Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

A39B39

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N331TK · BOEING 737 MAX 8 · operated by AMERICAN AIRLINES INC

Hex
A39B39
Octal
50715471
Decimal
10,722,105
Country
US
Tail
N331TK
Type
B38M
Broadcasting now · callsign AAL2851 · 37,000 ft
Flights observed
410
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 22:15 UTC

Current position

A39B39 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A39B39 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
AAL2405 American Airlines 6 2026-04-20
AAL2231 American Airlines 6 2026-04-14
AAL2995 American Airlines 5 2026-04-29
AAL2744 American Airlines 5 2026-05-21
AAL2010 American Airlines 5 2026-05-11
AAL2968 American Airlines 4 2026-04-18
AAL2871 American Airlines 4 2026-05-26
AAL2689 American Airlines 4 2026-07-23
AAL2606 American Airlines 4 2026-07-25
AAL2140 American Airlines 4 2026-07-26
AAL2134 - 4 2026-07-04
AAL1798 American Airlines 4 2026-04-30
AAL1617 American Airlines 4 2026-06-19
AAL924 American Airlines 3 2026-06-16
AAL923 American Airlines 3 2026-06-16
AAL920 American Airlines 3 2026-05-23
AAL763 American Airlines 3 2026-06-08
AAL578 American Airlines 3 2026-06-08
AAL505 American Airlines 3 2026-04-29
AAL438 - 3 2026-06-12

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 AAL2140 LGA → DCA Jul 26, 20:05 UTCJul 26, 22:15 UTC2h 10m
2026-07-26 AAL2140 LGA → DCA Jul 26, 15:25 UTCJul 26, 18:15 UTC2h 50m
2026-07-26 AAL1825 SYR → CLT Jul 26, 12:55 UTCJul 26, 13:55 UTC1h 0m
2026-07-26 AAL3262 ORD → CLT Jul 26, 03:20 UTCJul 26, 04:25 UTC1h 5m
2026-07-25 AAL476 LAS → ORD Jul 25, 21:40 UTCJul 26, 01:25 UTC3h 45m
2026-07-25 AAL597 PHX → SFO Jul 25, 18:00 UTCJul 25, 20:35 UTC2h 35m
2026-07-25 AAL3121 DFW → LGA Jul 25, 11:10 UTCJul 25, 14:30 UTC3h 20m
2026-07-25 AAL3121 DFW → LGA Jul 25, 11:00 UTCJul 25, 14:36 UTC3h 36m
2026-07-25 AAL2606 CLT → MSN Jul 25, 00:20 UTCJul 25, 01:50 UTC1h 30m
2026-07-24 AAL2606 CLT → MSN Jul 24, 22:55 UTCJul 24, 23:10 UTC15m
2026-07-24 AAL1256 MIA → BDL Jul 24, 18:15 UTCJul 24, 20:40 UTC2h 25m
2026-07-24 AAL1136 MIA → SXM Jul 24, 12:20 UTCJul 24, 18:15 UTC5h 55m
2026-07-24 AAL1136 MIA → SXM Jul 24, 12:18 UTCJul 24, 15:59 UTC3h 41m
2026-07-23 AAL2689 ORD → BDL Jul 23, 16:25 UTCJul 23, 20:31 UTC4h 6m
2026-07-23 AAL2689 ORD → BDL Jul 23, 16:30 UTCJul 23, 20:40 UTC4h 10m
2026-07-23 AAL1694 TPA → DFW Jul 23, 13:04 UTCJul 23, 14:42 UTC1h 38m
2026-07-23 AAL1694 TPA → DFW Jul 23, 13:05 UTCJul 23, 14:35 UTC1h 30m
2026-07-23 AAL1197 MKE → CLT Jul 23, 04:25 UTCJul 23, 05:50 UTC1h 25m
2026-07-23 AAL1197 MKE → CLT Jul 23, 04:25 UTCJul 23, 05:49 UTC1h 24m
2026-07-22 AAL3191 LGA → MIA Jul 22, 22:55 UTCJul 23, 03:10 UTC4h 15m
2026-07-22 AAL3283 LAX → DCA Jul 22, 19:10 UTCJul 22, 20:00 UTC50m
2026-07-22 AAL3283 LAX → DCA Jul 22, 15:35 UTCJul 22, 19:05 UTC3h 30m
2026-07-22 AAL1209 PHL → PHX Jul 22, 04:30 UTCJul 22, 05:25 UTC55m
2026-07-21 AAL1639 CLT → LGA Jul 21, 19:05 UTCJul 22, 01:55 UTC6h 50m
2026-07-21 AAL518 SAN → ORD Jul 21, 13:40 UTCJul 21, 17:30 UTC3h 50m
2026-07-21 AAL2463 SNA → PHX Jul 21, 01:15 UTCJul 21, 05:50 UTC4h 35m
2026-07-20 AAL1126 BOG → MIA Jul 20, 20:09 UTCJul 20, 23:29 UTC3h 20m
2026-07-20 AAL1126 - Jul 20, 20:10 UTCJul 20, 20:15 UTC5m
2026-07-20 AAL1123 - Jul 20, 15:20 UTCJul 20, 15:45 UTC25m
2026-07-20 AAL1123 MIA → BOG Jul 20, 15:19 UTCJul 20, 18:31 UTC3h 12m
2026-07-20 AAL9787 VQQ → MIA Jul 20, 12:25 UTCJul 20, 13:20 UTC55m
2026-07-20 AAL9787 VQQ → MIA Jul 20, 12:25 UTCJul 20, 13:20 UTC55m
2026-07-08 AAL9781 - Jul 8, 22:15 UTCJul 8, 23:05 UTC50m
2026-07-08 AAL9603 SEA → MIA Jul 8, 15:09 UTCJul 8, 20:29 UTC5h 20m
2026-07-08 AAL9603 SEA → MIA Jul 8, 15:10 UTCJul 8, 20:30 UTC5h 20m
2026-07-06 AAL654 - Jul 6, 12:35 UTCJul 6, 18:10 UTC5h 35m
2026-07-06 AAL2321 PHL → LAX Jul 6, 01:35 UTCJul 6, 03:05 UTC1h 30m
2026-07-05 AAL1758 DEN → CLT Jul 5, 20:25 UTCJul 5, 23:11 UTC2h 46m
2026-07-05 AAL1758 - Jul 5, 20:30 UTCJul 5, 23:15 UTC2h 45m
2026-07-05 AAL1758 - Jul 5, 15:45 UTCJul 5, 18:40 UTC2h 55m
2026-07-05 AAL2866 - Jul 5, 12:15 UTCJul 5, 13:40 UTC1h 25m
2026-07-04 AAL2134 - Jul 4, 15:55 UTCJul 4, 17:25 UTC1h 30m
2026-07-04 AAL2866 - Jul 4, 12:15 UTCJul 4, 13:40 UTC1h 25m
2026-07-04 AAL1072 - Jul 4, 02:05 UTCJul 4, 03:55 UTC1h 50m
2026-07-03 AAL2788 COS → DFW Jul 3, 20:20 UTCJul 4, 00:07 UTC3h 47m
2026-07-03 AAL2795 ORD → MCO Jul 3, 15:00 UTCJul 3, 21:20 UTC6h 20m
2026-07-03 AAL1575 - Jul 3, 11:50 UTCJul 3, 13:00 UTC1h 10m
2026-07-02 AAL1997 - Jul 2, 16:45 UTCJul 2, 21:00 UTC4h 15m
2026-07-02 AAL1741 - Jul 2, 13:15 UTCJul 2, 14:35 UTC1h 20m
2026-07-01 AAL3251 - Jul 1, 23:50 UTCJul 2, 02:50 UTC3h 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 N331TK page for operator, model, and routing details .

Mode-S A39B39 frequently asked

What is Mode-S code A39B39?
A39B39 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N331TK.
Where is Mode-S A39B39 registered?
Mode-S code A39B39 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 A39B39 broadcasting right now?
Yes. Mode-S A39B39 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A39B39, octal 50715471, decimal 10,722,105.
What flights does A39B39 operate?
Mode-S A39B39 has broadcast 20 distinct callsigns, including AAL2405, AAL2231, AAL2995, AAL2744, AAL2010.