sensors Mode-S transponder

A21127

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N232NN · EMBRAER ERJ-170-200 (long wing) · operated by AMERICAN AIRLINES INC

Hex
A21127
Octal
50410447
Decimal
10,621,223
Country
US
Tail
N232NN
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 A21127.

Country allocation

The ICAO 24-bit address A21127 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
ENY4190 - 2 2026-04-13
ENY4179 Envoy Air 2 2026-04-13
ENY3502 - 2 2026-04-13
ENY4220 - 1 2026-04-12
ENY4067 Envoy Air 1 2026-04-14
ENY3517 - 1 2026-04-13
ENY3447 - 1 2026-04-13

Recent flights last 10

DateFlightRouteTakeoffLandingDuration
2026-04-14 ENY4067 DFW → STS Apr 14, 05:15 UTCApr 14, 05:30 UTC15m
2026-04-13 ENY4190 - Apr 13, 23:25 UTCApr 13, 23:40 UTC15m
2026-04-13 ENY4190 - Apr 13, 21:10 UTCApr 13, 22:20 UTC1h 10m
2026-04-13 ENY4179 DTW → DFW Apr 13, 18:40 UTCApr 13, 19:35 UTC55m
2026-04-13 ENY4179 DTW → DFW Apr 13, 17:11 UTCApr 13, 17:46 UTC35m
2026-04-13 ENY3517 - Apr 13, 14:35 UTCApr 13, 15:25 UTC50m
2026-04-13 ENY3447 - Apr 13, 02:20 UTCApr 13, 03:10 UTC50m
2026-04-13 ENY3502 - Apr 13, 00:20 UTCApr 13, 00:25 UTC5m
2026-04-12 ENY3502 - Apr 12, 23:55 UTCApr 13, 00:25 UTC30m
2026-04-12 ENY4220 - Apr 12, 17:15 UTCApr 12, 18:25 UTC1h 10m

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 N232NN page for operator, model, and routing details .

Mode-S A21127 frequently asked

What is Mode-S code A21127?
A21127 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N232NN.
Where is Mode-S A21127 registered?
Mode-S code A21127 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 A21127 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 A21127, octal 50410447, decimal 10,621,223.
What flights does A21127 operate?
Mode-S A21127 has broadcast 7 distinct callsigns, including ENY4190, ENY4179, ENY3502, ENY4220, ENY4067.