Apparatus

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sensors Mode-S transponder

A747CB

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N56859 · BOEING 757-300 · operated by UNITED AIRLINES INC

Hex
A747CB
Octal
51643713
Decimal
10,962,891
Country
US
Tail
N56859
Type
B753
No current signal · last broadcast 4h ago
Flights observed
248
Distinct callsigns
20
Country
US
Last broadcast
4h ago

Last known position

Most recent position reported by Mode-S A747CB.

Country allocation

The ICAO 24-bit address A747CB 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
UAL1721 - 10 2026-07-08
UAL1654 - 9 2026-07-12
UAL1722 - 8 2026-07-09
UAL501 - 7 2026-07-11
UAL457 - 7 2026-07-06
UAL4204 - 7 2026-06-04
UAL2814 - 7 2026-07-06
UAL2087 - 7 2026-06-19
UAL1718 - 7 2026-06-26
UAL1022 - 7 2026-07-12
UAL1719 - 6 2026-06-26
UAL2348 United Airlines 5 2026-06-10
UAL1829 - 5 2026-07-12
UAL1277 United Airlines 5 2026-05-14
UAL1217 - 5 2026-06-19
UAL8129 United Airlines 4 2026-06-13
UAL798 United Airlines 4 2026-05-19
UAL796 United Airlines 4 2026-05-14
UAL644 United Airlines 4 2026-05-20
UAL599 - 4 2026-06-20

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-13 UAL1777 SFO → ORD Jul 13, 22:35 UTCJul 14, 02:15 UTC3h 40m
2026-07-13 UAL2391 - Jul 13, 14:35 UTCJul 13, 16:45 UTC2h 10m
2026-07-12 UAL1654 - Jul 12, 23:40 UTCJul 13, 01:45 UTC2h 5m
2026-07-12 UAL1829 - Jul 12, 20:01 UTCJul 12, 21:55 UTC1h 55m
2026-07-12 UAL1829 DEN → IAH Jul 12, 19:49 UTCJul 12, 21:56 UTC2h 7m
2026-07-12 UAL1022 MCO → DEN Jul 12, 14:15 UTCJul 12, 17:35 UTC3h 20m
2026-07-11 UAL501 DEN → MCO Jul 11, 20:15 UTCJul 11, 23:15 UTC3h 0m
2026-07-11 UAL1865 IAD → DEN Jul 11, 14:33 UTCJul 11, 17:40 UTC3h 7m
2026-07-11 UAL1865 IAD → DEN Jul 11, 14:25 UTCJul 11, 17:45 UTC3h 20m
2026-07-10 UAL347 DEN → IAD Jul 10, 20:20 UTCJul 10, 23:15 UTC2h 55m
2026-07-10 UAL1865 IAD → DEN Jul 10, 14:25 UTCJul 10, 17:30 UTC3h 5m
2026-07-10 UAL8153 - Jul 10, 07:10 UTCJul 10, 11:40 UTC4h 30m
2026-07-10 UAL8153 LAX → IAD Jul 10, 06:58 UTCJul 10, 11:37 UTC4h 39m
2026-07-10 UAL1967 - Jul 10, 00:35 UTCJul 10, 04:35 UTC4h 0m
2026-07-09 UAL1954 SFO → ORD Jul 9, 17:30 UTCJul 9, 21:10 UTC3h 40m
2026-07-09 UAL246 - Jul 9, 11:30 UTCJul 9, 15:30 UTC4h 0m
2026-07-09 UAL8278 SFO → ORD Jul 9, 06:16 UTCJul 9, 09:32 UTC3h 16m
2026-07-09 UAL8278 SFO → ORD Jul 9, 06:15 UTCJul 9, 09:40 UTC3h 25m
2026-07-09 UAL1722 - Jul 9, 02:05 UTCJul 9, 02:40 UTC35m
2026-07-08 UAL1722 - Jul 8, 22:00 UTCJul 8, 22:15 UTC15m
2026-07-08 UAL1721 - Jul 8, 20:20 UTCJul 8, 20:35 UTC15m
2026-07-08 UAL1721 - Jul 8, 15:40 UTCJul 8, 16:15 UTC35m
2026-07-08 UAL1495 - Jul 8, 02:05 UTCJul 8, 06:10 UTC4h 5m
2026-07-08 UAL1495 ORD → SFO Jul 8, 01:47 UTCJul 8, 06:07 UTC4h 20m
2026-07-07 UAL2317 SFO → ORD Jul 7, 19:30 UTCJul 7, 23:05 UTC3h 35m
2026-07-07 UAL1116 SFO → AUS Jul 7, 13:03 UTCJul 7, 17:07 UTC4h 4m
2026-07-07 UAL1116 - Jul 7, 13:05 UTCJul 7, 17:15 UTC4h 10m
2026-07-06 UAL457 - Jul 6, 20:35 UTCJul 7, 00:10 UTC3h 35m
2026-07-06 UAL2814 ORD → LAX Jul 6, 14:18 UTCJul 6, 17:40 UTC3h 22m
2026-07-06 UAL2814 - Jul 6, 14:15 UTCJul 6, 17:45 UTC3h 30m
2026-07-05 UAL457 - Jul 5, 20:45 UTCJul 6, 00:20 UTC3h 35m
2026-07-05 UAL1868 IAD → LAX Jul 5, 13:58 UTCJul 5, 18:28 UTC4h 30m
2026-07-05 UAL1868 - Jul 5, 13:55 UTCJul 5, 18:35 UTC4h 40m
2026-07-05 UAL2282 - Jul 5, 06:45 UTCJul 5, 11:05 UTC4h 20m
2026-07-05 UAL2499 - Jul 5, 01:20 UTCJul 5, 04:55 UTC3h 35m
2026-07-05 UAL2499 ORD → LAX Jul 5, 01:32 UTCJul 5, 04:52 UTC3h 20m
2026-07-04 UAL1954 SFO → ORD Jul 4, 18:30 UTCJul 4, 23:10 UTC4h 40m
2026-07-04 UAL246 - Jul 4, 12:15 UTCJul 4, 16:30 UTC4h 15m
2026-07-04 UAL246 ORD → SFO Jul 4, 12:24 UTCJul 4, 16:23 UTC3h 59m
2026-07-04 UAL2278 SFO → ORD Jul 4, 06:00 UTCJul 4, 09:40 UTC3h 40m
2026-07-04 UAL1722 - Jul 4, 02:05 UTCJul 4, 02:45 UTC40m
2026-07-03 UAL1722 - Jul 3, 22:10 UTCJul 3, 22:20 UTC10m
2026-07-03 UAL1721 SFO → KOA Jul 3, 20:25 UTCJul 3, 20:40 UTC15m
2026-07-03 UAL1721 SFO → KOA Jul 3, 15:55 UTCJul 3, 16:20 UTC25m
2026-07-03 UAL1495 - Jul 3, 08:10 UTCJul 3, 12:05 UTC3h 55m
2026-07-02 UAL2317 SFO → ORD Jul 2, 19:20 UTCJul 2, 23:05 UTC3h 45m
2026-07-02 UAL1116 - Jul 2, 12:55 UTCJul 2, 16:55 UTC4h 0m
2026-07-02 UAL8122 SFO → ORD Jul 2, 06:15 UTCJul 2, 09:40 UTC3h 25m
2026-07-02 UAL1722 - Jul 2, 02:10 UTCJul 2, 02:55 UTC45m
2026-07-01 UAL1722 - Jul 1, 22:05 UTCJul 1, 22:15 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 N56859 page for operator, model, and routing details .

Mode-S A747CB frequently asked

What is Mode-S code A747CB?
A747CB is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N56859.
Where is Mode-S A747CB registered?
Mode-S code A747CB 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 A747CB 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 A747CB, octal 51643713, decimal 10,962,891.
What flights does A747CB operate?
Mode-S A747CB has broadcast 20 distinct callsigns, including UAL1721, UAL1654, UAL1722, UAL501, UAL457.