Apparatus

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sensors Mode-S transponder

A0B821

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N14534 · AIRBUS A-321neo · operated by UNITED AIRLINES INC

Hex
A0B821
Octal
50134041
Decimal
10,532,897
Country
US
Tail
N14534
Type
A21N
No current signal · last broadcast Jul 26, 21:50 UTC
Flights observed
439
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 21:50 UTC

Last known position

Most recent position reported by Mode-S A0B821.

Country allocation

The ICAO 24-bit address A0B821 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
UAL1411 United Airlines 6 2026-07-24
UAL1525 - 5 2026-07-07
UAL1023 - 5 2026-07-18
UAL1007 United Airlines 5 2026-07-23
UAL800 United Airlines 4 2026-06-01
UAL675 - 4 2026-06-21
UAL534 United Airlines 4 2026-07-25
UAL526 United Airlines 4 2026-07-23
UAL3779 - 4 2026-07-06
UAL2865 - 4 2026-06-19
UAL2806 United Airlines 4 2026-06-12
UAL2481 - 4 2026-07-01
UAL2099 United Airlines 4 2026-06-02
UAL2089 - 4 2026-07-05
UAL1940 - 4 2026-07-16
UAL1779 - 4 2026-07-16
UAL1649 United Airlines 4 2026-05-14
UAL1450 - 4 2026-07-08
UAL1382 - 4 2026-07-01
UAL1363 - 4 2026-07-02

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL2113 EWR → ATL Jul 26, 18:00 UTCJul 26, 21:50 UTC3h 50m
2026-07-26 UAL2361 SFO → IAH Jul 26, 12:33 UTCJul 26, 16:10 UTC3h 37m
2026-07-26 UAL2361 SFO → IAH Jul 26, 12:30 UTCJul 26, 14:15 UTC1h 45m
2026-07-25 UAL706 LAX → ORD Jul 25, 21:55 UTCJul 26, 01:05 UTC3h 10m
2026-07-25 UAL2440 ORD → AUS Jul 25, 16:30 UTCJul 25, 19:40 UTC3h 10m
2026-07-25 UAL530 ELP → ORD Jul 25, 10:20 UTCJul 25, 12:25 UTC2h 5m
2026-07-25 UAL534 HNL → LAX Jul 25, 00:00 UTCJul 25, 01:40 UTC1h 40m
2026-07-24 UAL2835 SEA → ORD Jul 24, 18:10 UTCJul 24, 21:50 UTC3h 40m
2026-07-24 UAL341 EWR → BOS Jul 24, 12:25 UTCJul 24, 16:15 UTC3h 50m
2026-07-24 UAL1411 SFO → EWR Jul 24, 00:25 UTCJul 24, 02:40 UTC2h 15m
2026-07-23 UAL1323 EWR → JAX Jul 23, 21:00 UTCJul 23, 22:35 UTC1h 35m
2026-07-23 UAL526 AMM → IAD Jul 23, 17:50 UTCJul 23, 19:20 UTC1h 30m
2026-07-23 UAL1758 DEN → KOA Jul 23, 13:35 UTCJul 23, 15:40 UTC2h 5m
2026-07-23 UAL1758 DEN → KOA Jul 23, 13:34 UTCJul 23, 15:35 UTC2h 1m
2026-07-23 UAL1007 ORD → ALB Jul 23, 04:40 UTCJul 23, 06:50 UTC2h 10m
2026-07-22 UAL2845 MCO → DEN Jul 22, 21:15 UTCJul 23, 01:00 UTC3h 45m
2026-07-22 UAL2292 EWR → DEN Jul 22, 16:50 UTCJul 22, 19:55 UTC3h 5m
2026-07-22 UAL2643 DEN → BOS Jul 22, 11:45 UTCJul 22, 13:40 UTC1h 55m
2026-07-21 UAL1954 RDM → SFO Jul 21, 23:30 UTCJul 22, 01:40 UTC2h 10m
2026-07-21 UAL1583 IAH → LGA Jul 21, 17:40 UTCJul 21, 20:50 UTC3h 10m
2026-07-21 UAL2316 DSM → DEN Jul 21, 14:20 UTCJul 21, 15:45 UTC1h 25m
2026-07-21 UAL1874 SFO → IND Jul 21, 10:30 UTCJul 21, 12:25 UTC1h 55m
2026-07-21 UAL1253 PHX → ORD Jul 21, 03:35 UTCJul 21, 05:35 UTC2h 0m
2026-07-20 UAL1770 EWR → SAV Jul 20, 22:25 UTCJul 21, 01:35 UTC3h 10m
2026-07-20 UAL2354 BUR → SFO Jul 20, 16:41 UTCJul 20, 20:20 UTC3h 39m
2026-07-20 UAL2354 BUR → SFO Jul 20, 16:50 UTCJul 20, 20:15 UTC3h 25m
2026-07-20 UAL1217 ORD → DEN Jul 20, 12:35 UTCJul 20, 14:35 UTC2h 0m
2026-07-19 UAL2311 IAH → RNO Jul 19, 23:00 UTCJul 20, 01:45 UTC2h 45m
2026-07-19 UAL1496 DEN → MIA Jul 19, 17:40 UTCJul 19, 21:30 UTC3h 50m
2026-07-19 UAL792 LAX → EWR Jul 19, 13:05 UTCJul 19, 16:10 UTC3h 5m
2026-07-19 UAL1924 SAN → SFO Jul 19, 06:20 UTCJul 19, 09:10 UTC2h 50m
2026-07-19 UAL767 IAH → ANC Jul 19, 02:13 UTCJul 19, 03:58 UTC1h 45m
2026-07-19 UAL767 IAH → ANC Jul 19, 02:00 UTCJul 19, 03:55 UTC1h 55m
2026-07-18 UAL1023 DEN → ORD Jul 18, 22:05 UTCJul 19, 00:15 UTC2h 10m
2026-07-18 UAL757 CLE → LAS Jul 18, 18:22 UTCJul 18, 20:29 UTC2h 7m
2026-07-18 UAL757 CLE → LAS Jul 18, 18:20 UTCJul 18, 20:30 UTC2h 10m
2026-07-18 UAL2271 LAX → SEA Jul 18, 14:10 UTCJul 18, 16:35 UTC2h 25m
2026-07-18 UAL2829 - Jul 18, 02:50 UTCJul 18, 04:45 UTC1h 55m
2026-07-17 UAL576J ORD → LAX Jul 17, 21:20 UTCJul 18, 00:55 UTC3h 35m
2026-07-17 UAL1946 - Jul 17, 15:40 UTCJul 17, 19:25 UTC3h 45m
2026-07-17 UAL8228 ORD → LAX Jul 17, 03:13 UTCJul 17, 06:41 UTC3h 28m
2026-07-17 UAL8228 ORD → LAX Jul 17, 03:14 UTCJul 17, 06:45 UTC3h 30m
2026-07-16 UAL1779 - Jul 16, 21:35 UTCJul 17, 01:25 UTC3h 50m
2026-07-16 UAL1940 DEN → SAN Jul 16, 18:00 UTCJul 16, 19:55 UTC1h 55m
2026-07-16 UAL2154 LGA → DEN Jul 16, 12:09 UTCJul 16, 15:35 UTC3h 25m
2026-07-16 UAL2033 DEN → LGA Jul 16, 00:30 UTCJul 16, 03:50 UTC3h 20m
2026-07-15 UAL2803 ORD → DEN Jul 15, 20:05 UTCJul 15, 21:55 UTC1h 50m
2026-07-15 UAL2618 SEA → ORD Jul 15, 14:10 UTCJul 15, 18:05 UTC3h 55m
2026-07-14 UAL1801 ORD → SEA Jul 14, 22:15 UTCJul 15, 02:00 UTC3h 44m
2026-07-14 UAL8127 - Jul 14, 17:10 UTCJul 14, 19:50 UTC2h 40m

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 N14534 page for operator, model, and routing details .

Mode-S A0B821 frequently asked

What is Mode-S code A0B821?
A0B821 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N14534.
Where is Mode-S A0B821 registered?
Mode-S code A0B821 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 A0B821 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 21:50 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A0B821, octal 50134041, decimal 10,532,897.
What flights does A0B821 operate?
Mode-S A0B821 has broadcast 20 distinct callsigns, including UAL1411, UAL1525, UAL1023, UAL1007, UAL800.