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 1h ago
Flights observed
394
Distinct callsigns
20
Country
US
Last broadcast
1h ago

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
UAL534 United Airlines 7 2026-06-11
UAL2197 United Airlines 7 2026-06-10
UAL2455 - 6 2026-07-09
UAL1792 - 6 2026-07-10
UAL1755 - 6 2026-06-21
UAL664 United Airlines 5 2026-04-18
UAL660T - 5 2026-04-13
UAL2618 - 5 2026-06-25
UAL2607 United Airlines 5 2026-04-29
UAL1505 - 5 2026-07-09
UAL1231 United Airlines 5 2026-06-15
UAL617 United Airlines 4 2026-05-05
UAL540 - 4 2026-06-18
UAL2803 United Airlines 4 2026-06-07
UAL2613 - 4 2026-07-09
UAL2481 - 4 2026-06-27
UAL2417 United Airlines 4 2026-06-15
UAL2040 United Airlines 4 2026-04-28
UAL1983 United Airlines 4 2026-04-18
UAL1954 - 4 2026-07-07

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
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
2026-07-12 UAL1496 DEN → MIA Jul 12, 16:25 UTCJul 12, 19:55 UTC3h 30m
2026-07-11 UAL800 BOS → DEN Jul 11, 22:25 UTCJul 12, 02:05 UTC3h 40m
2026-07-11 UAL800 BOS → DEN Jul 11, 22:23 UTCJul 12, 02:01 UTC3h 38m
2026-07-11 UAL1232 DEN → BOS Jul 11, 16:34 UTCJul 11, 20:42 UTC4h 8m
2026-07-11 UAL1232 DEN → BOS Jul 11, 17:05 UTCJul 11, 20:40 UTC3h 35m
2026-07-11 UAL2031 IAD → DEN Jul 11, 10:40 UTCJul 11, 13:50 UTC3h 10m
2026-07-11 UAL1412 DEN → IAD Jul 11, 02:17 UTCJul 11, 05:21 UTC3h 4m
2026-07-11 UAL1412 DEN → IAD Jul 11, 02:25 UTCJul 11, 05:20 UTC2h 55m
2026-07-10 UAL2297 - Jul 10, 20:00 UTCJul 11, 00:50 UTC4h 50m
2026-07-10 UAL558 DEN → BOS Jul 10, 14:10 UTCJul 10, 17:40 UTC3h 30m
2026-07-10 UAL1792 EWR → DEN Jul 10, 02:50 UTCJul 10, 06:40 UTC3h 50m
2026-07-09 UAL1505 DEN → EWR Jul 9, 21:35 UTCJul 10, 01:05 UTC3h 30m
2026-07-09 UAL2455 EWR → DEN Jul 9, 14:22 UTCJul 9, 17:59 UTC3h 37m
2026-07-09 UAL2455 - Jul 9, 14:20 UTCJul 9, 18:05 UTC3h 45m
2026-07-09 UAL2613 DEN → EWR Jul 9, 00:40 UTCJul 9, 04:00 UTC3h 20m
2026-07-08 UAL577 - Jul 8, 17:50 UTCJul 8, 21:25 UTC3h 35m
2026-07-08 UAL2345 DEN → EWR Jul 8, 12:10 UTCJul 8, 15:30 UTC3h 20m
2026-07-08 UAL8105 - Jul 8, 05:20 UTCJul 8, 07:20 UTC2h 0m
2026-07-07 UAL1954 - Jul 7, 23:50 UTCJul 8, 01:55 UTC2h 5m
2026-07-07 UAL1583 - Jul 7, 17:30 UTCJul 7, 20:35 UTC3h 5m
2026-07-07 UAL2316 DEN → LAS Jul 7, 14:23 UTCJul 7, 15:40 UTC1h 17m
2026-07-07 UAL2316 DEN → LAS Jul 7, 14:15 UTCJul 7, 15:45 UTC1h 30m
2026-07-07 UAL1792 EWR → DEN Jul 7, 03:28 UTCJul 7, 06:34 UTC3h 6m
2026-07-07 UAL1792 EWR → DEN Jul 7, 03:15 UTCJul 7, 06:40 UTC3h 25m
2026-07-06 UAL1505 DEN → EWR Jul 6, 21:20 UTCJul 7, 00:50 UTC3h 30m
2026-07-06 UAL2455 EWR → DEN Jul 6, 14:40 UTCJul 6, 18:05 UTC3h 25m
2026-07-06 UAL2295 ORD → EWR Jul 6, 11:15 UTCJul 6, 12:55 UTC1h 40m
2026-07-06 UAL212 - Jul 6, 00:15 UTCJul 6, 03:50 UTC3h 35m
2026-07-05 UAL1363 ORD → LAX Jul 5, 18:29 UTCJul 5, 22:01 UTC3h 32m
2026-07-05 UAL1363 - Jul 5, 18:30 UTCJul 5, 22:05 UTC3h 35m
2026-07-05 UAL2430 DEN → ORD Jul 5, 14:30 UTCJul 5, 16:25 UTC1h 55m
2026-07-05 UAL1874 - Jul 5, 10:20 UTCJul 5, 12:20 UTC2h 0m
2026-07-05 UAL475 - Jul 5, 01:50 UTCJul 5, 04:05 UTC2h 15m
2026-07-04 UAL1132 CUN → DEN Jul 4, 19:35 UTCJul 4, 23:20 UTC3h 45m
2026-07-04 UAL1119 DEN → CUN Jul 4, 14:10 UTCJul 4, 17:35 UTC3h 25m
2026-07-03 UAL1132 CUN → DEN Jul 3, 19:30 UTCJul 3, 23:00 UTC3h 30m
2026-07-03 UAL1119 DEN → CUN Jul 3, 14:15 UTCJul 3, 17:45 UTC3h 30m
2026-07-03 UAL1792 - Jul 3, 01:35 UTCJul 3, 05:10 UTC3h 35m
2026-07-02 UAL1505 DEN → EWR Jul 2, 19:55 UTCJul 2, 23:15 UTC3h 20m
2026-07-02 UAL1505 DEN → EWR Jul 2, 20:00 UTCJul 2, 23:08 UTC3h 8m
2026-07-02 UAL2455 EWR → DEN Jul 2, 14:10 UTCJul 2, 17:40 UTC3h 30m
2026-07-02 UAL2613 DEN → EWR Jul 2, 01:20 UTCJul 2, 04:25 UTC3h 5m
2026-07-01 UAL2845 MCO → DEN Jul 1, 20:30 UTCJul 1, 23:40 UTC3h 10m
2026-07-01 UAL2292 EWR → DEN Jul 1, 15:45 UTCJul 1, 18:55 UTC3h 10m

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 1h ago.
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 UAL534, UAL2197, UAL2455, UAL1792, UAL1755.