sensors Mode-S transponder

ABAB67

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N851DN · BOEING 737-900 · operated by DELTA AIR LINES INC

Hex
ABAB67
Octal
52725547
Decimal
11,250,535
Country
US
Tail
N851DN
Type
B739
No current signal · last broadcast 19h ago
Flights observed
11
Distinct callsigns
6
Country
US
Last broadcast
19h ago

Last known position

Most recent position reported by Mode-S ABAB67.

Country allocation

The ICAO 24-bit address ABAB67 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 6 distinct

Callsign Airline Flights Last seen
DAL365 Delta Air Lines 3 2026-04-14
DAL2401 - 3 2026-04-13
DAL937 Delta Air Lines 2 2026-04-12
DAL517 - 1 2026-04-13
DAL2950 - 1 2026-04-13
DAL1257 - 1 2026-04-13

Recent flights last 11

DateFlightRouteTakeoffLandingDuration
2026-04-14 DAL365 ATL → MEX Apr 14, 09:10 UTCApr 14, 09:55 UTC45m
2026-04-14 DAL365 ATL → MEX Apr 14, 07:10 UTCApr 14, 09:05 UTC1h 55m
2026-04-14 DAL365 ATL → MEX Apr 14, 05:50 UTCApr 14, 09:59 UTC4h 9m
2026-04-13 DAL517 - Apr 13, 21:15 UTCApr 13, 23:40 UTC2h 25m
2026-04-13 DAL2401 EWR → ATL Apr 13, 17:35 UTCApr 13, 19:25 UTC1h 50m
2026-04-13 DAL2401 - Apr 13, 15:50 UTCApr 13, 16:15 UTC25m
2026-04-13 DAL2401 - Apr 13, 14:31 UTCApr 13, 16:11 UTC1h 40m
2026-04-13 DAL2950 BWI → ATL Apr 13, 10:30 UTCApr 13, 11:55 UTC1h 25m
2026-04-13 DAL1257 - Apr 13, 00:43 UTCApr 13, 02:04 UTC1h 21m
2026-04-12 DAL937 MCI → BOS Apr 12, 19:56 UTCApr 12, 22:57 UTC3h 1m
2026-04-12 DAL937 MCI → BOS 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 N851DN page for operator, model, and routing details .

Mode-S ABAB67 frequently asked

What is Mode-S code ABAB67?
ABAB67 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N851DN.
Where is Mode-S ABAB67 registered?
Mode-S code ABAB67 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 ABAB67 broadcasting right now?
No active broadcast right now. Last signal was 19h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex ABAB67, octal 52725547, decimal 11,250,535.
What flights does ABAB67 operate?
Mode-S ABAB67 has broadcast 6 distinct callsigns, including DAL365, DAL2401, DAL937, DAL517, DAL2950.