Apparatus

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sensors Mode-S transponder

A2450B

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N24508 · operated by UNITED AIRLINES INC

Hex
A2450B
Octal
50442413
Decimal
10,634,507
Country
US
Tail
N24508
Type
A21N
No current signal · last broadcast Jul 26, 22:40 UTC
Flights observed
410
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 22:40 UTC

Last known position

Most recent position reported by Mode-S A2450B.

Country allocation

The ICAO 24-bit address A2450B 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
UAL695 - 6 2026-07-02
UAL2089 - 6 2026-07-02
UAL1779 - 6 2026-06-26
UAL531 - 5 2026-07-07
UAL2197 - 5 2026-07-09
UAL2091 United Airlines 5 2026-06-10
UAL1010 United Airlines 5 2026-05-14
UAL647 United Airlines 4 2026-05-28
UAL526 United Airlines 4 2026-07-26
UAL2865 United Airlines 4 2026-06-08
UAL2631 - 4 2026-07-05
UAL2262 United Airlines 4 2026-04-22
UAL2106 United Airlines 4 2026-06-10
UAL2099 - 4 2026-06-14
UAL2088 United Airlines 4 2026-06-13
UAL1996 United Airlines 4 2026-06-13
UAL1812 - 4 2026-07-12
UAL1773 United Airlines 4 2026-05-16
UAL1714 United Airlines 4 2026-06-09
UAL1643 United Airlines 4 2026-07-23

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL1323 EWR → JAX Jul 26, 21:00 UTCJul 26, 22:30 UTC1h 30m
2026-07-26 UAL526 AMM → IAD Jul 26, 17:35 UTCJul 26, 19:00 UTC1h 25m
2026-07-26 UAL1701 PHX → EWR Jul 26, 12:05 UTCJul 26, 15:35 UTC3h 30m
2026-07-25 UAL1715 DEN → EWR Jul 25, 23:25 UTCJul 26, 02:30 UTC3h 5m
2026-07-25 UAL1999 SFO → DEN Jul 25, 16:05 UTCJul 25, 19:40 UTC3h 35m
2026-07-25 UAL563 SNA → SFO Jul 25, 12:50 UTCJul 25, 14:30 UTC1h 40m
2026-07-25 UAL212 DEN → SBA Jul 25, 00:30 UTCJul 25, 04:10 UTC3h 40m
2026-07-24 UAL1363 SJC → DEN Jul 24, 18:20 UTCJul 24, 21:55 UTC3h 35m
2026-07-24 UAL2683 ORD → SAN Jul 24, 13:50 UTCJul 24, 16:10 UTC2h 20m
2026-07-23 UAL1382 PHX → EWR Jul 23, 23:40 UTCJul 24, 01:50 UTC2h 10m
2026-07-23 UAL2481 PSP → SFO Jul 23, 18:35 UTCJul 23, 21:00 UTC2h 25m
2026-07-23 UAL1643 RIC → DEN Jul 23, 14:25 UTCJul 23, 16:35 UTC2h 10m
2026-07-23 UAL1414 EWR → CHS Jul 23, 10:20 UTCJul 23, 12:40 UTC2h 20m
2026-07-23 UAL2331 IAD → RDU Jul 23, 00:15 UTCJul 23, 02:00 UTC1h 45m
2026-07-22 UAL1641 IAD → SFO Jul 22, 18:00 UTCJul 22, 21:20 UTC3h 20m
2026-07-22 UAL2300 - Jul 22, 12:20 UTCJul 22, 16:30 UTC4h 10m
2026-07-22 UAL1015 EWR → MIA Jul 22, 01:45 UTCJul 22, 03:55 UTC2h 10m
2026-07-21 UAL1693 - Jul 21, 21:55 UTCJul 21, 23:40 UTC1h 45m
2026-07-21 UAL1693 ORD → BOS Jul 21, 21:39 UTCJul 21, 23:37 UTC1h 58m
2026-07-21 UAL1069 SFO → LAX Jul 21, 14:15 UTCJul 21, 18:00 UTC3h 45m
2026-07-21 UAL1531 ORD → SAN Jul 21, 01:40 UTCJul 21, 05:20 UTC3h 40m
2026-07-20 UAL1625 EWR → DEN Jul 20, 20:50 UTCJul 20, 23:10 UTC2h 20m
2026-07-20 UAL1061 SEA → SFO Jul 20, 17:00 UTCJul 20, 19:00 UTC2h 0m
2026-07-20 UAL2774 DCA → ORD Jul 20, 13:45 UTCJul 20, 15:20 UTC1h 35m
2026-07-20 UAL2774 DCA → ORD Jul 20, 13:42 UTCJul 20, 15:21 UTC1h 39m
2026-07-19 UAL1369 - Jul 19, 23:15 UTCJul 20, 00:35 UTC1h 20m
2026-07-19 UAL1178 SMF → EWR Jul 19, 18:55 UTCJul 19, 21:45 UTC2h 50m
2026-07-19 UAL1972 ORD → SFO Jul 19, 14:35 UTCJul 19, 17:30 UTC2h 55m
2026-07-19 UAL787 SJC → IAH Jul 19, 06:20 UTCJul 19, 06:35 UTC15m
2026-07-19 UAL787 SJC → IAH Jul 19, 03:20 UTCJul 19, 05:25 UTC2h 5m
2026-07-18 UAL489 - Jul 18, 22:15 UTCJul 19, 00:15 UTC2h 0m
2026-07-18 UAL2168 - Jul 18, 18:05 UTCJul 18, 20:00 UTC1h 55m
2026-07-18 UAL1720 - Jul 18, 13:55 UTCJul 18, 15:50 UTC1h 55m
2026-07-18 UAL1974 DPA → DEN Jul 18, 02:09 UTCJul 18, 03:55 UTC1h 46m
2026-07-18 UAL1974 ORD → DEN Jul 18, 02:19 UTCJul 18, 03:55 UTC1h 36m
2026-07-17 UAL617 DEN → ORD Jul 17, 22:25 UTCJul 18, 00:25 UTC2h 0m
2026-07-17 UAL662 BOS → DEN Jul 17, 13:50 UTCJul 17, 17:40 UTC3h 50m
2026-07-17 UAL2331 - Jul 17, 00:35 UTCJul 17, 02:20 UTC1h 45m
2026-07-16 UAL617 DEN → ORD Jul 16, 19:50 UTCJul 16, 22:19 UTC2h 30m
2026-07-16 UAL662 BOS → DEN Jul 16, 14:05 UTCJul 16, 18:00 UTC3h 55m
2026-07-15 UAL597 DEN → BOS Jul 15, 20:25 UTCJul 15, 23:55 UTC3h 30m
2026-07-15 UAL581 ORD → DEN Jul 15, 16:30 UTCJul 15, 18:20 UTC1h 50m
2026-07-15 UAL1775 IAD → ORD Jul 15, 12:50 UTCJul 15, 14:20 UTC1h 30m
2026-07-15 UAL1924 DEN → IAD Jul 15, 06:15 UTCJul 15, 09:15 UTC3h 0m
2026-07-15 UAL2339 - Jul 15, 01:30 UTCJul 15, 03:25 UTC1h 55m
2026-07-14 UAL489 - Jul 14, 21:55 UTCJul 14, 23:50 UTC1h 54m
2026-07-14 UAL489 DEN → IAH Jul 14, 21:54 UTCJul 14, 23:44 UTC1h 50m
2026-07-14 UAL1999 EWR → DEN Jul 14, 16:05 UTCJul 14, 19:15 UTC3h 10m
2026-07-14 UAL563 - Jul 14, 12:30 UTCJul 14, 14:10 UTC1h 40m
2026-07-14 UAL353 - Jul 14, 05:55 UTCJul 14, 09:35 UTC3h 40m

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 N24508 page for operator, model, and routing details .

Mode-S A2450B frequently asked

What is Mode-S code A2450B?
A2450B is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N24508.
Where is Mode-S A2450B registered?
Mode-S code A2450B 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 A2450B broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 22:40 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A2450B, octal 50442413, decimal 10,634,507.
What flights does A2450B operate?
Mode-S A2450B has broadcast 20 distinct callsigns, including UAL695, UAL2089, UAL1779, UAL531, UAL2197.