Apparatus

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sensors Mode-S transponder

A9BF4B

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N727TW · BOEING 757-200 · operated by DELTA AIR LINES INC

Hex
A9BF4B
Octal
52337513
Decimal
11,124,555
Country
US
Tail
N727TW
Type
B752
Broadcasting now · callsign DAL329 · 10,025 ft
Flights observed
342
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 22:45 UTC

Current position

A9BF4B is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A9BF4B 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
DAL392 Delta Air Lines 25 2026-07-21
DAL329 Delta Air Lines 25 2026-07-17
DAL639 Delta Air Lines 19 2026-07-20
DAL987 - 18 2026-07-18
DAL318 Delta Air Lines 18 2026-07-20
DAL507 Delta Air Lines 17 2026-07-23
DAL695 Delta Air Lines 13 2026-07-23
DAL479 - 13 2026-07-19
DAL321 Delta Air Lines 13 2026-07-20
DAL383 Delta Air Lines 12 2026-06-11
DAL667 Delta Air Lines 11 2026-06-12
DAL437 Delta Air Lines 11 2026-07-19
DAL2004 - 10 2026-07-18
DAL1857 Delta Air Lines 10 2026-07-26
DAL2166 - 8 2026-07-18
DAL570 Delta Air Lines 5 2026-04-29
DAL556 Delta Air Lines 5 2026-06-07
DAL403 Delta Air Lines 5 2026-07-24
DAL363 Delta Air Lines 5 2026-06-24
DAL327 Delta Air Lines 5 2026-04-24

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 DAL1521 MCI → DTW Jul 26, 19:35 UTCJul 26, 22:45 UTC3h 10m
2026-07-26 DAL1857 MSP → PLS Jul 26, 13:40 UTCJul 26, 17:40 UTC4h 0m
2026-07-25 DAL361 DTW → SFO Jul 25, 19:15 UTCJul 25, 23:05 UTC3h 50m
2026-07-25 DAL361 DTW → SFO Jul 25, 13:10 UTCJul 25, 17:40 UTC4h 30m
2026-07-24 DAL1856 PLS → MSP Jul 24, 18:50 UTCJul 24, 22:45 UTC3h 55m
2026-07-24 DAL1856 PLS → MSP Jul 24, 18:49 UTCJul 24, 22:46 UTC3h 57m
2026-07-24 DAL403 ATL → RDU Jul 24, 12:12 UTCJul 24, 17:19 UTC5h 7m
2026-07-24 DAL403 ATL → RDU Jul 24, 12:15 UTCJul 24, 17:20 UTC5h 5m
2026-07-23 DAL396 LGA → ATL Jul 23, 23:50 UTCJul 24, 04:45 UTC4h 55m
2026-07-23 DAL750 ATL → DAY Jul 23, 17:45 UTCJul 23, 22:15 UTC4h 30m
2026-07-23 DAL695 BOS → LAS Jul 23, 11:05 UTCJul 23, 13:15 UTC2h 10m
2026-07-23 DAL507 LGA → ATL Jul 23, 04:20 UTCJul 23, 09:15 UTC4h 55m
2026-07-21 DAL392 DCA → LAX Jul 21, 22:20 UTCJul 22, 03:05 UTC4h 45m
2026-07-21 DAL392 DCA → LAX Jul 21, 15:50 UTCJul 21, 20:45 UTC4h 55m
2026-07-20 DAL318 BOS → SEA Jul 20, 20:55 UTCJul 21, 02:24 UTC5h 29m
2026-07-20 DAL318 BOS → SEA Jul 20, 20:55 UTCJul 21, 02:30 UTC5h 35m
2026-07-20 DAL639 CVG → DEN Jul 20, 13:55 UTCJul 20, 19:05 UTC5h 10m
2026-07-20 DAL639 CVG → DEN Jul 20, 13:54 UTCJul 20, 18:58 UTC5h 4m
2026-07-20 DAL321 JFK → LAS Jul 20, 02:34 UTCJul 20, 07:47 UTC5h 13m
2026-07-20 DAL321 JFK → LAS Jul 20, 02:35 UTCJul 20, 07:50 UTC5h 15m
2026-07-19 DAL437 SFO → ATL Jul 19, 17:55 UTCJul 19, 23:05 UTC5h 10m
2026-07-19 DAL479 BOS → LAX Jul 19, 10:45 UTCJul 19, 16:00 UTC5h 15m
2026-07-18 DAL2166 - Jul 18, 22:50 UTCJul 19, 03:45 UTC4h 55m
2026-07-18 DAL2004 BOS → LAX Jul 18, 15:30 UTCJul 18, 21:00 UTC5h 30m
2026-07-18 DAL987 ATL → BOS Jul 18, 11:21 UTCJul 18, 13:36 UTC2h 15m
2026-07-18 DAL987 - Jul 18, 11:20 UTCJul 18, 12:45 UTC1h 25m
2026-07-17 DAL329 SJU → MSP Jul 17, 21:10 UTCJul 18, 01:20 UTC4h 10m
2026-07-17 DAL329 SJU → MSP Jul 17, 21:09 UTCJul 18, 01:12 UTC4h 3m
2026-07-17 DAL329 SJU → MSP Jul 17, 15:10 UTCJul 17, 19:00 UTC3h 50m
2026-07-17 DAL695 BOS → ATL Jul 17, 11:04 UTCJul 17, 13:05 UTC2h 0m
2026-07-17 DAL507 - Jul 17, 04:39 UTCJul 17, 09:35 UTC4h 55m
2026-07-16 DAL392 DCA → LAX Jul 16, 21:00 UTCJul 17, 01:39 UTC4h 40m
2026-07-16 DAL392 DCA → LAX Jul 16, 20:57 UTCJul 17, 01:42 UTC4h 45m
2026-07-16 DAL392 LAX → DCA Jul 16, 14:45 UTCJul 16, 19:20 UTC4h 35m
2026-07-15 DAL318 BOS → LAX Jul 15, 21:05 UTCJul 16, 02:30 UTC5h 25m
2026-07-15 DAL639 - Jul 15, 13:45 UTCJul 15, 19:00 UTC5h 15m
2026-07-15 DAL321 BOS → LAX Jul 15, 00:52 UTCJul 15, 05:57 UTC5h 5m
2026-07-15 DAL321 BOS → LAX Jul 15, 00:55 UTCJul 15, 06:10 UTC5h 15m
2026-07-14 DAL437 - Jul 14, 18:00 UTCJul 14, 23:05 UTC5h 4m
2026-07-14 DAL479 - Jul 14, 11:20 UTCJul 14, 16:25 UTC5h 5m
2026-07-14 DAL507 - Jul 14, 04:15 UTCJul 14, 09:30 UTC5h 15m
2026-07-14 DAL507 LAX → BOS Jul 14, 04:15 UTCJul 14, 09:29 UTC5h 14m
2026-07-13 DAL318 BOS → LAX Jul 13, 20:50 UTCJul 14, 01:50 UTC5h 0m
2026-07-13 DAL639 - Jul 13, 13:55 UTCJul 13, 19:05 UTC5h 10m
2026-07-13 DAL392 DCA → LAX Jul 13, 01:45 UTCJul 13, 06:20 UTC4h 35m
2026-07-13 DAL392 DCA → LAX Jul 13, 01:41 UTCJul 13, 06:14 UTC4h 33m
2026-07-12 DAL392 - Jul 12, 19:01 UTCJul 12, 23:30 UTC4h 30m
2026-07-12 DAL479 BOS → LAX Jul 12, 10:40 UTCJul 12, 15:55 UTC5h 15m
2026-07-11 DAL2166 - Jul 11, 22:35 UTCJul 12, 02:45 UTC4h 10m
2026-07-11 DAL2166 LAX → BOS Jul 11, 22:32 UTCJul 12, 03:38 UTC5h 6m

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 N727TW page for operator, model, and routing details .

Mode-S A9BF4B frequently asked

What is Mode-S code A9BF4B?
A9BF4B is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N727TW.
Where is Mode-S A9BF4B registered?
Mode-S code A9BF4B 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 A9BF4B broadcasting right now?
Yes. Mode-S A9BF4B is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A9BF4B, octal 52337513, decimal 11,124,555.
What flights does A9BF4B operate?
Mode-S A9BF4B has broadcast 20 distinct callsigns, including DAL392, DAL329, DAL639, DAL987, DAL318.