Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

A21C4C

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N235NN · EMBRAER ERJ-170-200 (long wing) · operated by AMERICAN AIRLINES INC

Hex
A21C4C
Octal
50416114
Decimal
10,624,076
Country
US
Tail
N235NN
Type
E75L
Broadcasting now · callsign ENY4017 · 13,900 ft
Flights observed
320
Distinct callsigns
20
Country
US
Last broadcast
3h ago

Current position

A21C4C is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A21C4C 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 20 distinct

Callsign Airline Flights Last seen
ENY3560 Envoy Air 8 2026-05-29
ENY3415 Envoy Air 8 2026-04-26
ENY4236 Envoy Air 7 2026-04-26
ENY3509 Envoy Air 7 2026-04-26
ENY3939 Envoy Air 6 2026-05-18
ENY4289 - 5 2026-04-16
ENY4235 Envoy Air 5 2026-04-27
ENY3908 Envoy Air 5 2026-05-11
ENY3562 Envoy Air 5 2026-05-27
ENY3508 Envoy Air 5 2026-05-21
ENY4165 - 4 2026-04-16
ENY3609 Envoy Air 4 2026-05-09
ENY3592 Envoy Air 4 2026-04-14
ENY3569 Envoy Air 4 2026-05-19
ENY3503 Envoy Air 4 2026-04-27
ENY3496 - 4 2026-04-13
ENY3418 Envoy Air 4 2026-05-22
ENY3365 Envoy Air 4 2026-04-30
ENY4124 Envoy Air 3 2026-04-20
ENY4123 Envoy Air 3 2026-05-04

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-05-29 ENY3560 ORD → RDU May 29, 21:30 UTCMay 29, 22:10 UTC40m
2026-05-29 ENY3560 ORD → RDU May 29, 19:45 UTCMay 29, 20:25 UTC40m
2026-05-29 ENY3844 ORD → EYW May 29, 16:15 UTCMay 29, 17:45 UTC1h 30m
2026-05-29 ENY3844 ORD → EYW May 29, 13:20 UTCMay 29, 14:30 UTC1h 10m
2026-05-29 ENY3965 CMH → ORD May 29, 11:25 UTCMay 29, 11:50 UTC25m
2026-05-29 ENY4054 CLT → GSO May 29, 01:30 UTCMay 29, 01:50 UTC20m
2026-05-28 ENY3519 ORD → ORF May 28, 20:55 UTCMay 28, 22:35 UTC1h 40m
2026-05-28 ENY3519 ORD → ORF May 28, 20:49 UTCMay 28, 22:34 UTC1h 45m
2026-05-28 ENY3519 ORD → ORF May 28, 18:00 UTCMay 28, 19:35 UTC1h 35m
2026-05-28 ENY3563 BOS → IND May 28, 16:00 UTCMay 28, 16:40 UTC40m
2026-05-28 ENY3563 BOS → IND May 28, 15:55 UTCMay 28, 16:40 UTC45m
2026-05-28 ENY3563 BOS → IND May 28, 14:10 UTCMay 28, 14:45 UTC35m
2026-05-28 ENY3940 PHX → SBA May 28, 10:55 UTCMay 28, 11:55 UTC1h 0m
2026-05-28 ENY3940 PHX → SBA May 28, 10:54 UTCMay 28, 11:48 UTC54m
2026-05-28 ENY3917 BRO → DFW May 28, 03:00 UTCMay 28, 04:10 UTC1h 10m
2026-05-27 ENY3633 STL → ORD May 27, 23:55 UTCMay 28, 01:15 UTC1h 20m
2026-05-27 ENY3633 STL → ORD May 27, 21:20 UTCMay 27, 22:50 UTC1h 30m
2026-05-27 ENY3562 CWA → ORD May 27, 18:55 UTCMay 27, 19:35 UTC40m
2026-05-27 ENY3562 CWA → ORD May 27, 18:49 UTCMay 27, 19:35 UTC46m
2026-05-27 ENY3562 CWA → ORD May 27, 17:25 UTCMay 27, 18:00 UTC35m
2026-05-27 ENY3871 BOS → ORD May 27, 14:05 UTCMay 27, 15:35 UTC1h 30m
2026-05-27 ENY3960 CVG → ORD May 27, 03:24 UTCMay 27, 04:41 UTC1h 17m
2026-05-27 ENY3466 BOS → IND May 27, 00:55 UTCMay 27, 01:54 UTC1h 0m
2026-05-26 ENY3428 ORD → ORF May 26, 19:55 UTCMay 26, 21:40 UTC1h 45m
2026-05-26 ENY3428 ORD → ORF May 26, 15:05 UTCMay 26, 16:40 UTC1h 35m
2026-05-26 ENY3763 BNA → ORD May 26, 10:50 UTCMay 26, 11:30 UTC40m
2026-05-26 ENY3790 BDL → ORD May 26, 06:34 UTCMay 26, 07:15 UTC40m
2026-05-25 ENY3771 CVG → DFW May 25, 21:45 UTCMay 26, 00:00 UTC2h 15m
2026-05-25 ENY3771 CVG → DFW May 25, 19:00 UTCMay 25, 20:50 UTC1h 49m
2026-05-25 ENY3556 HRL → DFW May 25, 15:50 UTCMay 25, 17:15 UTC1h 25m
2026-05-25 ENY3556 HRL → DFW May 25, 15:45 UTCMay 25, 17:09 UTC1h 24m
2026-05-25 ENY3556 HRL → DFW May 25, 13:10 UTCMay 25, 14:30 UTC1h 20m
2026-05-25 ENY4107 FAR → ORD May 25, 10:10 UTCMay 25, 11:40 UTC1h 30m
2026-05-25 ENY3450 SDF → BOS May 25, 03:15 UTCMay 25, 05:25 UTC2h 10m
2026-05-24 ENY3593 DCA → BOS May 24, 19:55 UTCMay 24, 20:50 UTC55m
2026-05-24 ENY4010 BOS → ORD May 24, 17:50 UTCMay 24, 19:00 UTC1h 10m
2026-05-24 ENY4010 BOS → ORD May 24, 15:55 UTCMay 24, 16:50 UTC55m
2026-05-24 ENY3810 MTY → DFW May 24, 13:10 UTCMay 24, 14:25 UTC1h 15m
2026-05-24 ENY3810 MTY → DFW May 24, 13:08 UTCMay 24, 14:25 UTC1h 17m
2026-05-23 ENY3459 ORD → FAR May 23, 20:20 UTCMay 23, 21:45 UTC1h 25m
2026-05-23 ENY3549 CLT → MYR May 23, 18:35 UTCMay 23, 19:10 UTC35m
2026-05-23 ENY3549 CLT → MYR May 23, 17:15 UTCMay 23, 17:35 UTC20m
2026-05-23 ENY3628 ATL → DCA May 23, 15:00 UTCMay 23, 16:15 UTC1h 15m
2026-05-23 ENY3628 ATL → DCA May 23, 14:49 UTCMay 23, 16:10 UTC1h 21m
2026-05-23 ENY3628 ATL → DCA May 23, 12:45 UTCMay 23, 13:35 UTC50m
2026-05-23 ENY4075 CRP → DFW May 23, 10:15 UTCMay 23, 11:00 UTC45m
2026-05-23 ENY4116 CVG → BOS May 23, 04:00 UTCMay 23, 05:05 UTC1h 5m
2026-05-23 ENY4276 LEX → ORD May 23, 01:55 UTCMay 23, 02:55 UTC59m
2026-05-22 ENY4276 LEX → ORD May 22, 23:40 UTCMay 23, 00:30 UTC50m
2026-05-22 ENY3721 MQT → ORD May 22, 21:20 UTCMay 22, 22:35 UTC1h 15m

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 N235NN page for operator, model, and routing details .

Mode-S A21C4C frequently asked

What is Mode-S code A21C4C?
A21C4C is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N235NN.
Where is Mode-S A21C4C registered?
Mode-S code A21C4C 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 A21C4C broadcasting right now?
Yes. Mode-S A21C4C is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A21C4C, octal 50416114, decimal 10,624,076.
What flights does A21C4C operate?
Mode-S A21C4C has broadcast 20 distinct callsigns, including ENY3560, ENY3415, ENY4236, ENY3509, ENY3939.