Apparatus

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sensors Mode-S transponder

A631BA

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N499CA · CESSNA 402 Businessliner · operated by HYANNIS AIR SERVICE INC

Hex
A631BA
Octal
51430672
Decimal
10,891,706
Country
US
Tail
N499CA
Type
C402
No current signal · last broadcast Jun 15, 12:10 UTC
Flights observed
148
Distinct callsigns
20
Country
US
Last broadcast
Jun 15, 12:10 UTC

Last known position

Most recent position reported by Mode-S A631BA.

Country allocation

The ICAO 24-bit address A631BA 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
KAP616 Cape Air 17 2026-06-05
KAP519 Cape Air 15 2026-05-29
KAPT58 - 10 2026-05-12
KAP413 - 8 2026-06-14
KAPT818 - 7 2026-06-09
KAPT787 - 6 2026-06-01
KAP111 Cape Air 6 2026-05-23
KAP6 Cape Air 5 2026-06-12
KAP1271 Cape Air 5 2026-06-11
KAPT978 - 4 2026-05-21
KAPT605 - 4 2026-05-20
KAP916 Cape Air 4 2026-04-24
KAP3285 Cape Air 4 2026-06-09
KAP747 Cape Air 3 2026-04-26
KAP6789 Cape Air 3 2026-04-23
N499CA - 2 2026-05-18
KAPT9 - 2 2026-04-20
KAPT747 - 2 2026-04-27
KAPT40 - 2 2026-04-15
KAP85 Cape Air 2 2026-06-07

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-06-15 KAP2111 - Jun 15, 11:54 UTCJun 15, 12:10 UTC15m
2026-06-15 KAP2001 - Jun 15, 10:50 UTCJun 15, 11:10 UTC20m
2026-06-14 KAP413 - Jun 14, 23:35 UTCJun 14, 23:54 UTC20m
2026-06-14 KAP413 BOS → ACK Jun 14, 22:15 UTCJun 14, 22:55 UTC40m
2026-06-14 KAP2341 PVC → BOS Jun 14, 20:50 UTCJun 14, 21:15 UTC25m
2026-06-14 KAP413 BOS → PVC Jun 14, 18:50 UTCJun 14, 19:10 UTC20m
2026-06-14 KAP2141 PVC → BOS Jun 14, 17:35 UTCJun 14, 18:05 UTC30m
2026-06-14 KAP413 BOS → PVC Jun 14, 15:15 UTCJun 14, 15:35 UTC20m
2026-06-14 KAP2121 PVC → BOS Jun 14, 14:05 UTCJun 14, 14:30 UTC25m
2026-06-14 KAP413 - Jun 14, 13:00 UTCJun 14, 13:20 UTC20m
2026-06-14 KAP2101 PVC → BOS Jun 14, 12:10 UTCJun 14, 12:35 UTC25m
2026-06-13 KAP413 BOS → PVC Jun 13, 22:00 UTCJun 13, 22:25 UTC25m
2026-06-13 KAP2341 PVC → BOS Jun 13, 20:30 UTCJun 13, 20:50 UTC20m
2026-06-13 KAP413 BOS → PVC Jun 13, 18:55 UTCJun 13, 19:20 UTC25m
2026-06-13 KAP2141 PVC → BOS Jun 13, 17:35 UTCJun 13, 17:50 UTC15m
2026-06-12 KAP413 - Jun 12, 23:35 UTCJun 12, 23:50 UTC15m
2026-06-12 KAP3061 MVY → BOS Jun 12, 21:25 UTCJun 12, 22:45 UTC1h 20m
2026-06-12 KAP7141 - Jun 12, 20:10 UTCJun 12, 20:30 UTC20m
2026-06-12 KAP6 ACK → BOS Jun 12, 19:05 UTCJun 12, 19:25 UTC20m
2026-06-12 KAP5321 ACK → BOS Jun 12, 17:45 UTCJun 12, 18:20 UTC35m
2026-06-12 KAP6 ACK → BOS Jun 12, 15:35 UTCJun 12, 16:10 UTC35m
2026-06-12 KAP5301 ACK → BOS Jun 12, 14:15 UTCJun 12, 15:00 UTC45m
2026-06-12 KAP6 ACK → BOS Jun 12, 12:15 UTCJun 12, 12:50 UTC35m
2026-06-12 KAP6 ACK → BOS Jun 12, 11:05 UTCJun 12, 11:45 UTC40m
2026-06-12 KAP6 ACK → BOS Jun 12, 10:00 UTCJun 12, 10:10 UTC10m
2026-06-11 KAP5041 - Jun 11, 17:10 UTCJun 11, 18:25 UTC1h 15m
2026-06-11 KAP5041 - Jun 11, 14:55 UTCJun 11, 15:30 UTC35m
2026-06-11 KAP27 MVY → BOS Jun 11, 13:55 UTCJun 11, 14:10 UTC15m
2026-06-11 KAP1271 HYA → ACK Jun 11, 01:40 UTCJun 11, 02:45 UTC1h 5m
2026-06-11 KAP1271 HYA → ACK Jun 11, 00:40 UTCJun 11, 01:05 UTC25m
2026-06-09 KAP3285 MVY → BOS Jun 9, 23:35 UTCJun 9, 23:55 UTC20m
2026-06-09 KAP627 SLK → BOS Jun 9, 20:15 UTCJun 9, 21:35 UTC1h 20m
2026-06-09 KAP627 SLK → BOS Jun 9, 18:55 UTCJun 9, 19:25 UTC30m
2026-06-09 KAPT818 - Jun 9, 13:15 UTCJun 9, 14:45 UTC1h 30m
2026-06-09 KAP3285 MVY → BOS Jun 9, 01:25 UTCJun 9, 02:30 UTC1h 5m
2026-06-08 KAP5621 ACK → BOS Jun 8, 23:50 UTCJun 9, 00:30 UTC40m
2026-06-08 KAP3285 MVY → BOS Jun 8, 22:30 UTCJun 8, 23:00 UTC30m
2026-06-08 KAP5341 ACK → BOS Jun 8, 20:40 UTCJun 8, 21:25 UTC45m
2026-06-08 KAP3285 MVY → BOS Jun 8, 19:20 UTCJun 8, 19:35 UTC15m
2026-06-07 KAP85 ALB → BOS Jun 7, 20:05 UTCJun 7, 20:30 UTC25m
2026-06-07 KAP5062 ACK → BOS Jun 7, 19:00 UTCJun 7, 19:35 UTC35m
2026-06-07 KAP85 ALB → BOS Jun 7, 18:10 UTCJun 7, 18:20 UTC10m
2026-06-07 KAP101 JFK → HYA Jun 7, 16:15 UTCJun 7, 17:30 UTC1h 15m
2026-06-07 KAP100 ORD → STL Jun 7, 13:35 UTCJun 7, 14:55 UTC1h 20m
2026-06-05 KAP616 BOS → ACK Jun 5, 21:50 UTCJun 5, 22:50 UTC1h 0m
2026-06-05 KAP616 BOS → ACK Jun 5, 20:20 UTCJun 5, 20:50 UTC30m
2026-06-05 KAP616 BOS → ACK Jun 5, 18:10 UTCJun 5, 18:35 UTC25m
2026-06-05 KAP616 BOS → ACK Jun 5, 16:35 UTCJun 5, 17:00 UTC25m
2026-06-05 KAP616 BOS → ACK Jun 5, 15:20 UTCJun 5, 15:45 UTC25m
2026-06-05 KAP616 BOS → ACK Jun 5, 14:00 UTCJun 5, 14:20 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 N499CA page for operator, model, and routing details .

Mode-S A631BA frequently asked

What is Mode-S code A631BA?
A631BA is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N499CA.
Where is Mode-S A631BA registered?
Mode-S code A631BA 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 A631BA broadcasting right now?
No active broadcast right now. Last signal was Jun 15, 12:10 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A631BA, octal 51430672, decimal 10,891,706.
What flights does A631BA operate?
Mode-S A631BA has broadcast 20 distinct callsigns, including KAP616, KAP519, KAPT58, KAP413, KAPT818.