sensors Mode-S transponder

AC9ABC

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N911DQ · BOEING 737-900 · operated by DELTA AIR LINES INC

Hex
AC9ABC
Octal
53115274
Decimal
11,311,804
Country
US
Tail
N911DQ
Type
B739
Broadcasting now · callsign DAL2548 · 35,525 ft
Flights observed
7
Distinct callsigns
4
Country
US
Last broadcast
23h ago

Current position

AC9ABC is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address AC9ABC 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
DAL2588 - 3 2026-04-13
DAL708 Delta Air Lines 2 2026-04-13
DAL851 Delta Air Lines 1 2026-04-13
DAL2914 - 1 2026-04-12

Recent flights last 7

DateFlightRouteTakeoffLandingDuration
2026-04-13 DAL851 YYC → MSP Apr 13, 20:30 UTCApr 13, 23:40 UTC3h 10m
2026-04-13 DAL2588 - Apr 13, 16:15 UTCApr 13, 18:55 UTC2h 40m
2026-04-13 DAL2588 - Apr 13, 15:50 UTCApr 13, 18:55 UTC3h 5m
2026-04-13 DAL2588 - Apr 13, 14:48 UTCApr 13, 18:43 UTC3h 55m
2026-04-13 DAL708 LAX → DTW Apr 13, 00:20 UTCApr 13, 02:20 UTC2h 0m
2026-04-12 DAL708 LAX → DTW Apr 12, 23:55 UTCApr 13, 02:20 UTC2h 25m
2026-04-12 DAL2914 - Apr 12, 19:00 UTCApr 12, 20:15 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 N911DQ page for operator, model, and routing details .

Mode-S AC9ABC frequently asked

What is Mode-S code AC9ABC?
AC9ABC is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N911DQ.
Where is Mode-S AC9ABC registered?
Mode-S code AC9ABC 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 AC9ABC broadcasting right now?
Yes. Mode-S AC9ABC is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AC9ABC, octal 53115274, decimal 11,311,804.
What flights does AC9ABC operate?
Mode-S AC9ABC has broadcast 4 distinct callsigns, including DAL2588, DAL708, DAL851, DAL2914.