Apparatus

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sensors Mode-S transponder

A494C5

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N39450 · BOEING 737-900 · operated by UNITED AIRLINES INC

Hex
A494C5
Octal
51112305
Decimal
10,785,989
Country
US
Tail
N39450
Type
B739
No current signal · last broadcast Jul 26, 20:00 UTC
Flights observed
470
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 20:00 UTC

Last known position

Most recent position reported by Mode-S A494C5.

Country allocation

The ICAO 24-bit address A494C5 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
UAL2635 - 7 2026-06-29
UAL1554 United Airlines 6 2026-07-03
UAL1875 - 5 2026-07-19
UAL1813 United Airlines 5 2026-06-12
UAL658 - 4 2026-06-14
UAL619 United Airlines 4 2026-05-15
UAL593 United Airlines 4 2026-05-20
UAL2826 United Airlines 4 2026-06-14
UAL2396 United Airlines 4 2026-05-31
UAL2226 United Airlines 4 2026-06-13
UAL2207 - 4 2026-06-29
UAL1937 - 4 2026-07-11
UAL1342 - 4 2026-07-10
UAL1010 - 4 2026-06-21
UAL8125 - 3 2026-07-04
UAL759 - 3 2026-06-21
UAL651 - 3 2026-06-30
UAL644 United Airlines 3 2026-07-26
UAL503 United Airlines 3 2026-05-20
UAL486 United Airlines 3 2026-05-15

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL644 LAX → EWR Jul 26, 17:45 UTCJul 26, 20:00 UTC2h 15m
2026-07-26 UAL1500 RDU → EWR Jul 26, 14:00 UTCJul 26, 15:40 UTC1h 40m
2026-07-26 UAL2324 GEG → SFO Jul 26, 01:35 UTCJul 26, 02:55 UTC1h 20m
2026-07-25 UAL1417 DEN → RDU Jul 25, 20:10 UTCJul 26, 00:00 UTC3h 50m
2026-07-25 UAL2234 IAH → LAX Jul 25, 15:30 UTCJul 25, 17:40 UTC2h 10m
2026-07-25 UAL2425 EWR → MSY Jul 25, 01:15 UTCJul 25, 04:10 UTC2h 55m
2026-07-24 UAL8105 YYC → YYJ Jul 24, 22:35 UTCJul 24, 23:25 UTC50m
2026-07-24 UAL2497 ORD → BOS Jul 24, 17:20 UTCJul 24, 19:40 UTC2h 20m
2026-07-24 UAL2253 RDU → IAD Jul 24, 13:10 UTCJul 24, 15:15 UTC2h 5m
2026-07-24 UAL635 EWR → MSY Jul 24, 10:10 UTCJul 24, 11:15 UTC1h 5m
2026-07-24 UAL444 BNA → IAD Jul 24, 03:05 UTCJul 24, 04:00 UTC55m
2026-07-23 UAL444 BNA → IAD Jul 23, 20:25 UTCJul 24, 00:55 UTC4h 30m
2026-07-23 UAL2177 PDX → ORD Jul 23, 17:40 UTCJul 23, 18:50 UTC1h 10m
2026-07-23 UAL2356 BUR → SFO Jul 23, 14:40 UTCJul 23, 15:40 UTC1h 0m
2026-07-22 UAL2658 IAH → MCO Jul 22, 22:55 UTCJul 23, 01:30 UTC2h 35m
2026-07-22 UAL1056 SFO → CMH Jul 22, 19:05 UTCJul 22, 20:55 UTC1h 50m
2026-07-22 UAL1014 IAH → CUN Jul 22, 15:25 UTCJul 22, 17:15 UTC1h 50m
2026-07-21 UAL1516 LIR → IAH Jul 21, 15:00 UTCJul 21, 22:30 UTC7h 30m
2026-07-20 UAL588 ATL → EWR Jul 20, 22:41 UTCJul 21, 00:33 UTC1h 52m
2026-07-20 UAL588 ATL → EWR Jul 20, 22:35 UTCJul 21, 00:35 UTC1h 59m
2026-07-20 UAL414 - Jul 20, 16:35 UTCJul 20, 20:35 UTC4h 0m
2026-07-20 UAL1076 ORD → BOS Jul 20, 12:50 UTCJul 20, 14:40 UTC1h 50m
2026-07-20 UAL1672 DEN → SFO Jul 20, 02:45 UTCJul 20, 06:00 UTC3h 15m
2026-07-19 UAL1875 ORD → LAS Jul 19, 21:40 UTCJul 20, 00:50 UTC3h 10m
2026-07-19 UAL2443 MSN → ORD Jul 19, 19:20 UTCJul 19, 19:40 UTC20m
2026-07-19 UAL2443 MSN → ORD Jul 19, 18:20 UTCJul 19, 19:40 UTC1h 20m
2026-07-19 UAL2443 MSN → ORD Jul 19, 18:16 UTCJul 19, 19:05 UTC49m
2026-07-19 UAL2389 LGA → ORD Jul 19, 15:50 UTCJul 19, 16:35 UTC45m
2026-07-19 UAL656 - Jul 19, 13:10 UTCJul 19, 14:10 UTC1h 0m
2026-07-18 UAL2324 GEG → SFO Jul 18, 23:50 UTCJul 19, 01:20 UTC1h 30m
2026-07-18 UAL1126 IAD → DEN Jul 18, 19:05 UTCJul 18, 22:15 UTC3h 10m
2026-07-18 UAL1101 DEN → IAD Jul 18, 14:15 UTCJul 18, 17:15 UTC3h 0m
2026-07-18 UAL1101 DEN → IAD Jul 18, 14:18 UTCJul 18, 17:14 UTC2h 56m
2026-07-18 UAL773 DFW → DEN Jul 18, 10:55 UTCJul 18, 12:25 UTC1h 30m
2026-07-18 UAL773 DFW → DEN Jul 18, 10:59 UTCJul 18, 12:25 UTC1h 26m
2026-07-18 UAL2239 DEN → DFW Jul 18, 03:25 UTCJul 18, 04:55 UTC1h 30m
2026-07-17 UAL2146 LAX → DEN Jul 17, 23:25 UTCJul 18, 01:30 UTC2h 5m
2026-07-17 UAL774 MCO → IAH Jul 17, 19:49 UTCJul 17, 21:44 UTC1h 55m
2026-07-17 UAL1912 - Jul 17, 16:00 UTCJul 17, 18:00 UTC2h 0m
2026-07-17 UAL1093 - Jul 17, 12:19 UTCJul 17, 14:10 UTC1h 50m
2026-07-17 UAL1745 SFO → IAH Jul 17, 06:12 UTCJul 17, 09:21 UTC3h 9m
2026-07-17 UAL1745 PHX → DEN Jul 17, 03:45 UTCJul 17, 05:15 UTC1h 30m
2026-07-16 UAL8146 - Jul 16, 23:05 UTCJul 17, 02:30 UTC3h 25m
2026-07-16 UAL1239 ATL → ORD Jul 16, 16:35 UTCJul 16, 18:15 UTC1h 40m
2026-07-16 UAL425 ORD → ATL Jul 16, 13:45 UTCJul 16, 15:10 UTC1h 25m
2026-07-16 UAL2333 - Jul 16, 10:10 UTCJul 16, 12:00 UTC1h 50m
2026-07-15 UAL2362 - Jul 15, 23:50 UTCJul 16, 01:30 UTC1h 40m
2026-07-15 UAL440 - Jul 15, 18:50 UTCJul 15, 21:55 UTC3h 5m
2026-07-15 UAL2137 - Jul 15, 14:05 UTCJul 15, 16:55 UTC2h 50m
2026-07-15 UAL1778 ROC → ORD Jul 15, 10:35 UTCJul 15, 12:00 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 N39450 page for operator, model, and routing details .

Mode-S A494C5 frequently asked

What is Mode-S code A494C5?
A494C5 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N39450.
Where is Mode-S A494C5 registered?
Mode-S code A494C5 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 A494C5 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 20:00 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A494C5, octal 51112305, decimal 10,785,989.
What flights does A494C5 operate?
Mode-S A494C5 has broadcast 20 distinct callsigns, including UAL2635, UAL1554, UAL1875, UAL1813, UAL658.