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
Broadcasting now · callsign UAL2172 · 33,000 ft
Flights observed
174
Distinct callsigns
20
Country
US
Last broadcast
1h ago

Current position

AB5DD4 is currently broadcasting. Map zoomed to live position.

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
UAL2691 United Airlines 4 2026-05-14
UAL576 United Airlines 3 2026-05-05
UAL249 United Airlines 3 2026-05-11
UAL2474 United Airlines 3 2026-05-23
UAL1833 United Airlines 3 2026-05-14
UAL1693 United Airlines 3 2026-05-07
UAL1608 United Airlines 3 2026-05-30
UAL1239 United Airlines 3 2026-05-11
UAL8140 United Airlines 2 2026-05-05
UAL623 United Airlines 2 2026-05-10
UAL605 United Airlines 2 2026-04-24
UAL2772 United Airlines 2 2026-06-02
UAL2470 United Airlines 2 2026-05-29
UAL247 United Airlines 2 2026-04-26
UAL2468 United Airlines 2 2026-06-02
UAL2336 United Airlines 2 2026-05-11
UAL2272 United Airlines 2 2026-04-24
UAL2226 United Airlines 2 2026-05-05
UAL2171 United Airlines 2 2026-05-11

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-06-05 UAL1309 EWR → SNA Jun 5, 11:25 UTCJun 5, 14:00 UTC2h 35m
2026-06-04 UAL765 EWR → DFW Jun 4, 23:10 UTCJun 5, 01:15 UTC2h 5m
2026-06-04 UAL1391 LAS → EWR Jun 4, 19:40 UTCJun 4, 21:30 UTC1h 50m
2026-06-04 UAL2172 IAH → PHL Jun 4, 15:15 UTCJun 4, 18:00 UTC2h 45m
2026-06-04 UAL1309 EWR → SNA Jun 4, 11:20 UTCJun 4, 13:50 UTC2h 30m
2026-06-03 UAL1499 EWR → LAX Jun 3, 15:22 UTCJun 3, 18:36 UTC3h 14m
2026-06-03 UAL1499 EWR → LAX Jun 3, 15:15 UTCJun 3, 18:45 UTC3h 30m
2026-06-03 UAL1229 EWR → MCI Jun 3, 10:25 UTCJun 3, 13:35 UTC3h 10m
2026-06-03 UAL1439 EWR → SFO Jun 3, 03:50 UTCJun 3, 06:55 UTC3h 5m
2026-06-03 UAL1535 EWR → ORD Jun 3, 01:50 UTCJun 3, 02:45 UTC55m
2026-06-03 UAL1535 EWR → ORD Jun 3, 01:44 UTCJun 3, 02:59 UTC1h 15m
2026-06-02 UAL2772 MSY → IAH Jun 2, 20:45 UTCJun 2, 22:30 UTC1h 45m
2026-06-02 UAL2772 MSY → IAH Jun 2, 20:51 UTCJun 2, 22:35 UTC1h 44m
2026-06-02 UAL2468 TPA → EWR Jun 2, 16:40 UTCJun 2, 19:20 UTC2h 40m
2026-06-02 UAL2468 TPA → EWR Jun 2, 16:55 UTCJun 2, 19:16 UTC2h 21m
2026-06-02 UAL2690 LAS → IAH Jun 2, 13:35 UTCJun 2, 15:15 UTC1h 40m
2026-06-01 UAL2784 GUM → SFO Jun 1, 23:35 UTCJun 2, 00:35 UTC1h 0m
2026-06-01 UAL2792 IAD → SFO Jun 1, 20:25 UTCJun 1, 21:25 UTC1h 0m
2026-06-01 UAL2465 IAD → PWM Jun 1, 18:10 UTCJun 1, 18:55 UTC45m
2026-06-01 UAL1577 RNO → SFO Jun 1, 14:30 UTCJun 1, 16:05 UTC1h 35m
2026-06-01 UAL2747 EWR → INT Jun 1, 01:40 UTCJun 1, 03:05 UTC1h 25m
2026-05-31 UAL1639 OGG → SFO May 31, 22:50 UTCMay 31, 23:35 UTC45m
2026-05-31 UAL1639 OGG → SFO May 31, 19:45 UTCMay 31, 21:20 UTC1h 35m
2026-05-31 UAL1327 EWR → CMH May 31, 15:30 UTCMay 31, 18:15 UTC2h 45m
2026-05-31 UAL2739 SFO → LAX May 31, 12:50 UTCMay 31, 14:10 UTC1h 20m
2026-05-31 UAL1460 SFO → DEN May 31, 00:00 UTCMay 31, 01:11 UTC1h 11m
2026-05-30 UAL1608 MSN → DEN May 30, 19:26 UTCMay 30, 20:58 UTC1h 32m
2026-05-30 UAL1608 MSN → DEN May 30, 19:10 UTCMay 30, 21:00 UTC1h 50m
2026-05-30 UAL2080 ORD → SFO May 30, 15:20 UTCMay 30, 17:45 UTC2h 25m
2026-05-30 UAL1771 SEA → ORD May 30, 11:00 UTCMay 30, 13:25 UTC2h 25m
2026-05-30 UAL657 CHS → EWR May 30, 00:45 UTCMay 30, 02:55 UTC2h 10m
2026-05-29 UAL2470 DEN → MCI May 29, 22:15 UTCMay 29, 23:00 UTC45m
2026-05-29 UAL2470 DEN → MCI May 29, 22:01 UTCMay 29, 23:50 UTC1h 49m
2026-05-29 UAL2033 RNO → SFO May 29, 19:50 UTCMay 29, 20:10 UTC20m
2026-05-29 UAL2045 TPA → EWR May 29, 17:55 UTCMay 29, 18:10 UTC15m
2026-05-29 UAL1081 EWR → MIA May 29, 14:15 UTCMay 29, 15:55 UTC1h 40m
2026-05-29 UAL1081 EWR → MIA May 29, 14:05 UTCMay 29, 15:58 UTC1h 53m
2026-05-28 UAL1282 EWR → RSW May 28, 23:40 UTCMay 29, 01:15 UTC1h 35m
2026-05-28 UAL2822 SFO → GUM May 28, 20:10 UTCMay 28, 22:05 UTC1h 55m
2026-05-28 UAL1836 SEA → SFO May 28, 16:15 UTCMay 28, 18:15 UTC2h 0m
2026-05-28 UAL1049 CUN → EWR May 28, 12:50 UTCMay 28, 14:20 UTC1h 30m
2026-05-28 UAL1049 CUN → EWR May 28, 12:57 UTCMay 28, 14:15 UTC1h 18m
2026-05-28 UAL1762 SDF → DEN May 28, 01:30 UTCMay 28, 03:05 UTC1h 35m
2026-05-27 UAL568 IAH → SFO May 27, 20:45 UTCMay 28, 00:00 UTC3h 15m
2026-05-27 UAL1874 SFO → IND May 27, 16:25 UTCMay 27, 19:05 UTC2h 40m
2026-05-27 UAL225 ATL → DEN May 27, 12:45 UTCMay 27, 14:35 UTC1h 50m
2026-05-27 UAL1604 SFO → BNA May 27, 01:11 UTCMay 27, 02:50 UTC1h 39m
2026-05-26 UAL447 SFO → SEA May 26, 20:50 UTCMay 26, 22:59 UTC2h 10m
2026-05-26 UAL1357 IAD → SFO May 26, 16:40 UTCMay 26, 18:59 UTC2h 20m
2026-05-26 UAL1506 SFO → ORD May 26, 12:00 UTCMay 26, 14:20 UTC2h 20m

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?
Yes. Mode-S AB5DD4 is currently airborne.
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, UAL2691, UAL576, UAL249, UAL2474.