sensors Mode-S transponder

A63DF3

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N501DA · operated by DELTA AIR LINES INC

Hex
A63DF3
Octal
51436763
Decimal
10,894,835
Country
US
Tail
N501DA
Type
A21N
No current signal · last broadcast 1d ago
Flights observed
10
Distinct callsigns
5
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S A63DF3.

Country allocation

The ICAO 24-bit address A63DF3 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
DAL477 - 3 2026-04-13
DAL356 Delta Air Lines 3 2026-04-13
DAL614 - 2 2026-04-13
DAL615 - 1 2026-04-12
DAL344 Delta Air Lines 1 2026-04-13

Recent flights last 10

DateFlightRouteTakeoffLandingDuration
2026-04-13 DAL344 SEA → LIH Apr 13, 21:45 UTCApr 13, 22:35 UTC50m
2026-04-13 DAL356 SFO → JFK Apr 13, 16:15 UTCApr 13, 18:35 UTC2h 20m
2026-04-13 DAL356 SFO → JFK Apr 13, 15:50 UTCApr 13, 18:35 UTC2h 45m
2026-04-13 DAL356 SFO → JFK Apr 13, 12:57 UTCApr 13, 18:43 UTC5h 46m
2026-04-13 DAL477 - Apr 13, 08:20 UTCApr 13, 11:20 UTC3h 0m
2026-04-13 DAL477 - Apr 13, 07:55 UTCApr 13, 11:20 UTC3h 25m
2026-04-13 DAL477 - Apr 13, 07:00 UTCApr 13, 08:15 UTC1h 15m
2026-04-13 DAL614 - Apr 13, 03:55 UTCApr 13, 04:05 UTC10m
2026-04-13 DAL614 - Apr 13, 00:45 UTCApr 13, 04:05 UTC3h 20m
2026-04-12 DAL615 - Apr 12, 17:40 UTCApr 12, 21:57 UTC4h 17m

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 N501DA page for operator, model, and routing details .

Mode-S A63DF3 frequently asked

What is Mode-S code A63DF3?
A63DF3 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N501DA.
Where is Mode-S A63DF3 registered?
Mode-S code A63DF3 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 A63DF3 broadcasting right now?
No active broadcast right now. Last signal was 1d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A63DF3, octal 51436763, decimal 10,894,835.
What flights does A63DF3 operate?
Mode-S A63DF3 has broadcast 5 distinct callsigns, including DAL477, DAL356, DAL614, DAL615, DAL344.