Apparatus

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sensors Mode-S transponder

A4DAB6

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N41135 · BOEING 757-200 · operated by UNITED AIRLINES INC

Hex
A4DAB6
Octal
51155266
Decimal
10,803,894
Country
US
Tail
N41135
Type
B752
No current signal · last broadcast Jul 26, 18:30 UTC
Flights observed
289
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 18:30 UTC

Last known position

Most recent position reported by Mode-S A4DAB6.

Country allocation

The ICAO 24-bit address A4DAB6 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
UAL2641 United Airlines 8 2026-07-01
UAL228 - 8 2026-07-12
UAL1095 - 8 2026-06-14
UAL978 - 7 2026-07-11
UAL712 United Airlines 7 2026-07-24
UAL336 - 7 2026-06-14
UAL316 - 7 2026-07-12
UAL2434 - 7 2026-07-16
UAL2359 United Airlines 7 2026-05-15
UAL229 - 7 2026-07-10
UAL350 - 6 2026-07-13
UAL289 United Airlines 6 2026-07-23
UAL2127 - 6 2026-07-16
UAL979 - 5 2026-07-11
UAL288 United Airlines 5 2026-07-23
UAL2743 - 5 2026-07-01
UAL271 United Airlines 5 2026-07-05
UAL270 - 5 2026-07-05
UAL1758 United Airlines 5 2026-05-28
UAL1209 United Airlines 5 2026-05-08

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL1403 JAX → EWR Jul 26, 13:35 UTCJul 26, 18:25 UTC4h 50m
2026-07-26 UAL1403 JAX → EWR Jul 26, 13:28 UTCJul 26, 18:24 UTC4h 56m
2026-07-24 UAL712 ORD → DEL Jul 24, 00:25 UTCJul 24, 05:35 UTC5h 10m
2026-07-23 UAL2759 IAD → EWR Jul 23, 19:10 UTCJul 23, 20:40 UTC1h 30m
2026-07-23 UAL289 EWR → RDU Jul 23, 08:40 UTCJul 23, 16:10 UTC7h 30m
2026-07-23 UAL288 DCA → ORD Jul 23, 00:20 UTCJul 23, 06:50 UTC6h 30m
2026-07-23 UAL288 DCA → ORD Jul 23, 00:07 UTCJul 23, 06:43 UTC6h 36m
2026-07-22 UAL913 HNL → SFO Jul 22, 14:05 UTCJul 22, 20:35 UTC6h 30m
2026-07-22 UAL912 KEF → ORD Jul 22, 11:35 UTCJul 22, 11:55 UTC20m
2026-07-21 UAL289 EWR → RDU Jul 21, 08:45 UTCJul 21, 09:20 UTC35m
2026-07-21 UAL289 EWR → RDU Jul 21, 08:47 UTCJul 21, 16:05 UTC7h 18m
2026-07-21 UAL289 EWR → RDU Jul 21, 08:47 UTCJul 21, 16:05 UTC7h 18m
2026-07-20 UAL288 DCA → ORD Jul 20, 23:47 UTCJul 21, 06:15 UTC6h 28m
2026-07-20 UAL288 DCA → ORD Jul 20, 23:40 UTCJul 21, 06:20 UTC6h 40m
2026-07-20 UAL2053 SFO → PDX Jul 20, 19:00 UTCJul 20, 20:55 UTC1h 55m
2026-07-20 UAL239 OPO → EWR Jul 20, 09:20 UTCJul 20, 16:40 UTC7h 20m
2026-07-20 UAL238 CLE → ORD Jul 20, 01:05 UTCJul 20, 07:30 UTC6h 25m
2026-07-19 UAL2759 ORD → EWR Jul 19, 18:55 UTCJul 19, 20:30 UTC1h 35m
2026-07-19 UAL289 - Jul 19, 08:45 UTCJul 19, 15:55 UTC7h 10m
2026-07-19 UAL289 SNN → ORD Jul 19, 08:47 UTCJul 19, 15:48 UTC7h 1m
2026-07-19 UAL288 - Jul 19, 00:15 UTCJul 19, 06:55 UTC6h 40m
2026-07-17 UAL913 KEF → ORD Jul 17, 12:15 UTCJul 17, 18:25 UTC6h 10m
2026-07-17 UAL138 KEF → EWR Jul 17, 02:10 UTCJul 17, 07:05 UTC4h 55m
2026-07-16 UAL2127 - Jul 16, 17:45 UTCJul 16, 22:40 UTC4h 55m
2026-07-16 UAL2434 - Jul 16, 10:40 UTCJul 16, 15:40 UTC5h 0m
2026-07-16 UAL2759 - Jul 16, 02:10 UTCJul 16, 03:35 UTC1h 25m
2026-07-15 UAL119 - Jul 15, 12:45 UTCJul 15, 20:10 UTC7h 25m
2026-07-15 UAL119 EDI → ORD Jul 15, 12:53 UTCJul 15, 19:52 UTC6h 59m
2026-07-15 UAL118 - Jul 15, 03:40 UTCJul 15, 05:55 UTC2h 15m
2026-07-15 UAL118 ORD → EDI Jul 15, 03:42 UTCJul 15, 10:25 UTC6h 43m
2026-07-14 UAL661 - Jul 14, 23:55 UTCJul 15, 01:30 UTC1h 35m
2026-07-14 UAL661 EWR → ORD Jul 14, 23:57 UTCJul 15, 01:22 UTC1h 25m
2026-07-14 UAL661 EWR → EWR Jul 14, 23:40 UTCJul 14, 23:45 UTC5m
2026-07-14 UAL351 - Jul 14, 08:00 UTCJul 14, 15:45 UTC7h 45m
2026-07-13 UAL350 EWR → AGP Jul 13, 23:20 UTCJul 14, 06:04 UTC6h 44m
2026-07-13 UAL350 - Jul 13, 23:10 UTCJul 14, 06:10 UTC7h 0m
2026-07-13 UAL239 OPO → EWR Jul 13, 08:25 UTCJul 13, 14:55 UTC6h 30m
2026-07-13 UAL239 OPO → EWR Jul 13, 08:01 UTCJul 13, 15:00 UTC7h 0m
2026-07-12 UAL238 - Jul 12, 23:40 UTCJul 13, 05:55 UTC6h 15m
2026-07-12 UAL316 - Jul 12, 13:10 UTCJul 12, 13:55 UTC45m
2026-07-12 UAL316 DUB → EWR Jul 12, 12:46 UTCJul 12, 19:50 UTC7h 4m
2026-07-12 UAL228 IAD → DUB Jul 12, 04:05 UTCJul 12, 10:20 UTC6h 15m
2026-07-11 UAL979 EDI → IAD Jul 11, 12:05 UTCJul 11, 19:30 UTC7h 25m
2026-07-11 UAL978 IAD → EDI Jul 11, 02:35 UTCJul 11, 09:10 UTC6h 35m
2026-07-10 UAL229 - Jul 10, 11:50 UTCJul 10, 12:40 UTC50m
2026-07-10 UAL229 DUB → IAD Jul 10, 11:51 UTCJul 10, 19:25 UTC7h 34m
2026-07-10 UAL228 IAD → DUB Jul 10, 03:15 UTCJul 10, 09:25 UTC6h 10m
2026-07-09 UAL336T SFO → SAN Jul 9, 18:25 UTCJul 9, 22:55 UTC4h 30m
2026-07-06 UAL1777 - Jul 6, 12:35 UTCJul 6, 18:00 UTC5h 25m
2026-07-06 UAL698 SFO → EWR Jul 6, 04:35 UTCJul 6, 09:30 UTC4h 55m

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 N41135 page for operator, model, and routing details .

Mode-S A4DAB6 frequently asked

What is Mode-S code A4DAB6?
A4DAB6 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N41135.
Where is Mode-S A4DAB6 registered?
Mode-S code A4DAB6 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 A4DAB6 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 18:30 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A4DAB6, octal 51155266, decimal 10,803,894.
What flights does A4DAB6 operate?
Mode-S A4DAB6 has broadcast 20 distinct callsigns, including UAL2641, UAL228, UAL1095, UAL978, UAL712.