sensors Mode-S transponder

AB879F

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N842DN · BOEING 737-900 · operated by DELTA AIR LINES INC

Hex
AB879F
Octal
52703637
Decimal
11,241,375
Country
US
Tail
N842DN
Type
B739
Broadcasting now · callsign DAL2949 · 31,000 ft
Flights observed
7
Distinct callsigns
3
Country
US
Last broadcast
1d ago

Current position

AB879F is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address AB879F 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 3 distinct

Callsign Airline Flights Last seen
DAL1877 - 3 2026-04-13
DAL2843 Delta Air Lines 2 2026-04-13
DAL1835 Delta Air Lines 2 2026-04-13

Recent flights last 7

DateFlightRouteTakeoffLandingDuration
2026-04-13 DAL2843 LAS → SEA Apr 13, 21:25 UTCApr 13, 23:40 UTC2h 15m
2026-04-13 DAL2843 LAS → SEA Apr 13, 18:00 UTCApr 13, 19:30 UTC1h 30m
2026-04-13 DAL1877 - Apr 13, 14:54 UTCApr 13, 15:57 UTC1h 3m
2026-04-13 DAL1877 - Apr 13, 12:20 UTCApr 13, 13:00 UTC40m
2026-04-13 DAL1877 - Apr 13, 12:05 UTCApr 13, 12:15 UTC10m
2026-04-13 DAL1835 PUJ → MSP Apr 13, 00:20 UTCApr 13, 01:40 UTC1h 20m
2026-04-12 DAL1835 PUJ → MSP Apr 12, 23:55 UTCApr 13, 01:40 UTC1h 45m

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 N842DN page for operator, model, and routing details .

Mode-S AB879F frequently asked

What is Mode-S code AB879F?
AB879F is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N842DN.
Where is Mode-S AB879F registered?
Mode-S code AB879F 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 AB879F broadcasting right now?
Yes. Mode-S AB879F is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AB879F, octal 52703637, decimal 11,241,375.
What flights does AB879F operate?
Mode-S AB879F has broadcast 3 distinct callsigns, including DAL1877, DAL2843, DAL1835.