Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

AA56B4

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N76515 · BOEING 737-800 · operated by UNITED AIRLINES INC

Hex
AA56B4
Octal
52453264
Decimal
11,163,316
Country
US
Tail
N76515
Type
B738
No current signal · last broadcast Jul 26, 20:45 UTC
Flights observed
298
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 20:45 UTC

Last known position

Most recent position reported by Mode-S AA56B4.

Country allocation

The ICAO 24-bit address AA56B4 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
UAL2498 - 4 2026-07-16
UAL2275 - 4 2026-07-08
UAL1604 United Airlines 4 2026-04-13
UAL1381 United Airlines 4 2026-07-21
UAL1182 United Airlines 4 2026-04-18
UAL2750 - 3 2026-06-27
UAL2644 - 3 2026-07-19
UAL251 - 3 2026-07-21
UAL2263 United Airlines 3 2026-07-22
UAL1555 United Airlines 3 2026-04-26
UAL1303 United Airlines 3 2026-07-23
UAL8290 United Airlines 2 2026-07-18
UAL799 United Airlines 2 2026-04-17
UAL784 - 2 2026-06-28
UAL783 - 2 2026-06-28
UAL728 United Airlines 2 2026-04-19
UAL722 United Airlines 2 2026-04-22
UAL705 - 2 2026-06-24
UAL671 - 2 2026-07-10
UAL590 United Airlines 2 2026-06-12

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL2401 ORD → NAS Jul 26, 18:25 UTCJul 26, 20:45 UTC2h 20m
2026-07-26 UAL2749 LAS → SFO Jul 26, 12:50 UTCJul 26, 14:40 UTC1h 50m
2026-07-26 UAL1340 FLL → EWR Jul 26, 06:25 UTCJul 26, 11:15 UTC4h 51m
2026-07-26 UAL1272 LAX → SFO Jul 26, 00:20 UTCJul 26, 04:05 UTC3h 45m
2026-07-25 UAL1271 SFO → MEX Jul 25, 22:10 UTCJul 25, 22:25 UTC15m
2026-07-25 UAL1271 SFO → MEX Jul 25, 18:30 UTCJul 25, 20:25 UTC1h 55m
2026-07-25 UAL611 CHS → EWR Jul 25, 10:20 UTCJul 25, 15:10 UTC4h 50m
2026-07-25 UAL1961 LAS → IAD Jul 25, 00:30 UTCJul 25, 03:30 UTC3h 0m
2026-07-24 UAL302 DFW → EWR Jul 24, 19:40 UTCJul 24, 22:15 UTC2h 35m
2026-07-24 UAL1915 SAN → SFO Jul 24, 15:45 UTCJul 24, 18:05 UTC2h 20m
2026-07-24 UAL1188 RDM → DEN Jul 24, 12:15 UTCJul 24, 14:10 UTC1h 55m
2026-07-24 UAL1588 EWR → SAV Jul 24, 01:45 UTCJul 24, 03:55 UTC2h 10m
2026-07-23 UAL1303 EWR → IAH Jul 23, 22:10 UTCJul 24, 00:20 UTC2h 10m
2026-07-23 UAL1303 EWR → IAH Jul 23, 22:04 UTCJul 24, 00:13 UTC2h 9m
2026-07-23 UAL2290 ORD → SFO Jul 23, 18:35 UTCJul 23, 20:25 UTC1h 50m
2026-07-23 UAL2290 ORD → SFO Jul 23, 18:34 UTCJul 23, 20:22 UTC1h 48m
2026-07-23 UAL343 DCA → ORD Jul 23, 15:05 UTCJul 23, 16:15 UTC1h 10m
2026-07-23 UAL2175 SLC → DEN Jul 23, 12:45 UTCJul 23, 13:45 UTC1h 0m
2026-07-23 UAL747 ORD → IAH Jul 23, 06:20 UTCJul 23, 09:35 UTC3h 15m
2026-07-22 UAL692 - Jul 22, 23:55 UTCJul 23, 03:55 UTC4h 0m
2026-07-22 UAL2263 EWR → FLL Jul 22, 14:50 UTCJul 22, 20:25 UTC5h 35m
2026-07-22 UAL631 - Jul 22, 11:10 UTCJul 22, 11:20 UTC10m
2026-07-22 UAL1359 IAH → EWR Jul 22, 01:15 UTCJul 22, 05:25 UTC4h 10m
2026-07-21 UAL1867 CZM → IAH Jul 21, 21:10 UTCJul 21, 23:00 UTC1h 50m
2026-07-21 UAL1919 IAH → CZM Jul 21, 17:35 UTCJul 21, 19:30 UTC1h 55m
2026-07-21 UAL251 - Jul 21, 14:10 UTCJul 21, 16:00 UTC1h 50m
2026-07-21 UAL1381 IAH → SAN Jul 21, 01:45 UTCJul 21, 03:25 UTC1h 40m
2026-07-20 UAL1326 SFO → BNA Jul 20, 23:20 UTCJul 21, 00:00 UTC39m
2026-07-20 UAL2270 LAS → IAH Jul 20, 20:05 UTCJul 20, 21:50 UTC1h 45m
2026-07-20 UAL1537 - Jul 20, 14:15 UTCJul 20, 17:40 UTC3h 25m
2026-07-20 UAL1510 DEN → PHL Jul 20, 02:15 UTCJul 20, 05:15 UTC3h 0m
2026-07-19 UAL2644 PHL → DEN Jul 19, 20:30 UTCJul 19, 23:50 UTC3h 20m
2026-07-19 UAL1575 MSP → EWR Jul 19, 15:50 UTCJul 19, 18:55 UTC3h 5m
2026-07-19 UAL1188 RDM → DEN Jul 19, 12:10 UTCJul 19, 14:05 UTC1h 55m
2026-07-19 UAL1588 DEN → RDM Jul 19, 02:10 UTCJul 19, 04:05 UTC1h 55m
2026-07-18 UAL1303 EWR → IAH Jul 18, 23:10 UTCJul 19, 00:40 UTC1h 30m
2026-07-18 UAL8290 ORD → ATL Jul 18, 19:45 UTCJul 18, 21:35 UTC1h 50m
2026-07-18 UAL8290 ORD → ATL Jul 18, 19:39 UTCJul 18, 21:29 UTC1h 50m
2026-07-18 UAL2306 ORD → BOS Jul 18, 14:15 UTCJul 18, 17:50 UTC3h 35m
2026-07-18 UAL1770 DEN → PDX Jul 18, 03:45 UTCJul 18, 05:55 UTC2h 10m
2026-07-18 UAL1910 SLC → DEN Jul 18, 00:29 UTCJul 18, 01:34 UTC1h 5m
2026-07-17 UAL8201 YYZ → MSP Jul 17, 21:10 UTCJul 17, 22:29 UTC1h 20m
2026-07-17 UAL795 - Jul 17, 14:04 UTCJul 17, 18:50 UTC4h 45m
2026-07-16 UAL2498 - Jul 16, 23:55 UTCJul 17, 02:15 UTC2h 20m
2026-07-16 UAL1854 - Jul 16, 15:00 UTCJul 16, 21:30 UTC6h 30m
2026-07-16 UAL532 - Jul 16, 11:34 UTCJul 16, 13:05 UTC1h 30m
2026-07-16 UAL2050 - Jul 16, 00:25 UTCJul 16, 01:55 UTC1h 30m
2026-07-15 UAL1242 - Jul 15, 16:05 UTCJul 15, 22:30 UTC6h 25m
2026-07-15 UAL2371 - Jul 15, 10:20 UTCJul 15, 13:25 UTC3h 5m
2026-07-15 UAL2371 IAH → EWR Jul 15, 10:15 UTCJul 15, 13:26 UTC3h 11m

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 N76515 page for operator, model, and routing details .

Mode-S AA56B4 frequently asked

What is Mode-S code AA56B4?
AA56B4 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N76515.
Where is Mode-S AA56B4 registered?
Mode-S code AA56B4 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 AA56B4 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 20:45 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AA56B4, octal 52453264, decimal 11,163,316.
What flights does AA56B4 operate?
Mode-S AA56B4 has broadcast 20 distinct callsigns, including UAL2498, UAL2275, UAL1604, UAL1381, UAL1182.