Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

A53B2B

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N436UA · AIRBUS A-320 · operated by UNITED AIRLINES INC

Hex
A53B2B
Octal
51235453
Decimal
10,828,587
Country
US
Tail
N436UA
Type
A320
No current signal · last broadcast 7h ago
Flights observed
124
Distinct callsigns
20
Country
US
Last broadcast
7h ago

Last known position

Most recent position reported by Mode-S A53B2B.

Country allocation

The ICAO 24-bit address A53B2B 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
UAL215 United Airlines 5 2026-05-22
UAL2315 United Airlines 4 2026-05-28
UAL1936 United Airlines 3 2026-04-18
UAL1878 United Airlines 3 2026-05-28
UAL1410 United Airlines 3 2026-05-25
UAL1359 United Airlines 3 2026-04-19
UAL764 United Airlines 2 2026-05-26
UAL758 United Airlines 2 2026-05-22
UAL732 United Airlines 2 2026-05-13
UAL625 United Airlines 2 2026-04-16
UAL581C United Airlines 2 2026-05-25
UAL557 United Airlines 2 2026-04-28
UAL485 United Airlines 2 2026-05-20
UAL481 United Airlines 2 2026-04-14
UAL3894 United Airlines 2 2026-05-13
UAL340 United Airlines 2 2026-05-29
UAL2865 United Airlines 2 2026-05-22
UAL2846 United Airlines 2 2026-05-29
UAL2832 United Airlines 2 2026-05-23
UAL2362 United Airlines 2 2026-05-29

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-05-29 UAL340 SFO → DEN May 29, 18:50 UTCMay 29, 21:05 UTC2h 15m
2026-05-29 UAL340 SFO → DEN May 29, 18:45 UTCMay 29, 20:47 UTC2h 2m
2026-05-29 UAL2846 ORD → ABQ May 29, 15:17 UTCMay 29, 17:27 UTC2h 10m
2026-05-29 UAL2846 ORD → ABQ May 29, 14:55 UTCMay 29, 16:45 UTC1h 50m
2026-05-29 UAL2333 ORD → SFO May 29, 10:15 UTCMay 29, 12:10 UTC1h 55m
2026-05-29 UAL2362 LGA → ORD May 29, 00:35 UTCMay 29, 02:10 UTC1h 35m
2026-05-28 UAL2315 BOS → ORD May 28, 21:40 UTCMay 28, 21:45 UTC5m
2026-05-28 UAL2315 BOS → ORD May 28, 20:40 UTCMay 28, 21:45 UTC1h 5m
2026-05-28 UAL2315 BOS → ORD May 28, 20:37 UTCMay 28, 21:24 UTC47m
2026-05-28 UAL1878 LGA → ORD May 28, 18:50 UTCMay 28, 19:40 UTC50m
2026-05-27 UAL2225 ALB → ORD May 27, 12:35 UTCMay 27, 14:35 UTC2h 0m
2026-05-27 UAL2792 IAD → SFO May 27, 00:00 UTCMay 27, 00:44 UTC45m
2026-05-26 UAL1655 BNA → EWR May 26, 19:25 UTCMay 26, 22:35 UTC3h 10m
2026-05-26 UAL764 DEN → BOS May 26, 15:05 UTCMay 26, 18:05 UTC3h 0m
2026-05-26 UAL764 DEN → BOS May 26, 15:15 UTCMay 26, 18:00 UTC2h 45m
2026-05-26 UAL1869 SFO → IAD May 26, 10:25 UTCMay 26, 12:05 UTC1h 40m
2026-05-26 UAL1178 SMF → EWR May 26, 01:10 UTCMay 26, 02:29 UTC1h 19m
2026-05-26 UAL1178 SMF → EWR May 26, 00:49 UTCMay 26, 02:35 UTC1h 45m
2026-05-25 UAL1410 IAH → PHL May 25, 23:10 UTCMay 25, 23:14 UTC5m
2026-05-25 UAL1410 IAH → PHL May 25, 22:25 UTCMay 25, 23:14 UTC50m
2026-05-25 UAL1410 IAH → PHL May 25, 22:16 UTCMay 25, 22:52 UTC36m
2026-05-25 UAL581C SFO → PSP May 25, 20:15 UTCMay 25, 20:43 UTC28m
2026-05-25 UAL581C SFO → PSP May 25, 19:59 UTCMay 25, 20:45 UTC45m
2026-05-25 UAL600 EWR → LAS May 25, 16:35 UTCMay 25, 17:45 UTC1h 10m
2026-05-25 UAL1778 EWR → SAT May 25, 13:55 UTCMay 25, 15:05 UTC1h 10m
2026-05-25 UAL2805 EWR → HNL May 25, 11:10 UTCMay 25, 12:25 UTC1h 15m
2026-05-25 UAL2700 GRR → IAH May 25, 02:50 UTCMay 25, 03:55 UTC1h 5m
2026-05-24 UAL2207 ORD → PIT May 24, 21:30 UTCMay 24, 21:45 UTC15m
2026-05-24 UAL1920 EUG → SFO May 24, 17:05 UTCMay 24, 19:15 UTC2h 10m
2026-05-24 UAL2034 IAH → SFO May 24, 14:35 UTCMay 24, 16:05 UTC1h 30m
2026-05-24 UAL2034 IAH → SFO May 24, 13:18 UTCMay 24, 16:12 UTC2h 54m
2026-05-23 UAL2832 OMA → ORD May 23, 23:50 UTCMay 24, 01:05 UTC1h 15m
2026-05-23 UAL2329 RNO → SFO May 23, 21:05 UTCMay 23, 22:05 UTC1h 0m
2026-05-23 UAL2832 OMA → ORD May 23, 00:00 UTCMay 23, 01:20 UTC1h 20m
2026-05-22 UAL2329 RNO → SFO May 22, 21:15 UTCMay 22, 22:20 UTC1h 5m
2026-05-22 UAL371 LAX → DEN May 22, 18:35 UTCMay 22, 19:45 UTC1h 10m
2026-05-22 UAL215 IAD → SFO May 22, 15:56 UTCMay 22, 16:47 UTC51m
2026-05-22 UAL215 IAD → SFO May 22, 15:45 UTCMay 22, 16:50 UTC1h 5m
2026-05-22 UAL758 DEN → ORD May 22, 13:00 UTCMay 22, 14:00 UTC1h 0m
2026-05-22 UAL758 DEN → ORD May 22, 12:52 UTCMay 22, 13:44 UTC52m
2026-05-22 UAL2865 DEN → ORD May 22, 00:25 UTCMay 22, 01:25 UTC1h 0m
2026-05-22 UAL2865 DEN → ORD May 22, 00:38 UTCMay 22, 01:22 UTC44m
2026-05-21 UAL2315 BOS → ORD May 21, 20:35 UTCMay 21, 21:40 UTC1h 5m
2026-05-21 UAL1878 LGA → ORD May 21, 18:15 UTCMay 21, 19:05 UTC50m
2026-05-21 UAL1878 LGA → ORD May 21, 18:24 UTCMay 21, 18:59 UTC35m
2026-05-21 UAL455 ORD → MSN May 21, 15:10 UTCMay 21, 16:25 UTC1h 15m
2026-05-21 UAL1285 BDL → IAH May 21, 13:05 UTCMay 21, 14:00 UTC55m
2026-05-21 UAL2218 SJU → EWR May 21, 02:10 UTCMay 21, 04:00 UTC1h 50m
2026-05-20 UAL2133 EWR → RSW May 20, 23:33 UTCMay 21, 00:16 UTC43m
2026-05-20 UAL2133 EWR → RSW May 20, 22:55 UTCMay 20, 23:15 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 N436UA page for operator, model, and routing details .

Mode-S A53B2B frequently asked

What is Mode-S code A53B2B?
A53B2B is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N436UA.
Where is Mode-S A53B2B registered?
Mode-S code A53B2B 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 A53B2B broadcasting right now?
No active broadcast right now. Last signal was 7h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A53B2B, octal 51235453, decimal 10,828,587.
What flights does A53B2B operate?
Mode-S A53B2B has broadcast 20 distinct callsigns, including UAL215, UAL2315, UAL1936, UAL1878, UAL1410.