Apparatus

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sensors Mode-S transponder

A448D3

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N37504 · BOEING 737 MAX 9 · operated by UNITED AIRLINES INC

Hex
A448D3
Octal
51044323
Decimal
10,766,547
Country
US
Tail
N37504
Type
B39M
No current signal · last broadcast 1h ago
Flights observed
352
Distinct callsigns
20
Country
US
Last broadcast
1h ago

Last known position

Most recent position reported by Mode-S A448D3.

Country allocation

The ICAO 24-bit address A448D3 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
UAL1651 - 5 2026-06-21
UAL1628 - 5 2026-06-15
UAL1462 - 5 2026-07-01
UAL2776 - 4 2026-07-13
UAL1857 United Airlines 4 2026-04-29
UAL1330 - 4 2026-04-15
UAL1289 - 4 2026-06-30
UAL1213 - 4 2026-06-21
UAL1210 - 4 2026-07-07
UAL1206 United Airlines 4 2026-05-10
UAL731 United Airlines 3 2026-05-28
UAL2636 - 3 2026-06-28
UAL2396 - 3 2026-07-14
UAL2379 United Airlines 3 2026-06-05
UAL2326 - 3 2026-07-09
UAL2223 - 3 2026-07-09
UAL2219 United Airlines 3 2026-06-13
UAL1778 - 3 2026-04-13
UAL1699 United Airlines 3 2026-04-14
UAL1501 - 3 2026-07-02

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 UAL2396 - Jul 14, 15:25 UTCJul 14, 16:45 UTC1h 20m
2026-07-14 UAL1041 TPA → EWR Jul 14, 11:40 UTCJul 14, 13:55 UTC2h 15m
2026-07-13 UAL2776 EWR → TPA Jul 13, 18:05 UTCJul 13, 20:35 UTC2h 30m
2026-07-13 UAL2776 EWR → TPA Jul 13, 18:03 UTCJul 13, 20:34 UTC2h 31m
2026-07-13 UAL2204 TPA → EWR Jul 13, 13:10 UTCJul 13, 15:30 UTC2h 20m
2026-07-11 UAL2375 DEN → TPA Jul 11, 20:00 UTCJul 11, 23:00 UTC3h 0m
2026-07-11 UAL2167 TPA → DEN Jul 11, 12:10 UTCJul 11, 15:25 UTC3h 15m
2026-07-10 UAL2865 ORD → TPA Jul 10, 23:50 UTCJul 11, 02:00 UTC2h 10m
2026-07-10 UAL2458 - Jul 10, 19:30 UTCJul 10, 22:05 UTC2h 36m
2026-07-10 UAL1397 - Jul 10, 14:20 UTCJul 10, 17:15 UTC2h 55m
2026-07-09 UAL600 - Jul 9, 22:20 UTCJul 10, 02:05 UTC3h 45m
2026-07-09 UAL2223 TPA → ORD Jul 9, 16:40 UTCJul 9, 19:20 UTC2h 40m
2026-07-09 UAL2326 ORD → TPA Jul 9, 13:05 UTCJul 9, 15:20 UTC2h 15m
2026-07-09 UAL2326 ORD → TPA Jul 9, 13:04 UTCJul 9, 15:16 UTC2h 12m
2026-07-09 UAL1640 FAI → ORD Jul 9, 05:52 UTCJul 9, 11:28 UTC5h 36m
2026-07-09 UAL1640 - Jul 9, 05:40 UTCJul 9, 08:45 UTC3h 5m
2026-07-08 UAL2223 ORD → FAI Jul 8, 22:05 UTCJul 9, 04:10 UTC6h 5m
2026-07-08 UAL2223 TPA → ORD Jul 8, 16:55 UTCJul 8, 19:10 UTC2h 15m
2026-07-08 UAL2326 ORD → TPA Jul 8, 12:50 UTCJul 8, 15:20 UTC2h 30m
2026-07-07 UAL352 DEN → ORD Jul 7, 23:20 UTCJul 8, 01:30 UTC2h 10m
2026-07-07 UAL1150 - Jul 7, 18:15 UTCJul 7, 20:15 UTC2h 0m
2026-07-07 UAL426 DTW → ORD Jul 7, 15:18 UTCJul 7, 15:55 UTC37m
2026-07-07 UAL1344 ORD → DTW Jul 7, 12:53 UTCJul 7, 13:33 UTC40m
2026-07-07 UAL1210 PHX → ORD Jul 7, 01:00 UTCJul 7, 04:00 UTC3h 0m
2026-07-06 UAL1254 DEN → PHX Jul 6, 21:55 UTCJul 6, 23:20 UTC1h 25m
2026-07-06 UAL730 COS → DEN Jul 6, 19:50 UTCJul 6, 20:10 UTC20m
2026-07-06 UAL730 COS → DEN Jul 6, 19:50 UTCJul 6, 20:15 UTC25m
2026-07-06 UAL1111 DEN → COS Jul 6, 18:00 UTCJul 6, 18:20 UTC20m
2026-07-06 UAL703 DEN → BIL Jul 6, 14:10 UTCJul 6, 16:00 UTC1h 50m
2026-07-06 UAL413 IAD → LAX Jul 6, 04:10 UTCJul 6, 09:00 UTC4h 50m
2026-07-05 UAL413 - Jul 5, 21:20 UTCJul 5, 23:15 UTC1h 55m
2026-07-05 UAL2071 SFO → MCO Jul 5, 14:25 UTCJul 5, 19:10 UTC4h 45m
2026-07-05 UAL693 - Jul 5, 00:35 UTCJul 5, 00:40 UTC5m
2026-07-05 UAL693 KOA → SFO Jul 5, 00:31 UTCJul 5, 05:13 UTC4h 42m
2026-07-04 UAL694 SFO → KOA Jul 4, 22:55 UTCJul 4, 23:05 UTC10m
2026-07-04 UAL694 SFO → KOA Jul 4, 18:20 UTCJul 4, 18:50 UTC30m
2026-07-04 UAL2209 PHX → SFO Jul 4, 14:35 UTCJul 4, 16:20 UTC1h 45m
2026-07-04 UAL1814 EWR → PHX Jul 4, 05:13 UTCJul 4, 09:33 UTC4h 20m
2026-07-04 UAL1814 EWR → PHX Jul 4, 05:10 UTCJul 4, 09:35 UTC4h 25m
2026-07-03 UAL665 - Jul 3, 15:45 UTCJul 4, 01:05 UTC9h 20m
2026-07-03 UAL1246 MSP → EWR Jul 3, 11:15 UTCJul 3, 13:20 UTC2h 5m
2026-07-03 UAL1246 MSP → EWR Jul 3, 11:15 UTCJul 3, 13:17 UTC2h 2m
2026-07-03 UAL1331 - Jul 3, 02:15 UTCJul 3, 04:35 UTC2h 20m
2026-07-02 UAL1501 TPA → EWR Jul 2, 22:00 UTCJul 3, 00:15 UTC2h 15m
2026-07-02 UAL2776 - Jul 2, 18:00 UTCJul 2, 20:20 UTC2h 20m
2026-07-01 UAL1462 - Jul 1, 13:10 UTCJul 1, 21:20 UTC8h 10m
2026-06-30 UAL2100 SEA → EWR Jun 30, 22:35 UTCJul 1, 03:05 UTC4h 30m
2026-06-30 UAL1289 - Jun 30, 15:55 UTCJun 30, 21:10 UTC5h 15m
2026-06-30 UAL2396 IAD → EWR Jun 30, 13:40 UTCJun 30, 14:35 UTC55m
2026-06-30 UAL1366 EWR → IAD Jun 30, 10:15 UTCJun 30, 11:00 UTC45m

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 N37504 page for operator, model, and routing details .

Mode-S A448D3 frequently asked

What is Mode-S code A448D3?
A448D3 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N37504.
Where is Mode-S A448D3 registered?
Mode-S code A448D3 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 A448D3 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 A448D3, octal 51044323, decimal 10,766,547.
What flights does A448D3 operate?
Mode-S A448D3 has broadcast 20 distinct callsigns, including UAL1651, UAL1628, UAL1462, UAL2776, UAL1857.