Apparatus

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sensors Mode-S transponder

A2B081

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N27213 · BOEING 737-800 · operated by UNITED AIRLINES INC

Hex
A2B081
Octal
50530201
Decimal
10,662,017
Country
US
Tail
N27213
Type
B738
No current signal · last broadcast Jul 26, 22:15 UTC
Flights observed
426
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 22:15 UTC

Last known position

Most recent position reported by Mode-S A2B081.

Country allocation

The ICAO 24-bit address A2B081 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
UAL1776 United Airlines 7 2026-07-23
UAL1422 United Airlines 6 2026-05-25
UAL3906 United Airlines 4 2026-04-18
UAL362 - 4 2026-07-06
UAL275 - 4 2026-07-01
UAL2442 - 4 2026-07-12
UAL1811 United Airlines 4 2026-07-23
UAL766 United Airlines 3 2026-04-20
UAL671 United Airlines 3 2026-05-24
UAL547 - 3 2026-06-21
UAL493 United Airlines 3 2026-07-23
UAL2725 United Airlines 3 2026-06-13
UAL2443 United Airlines 3 2026-04-30
UAL2270 United Airlines 3 2026-07-26
UAL2188 - 3 2026-07-11
UAL2150 - 3 2026-07-09
UAL1911 - 3 2026-07-02
UAL1816 - 3 2026-07-11
UAL1747 United Airlines 3 2026-06-15
UAL1720 - 3 2026-07-05

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL1199 EWR → CLT Jul 26, 21:20 UTCJul 26, 22:15 UTC55m
2026-07-26 UAL1547 IAD → SAT Jul 26, 17:30 UTCJul 26, 18:10 UTC40m
2026-07-26 UAL2270 LAS → IAH Jul 26, 12:05 UTCJul 26, 14:15 UTC2h 10m
2026-07-26 UAL2270 LAS → IAH Jul 26, 12:12 UTCJul 26, 15:36 UTC3h 24m
2026-07-26 UAL680 SAT → DEN Jul 26, 00:15 UTCJul 26, 03:20 UTC3h 5m
2026-07-25 UAL1534 EWR → FLL Jul 25, 21:00 UTCJul 25, 22:40 UTC1h 40m
2026-07-25 UAL2167 ORD → CVG Jul 25, 17:30 UTCJul 25, 18:45 UTC1h 15m
2026-07-25 UAL1891 CLE → EWR Jul 25, 14:25 UTCJul 25, 16:00 UTC1h 35m
2026-07-25 UAL667 IAD → LAX Jul 25, 03:10 UTCJul 25, 04:40 UTC1h 30m
2026-07-24 UAL1236 EWR → PHX Jul 24, 23:50 UTCJul 25, 01:57 UTC2h 7m
2026-07-24 UAL1236 EWR → PHX Jul 24, 23:35 UTCJul 25, 02:05 UTC2h 30m
2026-07-24 UAL1767 DEN → DCA Jul 24, 19:35 UTCJul 24, 22:10 UTC2h 35m
2026-07-24 UAL2375 PHL → ORD Jul 24, 15:55 UTCJul 24, 18:00 UTC2h 5m
2026-07-23 UAL1677 SFO → DFW Jul 23, 22:15 UTCJul 24, 02:10 UTC3h 55m
2026-07-23 UAL493 CLE → IAD Jul 23, 19:35 UTCJul 23, 20:05 UTC30m
2026-07-23 UAL493 CLE → IAD Jul 23, 19:12 UTCJul 23, 19:16 UTC4m
2026-07-23 UAL493 CLE → IAD Jul 23, 18:45 UTCJul 23, 18:55 UTC10m
2026-07-23 UAL2849 EWR → DOM Jul 23, 16:45 UTCJul 23, 17:35 UTC50m
2026-07-23 UAL1811 ORD → BDL Jul 23, 14:10 UTCJul 23, 14:20 UTC10m
2026-07-23 UAL1811 ORD → BDL Jul 23, 12:20 UTCJul 23, 14:10 UTC1h 50m
2026-07-23 UAL1811 ORD → BDL Jul 23, 12:22 UTCJul 23, 13:53 UTC1h 31m
2026-07-23 UAL1776 LAX → SFO Jul 23, 00:35 UTCJul 23, 01:55 UTC1h 20m
2026-07-23 UAL1776 LAX → SFO Jul 23, 00:33 UTCJul 23, 01:50 UTC1h 17m
2026-07-22 UAL2160 PHX → SFO Jul 22, 20:55 UTCJul 22, 22:40 UTC1h 45m
2026-07-22 UAL441 EWR → FLL Jul 22, 16:00 UTCJul 22, 17:50 UTC1h 50m
2026-07-22 UAL2771 HNL → ORD Jul 22, 12:20 UTCJul 22, 14:05 UTC1h 45m
2026-07-21 UAL1748 - Jul 21, 23:40 UTCJul 22, 00:55 UTC1h 15m
2026-07-21 UAL1398 COS → ORD Jul 21, 18:25 UTCJul 21, 20:25 UTC2h 0m
2026-07-21 UAL1082 - Jul 21, 15:00 UTCJul 21, 17:00 UTC2h 0m
2026-07-21 UAL1830 - Jul 21, 02:25 UTCJul 21, 04:00 UTC1h 35m
2026-07-21 UAL1830 - Jul 21, 02:10 UTCJul 21, 02:20 UTC10m
2026-07-20 UAL2306 ORD → BOS Jul 20, 23:05 UTCJul 21, 00:45 UTC1h 39m
2026-07-20 UAL1398 COS → ORD Jul 20, 18:25 UTCJul 20, 20:35 UTC2h 10m
2026-07-20 UAL1082 ORD → COS Jul 20, 14:55 UTCJul 20, 16:55 UTC2h 0m
2026-07-20 UAL1082 ORD → COS Jul 20, 14:43 UTCJul 20, 16:49 UTC2h 6m
2026-07-19 UAL2628 PHL → IAH Jul 19, 20:40 UTCJul 20, 00:00 UTC3h 20m
2026-07-19 UAL2822 ORD → PHX Jul 19, 16:25 UTCJul 19, 19:15 UTC2h 50m
2026-07-19 UAL466 - Jul 19, 14:00 UTCJul 19, 15:05 UTC1h 5m
2026-07-19 UAL1492 ORD → CMH Jul 19, 03:40 UTCJul 19, 04:20 UTC40m
2026-07-19 UAL1813 - Jul 19, 00:50 UTCJul 19, 01:55 UTC1h 5m
2026-07-19 UAL1813 CVG → ORD Jul 19, 00:22 UTCJul 19, 01:43 UTC1h 21m
2026-07-18 UAL2370 ORD → CVG Jul 18, 20:25 UTCJul 18, 21:15 UTC50m
2026-07-18 UAL1811 - Jul 18, 13:00 UTCJul 18, 14:45 UTC1h 45m
2026-07-18 UAL1776 LAX → SFO Jul 18, 05:08 UTCJul 18, 06:20 UTC1h 12m
2026-07-18 UAL1776 LAX → SFO Jul 18, 04:55 UTCJul 18, 06:20 UTC1h 25m
2026-07-18 UAL2446 - Jul 18, 01:20 UTCJul 18, 03:10 UTC1h 51m
2026-07-17 UAL1617 ORD → LGA Jul 17, 20:46 UTCJul 17, 22:38 UTC1h 52m
2026-07-17 UAL1617 ORD → LGA Jul 17, 20:44 UTCJul 17, 22:40 UTC1h 55m
2026-07-17 UAL378 ORD → EWR Jul 17, 16:24 UTCJul 17, 18:25 UTC2h 0m
2026-07-17 UAL762 - Jul 17, 12:30 UTCJul 17, 14:04 UTC1h 35m

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 N27213 page for operator, model, and routing details .

Mode-S A2B081 frequently asked

What is Mode-S code A2B081?
A2B081 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N27213.
Where is Mode-S A2B081 registered?
Mode-S code A2B081 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 A2B081 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 22:15 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A2B081, octal 50530201, decimal 10,662,017.
What flights does A2B081 operate?
Mode-S A2B081 has broadcast 20 distinct callsigns, including UAL1776, UAL1422, UAL3906, UAL362, UAL275.