sensors Mode-S transponder

AC4D1A

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N892DN · BOEING 737-900 · operated by DELTA AIR LINES INC

Hex
AC4D1A
Octal
53046432
Decimal
11,291,930
Country
US
Tail
N892DN
Type
B739
No current signal · last broadcast 13h ago
Flights observed
11
Distinct callsigns
7
Country
US
Last broadcast
13h ago

Last known position

Most recent position reported by Mode-S AC4D1A.

Country allocation

The ICAO 24-bit address AC4D1A 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 7 distinct

Callsign Airline Flights Last seen
DAL573 - 3 2026-04-14
DAL1828 - 2 2026-04-13
DAL1803 Delta Air Lines 2 2026-04-13
DAL2624 - 1 2026-04-13
DAL2407 Delta Air Lines 1 2026-04-13
DAL1958 - 1 2026-04-13
DAL1945 - 1 2026-04-12

Recent flights last 11

DateFlightRouteTakeoffLandingDuration
2026-04-14 DAL573 - Apr 14, 09:10 UTCApr 14, 10:10 UTC1h 0m
2026-04-14 DAL573 - Apr 14, 07:40 UTCApr 14, 09:05 UTC1h 25m
2026-04-14 DAL573 - Apr 14, 06:30 UTCApr 14, 10:07 UTC3h 37m
2026-04-13 DAL1803 SDQ → ATL Apr 13, 20:30 UTCApr 13, 22:10 UTC1h 40m
2026-04-13 DAL1803 SDQ → ATL Apr 13, 18:52 UTCApr 13, 22:03 UTC3h 11m
2026-04-13 DAL1958 - Apr 13, 14:15 UTCApr 13, 17:07 UTC2h 52m
2026-04-13 DAL2407 ORD → LGA Apr 13, 10:05 UTCApr 13, 11:00 UTC55m
2026-04-13 DAL2624 - Apr 13, 02:55 UTCApr 13, 03:48 UTC53m
2026-04-13 DAL1828 - Apr 13, 00:20 UTCApr 13, 00:45 UTC25m
2026-04-12 DAL1828 - Apr 12, 23:55 UTCApr 13, 00:45 UTC50m
2026-04-12 DAL1945 - Apr 12, 17:15 UTCApr 12, 18:25 UTC1h 10m

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 N892DN page for operator, model, and routing details .

Mode-S AC4D1A frequently asked

What is Mode-S code AC4D1A?
AC4D1A is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N892DN.
Where is Mode-S AC4D1A registered?
Mode-S code AC4D1A 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 AC4D1A broadcasting right now?
No active broadcast right now. Last signal was 13h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AC4D1A, octal 53046432, decimal 11,291,930.
What flights does AC4D1A operate?
Mode-S AC4D1A has broadcast 7 distinct callsigns, including DAL573, DAL1828, DAL1803, DAL2624, DAL2407.