Apparatus

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sensors Mode-S transponder

A4DAD4

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N41140 · BOEING 757-200 · operated by UNITED AIRLINES INC

Hex
A4DAD4
Octal
51155324
Decimal
10,803,924
Country
US
Tail
N41140
Type
B752
No current signal · last broadcast Jul 26, 20:30 UTC
Flights observed
298
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 20:30 UTC

Last known position

Most recent position reported by Mode-S A4DAD4.

Country allocation

The ICAO 24-bit address A4DAD4 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
UAL1759 United Airlines 28 2026-07-26
UAL1758 United Airlines 22 2026-07-25
UAL2307 United Airlines 15 2026-07-26
UAL2308 United Airlines 13 2026-07-24
UAL36 United Airlines 8 2026-07-21
UAL1283 - 8 2026-07-20
UAL979 - 6 2026-07-04
UAL37 United Airlines 6 2026-07-21
UAL351 United Airlines 6 2026-05-26
UAL336 United Airlines 6 2026-06-04
UAL2115 United Airlines 6 2026-06-03
UAL978 - 5 2026-07-04
UAL398 - 5 2026-07-07
UAL289 United Airlines 5 2026-05-28
UAL1343 - 5 2026-07-08
UAL399 - 4 2026-07-05
UAL310 United Airlines 4 2026-04-18
UAL274 United Airlines 4 2026-06-05
UAL2641 - 4 2026-07-22
UAL2626 - 4 2026-07-08

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL2307 DEN → LIH Jul 26, 18:20 UTCJul 26, 20:30 UTC2h 10m
2026-07-26 UAL1759 LGA → IAH Jul 26, 06:13 UTCJul 26, 12:36 UTC6h 23m
2026-07-26 UAL1759 LGA → IAH Jul 26, 06:13 UTCJul 26, 12:10 UTC5h 57m
2026-07-26 UAL1759 LGA → IAH Jul 26, 06:10 UTCJul 26, 06:20 UTC10m
2026-07-25 UAL1758 DEN → KOA Jul 25, 18:30 UTCJul 25, 20:45 UTC2h 15m
2026-07-25 UAL1759 LGA → IAH Jul 25, 10:25 UTCJul 25, 12:30 UTC2h 5m
2026-07-25 UAL1759 LGA → IAH Jul 25, 06:10 UTCJul 25, 06:15 UTC5m
2026-07-25 UAL1758 DEN → KOA Jul 25, 01:25 UTCJul 25, 01:30 UTC5m
2026-07-24 UAL1758 DEN → KOA Jul 24, 18:40 UTCJul 24, 20:50 UTC2h 10m
2026-07-24 UAL2308 IAH → SJC Jul 24, 05:40 UTCJul 24, 11:40 UTC6h 0m
2026-07-23 UAL2307 DEN → LIH Jul 23, 18:30 UTCJul 24, 01:30 UTC7h 0m
2026-07-23 UAL2307 DEN → LIH Jul 23, 18:30 UTCJul 24, 01:30 UTC7h 0m
2026-07-22 UAL663 DEN → ABQ Jul 22, 20:40 UTCJul 23, 00:40 UTC4h 0m
2026-07-22 UAL2743 HNL → SFO Jul 22, 14:10 UTCJul 22, 19:00 UTC4h 50m
2026-07-22 UAL2641 - Jul 22, 00:50 UTCJul 22, 05:25 UTC4h 35m
2026-07-21 UAL37 EDI → EWR Jul 21, 08:50 UTCJul 21, 15:55 UTC7h 5m
2026-07-21 UAL36 EWR → EDI Jul 21, 00:25 UTCJul 21, 06:35 UTC6h 10m
2026-07-20 UAL1283 DEN → EWR Jul 20, 19:05 UTCJul 20, 22:25 UTC3h 20m
2026-07-20 UAL1759 KOA → DEN Jul 20, 06:05 UTCJul 20, 12:30 UTC6h 25m
2026-07-20 UAL8158 SFO → RDU Jul 20, 01:20 UTCJul 20, 01:35 UTC15m
2026-07-19 UAL8158 SFO → RDU Jul 19, 18:35 UTCJul 19, 20:55 UTC2h 20m
2026-07-19 UAL1759 - Jul 19, 09:50 UTCJul 19, 12:20 UTC2h 30m
2026-07-19 UAL1759 - Jul 19, 06:10 UTCJul 19, 06:20 UTC10m
2026-07-18 UAL1758 - Jul 18, 18:35 UTCJul 18, 20:40 UTC2h 5m
2026-07-18 UAL1759 - Jul 18, 09:50 UTCJul 18, 12:15 UTC2h 25m
2026-07-18 UAL1759 - Jul 18, 06:00 UTCJul 18, 06:15 UTC15m
2026-07-17 UAL1758 - Jul 17, 18:55 UTCJul 17, 21:30 UTC2h 35m
2026-07-16 UAL663 - Jul 16, 20:15 UTCJul 16, 23:44 UTC3h 30m
2026-07-16 UAL1403 - Jul 16, 13:25 UTCJul 16, 18:19 UTC4h 55m
2026-07-16 UAL712 - Jul 16, 04:25 UTCJul 16, 09:35 UTC5h 10m
2026-07-15 UAL1283 DEN → EWR Jul 15, 23:45 UTCJul 16, 02:50 UTC3h 5m
2026-07-12 UAL2308 - Jul 12, 05:50 UTCJul 12, 12:10 UTC6h 20m
2026-07-11 UAL2307 - Jul 11, 18:25 UTCJul 12, 01:15 UTC6h 50m
2026-07-10 UAL663T EWR → DEN Jul 10, 20:07 UTCJul 11, 00:46 UTC4h 39m
2026-07-10 UAL663T - Jul 10, 20:05 UTCJul 11, 00:45 UTC4h 40m
2026-07-10 UAL1403 - Jul 10, 13:30 UTCJul 10, 18:20 UTC4h 50m
2026-07-09 UAL2191 - Jul 9, 18:35 UTCJul 9, 23:55 UTC5h 20m
2026-07-08 UAL2626 SFO → EWR Jul 8, 23:45 UTCJul 9, 04:20 UTC4h 35m
2026-07-08 UAL1343 - Jul 8, 16:00 UTCJul 8, 21:20 UTC5h 20m
2026-07-07 UAL2171 ORD → EWR Jul 7, 22:45 UTCJul 8, 00:35 UTC1h 50m
2026-07-07 UAL913 KEF → ORD Jul 7, 12:20 UTCJul 7, 18:40 UTC6h 20m
2026-07-07 UAL913 KEF → ORD Jul 7, 12:29 UTCJul 7, 18:21 UTC5h 52m
2026-07-07 UAL398 - Jul 7, 10:10 UTCJul 7, 10:35 UTC25m
2026-07-07 UAL398 - Jul 7, 05:10 UTCJul 7, 07:05 UTC1h 55m
2026-07-07 UAL398 IAD → KEF Jul 7, 04:55 UTCJul 7, 10:27 UTC5h 32m
2026-07-06 UAL229 - Jul 6, 16:05 UTCJul 6, 16:55 UTC50m
2026-07-06 UAL229 DUB → IAD Jul 6, 15:56 UTCJul 6, 23:20 UTC7h 24m
2026-07-06 UAL228 IAD → DUB Jul 6, 07:30 UTCJul 6, 13:55 UTC6h 25m
2026-07-05 UAL399 - Jul 5, 12:10 UTCJul 5, 12:20 UTC10m
2026-07-05 UAL399 KEF → IAD Jul 5, 12:14 UTCJul 5, 17:53 UTC5h 39m

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 N41140 page for operator, model, and routing details .

Mode-S A4DAD4 frequently asked

What is Mode-S code A4DAD4?
A4DAD4 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N41140.
Where is Mode-S A4DAD4 registered?
Mode-S code A4DAD4 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 A4DAD4 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 20:30 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A4DAD4, octal 51155324, decimal 10,803,924.
What flights does A4DAD4 operate?
Mode-S A4DAD4 has broadcast 20 distinct callsigns, including UAL1759, UAL1758, UAL2307, UAL2308, UAL36.