Apparatus

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sensors Mode-S transponder

A6ED61

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N54538 · AIRBUS A-321neo · operated by UNITED AIRLINES INC

Hex
A6ED61
Octal
51566541
Decimal
10,939,745
Country
US
Tail
N54538
Type
A21N
No current signal · last broadcast Jul 26, 22:15 UTC
Flights observed
438
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 22:15 UTC

Last known position

Most recent position reported by Mode-S A6ED61.

Country allocation

The ICAO 24-bit address A6ED61 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
UAL1792 United Airlines 8 2026-07-26
UAL534 United Airlines 7 2026-06-11
UAL2455 United Airlines 7 2026-07-25
UAL2197 United Airlines 7 2026-06-10
UAL1755 - 6 2026-06-21
UAL1505 United Airlines 6 2026-07-25
UAL1119 - 6 2026-07-19
UAL664 United Airlines 5 2026-04-18
UAL660T - 5 2026-04-13
UAL540 United Airlines 5 2026-07-21
UAL2618 - 5 2026-06-25
UAL2607 United Airlines 5 2026-04-29
UAL1779 United Airlines 5 2026-07-23
UAL1231 United Airlines 5 2026-06-15
UAL1132 - 5 2026-07-19
UAL617 United Airlines 4 2026-05-05
UAL2803 United Airlines 4 2026-06-07
UAL2758 United Airlines 4 2026-07-20
UAL2613 - 4 2026-07-09
UAL2481 - 4 2026-06-27

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL576 MIA → DEN Jul 26, 22:05 UTCJul 26, 22:15 UTC10m
2026-07-26 UAL1946 ORD → LGA Jul 26, 15:20 UTCJul 26, 18:55 UTC3h 35m
2026-07-26 UAL1093 LAX → SFO Jul 26, 11:40 UTCJul 26, 13:30 UTC1h 50m
2026-07-26 UAL1093 LAX → SFO Jul 26, 11:45 UTCJul 26, 13:25 UTC1h 40m
2026-07-26 UAL1792 IAH → EWR Jul 26, 02:28 UTCJul 26, 05:43 UTC3h 15m
2026-07-26 UAL1792 IAH → EWR Jul 26, 02:15 UTCJul 26, 05:45 UTC3h 30m
2026-07-25 UAL1505 EWR → DEN Jul 25, 21:40 UTCJul 26, 00:40 UTC3h 0m
2026-07-25 UAL2455 EWR → ATL Jul 25, 14:25 UTCJul 25, 18:05 UTC3h 40m
2026-07-24 UAL1715 DEN → EWR Jul 24, 23:19 UTCJul 25, 02:21 UTC3h 2m
2026-07-24 UAL1715 DEN → EWR Jul 24, 23:15 UTCJul 25, 02:15 UTC3h 0m
2026-07-24 UAL1565 SFO → PHX Jul 24, 19:40 UTCJul 24, 21:45 UTC2h 5m
2026-07-24 UAL660 EWR → CHS Jul 24, 14:10 UTCJul 24, 17:50 UTC3h 40m
2026-07-23 UAL1779 MIA → EWR Jul 23, 21:45 UTCJul 24, 01:20 UTC3h 35m
2026-07-23 UAL1940 IAD → ATL Jul 23, 18:10 UTCJul 23, 20:10 UTC2h 0m
2026-07-23 UAL2154 ORD → TPA Jul 23, 12:15 UTCJul 23, 14:15 UTC2h 0m
2026-07-23 UAL2154 ORD → TPA Jul 23, 11:56 UTCJul 23, 15:52 UTC3h 56m
2026-07-23 UAL2033 RNO → SFO Jul 23, 02:28 UTCJul 23, 05:24 UTC2h 56m
2026-07-23 UAL2033 RNO → SFO Jul 23, 02:20 UTCJul 23, 05:25 UTC3h 5m
2026-07-22 UAL1729 DEN → EWR Jul 22, 19:55 UTCJul 22, 23:50 UTC3h 55m
2026-07-22 UAL1729 DEN → EWR Jul 22, 19:39 UTCJul 22, 23:52 UTC4h 13m
2026-07-22 UAL1442 DEN → LGA Jul 22, 14:25 UTCJul 22, 17:35 UTC3h 10m
2026-07-22 UAL3890 NAS → EWR Jul 22, 04:50 UTCJul 22, 05:25 UTC35m
2026-07-22 UAL1482 SAT → SFO Jul 22, 00:10 UTCJul 22, 03:40 UTC3h 30m
2026-07-21 UAL1482 SAT → SFO Jul 21, 23:50 UTCJul 22, 03:28 UTC3h 38m
2026-07-21 UAL1812 DEN → EWR Jul 21, 19:40 UTCJul 21, 22:00 UTC2h 20m
2026-07-21 UAL8130 ORD → ALB Jul 21, 15:45 UTCJul 21, 17:35 UTC1h 50m
2026-07-21 UAL1799 MIA → EWR Jul 21, 11:45 UTCJul 21, 13:50 UTC2h 5m
2026-07-21 UAL1457 DEN → LGA Jul 21, 05:45 UTCJul 21, 09:15 UTC3h 30m
2026-07-21 UAL540 PDX → DEN Jul 21, 01:50 UTCJul 21, 03:50 UTC2h 0m
2026-07-20 UAL2758 IAD → EWR Jul 20, 21:50 UTCJul 20, 23:50 UTC2h 0m
2026-07-20 UAL2758 IAD → EWR Jul 20, 21:48 UTCJul 20, 23:48 UTC2h 0m
2026-07-20 UAL1013 DEN → LAX Jul 20, 18:40 UTCJul 20, 20:30 UTC1h 50m
2026-07-20 UAL1963 - Jul 20, 14:25 UTCJul 20, 17:15 UTC2h 50m
2026-07-20 UAL616 SJC → ORD Jul 20, 02:00 UTCJul 20, 04:45 UTC2h 45m
2026-07-19 UAL1132 CUN → DEN Jul 19, 19:35 UTCJul 19, 23:00 UTC3h 25m
2026-07-19 UAL1119 DEN → CUN Jul 19, 14:25 UTCJul 19, 18:00 UTC3h 35m
2026-07-19 UAL1119 DEN → CUN Jul 19, 14:11 UTCJul 19, 17:55 UTC3h 44m
2026-07-16 UAL1132 CUN → DEN Jul 16, 19:50 UTCJul 16, 23:25 UTC3h 35m
2026-07-16 UAL1119 DEN → CUN Jul 16, 14:11 UTCJul 16, 17:52 UTC3h 41m
2026-07-16 UAL1119 - Jul 16, 14:20 UTCJul 16, 16:15 UTC1h 55m
2026-07-15 UAL1714 MCO → DEN Jul 15, 12:10 UTCJul 15, 15:20 UTC3h 10m
2026-07-14 UAL1382 - Jul 14, 23:35 UTCJul 15, 01:45 UTC2h 10m
2026-07-14 UAL1583 - Jul 14, 17:40 UTCJul 14, 20:55 UTC3h 15m
2026-07-14 UAL2316 DEN → LAS Jul 14, 14:15 UTCJul 14, 15:45 UTC1h 30m
2026-07-14 UAL495 IAD → DEN Jul 14, 03:20 UTCJul 14, 06:15 UTC2h 55m
2026-07-13 UAL421 DEN → IAD Jul 13, 22:25 UTCJul 14, 01:30 UTC3h 5m
2026-07-13 UAL2061 - Jul 13, 18:25 UTCJul 13, 20:20 UTC1h 55m
2026-07-13 UAL2361 ORD → LAX Jul 13, 12:15 UTCJul 13, 15:45 UTC3h 30m
2026-07-12 UAL2311 - Jul 12, 22:20 UTCJul 13, 01:15 UTC2h 55m
2026-07-12 UAL1496 DEN → MIA Jul 12, 16:25 UTCJul 12, 19:53 UTC3h 28m

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 N54538 page for operator, model, and routing details .

Mode-S A6ED61 frequently asked

What is Mode-S code A6ED61?
A6ED61 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N54538.
Where is Mode-S A6ED61 registered?
Mode-S code A6ED61 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 A6ED61 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 A6ED61, octal 51566541, decimal 10,939,745.
What flights does A6ED61 operate?
Mode-S A6ED61 has broadcast 20 distinct callsigns, including UAL1792, UAL534, UAL2455, UAL2197, UAL1755.