sensors Mode-S transponder

A515AD

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N427AN · AIRBUS A-321neo · operated by AMERICAN AIRLINES INC

Hex
A515AD
Octal
51212655
Decimal
10,818,989
Country
US
Tail
N427AN
Type
A21N
No current signal · last broadcast 23h ago
Flights observed
11
Distinct callsigns
5
Country
US
Last broadcast
23h ago

Last known position

Most recent position reported by Mode-S A515AD.

Country allocation

The ICAO 24-bit address A515AD 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
AAL1570 American Airlines 4 2026-04-13
AAL2296 - 3 2026-04-13
AAL2490 - 2 2026-04-13
AAL2175 - 1 2026-04-12
AAL1447 American Airlines 1 2026-04-13

Recent flights last 11

DateFlightRouteTakeoffLandingDuration
2026-04-13 AAL1447 MIA → HAV Apr 13, 22:15 UTCApr 14, 00:27 UTC2h 12m
2026-04-13 AAL1570 ATL → PHL Apr 13, 19:50 UTCApr 13, 20:50 UTC1h 0m
2026-04-13 AAL1570 ATL → PHL Apr 13, 17:55 UTCApr 13, 21:14 UTC3h 19m
2026-04-13 AAL1570 ATL → PHL Apr 13, 15:50 UTCApr 13, 16:05 UTC15m
2026-04-13 AAL1570 ATL → PHL Apr 13, 13:20 UTCApr 13, 16:23 UTC3h 3m
2026-04-13 AAL2490 - Apr 13, 08:20 UTCApr 13, 10:20 UTC2h 0m
2026-04-13 AAL2490 - Apr 13, 08:00 UTCApr 13, 10:29 UTC2h 29m
2026-04-13 AAL2296 - Apr 13, 04:20 UTCApr 13, 05:55 UTC1h 35m
2026-04-13 AAL2296 - Apr 13, 03:55 UTCApr 13, 05:55 UTC2h 0m
2026-04-13 AAL2296 - Apr 13, 00:31 UTCApr 13, 05:57 UTC5h 26m
2026-04-12 AAL2175 - Apr 12, 18:45 UTCApr 12, 20:15 UTC1h 30m

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 N427AN page for operator, model, and routing details .

Mode-S A515AD frequently asked

What is Mode-S code A515AD?
A515AD is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N427AN.
Where is Mode-S A515AD registered?
Mode-S code A515AD 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 A515AD broadcasting right now?
No active broadcast right now. Last signal was 23h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A515AD, octal 51212655, decimal 10,818,989.
What flights does A515AD operate?
Mode-S A515AD has broadcast 5 distinct callsigns, including AAL1570, AAL2296, AAL2490, AAL2175, AAL1447.