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sensors Mode-S transponder

AA56B5

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N76516 · BOEING 737-800 · operated by UNITED AIRLINES INC

Hex
AA56B5
Octal
52453265
Decimal
11,163,317
Country
US
Tail
N76516
Type
B738
No current signal · last broadcast 21h ago
Flights observed
381
Distinct callsigns
20
Country
US
Last broadcast
21h ago

Last known position

Most recent position reported by Mode-S AA56B5.

Country allocation

The ICAO 24-bit address AA56B5 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
UAL2199 United Airlines 5 2026-07-07
UAL600 United Airlines 4 2026-05-12
UAL2668 - 4 2026-07-13
UAL2257 - 4 2026-04-13
UAL2159 - 4 2026-06-18
UAL1816 - 4 2026-06-18
UAL1781 United Airlines 4 2026-06-02
UAL1325 - 4 2026-07-13
UAL1311 United Airlines 4 2026-06-01
UAL708 - 3 2026-06-18
UAL669 - 3 2026-07-07
UAL645 - 3 2026-06-15
UAL2156 United Airlines 3 2026-06-28
UAL2098 - 3 2026-06-19
UAL204 United Airlines 3 2026-05-05
UAL1910 - 3 2026-07-01
UAL1851 - 3 2026-04-17
UAL1787 United Airlines 3 2026-05-21
UAL1776 - 3 2026-07-07
UAL1537 - 3 2026-07-08

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-13 UAL2652 ORD → CLE Jul 13, 23:18 UTCJul 13, 23:54 UTC36m
2026-07-13 UAL2652 ORD → CLE Jul 13, 23:05 UTCJul 13, 23:55 UTC50m
2026-07-13 UAL1325 DCA → ORD Jul 13, 19:50 UTCJul 13, 21:20 UTC1h 30m
2026-07-13 UAL2668 - Jul 13, 16:35 UTCJul 13, 18:05 UTC1h 30m
2026-07-11 UAL590 - Jul 11, 21:40 UTCJul 11, 23:25 UTC1h 45m
2026-07-11 UAL1720 - Jul 11, 17:20 UTCJul 11, 20:10 UTC2h 50m
2026-07-11 UAL1645 - Jul 11, 12:15 UTCJul 11, 14:55 UTC2h 40m
2026-07-11 UAL1790 DEN → CLE Jul 11, 01:25 UTCJul 11, 03:50 UTC2h 25m
2026-07-10 UAL730 COS → DEN Jul 10, 20:25 UTCJul 10, 20:50 UTC25m
2026-07-10 UAL1111 DEN → COS Jul 10, 18:55 UTCJul 10, 19:15 UTC20m
2026-07-10 UAL2412 - Jul 10, 14:10 UTCJul 10, 17:40 UTC3h 30m
2026-07-10 UAL1605 - Jul 10, 08:00 UTCJul 10, 13:00 UTC5h 0m
2026-07-10 UAL2282 - Jul 10, 05:15 UTCJul 10, 05:55 UTC40m
2026-07-10 UAL751 SFO → LAS Jul 10, 02:56 UTCJul 10, 04:06 UTC1h 10m
2026-07-10 UAL751 - Jul 10, 03:00 UTCJul 10, 04:10 UTC1h 10m
2026-07-09 UAL2478 LAS → SFO Jul 9, 22:35 UTCJul 9, 23:50 UTC1h 15m
2026-07-09 UAL2449 SFO → LAS Jul 9, 20:00 UTCJul 9, 21:10 UTC1h 10m
2026-07-09 UAL1113 - Jul 9, 17:10 UTCJul 9, 18:20 UTC1h 10m
2026-07-09 UAL1113 SAN → SFO Jul 9, 17:02 UTCJul 9, 18:07 UTC1h 5m
2026-07-09 UAL1980 - Jul 9, 13:45 UTCJul 9, 14:50 UTC1h 5m
2026-07-09 UAL1980 SFO → SAN Jul 9, 13:57 UTCJul 9, 14:50 UTC53m
2026-07-09 UAL2615 LAS → SFO Jul 9, 04:45 UTCJul 9, 06:00 UTC1h 15m
2026-07-09 UAL2615 LAS → SFO Jul 9, 04:47 UTCJul 9, 05:55 UTC1h 8m
2026-07-09 UAL655 DEN → LAS Jul 9, 02:05 UTCJul 9, 03:35 UTC1h 30m
2026-07-08 UAL725 - Jul 8, 23:35 UTCJul 9, 00:35 UTC1h 0m
2026-07-08 UAL691 DEN → ABQ Jul 8, 20:15 UTCJul 8, 21:05 UTC50m
2026-07-08 UAL1537 PHL → DEN Jul 8, 14:15 UTCJul 8, 17:35 UTC3h 20m
2026-07-07 UAL1776 ORD → PHL Jul 7, 23:32 UTCJul 8, 01:15 UTC1h 43m
2026-07-07 UAL1776 - Jul 7, 23:45 UTCJul 8, 01:15 UTC1h 30m
2026-07-07 UAL2199 LGA → DEN Jul 7, 20:50 UTCJul 7, 21:00 UTC10m
2026-07-07 UAL2199 LGA → DEN Jul 7, 18:44 UTCJul 7, 20:31 UTC1h 47m
2026-07-07 UAL2199 LGA → DEN Jul 7, 18:50 UTCJul 7, 21:00 UTC2h 10m
2026-07-07 UAL669 ORD → LGA Jul 7, 15:46 UTCJul 7, 17:12 UTC1h 26m
2026-07-07 UAL669 ORD → LGA Jul 7, 15:35 UTCJul 7, 17:10 UTC1h 35m
2026-07-07 UAL2822 LGA → ORD Jul 7, 11:40 UTCJul 7, 13:30 UTC1h 50m
2026-07-07 UAL1623 ORD → LGA Jul 7, 00:40 UTCJul 7, 02:40 UTC2h 0m
2026-07-06 UAL1325 DCA → ORD Jul 6, 19:55 UTCJul 6, 21:40 UTC1h 45m
2026-07-06 UAL2668 ORD → DCA Jul 6, 16:30 UTCJul 6, 17:50 UTC1h 20m
2026-07-06 UAL1355 - Jul 6, 13:05 UTCJul 6, 14:10 UTC1h 5m
2026-07-05 UAL2725 - Jul 5, 21:50 UTCJul 6, 00:10 UTC2h 20m
2026-07-05 UAL1706 - Jul 5, 17:35 UTCJul 5, 19:45 UTC2h 10m
2026-07-05 UAL1524 - Jul 5, 13:45 UTCJul 5, 16:15 UTC2h 30m
2026-07-04 UAL525 AUS → IAD Jul 4, 12:40 UTCJul 4, 15:20 UTC2h 40m
2026-07-04 UAL2674 - Jul 4, 00:05 UTCJul 4, 00:30 UTC25m
2026-07-03 UAL1976 BOS → IAH Jul 3, 18:05 UTCJul 3, 21:35 UTC3h 30m
2026-07-03 UAL1977 LAX → SFO Jul 3, 13:05 UTCJul 3, 16:30 UTC3h 25m
2026-07-03 UAL1977 LAX → SFO Jul 3, 13:00 UTCJul 3, 16:25 UTC3h 25m
2026-07-03 UAL631 - Jul 3, 07:40 UTCJul 3, 11:40 UTC4h 0m
2026-07-03 UAL1359 - Jul 3, 01:50 UTCJul 3, 06:00 UTC4h 10m
2026-07-02 UAL1867 - Jul 2, 21:10 UTCJul 2, 23:00 UTC1h 50m

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 N76516 page for operator, model, and routing details .

Mode-S AA56B5 frequently asked

What is Mode-S code AA56B5?
AA56B5 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N76516.
Where is Mode-S AA56B5 registered?
Mode-S code AA56B5 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 AA56B5 broadcasting right now?
No active broadcast right now. Last signal was 21h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AA56B5, octal 52453265, decimal 11,163,317.
What flights does AA56B5 operate?
Mode-S AA56B5 has broadcast 20 distinct callsigns, including UAL2199, UAL600, UAL2668, UAL2257, UAL2159.