Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

A5EF0E

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N48127 · BOEING 757-200 · operated by UNITED AIRLINES INC

Hex
A5EF0E
Octal
51367416
Decimal
10,874,638
Country
US
Tail
N48127
Type
B752
No current signal · last broadcast Jul 26, 21:00 UTC
Flights observed
199
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 21:00 UTC

Last known position

Most recent position reported by Mode-S A5EF0E.

Country allocation

The ICAO 24-bit address A5EF0E 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
UAL317 United Airlines 7 2026-07-18
UAL2248 - 7 2026-07-16
UAL2191 United Airlines 7 2026-05-05
UAL648 - 6 2026-07-16
UAL270 United Airlines 6 2026-05-08
UAL2434 United Airlines 6 2026-04-28
UAL2127 United Airlines 6 2026-04-28
UAL1802 United Airlines 6 2026-04-15
UAL399 - 5 2026-07-22
UAL316 - 5 2026-07-18
UAL310 United Airlines 5 2026-07-22
UAL560 United Airlines 4 2026-04-15
UAL36 United Airlines 4 2026-04-17
UAL332 United Airlines 4 2026-05-13
UAL311 United Airlines 4 2026-07-23
UAL398 United Airlines 3 2026-07-24
UAL37 United Airlines 3 2026-04-17
UAL351 United Airlines 3 2026-05-10
UAL350 United Airlines 3 2026-05-09
UAL289 United Airlines 3 2026-07-26

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL2759 IAD → EWR Jul 26, 19:10 UTCJul 26, 20:50 UTC1h 40m
2026-07-26 UAL289 EWR → RDU Jul 26, 08:30 UTCJul 26, 16:15 UTC7h 45m
2026-07-25 UAL288 DCA → ORD Jul 25, 23:45 UTCJul 26, 06:20 UTC6h 35m
2026-07-25 UAL119 ORD → EDI Jul 25, 10:45 UTCJul 25, 18:55 UTC8h 10m
2026-07-25 UAL118 ORD → EDI Jul 25, 01:27 UTCJul 25, 07:42 UTC6h 15m
2026-07-25 UAL118 ORD → EDI Jul 25, 00:55 UTCJul 25, 07:45 UTC6h 50m
2026-07-24 UAL2788 DEN → EWR Jul 24, 19:45 UTCJul 24, 21:35 UTC1h 50m
2026-07-24 UAL139 EWR → KEF Jul 24, 11:15 UTCJul 24, 17:05 UTC5h 50m
2026-07-24 UAL139 EWR → KEF Jul 24, 11:19 UTCJul 24, 16:58 UTC5h 39m
2026-07-24 UAL398 EWR → TPA Jul 24, 08:05 UTCJul 24, 08:25 UTC20m
2026-07-24 UAL398 EWR → TPA Jul 24, 03:00 UTCJul 24, 05:00 UTC2h 0m
2026-07-23 UAL311 BOS → LAX Jul 23, 08:10 UTCJul 23, 15:10 UTC7h 0m
2026-07-22 UAL310 EWR → SFO Jul 22, 23:30 UTCJul 23, 06:05 UTC6h 35m
2026-07-22 UAL399 - Jul 22, 11:40 UTCJul 22, 17:30 UTC5h 50m
2026-07-22 UAL399 KEF → IAD Jul 22, 11:49 UTCJul 22, 17:50 UTC6h 1m
2026-07-22 UAL398 EWR → TPA Jul 22, 03:10 UTCJul 22, 05:05 UTC1h 55m
2026-07-21 UAL399 - Jul 21, 15:25 UTCJul 21, 18:00 UTC2h 35m
2026-07-21 UAL399 - Jul 21, 11:55 UTCJul 21, 12:10 UTC15m
2026-07-21 UAL399 KEF → IAD Jul 21, 11:59 UTCJul 21, 17:55 UTC5h 56m
2026-07-21 UAL138 KEF → EWR Jul 21, 06:40 UTCJul 21, 07:00 UTC20m
2026-07-21 UAL138 KEF → EWR Jul 21, 02:15 UTCJul 21, 04:00 UTC1h 45m
2026-07-20 UAL274 RDU → EWR Jul 20, 19:20 UTCJul 21, 00:15 UTC4h 54m
2026-07-19 UAL336 SFO → EWR Jul 19, 18:35 UTCJul 19, 20:00 UTC1h 25m
2026-07-19 UAL1558 - Jul 19, 03:40 UTCJul 19, 09:00 UTC5h 20m
2026-07-19 UAL1558 EWR → SFO Jul 19, 03:08 UTCJul 19, 08:55 UTC5h 47m
2026-07-18 UAL316 - Jul 18, 14:50 UTCJul 18, 21:45 UTC6h 55m
2026-07-18 UAL316 DUB → EWR Jul 18, 14:46 UTCJul 18, 21:40 UTC6h 54m
2026-07-18 UAL317 IAH → PHL Jul 18, 05:15 UTCJul 18, 07:00 UTC1h 45m
2026-07-18 UAL317 IAH → PHL Jul 18, 05:02 UTCJul 18, 11:23 UTC6h 21m
2026-07-16 UAL2248 SFO → EWR Jul 16, 22:40 UTCJul 17, 03:34 UTC4h 55m
2026-07-16 UAL648 - Jul 16, 15:45 UTCJul 16, 20:49 UTC5h 5m
2026-07-15 UAL2248 SFO → EWR Jul 15, 22:30 UTCJul 16, 03:45 UTC5h 15m
2026-07-15 UAL648 - Jul 15, 15:20 UTCJul 15, 20:30 UTC5h 10m
2026-07-14 UAL239 OPO → EWR Jul 14, 08:25 UTCJul 14, 15:04 UTC6h 39m
2026-07-14 UAL239 OPO → EWR Jul 14, 08:10 UTCJul 14, 15:05 UTC6h 55m
2026-07-13 UAL238 - Jul 13, 23:30 UTCJul 14, 05:50 UTC6h 20m
2026-07-13 UAL2759 ORD → EWR Jul 13, 18:59 UTCJul 13, 20:32 UTC1h 33m
2026-07-13 UAL2759 ORD → EWR Jul 13, 18:50 UTCJul 13, 20:35 UTC1h 45m
2026-07-13 UAL289 - Jul 13, 08:40 UTCJul 13, 09:15 UTC35m
2026-07-13 UAL289 SNN → ORD Jul 13, 08:47 UTCJul 13, 16:03 UTC7h 16m
2026-07-12 UAL288 - Jul 12, 23:45 UTCJul 13, 06:30 UTC6h 45m
2026-07-12 UAL2788 - Jul 12, 19:01 UTCJul 12, 21:00 UTC2h 0m
2026-07-12 UAL239 OPO → EWR Jul 12, 08:10 UTCJul 12, 15:10 UTC7h 0m
2026-07-11 UAL238 EWR → OPO Jul 11, 23:25 UTCJul 12, 05:45 UTC6h 20m
2026-07-11 UAL316 - Jul 11, 13:15 UTCJul 11, 14:00 UTC45m
2026-07-11 UAL316 DUB → EWR Jul 11, 13:16 UTCJul 11, 19:55 UTC6h 39m
2026-07-11 UAL317 EWR → DUB Jul 11, 05:25 UTCJul 11, 11:25 UTC6h 0m
2026-07-10 UAL2248 SFO → EWR Jul 10, 22:35 UTCJul 11, 03:20 UTC4h 45m
2026-07-10 UAL648J EWR → SFO Jul 10, 15:02 UTCJul 10, 20:44 UTC5h 42m
2026-07-10 UAL648J - Jul 10, 15:30 UTCJul 10, 20:55 UTC5h 25m

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 N48127 page for operator, model, and routing details .

Mode-S A5EF0E frequently asked

What is Mode-S code A5EF0E?
A5EF0E is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N48127.
Where is Mode-S A5EF0E registered?
Mode-S code A5EF0E 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 A5EF0E broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 21:00 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A5EF0E, octal 51367416, decimal 10,874,638.
What flights does A5EF0E operate?
Mode-S A5EF0E has broadcast 20 distinct callsigns, including UAL317, UAL2248, UAL2191, UAL648, UAL270.