Apparatus

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sensors Mode-S transponder

A4495D

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N37542 · BOEING 737 MAX 9 · operated by UNITED AIRLINES INC

Hex
A4495D
Octal
51044535
Decimal
10,766,685
Country
US
Tail
N37542
Type
B39M
No current signal · last broadcast Jul 26, 21:15 UTC
Flights observed
439
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 21:15 UTC

Last known position

Most recent position reported by Mode-S A4495D.

Country allocation

The ICAO 24-bit address A4495D 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
UAL701 - 4 2026-07-08
UAL2611 United Airlines 4 2026-06-23
UAL2601 United Airlines 4 2026-05-07
UAL2495 - 4 2026-07-08
UAL1987 United Airlines 4 2026-07-25
UAL1441 United Airlines 4 2026-05-12
UAL1239 United Airlines 4 2026-06-02
UAL1047 United Airlines 4 2026-07-26
UAL670 United Airlines 3 2026-04-14
UAL594 United Airlines 3 2026-04-16
UAL520 United Airlines 3 2026-04-16
UAL2777 United Airlines 3 2026-07-26
UAL2772 - 3 2026-07-15
UAL2738 United Airlines 3 2026-05-07
UAL2620 United Airlines 3 2026-07-24
UAL2353 - 3 2026-07-09
UAL2168 United Airlines 3 2026-06-06
UAL210 - 3 2026-06-27
UAL2095 United Airlines 3 2026-06-07
UAL1948 United Airlines 3 2026-07-21

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL2777 EWR → TPA Jul 26, 19:20 UTCJul 26, 21:15 UTC1h 55m
2026-07-26 UAL1197 PBI → EWR Jul 26, 15:10 UTCJul 26, 17:15 UTC2h 5m
2026-07-26 UAL1197 PBI → EWR Jul 26, 15:21 UTCJul 26, 17:49 UTC2h 28m
2026-07-26 UAL1771 SEA → ORD Jul 26, 11:20 UTCJul 26, 13:40 UTC2h 20m
2026-07-26 UAL1047 CUN → EWR Jul 26, 00:35 UTCJul 26, 03:50 UTC3h 15m
2026-07-25 UAL1987 EWR → CUN Jul 25, 17:50 UTCJul 25, 21:15 UTC3h 25m
2026-07-25 UAL408 - Jul 25, 13:05 UTCJul 25, 15:35 UTC2h 30m
2026-07-25 UAL1769 RDU → SFO Jul 25, 06:15 UTCJul 25, 11:25 UTC5h 10m
2026-07-24 UAL2620 SFO → MSY Jul 24, 23:45 UTCJul 25, 04:40 UTC4h 55m
2026-07-24 UAL609 EWR → RDU Jul 24, 20:05 UTCJul 24, 21:15 UTC1h 10m
2026-07-24 UAL609 EWR → RDU Jul 24, 20:08 UTCJul 24, 22:10 UTC2h 2m
2026-07-24 UAL356 DEN → TPA Jul 24, 14:00 UTCJul 24, 17:00 UTC3h 0m
2026-07-24 UAL602 BWI → SFO Jul 24, 03:00 UTCJul 24, 06:05 UTC3h 5m
2026-07-23 UAL1182 ORD → MCI Jul 23, 22:25 UTCJul 24, 00:25 UTC2h 0m
2026-07-23 UAL1598 IAH → EWR Jul 23, 16:15 UTCJul 23, 19:42 UTC3h 27m
2026-07-23 UAL1598 IAH → EWR Jul 23, 16:15 UTCJul 23, 17:15 UTC1h 0m
2026-07-23 UAL1607 IND → DEN Jul 23, 12:15 UTCJul 23, 14:40 UTC2h 25m
2026-07-23 UAL1607 IND → DEN Jul 23, 12:14 UTCJul 23, 14:32 UTC2h 18m
2026-07-22 UAL1902 SFO → IND Jul 22, 18:57 UTCJul 22, 22:34 UTC3h 37m
2026-07-22 UAL1902 SFO → IND Jul 22, 18:45 UTCJul 22, 22:35 UTC3h 50m
2026-07-22 UAL1668 LAX → AUS Jul 22, 14:00 UTCJul 22, 17:05 UTC3h 5m
2026-07-22 UAL2126 EWR → MBJ Jul 22, 02:02 UTCJul 22, 05:07 UTC3h 5m
2026-07-22 UAL2126 EWR → MBJ Jul 22, 01:55 UTCJul 22, 05:10 UTC3h 15m
2026-07-21 UAL1948 IAH → SFO Jul 21, 19:05 UTCJul 22, 00:05 UTC5h 0m
2026-07-21 UAL1052 EWR → CUN Jul 21, 14:00 UTCJul 21, 17:30 UTC3h 30m
2026-07-21 UAL427 BOS → ORD Jul 21, 06:15 UTCJul 21, 11:25 UTC5h 10m
2026-07-21 UAL427 BOS → ORD Jul 21, 05:45 UTCJul 21, 11:22 UTC5h 37m
2026-07-20 UAL2054 MSY → IAH Jul 20, 22:35 UTCJul 21, 03:00 UTC4h 24m
2026-07-20 UAL2125 BNA → IAD Jul 20, 18:50 UTCJul 20, 19:15 UTC25m
2026-07-20 UAL2125 BNA → IAD Jul 20, 18:53 UTCJul 20, 20:10 UTC1h 17m
2026-07-20 UAL2414 - Jul 20, 16:10 UTCJul 20, 17:10 UTC1h 0m
2026-07-20 UAL2414 ORD → BNA Jul 20, 16:08 UTCJul 20, 17:10 UTC1h 2m
2026-07-20 UAL752 - Jul 20, 11:10 UTCJul 20, 14:00 UTC2h 50m
2026-07-19 UAL2294 ORD → FLL Jul 19, 23:30 UTCJul 20, 02:05 UTC2h 35m
2026-07-19 UAL1710 JAX → ORD Jul 19, 18:05 UTCJul 19, 22:00 UTC3h 55m
2026-07-19 UAL2428 ORD → SAN Jul 19, 12:55 UTCJul 19, 16:25 UTC3h 30m
2026-07-19 UAL1752 - Jul 19, 04:50 UTCJul 19, 06:55 UTC2h 5m
2026-07-19 UAL1752 IAH → ORD Jul 19, 04:03 UTCJul 19, 06:43 UTC2h 40m
2026-07-18 UAL1058 CUN → IAH Jul 18, 22:50 UTCJul 19, 00:40 UTC1h 50m
2026-07-18 UAL1679 SFO → CUN Jul 18, 16:20 UTCJul 18, 21:10 UTC4h 50m
2026-07-17 UAL1118 CUN → SFO Jul 17, 22:21 UTCJul 18, 03:25 UTC5h 4m
2026-07-17 UAL1118 - Jul 17, 22:25 UTCJul 17, 22:55 UTC30m
2026-07-17 UAL1618 IAD → CUN Jul 17, 17:40 UTCJul 17, 20:44 UTC3h 5m
2026-07-17 UAL1858 - Jul 17, 14:15 UTCJul 17, 15:15 UTC1h 0m
2026-07-17 UAL2355 - Jul 17, 11:00 UTCJul 17, 12:25 UTC1h 25m
2026-07-16 UAL286 - Jul 16, 22:30 UTCJul 17, 01:35 UTC3h 5m
2026-07-16 UAL1155 - Jul 16, 16:44 UTCJul 16, 19:55 UTC3h 10m
2026-07-16 UAL577 MCO → EWR Jul 16, 11:54 UTCJul 16, 14:05 UTC2h 10m
2026-07-15 UAL3922 - Jul 15, 23:25 UTCJul 16, 01:30 UTC2h 5m
2026-07-15 UAL2612 - Jul 15, 18:10 UTCJul 15, 20:30 UTC2h 20m

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 N37542 page for operator, model, and routing details .

Mode-S A4495D frequently asked

What is Mode-S code A4495D?
A4495D is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N37542.
Where is Mode-S A4495D registered?
Mode-S code A4495D 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 A4495D 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 A4495D, octal 51044535, decimal 10,766,685.
What flights does A4495D operate?
Mode-S A4495D has broadcast 20 distinct callsigns, including UAL701, UAL2611, UAL2601, UAL2495, UAL1987.