Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

AA2BC4

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N75435 · BOEING 737-900 · operated by UNITED AIRLINES INC

Hex
AA2BC4
Octal
52425704
Decimal
11,152,324
Country
US
Tail
N75435
Type
B739
No current signal · last broadcast Jul 26, 22:05 UTC
Flights observed
422
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 22:05 UTC

Last known position

Most recent position reported by Mode-S AA2BC4.

Country allocation

The ICAO 24-bit address AA2BC4 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
UAL1393 - 7 2026-07-17
UAL721 - 6 2026-07-10
UAL2784 - 5 2026-07-06
UAL2269 - 5 2026-07-12
UAL1695 - 5 2026-06-29
UAL644 United Airlines 4 2026-06-13
UAL555 United Airlines 4 2026-05-16
UAL2330 United Airlines 4 2026-04-19
UAL2288 - 4 2026-07-12
UAL2217 United Airlines 4 2026-04-19
UAL2078 United Airlines 4 2026-04-13
UAL1782 - 4 2026-06-27
UAL1273 - 4 2026-06-29
UAL1183 United Airlines 4 2026-06-20
UAL570 United Airlines 3 2026-05-20
UAL485 United Airlines 3 2026-07-20
UAL2741 - 3 2026-07-15
UAL2737 United Airlines 3 2026-04-18
UAL2672 - 3 2026-07-18
UAL2443 United Airlines 3 2026-07-20

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL1434 SFO → LAX Jul 26, 16:55 UTCJul 26, 21:50 UTC4h 55m
2026-07-26 UAL1549 ORD → PSP Jul 26, 12:45 UTCJul 26, 15:20 UTC2h 35m
2026-07-26 UAL2425 EWR → MSY Jul 26, 01:20 UTCJul 26, 04:20 UTC3h 0m
2026-07-25 UAL1051 CUN → EWR Jul 25, 18:25 UTCJul 25, 21:50 UTC3h 25m
2026-07-25 UAL1051 CUN → EWR Jul 25, 18:30 UTCJul 25, 21:45 UTC3h 15m
2026-07-25 UAL1018 SJC → IAH Jul 25, 15:10 UTCJul 25, 16:55 UTC1h 45m
2026-07-25 UAL2773 HNL → ORD Jul 25, 11:15 UTCJul 25, 13:10 UTC1h 55m
2026-07-24 UAL2778 HKG → SFO Jul 24, 23:45 UTCJul 25, 01:40 UTC1h 55m
2026-07-24 UAL1545 SFO → LAX Jul 24, 19:25 UTCJul 24, 22:00 UTC2h 35m
2026-07-24 UAL2067 IAH → LGA Jul 24, 15:40 UTCJul 24, 18:00 UTC2h 20m
2026-07-24 UAL715 ORD → PBI Jul 24, 11:45 UTCJul 24, 14:00 UTC2h 15m
2026-07-24 UAL1641 IAD → SFO Jul 24, 01:25 UTCJul 24, 02:15 UTC50m
2026-07-23 UAL2160 PHX → SFO Jul 23, 19:30 UTCJul 23, 21:45 UTC2h 15m
2026-07-23 UAL2160 PHX → SFO Jul 23, 19:30 UTCJul 23, 21:16 UTC1h 46m
2026-07-23 UAL441 EWR → FLL Jul 23, 16:05 UTCJul 23, 17:45 UTC1h 40m
2026-07-23 UAL2420 RSW → IAH Jul 23, 11:35 UTCJul 23, 13:35 UTC2h 0m
2026-07-23 UAL2420 RSW → IAH Jul 23, 11:41 UTCJul 23, 13:20 UTC1h 39m
2026-07-23 UAL2042 ORD → BDL Jul 23, 00:20 UTCJul 23, 02:30 UTC2h 10m
2026-07-22 UAL2853 DEN → EWR Jul 22, 19:00 UTCJul 22, 21:45 UTC2h 45m
2026-07-22 UAL1500 RDU → EWR Jul 22, 15:05 UTCJul 22, 16:55 UTC1h 50m
2026-07-22 UAL2324 GEG → SFO Jul 22, 01:55 UTCJul 22, 03:20 UTC1h 25m
2026-07-21 UAL1126 LAS → EWR Jul 21, 20:35 UTCJul 22, 00:05 UTC3h 30m
2026-07-21 UAL1101 DEN → IAD Jul 21, 14:25 UTCJul 21, 18:05 UTC3h 40m
2026-07-21 UAL773 DFW → DEN Jul 21, 11:00 UTCJul 21, 12:25 UTC1h 25m
2026-07-21 UAL424 IAD → SFO Jul 21, 01:40 UTCJul 21, 04:35 UTC2h 55m
2026-07-20 UAL485 LAS → EWR Jul 20, 22:15 UTCJul 20, 23:50 UTC1h 35m
2026-07-20 UAL2443 MSN → ORD Jul 20, 18:40 UTCJul 20, 19:40 UTC1h 0m
2026-07-20 UAL2389 LGA → ORD Jul 20, 16:15 UTCJul 20, 17:05 UTC50m
2026-07-20 UAL567 BOS → ORD Jul 20, 13:05 UTCJul 20, 14:10 UTC1h 5m
2026-07-20 UAL2005 DFW → SFO Jul 20, 02:25 UTCJul 20, 03:30 UTC1h 5m
2026-07-19 UAL1933 SNA → ORD Jul 19, 16:20 UTCJul 19, 17:25 UTC1h 5m
2026-07-19 UAL8235 CMH → ORD Jul 19, 04:38 UTCJul 19, 05:25 UTC47m
2026-07-19 UAL8235 CMH → ORD Jul 19, 04:30 UTCJul 19, 05:25 UTC55m
2026-07-18 UAL1686 IAH → SNA Jul 18, 22:10 UTCJul 19, 01:20 UTC3h 10m
2026-07-18 UAL2225 - Jul 18, 15:00 UTCJul 18, 18:00 UTC3h 0m
2026-07-18 UAL2672 - Jul 18, 10:25 UTCJul 18, 12:20 UTC1h 55m
2026-07-18 UAL8110 - Jul 18, 01:50 UTCJul 18, 03:30 UTC1h 41m
2026-07-17 UAL1393 IAD → ORD Jul 17, 22:40 UTCJul 18, 00:19 UTC1h 40m
2026-07-17 UAL2057 SAV → IAD Jul 17, 16:15 UTCJul 17, 17:30 UTC1h 15m
2026-07-17 UAL2244 IAD → SAV Jul 17, 13:15 UTCJul 17, 14:24 UTC1h 10m
2026-07-17 UAL635 EWR → MSY Jul 17, 10:10 UTCJul 17, 11:10 UTC1h 0m
2026-07-17 UAL444J IAD → BDL Jul 17, 03:25 UTCJul 17, 04:20 UTC55m
2026-07-17 UAL2202 ORD → IAD Jul 17, 00:25 UTCJul 17, 01:45 UTC1h 20m
2026-07-16 UAL1623 - Jul 16, 19:55 UTCJul 16, 21:50 UTC1h 55m
2026-07-16 UAL1623 - Jul 16, 17:40 UTCJul 16, 18:05 UTC25m
2026-07-16 UAL2816 - Jul 16, 13:54 UTCJul 16, 16:15 UTC2h 20m
2026-07-15 UAL2741 - Jul 15, 23:20 UTCJul 16, 02:05 UTC2h 45m
2026-07-15 UAL2741 - Jul 15, 20:20 UTCJul 15, 21:10 UTC50m
2026-07-15 UAL1653 CUN → LAX Jul 15, 13:10 UTCJul 15, 17:45 UTC4h 35m
2026-07-15 UAL1145 SFO → CUN Jul 15, 06:50 UTCJul 15, 11:35 UTC4h 45m

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 N75435 page for operator, model, and routing details .

Mode-S AA2BC4 frequently asked

What is Mode-S code AA2BC4?
AA2BC4 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N75435.
Where is Mode-S AA2BC4 registered?
Mode-S code AA2BC4 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 AA2BC4 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 22:05 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AA2BC4, octal 52425704, decimal 11,152,324.
What flights does AA2BC4 operate?
Mode-S AA2BC4 has broadcast 20 distinct callsigns, including UAL1393, UAL721, UAL2784, UAL2269, UAL1695.