sensors Mode-S transponder

AA9EEF

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N78361 · EMBRAER ERJ-170-200 (long wing) · operated by UNITED AIRLINES INC

Hex
AA9EEF
Octal
52517357
Decimal
11,181,807
Country
US
Tail
N78361
Type
E75L
No current signal · last broadcast 1d ago
Flights observed
10
Distinct callsigns
7
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S AA9EEF.

Country allocation

The ICAO 24-bit address AA9EEF 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 7 distinct

Callsign Airline Flights Last seen
SKW5633 SkyWest Airlines 3 2026-04-13
SKW5760 - 2 2026-04-13
SKW5299 - 1 2026-04-12
SKW4809 - 1 2026-04-13
SKW4804 - 1 2026-04-13
SKW4681 SkyWest Airlines 1 2026-04-13
SKW4664 - 1 2026-04-13

Recent flights last 10

DateFlightRouteTakeoffLandingDuration
2026-04-13 SKW4664 - Apr 13, 22:50 UTCApr 13, 23:45 UTC55m
2026-04-13 SKW5760 - Apr 13, 19:50 UTCApr 13, 21:00 UTC1h 10m
2026-04-13 SKW5760 - Apr 13, 19:45 UTCApr 13, 21:35 UTC1h 50m
2026-04-13 SKW4804 - Apr 13, 17:07 UTCApr 13, 18:37 UTC1h 30m
2026-04-13 SKW4809 ORD → ICT Apr 13, 14:20 UTCApr 13, 15:50 UTC1h 30m
2026-04-13 SKW5633 LEX → ORD Apr 13, 12:20 UTCApr 13, 12:40 UTC20m
2026-04-13 SKW5633 LEX → ORD Apr 13, 11:55 UTCApr 13, 12:40 UTC45m
2026-04-13 SKW5633 LEX → ORD Apr 13, 11:20 UTCApr 13, 12:36 UTC1h 16m
2026-04-13 SKW4681 DEN → LEX Apr 13, 00:20 UTCApr 13, 02:40 UTC2h 20m
2026-04-12 SKW5299 - Apr 12, 18:00 UTCApr 12, 18:31 UTC31m

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 N78361 page for operator, model, and routing details .

Mode-S AA9EEF frequently asked

What is Mode-S code AA9EEF?
AA9EEF is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N78361.
Where is Mode-S AA9EEF registered?
Mode-S code AA9EEF 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 AA9EEF 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 AA9EEF, octal 52517357, decimal 11,181,807.
What flights does AA9EEF operate?
Mode-S AA9EEF has broadcast 7 distinct callsigns, including SKW5633, SKW5760, SKW5299, SKW4809, SKW4804.