Apparatus

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sensors Mode-S transponder

A1E2C4

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N220UA · BOEING 777-200 · operated by UNITED AIRLINES INC

Hex
A1E2C4
Octal
50361304
Decimal
10,609,348
Country
US
Tail
N220UA
Type
B772
No current signal · last broadcast Jul 26, 14:00 UTC
Flights observed
273
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 14:00 UTC

Last known position

Most recent position reported by Mode-S A1E2C4.

Country allocation

The ICAO 24-bit address A1E2C4 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
UAL1805 United Airlines 27 2026-07-22
UAL383 United Airlines 24 2026-07-21
UAL1806 United Airlines 20 2026-07-26
UAL384 - 16 2026-07-20
UAL1736 United Airlines 14 2026-07-22
UAL1158 - 14 2026-07-15
UAL300 - 13 2026-07-17
UAL1170 United Airlines 12 2026-07-26
UAL1735 United Airlines 11 2026-07-22
UAL2475 - 10 2026-06-14
UAL2358 - 10 2026-07-16
UAL2280 United Airlines 9 2026-06-14
UAL1777 United Airlines 8 2026-06-15
UAL1169 United Airlines 8 2026-07-24
UAL1157 - 8 2026-07-18
UAL604 - 7 2026-07-16
UAL543 - 7 2026-06-16
UAL1818 - 7 2026-07-15
UAL253 - 5 2026-06-20
UAL2391 United Airlines 5 2026-05-17

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL1806 MCI → EWR Jul 26, 11:35 UTCJul 26, 13:55 UTC2h 20m
2026-07-26 UAL1806 MCI → EWR Jul 26, 08:10 UTCJul 26, 08:20 UTC10m
2026-07-26 UAL1170 LAX → HNL Jul 26, 00:20 UTCJul 26, 05:35 UTC5h 15m
2026-07-24 UAL1169 BDL → ORD Jul 24, 07:55 UTCJul 24, 12:25 UTC4h 30m
2026-07-24 UAL1170 LAX → HNL Jul 24, 05:30 UTCJul 24, 06:00 UTC30m
2026-07-24 UAL1170 LAX → HNL Jul 24, 00:45 UTCJul 24, 01:10 UTC25m
2026-07-24 UAL1170 LAX → HNL Jul 24, 00:31 UTCJul 24, 05:54 UTC5h 23m
2026-07-23 UAL1169 BDL → ORD Jul 23, 08:05 UTCJul 23, 12:45 UTC4h 40m
2026-07-22 UAL1805 LAS → EWR Jul 22, 22:23 UTCJul 23, 05:53 UTC7h 30m
2026-07-22 UAL1805 LAS → EWR Jul 22, 23:00 UTCJul 23, 01:10 UTC2h 10m
2026-07-22 UAL1735 LAS → EWR Jul 22, 11:10 UTCJul 22, 12:30 UTC1h 20m
2026-07-22 UAL1736 DEN → OGG Jul 22, 01:10 UTCJul 22, 01:20 UTC10m
2026-07-21 UAL1736 - Jul 21, 18:35 UTCJul 21, 20:35 UTC2h 0m
2026-07-21 UAL383 HNL → DEN Jul 21, 06:00 UTCJul 21, 12:05 UTC6h 5m
2026-07-20 UAL384 DEN → HNL Jul 20, 18:23 UTCJul 21, 01:06 UTC6h 43m
2026-07-20 UAL384 - Jul 20, 18:25 UTCJul 20, 20:40 UTC2h 15m
2026-07-20 UAL1806 - Jul 20, 11:55 UTCJul 20, 14:05 UTC2h 10m
2026-07-20 UAL1170 LAX → HNL Jul 20, 05:50 UTCJul 20, 06:00 UTC10m
2026-07-20 UAL1170 LAX → HNL Jul 20, 00:55 UTCJul 20, 01:50 UTC55m
2026-07-18 UAL1157 - Jul 18, 23:25 UTCJul 19, 04:00 UTC4h 35m
2026-07-17 UAL300 - Jul 17, 21:15 UTCJul 18, 02:00 UTC4h 45m
2026-07-17 UAL1147 IAD → SFO Jul 17, 12:55 UTCJul 17, 17:30 UTC4h 35m
2026-07-16 UAL1791 - Jul 16, 21:10 UTCJul 17, 01:45 UTC4h 35m
2026-07-16 UAL2358 - Jul 16, 15:10 UTCJul 16, 18:34 UTC3h 25m
2026-07-16 UAL2358 IAH → SFO Jul 16, 15:08 UTCJul 16, 18:18 UTC3h 10m
2026-07-16 UAL604 - Jul 16, 08:05 UTCJul 16, 11:25 UTC3h 20m
2026-07-15 UAL1818 - Jul 15, 23:45 UTCJul 16, 04:10 UTC4h 25m
2026-07-15 UAL1158 LAX → HNL Jul 15, 19:38 UTCJul 15, 21:45 UTC2h 7m
2026-07-15 UAL1158 - Jul 15, 16:35 UTCJul 15, 21:45 UTC5h 10m
2026-07-14 UAL1157 - Jul 14, 23:15 UTCJul 15, 03:55 UTC4h 40m
2026-07-14 UAL1170 - Jul 14, 05:05 UTCJul 14, 10:00 UTC4h 55m
2026-07-12 UAL1157 - Jul 12, 23:30 UTCJul 13, 04:20 UTC4h 50m
2026-07-12 UAL1158 - Jul 12, 16:40 UTCJul 12, 21:30 UTC4h 50m
2026-07-12 UAL1158 LAX → HNL Jul 12, 16:31 UTCJul 12, 21:32 UTC5h 1m
2026-07-12 UAL1169 - Jul 12, 07:55 UTCJul 12, 12:45 UTC4h 50m
2026-07-11 UAL384 - Jul 11, 18:20 UTCJul 12, 00:55 UTC6h 35m
2026-07-11 UAL383 - Jul 11, 05:55 UTCJul 11, 11:50 UTC5h 55m
2026-07-10 UAL384 - Jul 10, 18:15 UTCJul 11, 00:55 UTC6h 40m
2026-07-10 UAL383 - Jul 10, 05:55 UTCJul 10, 11:45 UTC5h 50m
2026-07-09 UAL384 - Jul 9, 20:55 UTCJul 10, 03:50 UTC6h 55m
2026-07-08 UAL1806 - Jul 8, 08:05 UTCJul 8, 14:15 UTC6h 10m
2026-07-08 UAL1806 HNL → DEN Jul 8, 07:59 UTCJul 8, 14:09 UTC6h 10m
2026-07-07 UAL1805 - Jul 7, 22:25 UTCJul 8, 05:10 UTC6h 45m
2026-07-06 UAL1806 - Jul 6, 08:10 UTCJul 6, 14:00 UTC5h 50m
2026-07-05 UAL1805 - Jul 5, 22:20 UTCJul 6, 05:05 UTC6h 45m
2026-07-05 UAL383 - Jul 5, 09:40 UTCJul 5, 11:50 UTC2h 10m
2026-07-05 UAL383 - Jul 5, 06:05 UTCJul 5, 06:20 UTC15m
2026-07-04 UAL384 DEN → HNL Jul 4, 18:20 UTCJul 5, 01:00 UTC6h 40m
2026-07-04 UAL1806 - Jul 4, 08:00 UTCJul 4, 13:50 UTC5h 50m
2026-07-03 UAL1805 - Jul 3, 22:25 UTCJul 4, 00:50 UTC2h 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 N220UA page for operator, model, and routing details .

Mode-S A1E2C4 frequently asked

What is Mode-S code A1E2C4?
A1E2C4 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N220UA.
Where is Mode-S A1E2C4 registered?
Mode-S code A1E2C4 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 A1E2C4 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 14:00 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A1E2C4, octal 50361304, decimal 10,609,348.
What flights does A1E2C4 operate?
Mode-S A1E2C4 has broadcast 20 distinct callsigns, including UAL1805, UAL383, UAL1806, UAL384, UAL1736.