Apparatus

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sensors Mode-S transponder

A641BF

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N502DX · AIRBUS A-321neo · operated by DELTA AIR LINES INC

Hex
A641BF
Octal
51440677
Decimal
10,895,807
Country
US
Tail
N502DX
Type
A21N
Broadcasting now · callsign DAL419 · 4,600 ft
Flights observed
11
Distinct callsigns
5
Country
US
Last broadcast
1d ago

Current position

A641BF is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A641BF 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 5 distinct

Callsign Airline Flights Last seen
DAL800 Delta Air Lines 5 2026-04-13
DAL338 - 3 2026-04-13
DAL841 - 1 2026-04-13
DAL699 - 1 2026-04-12
DAL1194 - 1 2026-04-13

Recent flights last 11

DateFlightRouteTakeoffLandingDuration
2026-04-13 DAL841 SLC → LAX Apr 13, 21:20 UTCApr 13, 22:55 UTC1h 35m
2026-04-13 DAL1194 LAX → SLC Apr 13, 18:10 UTCApr 13, 19:30 UTC1h 20m
2026-04-13 DAL800 DEN → ATL Apr 13, 16:15 UTCApr 13, 16:35 UTC20m
2026-04-13 DAL800 DEN → ATL Apr 13, 15:50 UTCApr 13, 16:35 UTC45m
2026-04-13 DAL800 DEN → ATL Apr 13, 12:20 UTCApr 13, 16:15 UTC3h 55m
2026-04-13 DAL800 DEN → ATL Apr 13, 11:55 UTCApr 13, 15:50 UTC3h 55m
2026-04-13 DAL800 DEN → ATL Apr 13, 11:27 UTCApr 13, 16:30 UTC5h 3m
2026-04-13 DAL338 - Apr 13, 00:20 UTCApr 13, 01:00 UTC40m
2026-04-12 DAL338 - Apr 12, 23:55 UTCApr 13, 01:00 UTC1h 5m
2026-04-12 DAL338 - Apr 12, 19:30 UTCApr 12, 20:15 UTC45m
2026-04-12 DAL699 - Apr 12, 17:15 UTCApr 12, 17:30 UTC15m

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 N502DX page for operator, model, and routing details .

Mode-S A641BF frequently asked

What is Mode-S code A641BF?
A641BF is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N502DX.
Where is Mode-S A641BF registered?
Mode-S code A641BF 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 A641BF broadcasting right now?
Yes. Mode-S A641BF is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A641BF, octal 51440677, decimal 10,895,807.
What flights does A641BF operate?
Mode-S A641BF has broadcast 5 distinct callsigns, including DAL800, DAL338, DAL841, DAL699, DAL1194.