UTC4h 50m
2026-07-16 UAL2679 - Jul 16, 15:14 UTCJul 16, 20:09 UTC4h 55m
2026-07-16 UAL2679 EWR → LAX Jul 16, 15:07 UTCJul 16, 20:04 UTC4h 57m
2026-07-16 UAL887 - Jul 16, 04:55 UTCJul 16, 12:00 UTC7h 5m
2026-07-16 UAL887 LIM → EWR Jul 16, 04:29 UTCJul 16, 11:56 UTC7h 27m
2026-07-15 UAL886 - Jul 15, 19:30 UTCJul 16, 02:30 UTC7h 0m
2026-07-15 UAL351 - Jul 15, 07:50 UTCJul 15, 15:55 UTC8h 5m
2026-07-14 UAL350 - Jul 14, 22:10 UTCJul 15, 05:05 UTC6h 54m
2026-07-14 UAL316 DUB → EWR Jul 14, 13:20 UTCJul 14, 20:00 UTC6h 40m
2026-07-14 UAL317 - Jul 14, 05:00 UTCJul 14, 11:15 UTC6h 15m
2026-07-14 UAL317 EWR → DUB Jul 14, 04:42 UTCJul 14, 11:02 UTC6h 20m
2026-07-13 UAL2227 - Jul 13, 21:15 UTCJul 14, 02:15 UTC5h 0m
2026-07-13 UAL2227 LAX → EWR Jul 13, 21:10 UTCJul 14, 02:15 UTC5h 5m
2026-07-13 UAL2679 - Jul 13, 14:55 UTCJul 13, 19:50 UTC4h 55m
2026-07-13 UAL887 - Jul 13, 04:45 UTCJul 13, 11:55 UTC7h 10m
2026-07-12 UAL886 - Jul 12, 19:20 UTCJul 13, 02:20 UTC7h 0m
2026-07-12 UAL351 - Jul 12, 08:01 UTCJul 12, 08:30 UTC30m
2026-07-12 UAL351 AGP → EWR Jul 12, 07:52 UTCJul 12, 15:49 UTC7h 57m
2026-07-12 UAL351 AGP → EWR Jul 12, 07:52 UTCJul 12, 15:46 UTC7h 54m
2026-07-11 UAL350 - Jul 11, 22:35 UTCJul 11, 23:40 UTC1h 5m
2026-07-11 UAL350 EWR → AGP Jul 11, 22:20 UTCJul 12, 05:06 UTC6h 46m
2026-07-11 UAL1403 - Jul 11, 13:15 UTCJul 11, 18:05 UTC4h 50m
2026-07-11 UAL1403 LAX → EWR Jul 11, 13:18 UTCJul 11, 18:06 UTC4h 48m
2026-07-11 UAL712 EWR → LAX Jul 11, 00:38 UTCJul 11, 06:49 UTC6h 11m
2026-07-11 UAL712 EWR → LAX Jul 11, 01:25 UTCJul 11, 06:45 UTC5h 20m
2026-07-10 UAL2127 - Jul 10, 17:55 UTCJul 10, 22:25 UTC4h 30m
2026-07-10 UAL2127 LAX → EWR Jul 10, 17:49 UTCJul 10, 22:23 UTC4h 34m
2026-07-10 UAL2434 - Jul 10, 10:20 UTCJul 10, 15:35 UTC5h 15m
2026-07-09 UAL1700 - Jul 9, 23:25 UTCJul 10, 04:15 UTC4h 50m
2026-07-09 UAL1700 LAX → EWR Jul 9, 23:26 UTCJul 10, 04:12 UTC4h 46m
2026-07-09 UAL2679 EWR → LAX Jul 9, 15:32 UTCJul 9, 20:32 UTC5h 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 N33103 page for operator, model, and routing details .

Mode-S A39BFA frequently asked

What is Mode-S code A39BFA?
A39BFA is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N33103.
Where is Mode-S A39BFA registered?
Mode-S code A39BFA 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 A39BFA broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 19:40 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A39BFA, octal 50715772, decimal 10,722,298.
What flights does A39BFA operate?
Mode-S A39BFA has broadcast 20 distinct callsigns, including UAL1759, UAL1758, UAL887, UAL351, UAL2679.