Apparatus

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sensors Mode-S transponder

AB5DD4

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N831UA · AIRBUS A-319 · operated by UNITED AIRLINES INC

Hex
AB5DD4
Octal
52656724
Decimal
11,230,676
Country
US
Tail
N831UA
Type
A319
No current signal · last broadcast Jul 26, 22:15 UTC
Flights observed
413
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 22:15 UTC

Last known position

Most recent position reported by Mode-S AB5DD4.

Country allocation

The ICAO 24-bit address AB5DD4 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
UAL533 United Airlines 5 2026-05-17
UAL515 - 5 2026-07-16
UAL2190 - 5 2026-07-20
UAL793 - 4 2026-07-13
UAL482 - 4 2026-07-20
UAL2691 United Airlines 4 2026-05-14
UAL2233 - 4 2026-07-16
UAL2148 United Airlines 4 2026-07-19
UAL1836 United Airlines 4 2026-07-24
UAL1517 - 4 2026-07-13
UAL1376 - 4 2026-06-28
UAL1211 - 4 2026-07-20
UAL745 - 3 2026-07-12
UAL648 - 3 2026-06-30
UAL623 United Airlines 3 2026-07-18
UAL622 - 3 2026-07-13
UAL576 United Airlines 3 2026-05-05
UAL530 - 3 2026-07-12
UAL425 - 3 2026-06-26
UAL404 - 3 2026-07-16

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL1728 SFO → IAH Jul 26, 20:55 UTCJul 26, 22:10 UTC1h 15m
2026-07-26 UAL792 LAX → EWR Jul 26, 18:05 UTCJul 26, 19:10 UTC1h 5m
2026-07-26 UAL384 DEN → HNL Jul 26, 13:15 UTCJul 26, 15:40 UTC2h 25m
2026-07-26 UAL1470 EWR → SDQ Jul 26, 00:25 UTCJul 26, 02:20 UTC1h 55m
2026-07-26 UAL1470 EWR → SDQ Jul 26, 00:25 UTCJul 26, 02:30 UTC2h 5m
2026-07-25 UAL2033 RNO → SFO Jul 25, 20:00 UTCJul 25, 20:35 UTC35m
2026-07-25 UAL2045 TPA → EWR Jul 25, 17:46 UTCJul 25, 18:00 UTC14m
2026-07-25 UAL2045 TPA → EWR Jul 25, 17:40 UTCJul 25, 17:55 UTC15m
2026-07-25 UAL1521 IAD → MSY Jul 25, 14:35 UTCJul 25, 16:00 UTC1h 25m
2026-07-24 UAL549 BOS → ORD Jul 24, 23:50 UTCJul 25, 01:10 UTC1h 20m
2026-07-24 UAL696 RIC → DEN Jul 24, 19:45 UTCJul 24, 21:50 UTC2h 5m
2026-07-24 UAL1836 SEA → SFO Jul 24, 16:15 UTCJul 24, 18:10 UTC1h 55m
2026-07-24 UAL1262 ORD → BOS Jul 24, 01:15 UTCJul 24, 03:05 UTC1h 50m
2026-07-23 UAL2750 PVR → SFO Jul 23, 20:01 UTCJul 23, 21:15 UTC1h 14m
2026-07-23 UAL2750 PVR → SFO Jul 23, 20:05 UTCJul 23, 21:25 UTC1h 20m
2026-07-23 UAL1045 DEN → IAD Jul 23, 16:50 UTCJul 23, 18:20 UTC1h 30m
2026-07-23 UAL8251 SEA → DEN Jul 23, 03:25 UTCJul 23, 04:45 UTC1h 20m
2026-07-22 UAL314 DEN → EWR Jul 22, 20:00 UTCJul 23, 02:15 UTC6h 15m
2026-07-22 UAL1464 EWR → FLL Jul 22, 16:15 UTCJul 22, 18:50 UTC2h 35m
2026-07-21 UAL439 EWR → GRR Jul 21, 23:40 UTCJul 22, 01:25 UTC1h 45m
2026-07-21 UAL1711 SFO → CLE Jul 21, 21:35 UTCJul 21, 22:05 UTC30m
2026-07-21 UAL1091 - Jul 21, 18:00 UTCJul 21, 19:50 UTC1h 50m
2026-07-21 UAL1060 - Jul 21, 14:45 UTCJul 21, 16:30 UTC1h 45m
2026-07-21 UAL1085 - Jul 21, 11:15 UTCJul 21, 13:05 UTC1h 50m
2026-07-21 UAL429 IAH → MEX Jul 21, 03:15 UTCJul 21, 05:05 UTC1h 50m
2026-07-20 UAL2376 - Jul 20, 23:40 UTCJul 21, 01:10 UTC1h 30m
2026-07-20 UAL1211 - Jul 20, 20:30 UTCJul 20, 22:10 UTC1h 40m
2026-07-20 UAL2190 - Jul 20, 16:50 UTCJul 20, 19:15 UTC2h 25m
2026-07-20 UAL2190 DCA → IAH Jul 20, 16:28 UTCJul 20, 19:08 UTC2h 40m
2026-07-20 UAL482 - Jul 20, 12:20 UTCJul 20, 13:45 UTC1h 25m
2026-07-19 UAL2148 EWR → SAT Jul 19, 22:35 UTCJul 20, 00:40 UTC2h 5m
2026-07-19 UAL1314 EWR → JAX Jul 19, 19:33 UTCJul 19, 20:51 UTC1h 18m
2026-07-19 UAL705 - Jul 19, 15:10 UTCJul 19, 16:25 UTC1h 15m
2026-07-19 UAL2753 ORD → BUF Jul 19, 12:40 UTCJul 19, 13:50 UTC1h 10m
2026-07-19 UAL1744 IAD → ORD Jul 19, 02:45 UTCJul 19, 04:50 UTC2h 5m
2026-07-18 UAL623 LGA → ORD Jul 18, 18:40 UTCJul 18, 21:00 UTC2h 20m
2026-07-18 UAL2145 MFR → SFO Jul 18, 11:25 UTCJul 18, 12:35 UTC1h 10m
2026-07-18 UAL2496 - Jul 18, 01:00 UTCJul 18, 02:05 UTC1h 5m
2026-07-17 UAL2680 IND → ORD Jul 17, 22:25 UTCJul 17, 23:25 UTC1h 0m
2026-07-17 UAL2680 IND → ORD Jul 17, 22:27 UTCJul 17, 23:23 UTC56m
2026-07-17 UAL1687 MSY → SFO Jul 17, 17:30 UTCJul 17, 19:25 UTC1h 55m
2026-07-17 UAL1586 - Jul 17, 15:40 UTCJul 17, 16:24 UTC45m
2026-07-17 UAL358 - Jul 17, 13:29 UTCJul 17, 14:15 UTC45m
2026-07-17 UAL358 IAH → DFW Jul 17, 13:13 UTCJul 17, 14:11 UTC58m
2026-07-17 UAL2744 - Jul 17, 10:20 UTCJul 17, 11:04 UTC45m
2026-07-16 UAL2140 SFO → IAH Jul 16, 23:49 UTCJul 17, 00:30 UTC40m
2026-07-16 UAL2140 SFO → IAH Jul 16, 23:53 UTCJul 17, 00:32 UTC39m
2026-07-16 UAL404 - Jul 16, 21:25 UTCJul 16, 22:10 UTC45m
2026-07-16 UAL515 - Jul 16, 16:35 UTCJul 16, 19:55 UTC3h 20m
2026-07-16 UAL2233 - Jul 16, 11:40 UTCJul 16, 15:05 UTC3h 25m

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 N831UA page for operator, model, and routing details .

Mode-S AB5DD4 frequently asked

What is Mode-S code AB5DD4?
AB5DD4 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N831UA.
Where is Mode-S AB5DD4 registered?
Mode-S code AB5DD4 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 AB5DD4 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 22:15 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AB5DD4, octal 52656724, decimal 11,230,676.
What flights does AB5DD4 operate?
Mode-S AB5DD4 has broadcast 20 distinct callsigns, including UAL533, UAL515, UAL2190, UAL793, UAL482.