sensors Mode-S transponder

AE5651

ICAO 24-bit transponder address

Currently assigned to 12-20440 · SIKORSKY UH-60 Black Hawk

Hex
AE5651
Octal
53453121
Decimal
11,425,361
Tail
12-20440
Type
H60
No current signal · last broadcast 1d ago
Flights observed
11
Distinct callsigns
7
Country
-
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S AE5651.

Callsign history 7 distinct

Callsign Airline Flights Last seen
SURF75 - 2 2026-06-30
SURF49 - 2 2026-07-16
SURF31 - 2 2026-06-27
SURF11 - 2 2026-07-16
SURF18 - 1 2026-07-08
SURF15 - 1 2026-07-02
SURF14 - 1 2026-07-15

Recent flights last 11

DateFlightRouteTakeoffLandingDuration
2026-07-16 SURF11 - Jul 16, 14:25 UTCJul 16, 15:00 UTC35m
2026-07-16 SURF49 - Jul 16, 03:00 UTCJul 16, 03:10 UTC10m
2026-07-15 SURF14 HHI → HHI Jul 15, 14:10 UTCJul 15, 14:35 UTC25m
2026-07-15 SURF11 - Jul 15, 00:40 UTCJul 15, 01:15 UTC35m
2026-07-08 SURF18 - Jul 8, 03:10 UTCJul 8, 03:25 UTC15m
2026-07-02 SURF15 - Jul 2, 06:30 UTCJul 2, 06:41 UTC11m
2026-06-30 SURF75 - Jun 30, 06:10 UTCJun 30, 06:30 UTC20m
2026-06-30 SURF75 - Jun 30, 03:40 UTCJun 30, 03:50 UTC10m
2026-06-27 SURF31 HHI → HHI Jun 27, 02:45 UTCJun 27, 03:20 UTC35m
2026-06-26 SURF31 - Jun 26, 01:15 UTCJun 26, 01:34 UTC20m
2026-06-25 SURF49 - Jun 25, 20:34 UTCJun 25, 20:54 UTC20m

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 12-20440 page for operator, model, and routing details .

Mode-S AE5651 frequently asked

What is Mode-S code AE5651?
AE5651 is an ICAO 24-bit transponder address. Assigned to 12-20440.
Is AE5651 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 AE5651, octal 53453121, decimal 11,425,361.
What flights does AE5651 operate?
Mode-S AE5651 has broadcast 7 distinct callsigns, including SURF75, SURF49, SURF31, SURF11, SURF18.