sensors Mode-S transponder

A21EFB

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N236BZ · operated by WILMINGTON TRUST CO TRUSTEE

Hex
A21EFB
Octal
50417373
Decimal
10,624,763
Country
US
Tail
N236BZ
Type
BCS3
No current signal · last broadcast 14h ago
Flights observed
16
Distinct callsigns
5
Country
US
Last broadcast
14h ago

Last known position

Most recent position reported by Mode-S A21EFB.

Country allocation

The ICAO 24-bit address A21EFB 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
MXY329 - 5 2026-04-13
MXY353 Breeze Airways 3 2026-04-13
MXY352 Breeze Airways 3 2026-04-13
MXY328 - 3 2026-04-13
MXY351 - 2 2026-04-14

Recent flights last 16

DateFlightRouteTakeoffLandingDuration
2026-04-14 MXY351 - Apr 14, 09:10 UTCApr 14, 10:10 UTC1h 0m
2026-04-14 MXY351 - Apr 14, 07:15 UTCApr 14, 09:05 UTC1h 50m
2026-04-13 MXY329 - Apr 13, 21:50 UTCApr 13, 23:25 UTC1h 35m
2026-04-13 MXY329 - Apr 13, 19:50 UTCApr 13, 20:35 UTC45m
2026-04-13 MXY329 - Apr 13, 18:45 UTCApr 13, 20:10 UTC1h 25m
2026-04-13 MXY328 - Apr 13, 16:15 UTCApr 13, 17:25 UTC1h 10m
2026-04-13 MXY328 - Apr 13, 15:45 UTCApr 13, 16:15 UTC30m
2026-04-13 MXY328 - Apr 13, 13:10 UTCApr 13, 14:35 UTC1h 25m
2026-04-13 MXY353 LAX → MSY Apr 13, 08:20 UTCApr 13, 10:35 UTC2h 15m
2026-04-13 MXY353 LAX → MSY Apr 13, 07:55 UTCApr 13, 10:35 UTC2h 40m
2026-04-13 MXY353 LAX → MSY Apr 13, 07:25 UTCApr 13, 08:15 UTC50m
2026-04-13 MXY352 MSY → LAX Apr 13, 04:20 UTCApr 13, 05:30 UTC1h 10m
2026-04-13 MXY352 MSY → LAX Apr 13, 03:55 UTCApr 13, 05:30 UTC1h 35m
2026-04-13 MXY352 MSY → LAX Apr 13, 01:35 UTCApr 13, 04:15 UTC2h 40m
2026-04-12 MXY329 - Apr 12, 19:25 UTCApr 12, 20:15 UTC50m
2026-04-12 MXY329 - Apr 12, 17:15 UTCApr 12, 17:55 UTC40m

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 N236BZ page for operator, model, and routing details .

Mode-S A21EFB frequently asked

What is Mode-S code A21EFB?
A21EFB is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N236BZ.
Where is Mode-S A21EFB registered?
Mode-S code A21EFB 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 A21EFB broadcasting right now?
No active broadcast right now. Last signal was 14h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A21EFB, octal 50417373, decimal 10,624,763.
What flights does A21EFB operate?
Mode-S A21EFB has broadcast 5 distinct callsigns, including MXY329, MXY353, MXY352, MXY328, MXY351.