sensors Mode-S transponder

AC66D5

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N899AT · BOEING 717-200 · operated by DELTA AIR LINES INC

Hex
AC66D5
Octal
53063325
Decimal
11,298,517
Country
US
Tail
N899AT
Type
B712
No current signal · last broadcast 1d ago
Flights observed
9
Distinct callsigns
5
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S AC66D5.

Country allocation

The ICAO 24-bit address AC66D5 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
DAL2968 - 4 2026-04-13
DAL1716 Delta Air Lines 2 2026-04-13
DAL2358 Delta Air Lines 1 2026-04-12
DAL1145 - 1 2026-04-12
DAL1118 - 1 2026-04-13

Recent flights last 9

DateFlightRouteTakeoffLandingDuration
2026-04-13 DAL1118 - Apr 13, 21:35 UTCApr 13, 22:25 UTC50m
2026-04-13 DAL1716 ATL → RDU Apr 13, 18:45 UTCApr 13, 19:35 UTC50m
2026-04-13 DAL1716 ATL → RDU Apr 13, 16:35 UTCApr 13, 17:25 UTC50m
2026-04-13 DAL2968 - Apr 13, 14:11 UTCApr 13, 15:29 UTC1h 18m
2026-04-13 DAL2968 - Apr 13, 12:20 UTCApr 13, 12:30 UTC10m
2026-04-13 DAL2968 - Apr 13, 11:55 UTCApr 13, 12:30 UTC35m
2026-04-13 DAL2968 - Apr 13, 11:25 UTCApr 13, 12:15 UTC50m
2026-04-12 DAL2358 RSW → BOS Apr 12, 23:55 UTCApr 13, 00:05 UTC10m
2026-04-12 DAL1145 - Apr 12, 17:15 UTCApr 12, 18:30 UTC1h 15m

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 N899AT page for operator, model, and routing details .

Mode-S AC66D5 frequently asked

What is Mode-S code AC66D5?
AC66D5 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N899AT.
Where is Mode-S AC66D5 registered?
Mode-S code AC66D5 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 AC66D5 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 AC66D5, octal 53063325, decimal 11,298,517.
What flights does AC66D5 operate?
Mode-S AC66D5 has broadcast 5 distinct callsigns, including DAL2968, DAL1716, DAL2358, DAL1145, DAL1118.