Apparatus

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sensors Mode-S transponder

A553CE

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N442UA · AIRBUS A-320 · operated by UNITED AIRLINES INC

Hex
A553CE
Octal
51251716
Decimal
10,834,894
Country
US
Tail
N442UA
Type
A320
No current signal · last broadcast Jul 26, 20:45 UTC
Flights observed
449
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 20:45 UTC

Last known position

Most recent position reported by Mode-S A553CE.

Country allocation

The ICAO 24-bit address A553CE 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
UAL817 - 10 2026-07-07
UAL718 United Airlines 9 2026-07-07
UAL2232 United Airlines 5 2026-07-24
UAL790 United Airlines 4 2026-05-28
UAL335 - 4 2026-07-14
UAL2386 - 4 2026-07-14
UAL2383 United Airlines 4 2026-07-20
UAL2315 United Airlines 4 2026-04-29
UAL2118 United Airlines 4 2026-04-21
UAL1578 - 4 2026-07-15
UAL1508 - 4 2026-07-14
UAL1483 - 4 2026-07-03
UAL1413 United Airlines 4 2026-05-21
UAL1220 - 4 2026-07-09
UAL1007 United Airlines 4 2026-07-26
UAL671 - 3 2026-07-13
UAL636 United Airlines 3 2026-04-24
UAL578 United Airlines 3 2026-06-14
UAL562 United Airlines 3 2026-06-22
UAL493 - 3 2026-06-27

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL1007 ORD → ALB Jul 26, 18:55 UTCJul 26, 20:45 UTC1h 50m
2026-07-26 UAL2625 PHX → EWR Jul 26, 15:55 UTCJul 26, 17:35 UTC1h 40m
2026-07-26 UAL2418 IAD → BDL Jul 26, 13:30 UTCJul 26, 14:55 UTC1h 25m
2026-07-26 UAL1762 SDF → DEN Jul 26, 01:25 UTCJul 26, 02:55 UTC1h 30m
2026-07-25 UAL1380 IAD → DFW Jul 25, 21:45 UTCJul 25, 23:30 UTC1h 45m
2026-07-25 UAL652 - Jul 25, 19:00 UTCJul 25, 20:35 UTC1h 35m
2026-07-25 UAL489 DEN → IAH Jul 25, 15:50 UTCJul 25, 17:50 UTC2h 0m
2026-07-25 UAL1704 EWR → MSP Jul 25, 01:40 UTCJul 25, 03:35 UTC1h 55m
2026-07-24 UAL531 EWR → PBI Jul 24, 22:43 UTCJul 24, 23:34 UTC51m
2026-07-24 UAL531 EWR → PBI Jul 24, 20:00 UTCJul 24, 23:40 UTC3h 40m
2026-07-24 UAL2232 ORD → MSP Jul 24, 16:51 UTCJul 24, 18:14 UTC1h 23m
2026-07-24 UAL2232 ORD → MSP Jul 24, 16:40 UTCJul 24, 18:20 UTC1h 40m
2026-07-24 UAL773 DEN → MSP Jul 24, 13:50 UTCJul 24, 15:20 UTC1h 30m
2026-07-24 UAL235T MSP → DEN Jul 24, 05:35 UTCJul 24, 07:10 UTC1h 35m
2026-07-23 UAL773 DEN → MSP Jul 23, 21:40 UTCJul 23, 23:10 UTC1h 30m
2026-07-23 UAL1023 DEN → TPA Jul 23, 18:05 UTCJul 23, 20:05 UTC2h 0m
2026-07-23 UAL2149 DEN → SMF Jul 23, 14:30 UTCJul 23, 16:30 UTC2h 0m
2026-07-23 UAL1035 DCA → ORD Jul 23, 02:25 UTCJul 23, 04:25 UTC2h 0m
2026-07-22 UAL1883 SFO → SJD Jul 22, 22:15 UTCJul 23, 01:05 UTC2h 50m
2026-07-22 UAL2033 RNO → SFO Jul 22, 19:55 UTCJul 22, 20:20 UTC25m
2026-07-22 UAL2045 TPA → EWR Jul 22, 18:10 UTCJul 22, 18:25 UTC15m
2026-07-22 UAL255 ATL → EWR Jul 22, 13:55 UTCJul 22, 16:10 UTC2h 15m
2026-07-22 UAL1204 DEN → SJC Jul 22, 00:30 UTCJul 22, 02:20 UTC1h 50m
2026-07-21 UAL314 DEN → EWR Jul 21, 19:55 UTCJul 21, 22:35 UTC2h 40m
2026-07-21 UAL1464 EWR → FLL Jul 21, 16:20 UTCJul 21, 18:45 UTC2h 25m
2026-07-21 UAL355 BUR → SFO Jul 21, 13:50 UTCJul 21, 15:05 UTC1h 15m
2026-07-21 UAL1515 - Jul 21, 00:25 UTCJul 21, 03:25 UTC3h 0m
2026-07-20 UAL2262 LAS → SFO Jul 20, 21:45 UTCJul 20, 23:00 UTC1h 15m
2026-07-20 UAL2082 MDT → ORD Jul 20, 17:30 UTCJul 20, 19:30 UTC2h 0m
2026-07-20 UAL2082 MDT → ORD Jul 20, 17:37 UTCJul 20, 19:27 UTC1h 50m
2026-07-20 UAL2383 PHL → DEN Jul 20, 12:45 UTCJul 20, 15:50 UTC3h 5m
2026-07-20 UAL2671 DEN → RDU Jul 20, 00:35 UTCJul 20, 03:25 UTC2h 50m
2026-07-19 UAL2110 - Jul 19, 17:50 UTCJul 19, 22:25 UTC4h 35m
2026-07-19 UAL2811 DEN → LAX Jul 19, 01:50 UTCJul 19, 16:10 UTC14h 20m
2026-07-18 UAL625 BOS → ORD Jul 18, 21:50 UTCJul 19, 00:30 UTC2h 40m
2026-07-18 UAL2004 DEN → ECP Jul 18, 17:30 UTCJul 18, 20:10 UTC2h 40m
2026-07-18 UAL1666 - Jul 18, 13:45 UTCJul 18, 16:05 UTC2h 20m
2026-07-18 UAL1615 DEN → CVG Jul 18, 00:15 UTCJul 18, 02:35 UTC2h 20m
2026-07-17 UAL479 - Jul 17, 19:45 UTCJul 17, 22:05 UTC2h 20m
2026-07-17 UAL479 CVG → DEN Jul 17, 19:43 UTCJul 17, 22:04 UTC2h 21m
2026-07-17 UAL1978 DEN → CVG Jul 17, 15:55 UTCJul 17, 18:10 UTC2h 15m
2026-07-16 UAL2200 DEN → DEN Jul 16, 22:55 UTCJul 17, 14:15 UTC15h 20m
2026-07-16 UAL1717 JAC → DEN Jul 16, 20:12 UTCJul 16, 20:59 UTC47m
2026-07-16 UAL2193 - Jul 16, 17:30 UTCJul 16, 18:05 UTC35m
2026-07-16 UAL2742 FSD → DEN Jul 16, 14:55 UTCJul 16, 16:05 UTC1h 10m
2026-07-15 UAL645 DEN → FSD Jul 15, 23:50 UTCJul 16, 00:55 UTC1h 5m
2026-07-15 UAL1790 SBA → DEN Jul 15, 20:25 UTCJul 15, 22:30 UTC2h 5m
2026-07-15 UAL1578 - Jul 15, 18:25 UTCJul 15, 19:10 UTC45m
2026-07-15 UAL1578 SEA → SFO Jul 15, 14:50 UTCJul 15, 16:50 UTC2h 0m
2026-07-15 UAL8170 SFO → SEA Jul 15, 04:05 UTCJul 15, 05:30 UTC1h 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 N442UA page for operator, model, and routing details .

Mode-S A553CE frequently asked

What is Mode-S code A553CE?
A553CE is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N442UA.
Where is Mode-S A553CE registered?
Mode-S code A553CE 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 A553CE broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 20:45 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A553CE, octal 51251716, decimal 10,834,894.
What flights does A553CE operate?
Mode-S A553CE has broadcast 20 distinct callsigns, including UAL817, UAL718, UAL2232, UAL790, UAL335.