Apparatus

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sensors Mode-S transponder

A12EE0

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N17550 · BOEING 737 MAX 9 · operated by UNITED AIRLINES INC

Hex
A12EE0
Octal
50227340
Decimal
10,563,296
Country
US
Tail
N17550
Type
B39M
No current signal · last broadcast 1d ago
Flights observed
381
Distinct callsigns
20
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S A12EE0.

Country allocation

The ICAO 24-bit address A12EE0 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
UAL1397 United Airlines 6 2026-05-30
UAL1233 United Airlines 6 2026-06-08
UAL668 United Airlines 4 2026-04-15
UAL1330 - 4 2026-04-14
UAL1260 United Airlines 4 2026-06-21
UAL1034 United Airlines 4 2026-06-11
UAL515 United Airlines 3 2026-04-16
UAL2667 United Airlines 3 2026-06-24
UAL2611 United Airlines 3 2026-06-12
UAL2458 United Airlines 3 2026-05-30
UAL2383 - 3 2026-04-13
UAL2219 - 3 2026-04-14
UAL2168 - 3 2026-06-17
UAL2095 United Airlines 3 2026-05-24
UAL2075 - 3 2026-06-25
UAL2016 United Airlines 3 2026-05-19
UAL1947 - 3 2026-06-22
UAL1742 - 3 2026-07-11
UAL1650 - 3 2026-07-05
UAL1473 - 3 2026-06-29

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-12 UAL2022 - Jul 12, 13:50 UTCJul 12, 14:40 UTC50m
2026-07-12 UAL2022 - Jul 12, 11:30 UTCJul 12, 11:40 UTC10m
2026-07-12 UAL2025 - Jul 12, 01:10 UTCJul 12, 01:30 UTC20m
2026-07-11 UAL2025 - Jul 11, 22:05 UTCJul 11, 22:50 UTC45m
2026-07-11 UAL1742 SMF → IAD Jul 11, 15:20 UTCJul 11, 20:00 UTC4h 40m
2026-07-10 UAL2435 IAD → SMF Jul 10, 22:10 UTCJul 11, 03:20 UTC5h 10m
2026-07-10 UAL2125 BNA → IAD Jul 10, 18:50 UTCJul 10, 20:10 UTC1h 20m
2026-07-10 UAL2125 BNA → IAD Jul 10, 18:53 UTCJul 10, 20:10 UTC1h 17m
2026-07-10 UAL2414 ORD → BNA Jul 10, 16:08 UTCJul 10, 17:06 UTC58m
2026-07-10 UAL2414 ORD → BNA Jul 10, 16:05 UTCJul 10, 17:05 UTC1h 0m
2026-07-10 UAL1210 - Jul 10, 05:50 UTCJul 10, 06:10 UTC20m
2026-07-10 UAL1210 RFD → ORD Jul 10, 05:37 UTCJul 10, 05:56 UTC19m
2026-07-10 UAL1210 - Jul 10, 01:05 UTCJul 10, 04:35 UTC3h 30m
2026-07-09 UAL1254 DEN → PHX Jul 9, 22:20 UTCJul 9, 23:50 UTC1h 30m
2026-07-09 UAL730 COS → DEN Jul 9, 20:15 UTCJul 9, 20:35 UTC20m
2026-07-09 UAL1111 DEN → COS Jul 9, 17:40 UTCJul 9, 18:00 UTC20m
2026-07-09 UAL2412 BWI → DEN Jul 9, 12:55 UTCJul 9, 16:10 UTC3h 15m
2026-07-09 UAL1605 - Jul 9, 06:10 UTCJul 9, 10:50 UTC4h 40m
2026-07-09 UAL2755 - Jul 9, 00:50 UTCJul 9, 03:40 UTC2h 50m
2026-07-08 UAL1123 - Jul 8, 20:05 UTCJul 8, 22:00 UTC1h 55m
2026-07-08 UAL1123 CUN → IAH Jul 8, 20:08 UTCJul 8, 22:14 UTC2h 6m
2026-07-08 UAL1054 EWR → CUN Jul 8, 14:50 UTCJul 8, 18:15 UTC3h 25m
2026-07-08 UAL1105 MCO → EWR Jul 8, 10:35 UTCJul 8, 12:40 UTC2h 5m
2026-07-07 UAL1571 - Jul 7, 22:55 UTCJul 8, 00:50 UTC1h 55m
2026-07-07 UAL1711 - Jul 7, 17:35 UTCJul 7, 20:05 UTC2h 30m
2026-07-07 UAL574 ORD → LAS Jul 7, 12:40 UTCJul 7, 15:45 UTC3h 5m
2026-07-06 UAL651 - Jul 6, 23:50 UTCJul 7, 02:25 UTC2h 35m
2026-07-06 UAL2635 ORD → FLL Jul 6, 19:40 UTCJul 6, 22:20 UTC2h 40m
2026-07-06 UAL356 PHX → ORD Jul 6, 14:00 UTCJul 6, 17:00 UTC3h 0m
2026-07-06 UAL602 ORD → PHX Jul 6, 02:00 UTCJul 6, 05:05 UTC3h 5m
2026-07-05 UAL1650 - Jul 5, 18:15 UTCJul 5, 23:25 UTC5h 10m
2026-07-05 UAL1203 IAD → AUA Jul 5, 12:55 UTCJul 5, 16:45 UTC3h 50m
2026-07-04 UAL1133 CUN → IAD Jul 4, 21:45 UTCJul 5, 00:40 UTC2h 55m
2026-07-04 UAL1276 - Jul 4, 16:10 UTCJul 4, 20:00 UTC3h 50m
2026-07-04 UAL1276 LAX → CUN Jul 4, 15:55 UTCJul 4, 20:13 UTC4h 18m
2026-07-04 UAL1670 - Jul 4, 08:25 UTCJul 4, 13:00 UTC4h 35m
2026-07-04 UAL1670 SAL → LAX Jul 4, 08:10 UTCJul 4, 12:55 UTC4h 45m
2026-07-04 UAL1461 - Jul 4, 02:25 UTCJul 4, 02:45 UTC20m
2026-07-04 UAL1461 - Jul 4, 00:30 UTCJul 4, 00:50 UTC20m
2026-07-04 UAL1461 IAH → SAL Jul 4, 00:31 UTCJul 4, 02:58 UTC2h 27m
2026-07-03 UAL1123 - Jul 3, 19:55 UTCJul 3, 21:55 UTC2h 0m
2026-07-03 UAL1054 EWR → CUN Jul 3, 15:00 UTCJul 3, 18:20 UTC3h 20m
2026-07-03 UAL1054 EWR → CUN Jul 3, 14:55 UTCJul 3, 18:17 UTC3h 22m
2026-07-03 UAL570 BOS → EWR Jul 3, 12:15 UTCJul 3, 13:00 UTC45m
2026-07-03 UAL521 - Jul 3, 00:00 UTCJul 3, 03:20 UTC3h 20m
2026-07-02 UAL2690 - Jul 2, 18:35 UTCJul 2, 22:05 UTC3h 30m
2026-07-02 UAL1227 MCO → EWR Jul 2, 14:20 UTCJul 2, 16:40 UTC2h 20m
2026-07-02 UAL788 - Jul 2, 10:50 UTCJul 2, 12:55 UTC2h 5m
2026-07-01 UAL3752 - Jul 1, 23:35 UTCJul 2, 00:35 UTC1h 0m
2026-07-01 UAL3777 - Jul 1, 21:25 UTCJul 1, 22:00 UTC35m

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 N17550 page for operator, model, and routing details .

Mode-S A12EE0 frequently asked

What is Mode-S code A12EE0?
A12EE0 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N17550.
Where is Mode-S A12EE0 registered?
Mode-S code A12EE0 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 A12EE0 broadcasting right now?
No active broadcast right now. Last signal was 1d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A12EE0, octal 50227340, decimal 10,563,296.
What flights does A12EE0 operate?
Mode-S A12EE0 has broadcast 20 distinct callsigns, including UAL1397, UAL1233, UAL668, UAL1330, UAL1260.