Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

A12B4D

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N17461 · operated by UNITED AIRLINES INC

Hex
A12B4D
Octal
50225515
Decimal
10,562,381
Country
US
Tail
N17461
No current signal · last broadcast 1d ago
Flights observed
76
Distinct callsigns
20
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S A12B4D.

Country allocation

The ICAO 24-bit address A12B4D 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
BOE123 - 4 2026-06-08
UAL2219 - 3 2026-07-17
BOE961 - 3 2026-06-27
UAL790 United Airlines 2 2026-07-24
UAL535 - 2 2026-07-13
UAL404 - 2 2026-07-18
UAL3821 - 2 2026-07-07
UAL3820 United Airlines 2 2026-07-09
UAL2825 - 2 2026-07-10
UAL2090 United Airlines 2 2026-07-25
UAL1947 United Airlines 2 2026-07-23
UAL1942 United Airlines 2 2026-07-24
UAL1543 - 2 2026-07-17
UAL8137 United Airlines 1 2026-07-25
UAL788 - 1 2026-07-17
UAL701 United Airlines 1 2026-07-26
UAL636 - 1 2026-07-12
UAL600 United Airlines 1 2026-07-21
UAL512 United Airlines 1 2026-07-23
UAL499 - 1 2026-07-15

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL701 MSY → EWR Jul 26, 20:50 UTCJul 26, 21:15 UTC25m
2026-07-26 UAL462 EWR → PBI Jul 26, 14:25 UTCJul 26, 18:10 UTC3h 45m
2026-07-26 UAL2384 ORD → SFO Jul 26, 06:25 UTCJul 26, 07:30 UTC1h 6m
2026-07-26 UAL2482 SFO → HNL Jul 26, 00:40 UTCJul 26, 04:30 UTC3h 50m
2026-07-25 UAL2090 IAH → PHL Jul 25, 19:30 UTCJul 25, 22:50 UTC3h 20m
2026-07-25 UAL2090 IAH → PHL Jul 25, 19:34 UTCJul 25, 22:44 UTC3h 10m
2026-07-25 UAL1257 DEN → LGA Jul 25, 12:10 UTCJul 25, 17:20 UTC5h 10m
2026-07-25 UAL8137 CLE → YYZ Jul 25, 00:20 UTCJul 25, 03:45 UTC3h 25m
2026-07-24 UAL1942 MSY → SFO Jul 24, 20:20 UTCJul 24, 21:15 UTC55m
2026-07-24 UAL1942 MSY → SFO Jul 24, 20:17 UTCJul 24, 22:25 UTC2h 8m
2026-07-24 UAL790 DEN → AUS Jul 24, 17:51 UTCJul 24, 18:49 UTC58m
2026-07-24 UAL790 DEN → AUS Jul 24, 17:50 UTCJul 24, 18:50 UTC1h 0m
2026-07-24 UAL2177 PDX → ORD Jul 24, 11:05 UTCJul 24, 16:10 UTC5h 5m
2026-07-24 UAL2117 SAN → SFO Jul 24, 04:30 UTCJul 24, 08:35 UTC4h 5m
2026-07-23 UAL512 SAN → SFO Jul 23, 20:40 UTCJul 24, 02:40 UTC6h 0m
2026-07-23 UAL1015 EWR → MIA Jul 23, 14:10 UTCJul 23, 19:20 UTC5h 10m
2026-07-23 UAL1947 LGA → IAH Jul 23, 06:15 UTCJul 23, 07:00 UTC45m
2026-07-23 UAL1947 LGA → IAH Jul 23, 02:45 UTCJul 23, 03:00 UTC15m
2026-07-22 UAL1260 SNA → SFO Jul 22, 19:45 UTCJul 23, 00:55 UTC5h 10m
2026-07-22 UAL2855 MCO → SFO Jul 22, 12:45 UTCJul 22, 17:35 UTC4h 50m
2026-07-21 UAL600 EWR → LAS Jul 21, 22:30 UTCJul 22, 02:10 UTC3h 40m
2026-07-21 UAL2223 CPT → IAD Jul 21, 16:45 UTCJul 21, 19:15 UTC2h 30m
2026-07-21 UAL2326 ORD → TPA Jul 21, 12:55 UTCJul 21, 15:05 UTC2h 10m
2026-07-21 UAL1210 EWR → ATL Jul 21, 01:05 UTCJul 21, 04:15 UTC3h 10m
2026-07-20 UAL1254 PSP → SFO Jul 20, 22:15 UTCJul 20, 23:55 UTC1h 39m
2026-07-20 UAL1715 DEN → EWR Jul 20, 18:20 UTCJul 20, 20:20 UTC2h 0m
2026-07-20 UAL1826 EWR → SAN Jul 20, 10:55 UTCJul 20, 15:50 UTC4h 55m
2026-07-20 UAL2235 MSY → EWR Jul 20, 01:00 UTCJul 20, 03:30 UTC2h 30m
2026-07-19 UAL246 - Jul 19, 19:30 UTCJul 19, 23:25 UTC3h 55m
2026-07-19 UAL1540 - Jul 19, 12:20 UTCJul 19, 17:25 UTC5h 5m
2026-07-18 UAL2444 - Jul 18, 13:10 UTCJul 18, 15:35 UTC2h 25m
2026-07-18 UAL404 - Jul 18, 00:35 UTCJul 18, 03:50 UTC3h 16m
2026-07-18 UAL404 IAH → EWR Jul 18, 00:21 UTCJul 18, 03:51 UTC3h 30m
2026-07-17 UAL2690 - Jul 17, 18:34 UTCJul 17, 21:34 UTC3h 0m
2026-07-17 UAL2120 MCO → EWR Jul 17, 14:35 UTCJul 17, 16:40 UTC2h 5m
2026-07-17 UAL788 EWR → MCO Jul 17, 10:50 UTCJul 17, 12:55 UTC2h 5m
2026-07-17 UAL2219 - Jul 17, 07:44 UTCJul 17, 08:40 UTC55m
2026-07-17 UAL2219 - Jul 17, 05:10 UTCJul 17, 05:20 UTC10m
2026-07-17 UAL2219 SJU → EWR Jul 17, 05:12 UTCJul 17, 08:36 UTC3h 24m
2026-07-17 UAL1543 - Jul 17, 03:20 UTCJul 17, 03:39 UTC20m
2026-07-17 UAL1543 - Jul 17, 00:14 UTCJul 17, 01:05 UTC50m
2026-07-16 UAL1480 EWR → EWR Jul 16, 14:40 UTCJul 16, 21:19 UTC6h 40m
2026-07-16 UAL2158 - Jul 16, 10:20 UTCJul 16, 12:40 UTC2h 20m
2026-07-16 UAL2650 - Jul 16, 01:00 UTCJul 16, 03:10 UTC2h 10m
2026-07-15 UAL499 BNA → EWR Jul 15, 00:35 UTCJul 15, 02:30 UTC1h 55m
2026-07-14 UAL2454 - Jul 14, 20:25 UTCJul 14, 22:00 UTC1h 35m
2026-07-14 UAL1975 LAS → EWR Jul 14, 14:25 UTCJul 14, 19:10 UTC4h 45m
2026-07-14 UAL406 SFO → LAS Jul 14, 04:45 UTCJul 14, 05:55 UTC1h 10m
2026-07-13 UAL2756 - Jul 13, 23:20 UTCJul 14, 02:40 UTC3h 20m
2026-07-13 UAL535 - Jul 13, 20:20 UTCJul 13, 21:25 UTC1h 5m

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 N17461 page for operator, model, and routing details .

Mode-S A12B4D frequently asked

What is Mode-S code A12B4D?
A12B4D is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N17461.
Where is Mode-S A12B4D registered?
Mode-S code A12B4D 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 A12B4D 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 A12B4D, octal 50225515, decimal 10,562,381.
What flights does A12B4D operate?
Mode-S A12B4D has broadcast 20 distinct callsigns, including BOE123, UAL2219, BOE961, UAL790, UAL535.