Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

ACB21B

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N917QS · CESSNA 680 Citation Latitude · operated by WHI AVIATION II LLC, JAMES COURTLAND, JAMES APRIL, MANGONE DOMINIC, MANGONE ALLENE, BLOCK ELLEN HASSENFELD

Hex
ACB21B
Octal
53131033
Decimal
11,317,787
Country
US
Tail
N917QS
Type
C68A
No current signal · last broadcast 1d ago
Flights observed
101
Distinct callsigns
2
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S ACB21B.

Country allocation

The ICAO 24-bit address ACB21B 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 2 distinct

Callsign Airline Flights Last seen
EJA917 - 97 2026-07-03
N917QS - 4 2026-06-12

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-03 EJA917 - Jul 3, 12:35 UTCJul 3, 13:40 UTC1h 5m
2026-07-02 EJA917 - Jul 2, 21:40 UTCJul 2, 21:55 UTC15m
2026-07-02 EJA917 - Jul 2, 20:25 UTCJul 2, 21:00 UTC35m
2026-07-02 EJA917 - Jul 2, 18:30 UTCJul 2, 19:00 UTC30m
2026-07-02 EJA917 - Jul 2, 16:35 UTCJul 2, 17:40 UTC1h 5m
2026-07-01 EJA917 - Jul 1, 17:55 UTCJul 1, 19:10 UTC1h 15m
2026-07-01 EJA917 - Jul 1, 15:30 UTCJul 1, 16:40 UTC1h 10m
2026-07-01 EJA917 MDW → UGN Jul 1, 14:15 UTCJul 1, 14:40 UTC25m
2026-06-28 EJA917 - Jun 28, 12:55 UTCJun 28, 13:40 UTC45m
2026-06-27 EJA917 - Jun 27, 14:25 UTCJun 27, 16:20 UTC1h 55m
2026-06-27 EJA917 - Jun 27, 13:09 UTCJun 27, 13:35 UTC25m
2026-06-26 EJA917 - Jun 26, 21:59 UTCJun 26, 23:55 UTC1h 55m
2026-06-26 EJA917 - Jun 26, 20:44 UTCJun 26, 21:04 UTC20m
2026-06-26 EJA917 - Jun 26, 17:35 UTCJun 26, 19:35 UTC2h 0m
2026-06-26 EJA917 - Jun 26, 15:20 UTCJun 26, 15:34 UTC15m
2026-06-25 EJA917 - Jun 25, 21:29 UTCJun 25, 23:44 UTC2h 15m
2026-06-25 EJA917 STP → PTK Jun 25, 18:10 UTCJun 25, 19:20 UTC1h 10m
2026-06-25 EJA917 - Jun 25, 13:40 UTCJun 25, 16:59 UTC3h 20m
2026-06-25 EJA917 - Jun 25, 00:44 UTCJun 25, 00:59 UTC15m
2026-06-23 EJA917 SJC → SJC Jun 23, 10:44 UTCJun 23, 11:10 UTC25m
2026-06-23 EJA917 SJC → SJC Jun 23, 06:34 UTCJun 23, 07:25 UTC50m
2026-06-23 EJA917 SJC → SJC Jun 23, 04:29 UTCJun 23, 05:09 UTC40m
2026-06-23 EJA917 SJC → SJC Jun 23, 00:50 UTCJun 23, 02:15 UTC1h 25m
2026-06-22 EJA917 SJC → SJC Jun 22, 09:34 UTCJun 22, 11:30 UTC1h 55m
2026-06-22 EJA917 SJC → SJC Jun 22, 00:10 UTCJun 22, 00:44 UTC35m
2026-06-19 EJA917 SJC → SJC Jun 19, 23:09 UTCJun 19, 23:54 UTC45m
2026-06-19 EJA917 SJC → SJC Jun 19, 09:04 UTCJun 19, 10:04 UTC1h 0m
2026-06-16 EJA917 - Jun 16, 21:20 UTCJun 16, 22:30 UTC1h 10m
2026-06-16 EJA917 - Jun 16, 15:45 UTCJun 16, 20:40 UTC4h 56m
2026-06-16 EJA917 - Jun 16, 13:44 UTCJun 16, 14:30 UTC45m
2026-06-15 EJA917 - Jun 15, 22:20 UTCJun 15, 23:39 UTC1h 20m
2026-06-15 EJA917 - Jun 15, 15:15 UTCJun 15, 17:10 UTC1h 55m
2026-06-15 EJA917 - Jun 15, 12:45 UTCJun 15, 14:20 UTC1h 35m
2026-06-14 EJA917 - Jun 14, 20:25 UTCJun 15, 00:05 UTC3h 40m
2026-06-14 EJA917 SBA → OAK Jun 14, 18:30 UTCJun 14, 19:15 UTC45m
2026-06-14 EJA917 - Jun 14, 15:15 UTCJun 14, 17:25 UTC2h 10m
2026-06-13 EJA917 - Jun 13, 20:50 UTCJun 14, 17:25 UTC20h 35m
2026-06-13 EJA917 - Jun 13, 20:40 UTCJun 14, 17:25 UTC20h 45m
2026-06-13 EJA917 - Jun 13, 15:35 UTCJun 13, 16:00 UTC25m
2026-06-13 EJA917 - Jun 13, 00:50 UTCJun 13, 01:35 UTC45m
2026-06-12 N917QS - Jun 12, 22:10 UTCJun 12, 23:40 UTC1h 30m
2026-06-12 N917QS - Jun 12, 19:05 UTCJun 12, 20:55 UTC1h 50m
2026-06-12 EJA917 APA → BFI Jun 12, 15:30 UTCJun 12, 17:50 UTC2h 20m
2026-06-11 EJA917 APA → BFI Jun 11, 22:00 UTCJun 11, 22:20 UTC20m
2026-06-11 EJA917 APA → BFI Jun 11, 16:35 UTCJun 11, 20:50 UTC4h 15m
2026-06-11 EJA917 APA → BFI Jun 11, 15:10 UTCJun 11, 15:20 UTC10m
2026-06-11 EJA917 APA → BFI Jun 11, 12:30 UTCJun 11, 14:05 UTC1h 35m
2026-06-10 EJA917 APA → BFI Jun 10, 21:40 UTCJun 10, 22:35 UTC55m
2026-06-10 EJA917 APA → BFI Jun 10, 18:55 UTCJun 10, 20:05 UTC1h 10m
2026-06-10 EJA917 APA → BFI Jun 10, 17:00 UTCJun 10, 17:25 UTC25m

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 N917QS page for operator, model, and routing details .

Mode-S ACB21B frequently asked

What is Mode-S code ACB21B?
ACB21B is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N917QS.
Where is Mode-S ACB21B registered?
Mode-S code ACB21B 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 ACB21B 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 ACB21B, octal 53131033, decimal 11,317,787.
What flights does ACB21B operate?
Mode-S ACB21B has broadcast 2 distinct callsigns, including EJA917, N917QS.