Apparatus

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sensors Mode-S transponder

A099A5

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N138HN · AIRBUS HELICOPTERS EC-135/635 · operated by AIR METHODS LLC

Hex
A099A5
Octal
50114645
Decimal
10,525,093
Country
US
Tail
N138HN
Type
EC35
No current signal · last broadcast 4h ago
Flights observed
78
Distinct callsigns
1
Country
US
Last broadcast
4h ago

Last known position

Most recent position reported by Mode-S A099A5.

Country allocation

The ICAO 24-bit address A099A5 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
N138HN - 77 2026-06-02

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-06-02 N138HN - Jun 2, 15:10 UTCJun 2, 15:35 UTC25m
2026-06-02 N138HN - Jun 2, 12:45 UTCJun 2, 13:10 UTC25m
2026-06-02 N138HN - Jun 2, 04:00 UTCJun 2, 04:15 UTC15m
2026-06-02 N138HN - Jun 2, 02:45 UTCJun 2, 03:10 UTC25m
2026-06-02 N138HN - Jun 2, 02:10 UTCJun 2, 02:15 UTC5m
2026-06-01 N138HN - Jun 1, 21:00 UTCJun 1, 21:20 UTC20m
2026-06-01 N138HN - Jun 1, 14:00 UTCJun 1, 14:30 UTC30m
2026-05-31 N138HN - May 31, 20:45 UTCMay 31, 22:20 UTC1h 35m
2026-05-31 N138HN - May 31, 19:45 UTCMay 31, 20:05 UTC20m
2026-05-31 N138HN - May 31, 18:50 UTCMay 31, 19:00 UTC10m
2026-05-31 N138HN - May 31, 17:30 UTCMay 31, 17:55 UTC25m
2026-05-30 N138HN - May 30, 23:50 UTCMay 30, 23:55 UTC5m
2026-05-30 N138HN - May 30, 20:00 UTCMay 30, 20:20 UTC20m
2026-05-30 N138HN - May 30, 18:30 UTCMay 30, 19:20 UTC50m
2026-05-30 N138HN - May 30, 18:10 UTCMay 30, 18:25 UTC15m
2026-05-30 N138HN - May 30, 17:15 UTCMay 30, 17:30 UTC15m
2026-05-30 N138HN - May 30, 15:45 UTCMay 30, 16:15 UTC30m
2026-05-30 N138HN - May 30, 14:50 UTCMay 30, 14:55 UTC5m
2026-05-30 N138HN - May 30, 07:30 UTCMay 30, 07:35 UTC5m
2026-05-30 N138HN - May 30, 06:55 UTCMay 30, 07:05 UTC10m
2026-05-30 N138HN - May 30, 06:05 UTCMay 30, 06:15 UTC10m
2026-05-30 N138HN - May 30, 00:55 UTCMay 30, 01:00 UTC5m
2026-05-30 N138HN - May 30, 00:00 UTCMay 30, 00:05 UTC5m
2026-05-29 N138HN - May 29, 21:55 UTCMay 29, 22:20 UTC25m
2026-05-29 N138HN - May 29, 20:10 UTCMay 29, 20:30 UTC20m
2026-05-29 N138HN - May 29, 19:55 UTCMay 29, 20:05 UTC10m
2026-05-29 N138HN - May 29, 14:50 UTCMay 29, 15:35 UTC45m
2026-05-29 N138HN - May 29, 10:15 UTCMay 29, 10:35 UTC20m
2026-05-29 N138HN - May 29, 07:00 UTCMay 29, 07:20 UTC20m
2026-05-29 - - May 29, 02:05 UTCMay 29, 02:15 UTC10m
2026-05-28 N138HN - May 28, 14:40 UTCMay 28, 15:10 UTC30m
2026-05-22 N138HN - May 22, 19:05 UTCMay 22, 19:45 UTC40m
2026-04-24 N138HN - Apr 24, 15:30 UTCApr 24, 17:05 UTC1h 35m
2026-04-24 N138HN - Apr 24, 01:35 UTCApr 24, 02:00 UTC25m
2026-04-24 N138HN - Apr 24, 00:40 UTCApr 24, 01:00 UTC20m
2026-04-23 N138HN - Apr 23, 17:35 UTCApr 23, 19:00 UTC1h 24m
2026-04-23 N138HN - Apr 23, 15:35 UTCApr 23, 16:05 UTC30m
2026-04-23 N138HN - Apr 23, 14:45 UTCApr 23, 15:05 UTC20m
2026-04-23 N138HN - Apr 23, 01:35 UTCApr 23, 02:15 UTC40m
2026-04-23 N138HN - Apr 23, 00:40 UTCApr 23, 00:55 UTC15m
2026-04-22 N138HN - Apr 22, 21:10 UTCApr 22, 21:20 UTC10m
2026-04-22 N138HN - Apr 22, 20:25 UTCApr 22, 20:35 UTC10m
2026-04-22 N138HN - Apr 22, 18:40 UTCApr 22, 18:50 UTC10m
2026-04-22 N138HN - Apr 22, 16:45 UTCApr 22, 16:55 UTC10m
2026-04-22 N138HN - Apr 22, 15:20 UTCApr 22, 16:10 UTC50m
2026-04-22 N138HN - Apr 22, 09:15 UTCApr 22, 09:55 UTC40m
2026-04-22 N138HN - Apr 22, 08:30 UTCApr 22, 08:40 UTC10m
2026-04-22 N138HN - Apr 22, 07:35 UTCApr 22, 07:45 UTC10m
2026-04-22 N138HN - Apr 22, 00:35 UTCApr 22, 00:45 UTC10m
2026-04-20 N138HN - Apr 20, 21:55 UTCApr 20, 22:40 UTC45m

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 N138HN page for operator, model, and routing details .

Mode-S A099A5 frequently asked

What is Mode-S code A099A5?
A099A5 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N138HN.
Where is Mode-S A099A5 registered?
Mode-S code A099A5 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 A099A5 broadcasting right now?
No active broadcast right now. Last signal was 4h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A099A5, octal 50114645, decimal 10,525,093.
What flights does A099A5 operate?
Mode-S A099A5 has broadcast 1 distinct callsign, including N138HN.