sensors Mode-S transponder

A99A21

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N718DS · operated by BELL TEXTRON INC

Hex
A99A21
Octal
52315041
Decimal
11,115,041
Country
US
Tail
N718DS
Type
B407
No current signal · last broadcast Jul 25, 03:45 UTC
Flights observed
58
Distinct callsigns
1
Country
US
Last broadcast
Jul 25, 03:45 UTC

Last known position

Most recent position reported by Mode-S A99A21.

Country allocation

The ICAO 24-bit address A99A21 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 1 distinct

Callsign Airline Flights Last seen
N718DS - 58 2026-07-25

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-25 N718DS - Jul 25, 02:50 UTCJul 25, 03:45 UTC55m
2026-07-23 N718DS - Jul 23, 19:45 UTCJul 23, 20:20 UTC35m
2026-07-23 N718DS - Jul 23, 18:30 UTCJul 23, 19:00 UTC30m
2026-07-23 N718DS - Jul 23, 17:15 UTCJul 23, 17:25 UTC10m
2026-07-23 N718DS - Jul 23, 13:20 UTCJul 23, 14:00 UTC40m
2026-07-20 N718DS - Jul 20, 20:00 UTCJul 20, 20:35 UTC35m
2026-07-20 N718DS - Jul 20, 16:00 UTCJul 20, 16:55 UTC55m
2026-07-20 N718DS - Jul 20, 13:20 UTCJul 20, 14:05 UTC45m
2026-07-17 N718DS - Jul 17, 18:29 UTCJul 17, 19:05 UTC35m
2026-07-16 N718DS - Jul 16, 15:00 UTCJul 16, 15:19 UTC20m
2026-07-15 N718DS - Jul 15, 18:10 UTCJul 15, 18:25 UTC15m
2026-07-13 N718DS - Jul 13, 05:55 UTCJul 13, 06:35 UTC40m
2026-07-13 N718DS - Jul 13, 03:01 UTCJul 13, 03:20 UTC20m
2026-07-12 N718DS - Jul 12, 22:55 UTCJul 12, 23:30 UTC35m
2026-07-12 N718DS - Jul 12, 02:20 UTCJul 12, 03:10 UTC50m
2026-07-11 N718DS - Jul 11, 02:45 UTCJul 11, 03:30 UTC45m
2026-07-09 N718DS - Jul 9, 22:25 UTCJul 9, 22:35 UTC10m
2026-07-09 N718DS - Jul 9, 05:20 UTCJul 9, 05:40 UTC20m
2026-07-07 N718DS - Jul 7, 16:15 UTCJul 7, 16:45 UTC30m
2026-06-26 N718DS - Jun 26, 22:10 UTCJun 27, 00:39 UTC2h 30m
2026-06-26 N718DS - Jun 26, 18:20 UTCJun 26, 18:54 UTC35m
2026-06-26 N718DS - Jun 26, 12:10 UTCJun 26, 13:49 UTC1h 40m
2026-06-25 N718DS - Jun 25, 13:24 UTCJun 25, 14:14 UTC50m
2026-06-23 N718DS - Jun 23, 15:55 UTCJun 23, 17:04 UTC1h 10m
2026-06-22 N718DS - Jun 22, 16:14 UTCJun 22, 16:34 UTC20m
2026-06-22 N718DS - Jun 22, 11:50 UTCJun 22, 12:10 UTC20m
2026-06-21 N718DS - Jun 21, 15:40 UTCJun 21, 16:34 UTC55m
2026-06-18 N718DS - Jun 18, 15:30 UTCJun 18, 16:30 UTC1h 0m
2026-06-09 N718DS - Jun 9, 20:05 UTCJun 9, 20:20 UTC15m
2026-05-25 N718DS - May 25, 19:00 UTCMay 25, 19:40 UTC39m
2026-05-25 N718DS - May 25, 13:35 UTCMay 25, 15:15 UTC1h 40m
2026-05-23 N718DS - May 23, 18:30 UTCMay 23, 19:05 UTC35m
2026-05-23 N718DS - May 23, 17:40 UTCMay 23, 17:55 UTC15m
2026-05-22 N718DS - May 22, 15:10 UTCMay 22, 16:25 UTC1h 15m
2026-05-21 N718DS - May 21, 17:30 UTCMay 21, 18:30 UTC1h 0m
2026-05-21 N718DS - May 21, 12:45 UTCMay 21, 13:30 UTC45m
2026-05-20 N718DS - May 20, 19:15 UTCMay 20, 19:30 UTC15m
2026-05-20 N718DS - May 20, 14:25 UTCMay 20, 15:15 UTC50m
2026-05-19 N718DS - May 19, 19:30 UTCMay 19, 19:40 UTC10m
2026-04-28 N718DS - Apr 28, 14:55 UTCApr 28, 15:50 UTC55m
2026-04-23 N718DS - Apr 23, 19:25 UTCApr 23, 19:40 UTC15m
2026-04-23 N718DS - Apr 23, 13:30 UTCApr 23, 14:10 UTC40m
2026-04-21 N718DS - Apr 21, 18:00 UTCApr 21, 18:10 UTC10m
2026-04-20 N718DS - Apr 20, 15:45 UTCApr 20, 16:05 UTC20m
2026-04-19 N718DS - Apr 19, 11:05 UTCApr 19, 11:35 UTC30m
2026-04-18 N718DS - Apr 18, 18:25 UTCApr 18, 19:40 UTC1h 15m
2026-04-18 N718DS - Apr 18, 16:40 UTCApr 18, 17:30 UTC50m
2026-04-18 N718DS - Apr 18, 15:50 UTCApr 18, 16:00 UTC10m
2026-04-18 N718DS - Apr 18, 13:35 UTCApr 18, 14:10 UTC35m
2026-04-17 N718DS - Apr 17, 21:35 UTCApr 17, 21:45 UTC10m

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 N718DS page for operator, model, and routing details .

Mode-S A99A21 frequently asked

What is Mode-S code A99A21?
A99A21 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N718DS.
Where is Mode-S A99A21 registered?
Mode-S code A99A21 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 A99A21 broadcasting right now?
No active broadcast right now. Last signal was Jul 25, 03:45 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A99A21, octal 52315041, decimal 11,115,041.
What flights does A99A21 operate?
Mode-S A99A21 has broadcast 1 distinct callsign, including N718DS.