Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

A273F5

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N25705 · BOEING 737-700 · operated by UNITED AIRLINES INC

Hex
A273F5
Octal
50471765
Decimal
10,646,517
Country
US
Tail
N25705
Type
B737
No current signal · last broadcast Jul 26, 21:15 UTC
Flights observed
371
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 21:15 UTC

Last known position

Most recent position reported by Mode-S A273F5.

Country allocation

The ICAO 24-bit address A273F5 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
UAL1690 United Airlines 8 2026-05-11
UAL2624 United Airlines 7 2026-04-18
UAL2465 - 7 2026-07-06
UAL661 United Airlines 6 2026-05-11
UAL1655 United Airlines 6 2026-05-13
UAL516 United Airlines 5 2026-05-03
UAL456 United Airlines 5 2026-05-15
UAL2066 United Airlines 5 2026-07-19
UAL1822 - 5 2026-07-19
UAL1559 - 5 2026-07-05
UAL1513 United Airlines 5 2026-05-10
UAL1458 United Airlines 5 2026-04-18
UAL1304 - 5 2026-07-04
UAL471 United Airlines 4 2026-07-19
UAL2652 United Airlines 4 2026-05-12
UAL2214 United Airlines 4 2026-07-25
UAL2180 United Airlines 4 2026-05-17
UAL764 United Airlines 3 2026-05-13
UAL658 United Airlines 3 2026-05-08
UAL567 United Airlines 3 2026-05-17

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL743 EWR → RSW Jul 26, 20:10 UTCJul 26, 21:15 UTC1h 5m
2026-07-26 UAL1348 IAD → RDU Jul 26, 15:00 UTCJul 26, 18:00 UTC3h 0m
2026-07-26 UAL2464 RSW → EWR Jul 26, 10:30 UTCJul 26, 12:55 UTC2h 25m
2026-07-26 UAL1259 SJC → DEN Jul 26, 02:05 UTCJul 26, 04:30 UTC2h 25m
2026-07-26 UAL1259 SJC → DEN Jul 26, 02:06 UTCJul 26, 04:31 UTC2h 25m
2026-07-25 UAL2178 QRO → IAH Jul 25, 21:05 UTCJul 25, 22:30 UTC1h 25m
2026-07-25 UAL2214 IAH → LGA Jul 25, 17:50 UTCJul 25, 18:55 UTC1h 5m
2026-07-25 UAL2214 IAH → LGA Jul 25, 17:45 UTCJul 25, 19:17 UTC1h 32m
2026-07-24 UAL1663 LAS → EWR Jul 24, 23:20 UTCJul 25, 16:10 UTC16h 50m
2026-07-24 UAL1381 IAH → SAN Jul 24, 19:20 UTCJul 24, 22:05 UTC2h 45m
2026-07-24 UAL2670 ORD → CLE Jul 24, 15:15 UTCJul 24, 17:55 UTC2h 40m
2026-07-24 UAL2399 MCO → IAH Jul 24, 11:35 UTCJul 24, 13:35 UTC2h 0m
2026-07-24 UAL2399 MCO → IAH Jul 24, 11:33 UTCJul 24, 13:28 UTC1h 55m
2026-07-23 UAL2846 ORD → ABQ Jul 23, 22:15 UTCJul 24, 00:00 UTC1h 45m
2026-07-23 UAL1725 SFO → OGG Jul 23, 19:20 UTCJul 23, 20:35 UTC1h 15m
2026-07-23 UAL2346 SFO → DFW Jul 23, 15:35 UTCJul 23, 16:45 UTC1h 10m
2026-07-23 UAL2346 SFO → DFW Jul 23, 15:25 UTCJul 23, 17:19 UTC1h 54m
2026-07-22 UAL2037 - Jul 22, 13:45 UTCJul 22, 14:50 UTC1h 5m
2026-07-22 UAL1106 ORD → DFW Jul 22, 01:35 UTCJul 22, 02:40 UTC1h 5m
2026-07-21 UAL2236 SFO → BOS Jul 21, 20:25 UTCJul 21, 23:30 UTC3h 5m
2026-07-21 UAL2606 - Jul 21, 15:30 UTCJul 21, 18:10 UTC2h 40m
2026-07-21 UAL410 LAX → LAS Jul 21, 12:55 UTCJul 21, 13:35 UTC40m
2026-07-20 UAL1869 SFO → IAD Jul 20, 22:00 UTCJul 21, 00:50 UTC2h 49m
2026-07-20 UAL1764 - Jul 20, 19:25 UTCJul 20, 20:15 UTC50m
2026-07-20 UAL632 IAD → LAX Jul 20, 16:50 UTCJul 20, 17:45 UTC55m
2026-07-20 UAL204 BOS → IAD Jul 20, 12:15 UTCJul 20, 15:40 UTC3h 25m
2026-07-19 UAL1822 IAD → ABQ Jul 19, 22:05 UTCJul 20, 01:30 UTC3h 25m
2026-07-19 UAL2607 - Jul 19, 19:30 UTCJul 19, 20:10 UTC40m
2026-07-19 UAL2066 ORD → PHL Jul 19, 17:12 UTCJul 19, 18:02 UTC50m
2026-07-19 UAL2066 ORD → PHL Jul 19, 17:15 UTCJul 19, 17:50 UTC35m
2026-07-19 UAL471 IAD → BOS Jul 19, 12:10 UTCJul 19, 15:15 UTC3h 5m
2026-07-19 UAL1869 IAD → SAT Jul 19, 06:20 UTCJul 19, 09:15 UTC2h 55m
2026-07-19 UAL2388 - Jul 19, 00:00 UTCJul 19, 02:30 UTC2h 30m
2026-07-18 UAL2388 IAH → IAD Jul 18, 23:59 UTCJul 19, 02:26 UTC2h 27m
2026-07-18 UAL2079 SFO → BOS Jul 18, 15:10 UTCJul 18, 19:50 UTC4h 40m
2026-07-18 UAL1859 - Jul 18, 10:55 UTCJul 18, 13:20 UTC2h 25m
2026-07-18 UAL1591 - Jul 18, 01:15 UTCJul 18, 03:55 UTC2h 41m
2026-07-17 UAL1853 MTY → IAH Jul 17, 22:15 UTCJul 17, 23:07 UTC52m
2026-07-17 UAL1853 - Jul 17, 22:10 UTCJul 17, 23:14 UTC1h 5m
2026-07-17 UAL1852 - Jul 17, 19:35 UTCJul 17, 20:40 UTC1h 5m
2026-07-17 UAL1852 IAH → MTY Jul 17, 19:40 UTCJul 17, 20:38 UTC58m
2026-07-17 UAL1089 - Jul 17, 15:44 UTCJul 17, 17:30 UTC1h 45m
2026-07-17 UAL1024 - Jul 17, 12:45 UTCJul 17, 14:30 UTC1h 45m
2026-07-17 UAL1024 IAH → MEX Jul 17, 12:37 UTCJul 17, 14:25 UTC1h 48m
2026-07-17 UAL8124 - Jul 17, 01:29 UTCJul 17, 04:10 UTC2h 40m
2026-07-16 UAL2748 - Jul 16, 21:30 UTCJul 17, 00:25 UTC2h 55m
2026-07-16 UAL3887 - Jul 16, 18:10 UTCJul 16, 19:20 UTC1h 10m
2026-07-07 UAL3876 - Jul 7, 01:20 UTCJul 7, 02:55 UTC1h 35m
2026-07-06 UAL291 - Jul 6, 21:05 UTCJul 6, 22:55 UTC1h 50m
2026-07-06 UAL2631 - Jul 6, 16:05 UTCJul 6, 17:50 UTC1h 45m

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 N25705 page for operator, model, and routing details .

Mode-S A273F5 frequently asked

What is Mode-S code A273F5?
A273F5 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N25705.
Where is Mode-S A273F5 registered?
Mode-S code A273F5 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 A273F5 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 21:15 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A273F5, octal 50471765, decimal 10,646,517.
What flights does A273F5 operate?
Mode-S A273F5 has broadcast 20 distinct callsigns, including UAL1690, UAL2624, UAL2465, UAL661, UAL1655.