Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

A9D59F

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N73256 · BOEING 737-800 · operated by UNITED AIRLINES INC

Hex
A9D59F
Octal
52352637
Decimal
11,130,271
Country
US
Tail
N73256
Type
B738
No current signal · last broadcast Jul 26, 21:45 UTC
Flights observed
206
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 21:45 UTC

Last known position

Most recent position reported by Mode-S A9D59F.

Country allocation

The ICAO 24-bit address A9D59F 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
UAL586 United Airlines 6 2026-07-22
UAL678 United Airlines 4 2026-04-20
UAL2152 United Airlines 4 2026-07-23
UAL2045 United Airlines 4 2026-06-21
UAL1316 - 4 2026-07-06
UAL719 - 3 2026-07-10
UAL644 United Airlines 3 2026-07-24
UAL354 - 3 2026-07-08
UAL2389 - 3 2026-07-13
UAL2236 United Airlines 3 2026-04-13
UAL2123 United Airlines 3 2026-07-23
UAL2116 United Airlines 3 2026-04-17
UAL1522 United Airlines 3 2026-07-26
UAL778 - 2 2026-07-15
UAL703K United Airlines 2 2026-07-24
UAL675 - 2 2026-07-07
UAL653 United Airlines 2 2026-04-17
UAL590 - 2 2026-06-28
UAL478 United Airlines 2 2026-07-24
UAL464 - 2 2026-07-18

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL453 LAX → SFO Jul 26, 20:25 UTCJul 26, 21:45 UTC1h 20m
2026-07-26 UAL1909 LAS → EWR Jul 26, 15:55 UTCJul 26, 18:45 UTC2h 50m
2026-07-26 UAL1522 FLL → EWR Jul 26, 12:15 UTCJul 26, 14:30 UTC2h 15m
2026-07-26 UAL1816 DEN → CLE Jul 26, 02:55 UTCJul 26, 05:05 UTC2h 10m
2026-07-25 UAL1255 MCI → EWR Jul 25, 03:30 UTCJul 25, 05:10 UTC1h 40m
2026-07-25 UAL295 DEN → GEG Jul 25, 00:30 UTCJul 25, 02:20 UTC1h 50m
2026-07-24 UAL478 DEN → ORD Jul 24, 20:35 UTCJul 24, 21:45 UTC1h 10m
2026-07-24 UAL703K DEN → BIL Jul 24, 18:10 UTCJul 24, 19:15 UTC1h 5m
2026-07-24 UAL703K DEN → BIL Jul 24, 18:07 UTCJul 24, 19:15 UTC1h 8m
2026-07-24 UAL644 LAX → EWR Jul 24, 14:05 UTCJul 24, 15:45 UTC1h 40m
2026-07-24 UAL644 LAX → EWR Jul 24, 14:05 UTCJul 24, 15:49 UTC1h 44m
2026-07-24 UAL1565 SFO → PHX Jul 24, 01:05 UTCJul 24, 02:35 UTC1h 30m
2026-07-23 UAL2152 SJD → DEN Jul 23, 20:43 UTCJul 23, 23:14 UTC2h 31m
2026-07-23 UAL2152 SJD → DEN Jul 23, 17:00 UTCJul 23, 23:20 UTC6h 20m
2026-07-23 UAL1241 DEN → CLE Jul 23, 12:25 UTCJul 23, 14:30 UTC2h 5m
2026-07-23 UAL1303 EWR → IAH Jul 23, 05:00 UTCJul 23, 07:10 UTC2h 10m
2026-07-23 UAL2123 AUS → SFO Jul 23, 02:15 UTCJul 23, 03:40 UTC1h 25m
2026-07-22 UAL586 DEN → MCI Jul 22, 20:20 UTCJul 22, 21:30 UTC1h 10m
2026-07-22 UAL586 DEN → MCI Jul 22, 19:59 UTCJul 22, 21:30 UTC1h 31m
2026-07-22 UAL586 DEN → MCI Jul 22, 15:55 UTCJul 22, 18:05 UTC2h 10m
2026-07-22 UAL2745 HNL → SFO Jul 22, 01:55 UTCJul 22, 03:55 UTC2h 0m
2026-07-21 UAL2123 AUS → SFO Jul 21, 23:05 UTCJul 22, 00:20 UTC1h 15m
2026-07-21 UAL586 - Jul 21, 20:10 UTCJul 21, 21:25 UTC1h 15m
2026-07-21 UAL1191 COS → DEN Jul 21, 16:25 UTCJul 21, 18:20 UTC1h 55m
2026-07-21 UAL2411 MSO → DEN Jul 21, 01:45 UTCJul 21, 03:40 UTC1h 55m
2026-07-20 UAL2757 - Jul 20, 20:40 UTCJul 20, 23:40 UTC3h 0m
2026-07-20 UAL1003 - Jul 20, 16:20 UTCJul 20, 19:15 UTC2h 55m
2026-07-20 UAL1561 - Jul 20, 12:40 UTCJul 20, 14:10 UTC1h 30m
2026-07-20 UAL696 RIC → DEN Jul 20, 03:55 UTCJul 20, 04:30 UTC35m
2026-07-19 UAL2108 EWR → CHS Jul 19, 23:40 UTCJul 20, 01:15 UTC1h 35m
2026-07-19 UAL2156 IAD → LAS Jul 19, 17:20 UTCJul 19, 21:35 UTC4h 15m
2026-07-19 UAL2156 IAD → LAS Jul 19, 17:21 UTCJul 19, 21:32 UTC4h 11m
2026-07-19 UAL525 AUS → IAD Jul 19, 12:40 UTCJul 19, 15:20 UTC2h 40m
2026-07-19 UAL8176 DEN → EWR Jul 19, 02:40 UTCJul 19, 03:10 UTC30m
2026-07-18 UAL1545 SFO → LAX Jul 18, 22:10 UTCJul 19, 01:05 UTC2h 55m
2026-07-18 UAL464 RSW → CLE Jul 18, 17:13 UTCJul 18, 19:17 UTC2h 4m
2026-07-18 UAL464 RSW → CLE Jul 18, 17:05 UTCJul 18, 19:25 UTC2h 20m
2026-07-18 UAL1100 - Jul 18, 13:25 UTCJul 18, 15:40 UTC2h 15m
2026-07-18 UAL1790 EWR → MYR Jul 18, 00:10 UTCJul 18, 02:35 UTC2h 25m
2026-07-17 UAL1534 EWR → FLL Jul 17, 20:50 UTCJul 17, 22:35 UTC1h 45m
2026-07-17 UAL2167 DEN → RNO Jul 17, 17:42 UTCJul 17, 19:17 UTC1h 35m
2026-07-17 UAL2167 - Jul 17, 17:30 UTCJul 17, 18:44 UTC1h 15m
2026-07-17 UAL644 DFW → DEN Jul 17, 14:24 UTCJul 17, 15:55 UTC1h 30m
2026-07-17 UAL1565 SFO → PHX Jul 17, 01:09 UTCJul 17, 02:45 UTC1h 35m
2026-07-16 UAL2152 DEN → DEN Jul 16, 16:09 UTCJul 16, 23:10 UTC7h 0m
2026-07-16 UAL1522 - Jul 16, 12:05 UTCJul 16, 14:15 UTC2h 10m
2026-07-16 UAL1816 - Jul 16, 01:35 UTCJul 16, 04:00 UTC2h 25m
2026-07-15 UAL453 - Jul 15, 20:35 UTCJul 15, 23:45 UTC3h 10m
2026-07-15 UAL1909 DEN → SYR Jul 15, 16:05 UTCJul 15, 19:00 UTC2h 55m
2026-07-15 UAL1234 GEG → DEN Jul 15, 12:40 UTCJul 15, 14:30 UTC1h 50m

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 N73256 page for operator, model, and routing details .

Mode-S A9D59F frequently asked

What is Mode-S code A9D59F?
A9D59F is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N73256.
Where is Mode-S A9D59F registered?
Mode-S code A9D59F 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 A9D59F broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 21:45 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A9D59F, octal 52352637, decimal 11,130,271.
What flights does A9D59F operate?
Mode-S A9D59F has broadcast 20 distinct callsigns, including UAL586, UAL678, UAL2152, UAL2045, UAL1316.