Apparatus

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sensors Mode-S transponder

A1240A

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N17279 · BOEING 737 MAX 8 · operated by UNITED AIRLINES INC

Hex
A1240A
Octal
50222012
Decimal
10,560,522
Country
US
Tail
N17279
Type
B38M
Broadcasting now · callsign UAL1790 · 7,850 ft
Flights observed
486
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 22:30 UTC

Current position

A1240A is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A1240A 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
UAL1901 - 9 2026-06-21
UAL231 United Airlines 6 2026-06-03
UAL1632 United Airlines 6 2026-07-21
UAL1138 United Airlines 6 2026-07-22
UAL1137 - 6 2026-06-21
UAL690 United Airlines 4 2026-07-25
UAL424 United Airlines 4 2026-04-28
UAL2313 United Airlines 4 2026-04-14
UAL230 United Airlines 4 2026-06-03
UAL2192 United Airlines 4 2026-04-13
UAL209 - 4 2026-07-07
UAL1971 United Airlines 4 2026-05-17
UAL1942 United Airlines 4 2026-06-08
UAL1918 United Airlines 4 2026-06-07
UAL1880 United Airlines 4 2026-07-24
UAL1876 United Airlines 4 2026-06-07
UAL1635 - 4 2026-07-12
UAL1629 - 4 2026-07-11
UAL1567 - 4 2026-07-15
UAL1566 - 4 2026-07-14

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL2476 SAN → DEN Jul 26, 20:15 UTCJul 26, 22:30 UTC2h 15m
2026-07-26 UAL784 SBA → SFO Jul 26, 14:25 UTCJul 26, 17:25 UTC3h 0m
2026-07-26 UAL783 LAX → IAD Jul 26, 00:15 UTCJul 26, 03:10 UTC2h 55m
2026-07-25 UAL1662 EWR → SFO Jul 25, 20:55 UTCJul 25, 21:50 UTC55m
2026-07-25 UAL1963 IAH → BDL Jul 25, 18:05 UTCJul 25, 19:20 UTC1h 15m
2026-07-25 UAL690 SEA → SFO Jul 25, 12:50 UTCJul 25, 15:35 UTC2h 45m
2026-07-25 UAL2398 IAD → EWR Jul 25, 00:28 UTCJul 25, 01:19 UTC51m
2026-07-25 UAL2398 IAD → EWR Jul 25, 00:20 UTCJul 25, 01:25 UTC1h 5m
2026-07-24 UAL1880 SXM → EWR Jul 24, 19:15 UTCJul 24, 22:45 UTC3h 30m
2026-07-24 UAL346 IAD → SXM Jul 24, 13:10 UTCJul 24, 16:30 UTC3h 20m
2026-07-24 UAL346 IAD → SXM Jul 24, 13:04 UTCJul 24, 16:58 UTC3h 54m
2026-07-24 UAL572 ORD → MSN Jul 24, 05:48 UTCJul 24, 11:46 UTC5h 58m
2026-07-24 UAL572 ORD → MSN Jul 24, 05:40 UTCJul 24, 08:30 UTC2h 50m
2026-07-23 UAL1592 DEN → BOS Jul 23, 22:45 UTCJul 24, 04:30 UTC5h 45m
2026-07-23 UAL708 DEN → SFO Jul 23, 18:45 UTCJul 23, 20:10 UTC1h 25m
2026-07-23 UAL2159 DCA → IAH Jul 23, 16:00 UTCJul 23, 17:15 UTC1h 15m
2026-07-23 UAL2159 DCA → IAH Jul 23, 16:04 UTCJul 23, 17:18 UTC1h 14m
2026-07-23 UAL2185 MSY → SFO Jul 23, 13:00 UTCJul 23, 14:10 UTC1h 10m
2026-07-23 UAL2185 - Jul 23, 12:10 UTCJul 23, 12:20 UTC10m
2026-07-23 UAL663 DEN → ABQ Jul 23, 06:05 UTCJul 23, 08:10 UTC2h 5m
2026-07-23 UAL486 CLE → DEN Jul 23, 01:15 UTCJul 23, 04:30 UTC3h 15m
2026-07-23 UAL486 CLE → DEN Jul 23, 00:55 UTCJul 23, 04:30 UTC3h 35m
2026-07-22 UAL1084 - Jul 22, 16:05 UTCJul 22, 20:05 UTC4h 0m
2026-07-22 UAL1138 GUA → LAX Jul 22, 11:40 UTCJul 22, 12:55 UTC1h 15m
2026-07-21 UAL1632 PDX → SFO Jul 21, 22:35 UTCJul 21, 22:55 UTC20m
2026-07-21 UAL1632 PDX → SFO Jul 21, 20:30 UTCJul 21, 21:00 UTC30m
2026-07-21 UAL539 PHL → SFO Jul 21, 17:05 UTCJul 21, 17:50 UTC45m
2026-07-21 UAL2074 IAD → DEN Jul 21, 14:45 UTCJul 21, 15:25 UTC40m
2026-07-20 UAL2198 IAH → BDL Jul 20, 23:25 UTCJul 21, 01:55 UTC2h 29m
2026-07-20 UAL1238 EWR → MIA Jul 20, 19:35 UTCJul 20, 21:45 UTC2h 10m
2026-07-20 UAL2617 SFO → LAX Jul 20, 14:50 UTCJul 20, 16:30 UTC1h 40m
2026-07-20 UAL2617 SFO → LAX Jul 20, 14:43 UTCJul 20, 17:45 UTC3h 2m
2026-07-19 UAL334 - Jul 19, 21:40 UTCJul 20, 01:25 UTC3h 45m
2026-07-19 UAL334 IAH → LGA Jul 19, 21:46 UTCJul 20, 01:20 UTC3h 34m
2026-07-19 UAL382C SFO → PHX Jul 19, 17:10 UTCJul 19, 19:50 UTC2h 40m
2026-07-19 UAL2047 - Jul 19, 13:15 UTCJul 19, 15:50 UTC2h 35m
2026-07-19 UAL2083 - Jul 19, 07:55 UTCJul 19, 08:30 UTC35m
2026-07-19 UAL2083 UIO → IAH Jul 19, 06:09 UTCJul 19, 10:55 UTC4h 46m
2026-07-18 UAL1002 DEN → SJC Jul 18, 23:55 UTCJul 19, 02:30 UTC2h 35m
2026-07-18 UAL1002 DEN → SJC Jul 18, 23:48 UTCJul 19, 04:36 UTC4h 48m
2026-07-18 UAL2170 EWR → DFW Jul 18, 19:50 UTCJul 18, 22:10 UTC2h 20m
2026-07-18 UAL2170 EWR → DFW Jul 18, 14:05 UTCJul 18, 16:50 UTC2h 45m
2026-07-18 UAL1789 - Jul 18, 10:20 UTCJul 18, 11:10 UTC50m
2026-07-18 UAL8182 IAD → RDU Jul 18, 03:05 UTCJul 18, 03:50 UTC45m
2026-07-18 UAL8182 IAD → RDU Jul 18, 02:35 UTCJul 18, 03:48 UTC1h 13m
2026-07-17 UAL1519 - Jul 17, 17:09 UTCJul 18, 00:35 UTC7h 25m
2026-07-17 UAL204 ABQ → IAD Jul 17, 12:15 UTCJul 17, 15:44 UTC3h 30m
2026-07-16 UAL1822 IAD → ABQ Jul 16, 22:05 UTCJul 17, 01:25 UTC3h 20m
2026-07-16 UAL2250 - Jul 16, 17:14 UTCJul 16, 20:09 UTC2h 55m
2026-07-16 UAL1789 - Jul 16, 12:34 UTCJul 16, 15:25 UTC2h 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 N17279 page for operator, model, and routing details .

Mode-S A1240A frequently asked

What is Mode-S code A1240A?
A1240A is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N17279.
Where is Mode-S A1240A registered?
Mode-S code A1240A 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 A1240A broadcasting right now?
Yes. Mode-S A1240A is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A1240A, octal 50222012, decimal 10,560,522.
What flights does A1240A operate?
Mode-S A1240A has broadcast 20 distinct callsigns, including UAL1901, UAL231, UAL1632, UAL1138, UAL1137.