sensors Mode-S transponder

AC50D1

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N893DN · BOEING 737-900 · operated by DELTA AIR LINES INC

Hex
AC50D1
Octal
53050321
Decimal
11,292,881
Country
US
Tail
N893DN
Type
B739
No current signal · last broadcast 1d ago
Flights observed
6
Distinct callsigns
4
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S AC50D1.

Country allocation

The ICAO 24-bit address AC50D1 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 4 distinct

Callsign Airline Flights Last seen
DAL349 Delta Air Lines 2 2026-04-12
DAL2312 - 2 2026-04-13
DAL1688 - 1 2026-04-13
DAL1531 - 1 2026-04-13

Recent flights last 6

DateFlightRouteTakeoffLandingDuration
2026-04-13 DAL2312 EWR → ATL Apr 13, 21:00 UTCApr 13, 22:45 UTC1h 45m
2026-04-13 DAL2312 - Apr 13, 17:29 UTCApr 13, 19:04 UTC1h 35m
2026-04-13 DAL1688 ABQ → ATL Apr 13, 13:15 UTCApr 13, 15:40 UTC2h 25m
2026-04-13 DAL1531 - Apr 13, 01:05 UTCApr 13, 04:00 UTC2h 55m
2026-04-12 DAL349 LGA → ATL Apr 12, 20:05 UTCApr 12, 20:15 UTC10m
2026-04-12 DAL349 LGA → ATL Apr 12, 17:15 UTCApr 12, 18:10 UTC55m

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 N893DN page for operator, model, and routing details .

Mode-S AC50D1 frequently asked

What is Mode-S code AC50D1?
AC50D1 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N893DN.
Where is Mode-S AC50D1 registered?
Mode-S code AC50D1 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 AC50D1 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 AC50D1, octal 53050321, decimal 11,292,881.
What flights does AC50D1 operate?
Mode-S AC50D1 has broadcast 4 distinct callsigns, including DAL349, DAL2312, DAL1688, DAL1531.