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sensors Mode-S transponder

A4991A

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N396AG · operated by SKYWEST LEASING INC

Hex
A4991A
Octal
51114432
Decimal
10,787,098
Country
US
Tail
N396AG
Type
P28A
No current signal · last broadcast 12h ago
Flights observed
127
Distinct callsigns
1
Country
US
Last broadcast
12h ago

Last known position

Most recent position reported by Mode-S A4991A.

Country allocation

The ICAO 24-bit address A4991A 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
ASI971 - 127 2026-07-17

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-17 ASI971 - Jul 17, 20:15 UTCJul 17, 21:25 UTC1h 10m
2026-07-17 ASI971 - Jul 17, 17:20 UTCJul 17, 18:44 UTC1h 25m
2026-07-12 ASI971 - Jul 12, 18:15 UTCJul 12, 19:40 UTC1h 25m
2026-07-09 ASI971 - Jul 9, 13:45 UTCJul 9, 14:10 UTC25m
2026-07-08 ASI971 - Jul 8, 23:35 UTCJul 9, 01:15 UTC1h 40m
2026-07-08 ASI971 - Jul 8, 14:40 UTCJul 8, 15:45 UTC1h 5m
2026-07-08 ASI971 - Jul 8, 12:45 UTCJul 8, 12:55 UTC10m
2026-07-02 ASI971 - Jul 2, 19:10 UTCJul 2, 20:45 UTC1h 35m
2026-07-02 ASI971 - Jul 2, 00:15 UTCJul 2, 01:55 UTC1h 40m
2026-07-01 ASI971 - Jul 1, 20:25 UTCJul 1, 21:10 UTC45m
2026-06-30 ASI971 - Jun 30, 14:20 UTCJun 30, 18:05 UTC3h 45m
2026-06-28 ASI971 - Jun 28, 21:30 UTCJun 28, 22:15 UTC45m
2026-06-27 ASI971 - Jun 27, 19:00 UTCJun 27, 22:25 UTC3h 25m
2026-06-26 ASI971 - Jun 26, 22:55 UTCJun 27, 00:34 UTC1h 40m
2026-06-26 ASI971 - Jun 26, 00:10 UTCJun 26, 01:24 UTC1h 15m
2026-06-24 ASI971 - Jun 24, 20:40 UTCJun 24, 21:54 UTC1h 15m
2026-06-23 ASI971 - Jun 23, 17:34 UTCJun 23, 19:00 UTC1h 25m
2026-06-22 ASI971 - Jun 22, 17:25 UTCJun 22, 17:34 UTC10m
2026-06-21 ASI971 - Jun 21, 17:24 UTCJun 21, 17:39 UTC15m
2026-06-20 ASI971 - Jun 20, 16:34 UTCJun 20, 18:34 UTC2h 0m
2026-06-19 ASI971 - Jun 19, 22:04 UTCJun 19, 22:45 UTC40m
2026-06-19 ASI971 - Jun 19, 15:14 UTCJun 19, 16:34 UTC1h 20m
2026-06-17 ASI971 - Jun 17, 23:35 UTCJun 18, 00:15 UTC40m
2026-06-17 ASI971 - Jun 17, 22:10 UTCJun 17, 22:35 UTC25m
2026-06-17 ASI971 - Jun 17, 20:30 UTCJun 17, 21:00 UTC30m
2026-06-17 ASI971 - Jun 17, 19:20 UTCJun 17, 19:35 UTC15m
2026-06-17 ASI971 - Jun 17, 17:05 UTCJun 17, 17:55 UTC50m
2026-06-17 ASI971 - Jun 17, 15:05 UTCJun 17, 16:30 UTC1h 25m
2026-06-12 ASI971 DVT → DVT Jun 12, 23:35 UTCJun 13, 01:50 UTC2h 15m
2026-06-12 ASI971 DVT → DVT Jun 12, 18:10 UTCJun 12, 19:40 UTC1h 30m
2026-06-12 ASI971 DVT → DVT Jun 12, 15:35 UTCJun 12, 17:10 UTC1h 35m
2026-06-11 ASI971 DVT → DVT Jun 11, 19:00 UTCJun 11, 20:25 UTC1h 25m
2026-06-11 ASI971 - Jun 11, 16:10 UTCJun 11, 17:25 UTC1h 15m
2026-06-11 ASI971 DVT → DVT Jun 11, 13:45 UTCJun 11, 15:25 UTC1h 40m
2026-06-11 ASI971 HII → DVT Jun 11, 07:30 UTCJun 11, 10:30 UTC3h 0m
2026-06-11 ASI971 - Jun 11, 04:55 UTCJun 11, 05:45 UTC50m
2026-06-11 ASI971 - Jun 11, 02:55 UTCJun 11, 04:10 UTC1h 15m
2026-06-10 ASI971 - Jun 10, 22:15 UTCJun 10, 23:30 UTC1h 15m
2026-06-10 ASI971 - Jun 10, 20:25 UTCJun 10, 21:25 UTC1h 0m
2026-06-10 ASI971 - Jun 10, 18:30 UTCJun 10, 19:45 UTC1h 15m
2026-06-10 ASI971 - Jun 10, 14:55 UTCJun 10, 16:10 UTC1h 15m
2026-06-09 ASI971 DVT → DVT Jun 9, 16:45 UTCJun 9, 17:15 UTC30m
2026-06-09 ASI971 - Jun 9, 15:40 UTCJun 9, 15:50 UTC10m
2026-06-08 ASI971 - Jun 8, 14:20 UTCJun 8, 17:40 UTC3h 20m
2026-06-07 ASI971 - Jun 7, 15:55 UTCJun 7, 18:35 UTC2h 40m
2026-06-06 ASI971 - Jun 6, 18:14 UTCJun 6, 20:14 UTC2h 0m
2026-06-06 ASI971 - Jun 6, 15:44 UTCJun 6, 17:05 UTC1h 20m
2026-06-05 ASI971 - Jun 5, 21:20 UTCJun 5, 21:55 UTC35m
2026-06-05 ASI971 - Jun 5, 15:20 UTCJun 5, 15:55 UTC35m
2026-06-04 ASI971 DVT → DVT Jun 4, 15:50 UTCJun 4, 16:10 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 N396AG page for operator, model, and routing details .

Mode-S A4991A frequently asked

What is Mode-S code A4991A?
A4991A is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N396AG.
Where is Mode-S A4991A registered?
Mode-S code A4991A 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 A4991A broadcasting right now?
No active broadcast right now. Last signal was 12h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A4991A, octal 51114432, decimal 10,787,098.
What flights does A4991A operate?
Mode-S A4991A has broadcast 1 distinct callsign, including ASI971.