Apparatus

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sensors Mode-S transponder

A11FA3

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N17128 · BOEING 757-200 · operated by UNITED AIRLINES INC

Hex
A11FA3
Octal
50217643
Decimal
10,559,395
Country
US
Tail
N17128
Type
B752
No current signal · last broadcast Jul 26, 22:45 UTC
Flights observed
285
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 22:45 UTC

Last known position

Most recent position reported by Mode-S A11FA3.

Country allocation

The ICAO 24-bit address A11FA3 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 10 2026-07-23
UAL316 United Airlines 9 2026-06-07
UAL229 United Airlines 9 2026-07-25
UAL1758 United Airlines 9 2026-05-24
UAL2115 United Airlines 8 2026-06-06
UAL1759 United Airlines 8 2026-05-25
UAL1340 - 8 2026-07-15
UAL912 United Airlines 7 2026-07-19
UAL271 United Airlines 7 2026-06-27
UAL2416 United Airlines 7 2026-04-30
UAL661 - 6 2026-07-17
UAL648 - 6 2026-07-03
UAL274 United Airlines 6 2026-07-26
UAL228 United Airlines 6 2026-07-25
UAL1343 United Airlines 6 2026-05-29
UAL1095 United Airlines 6 2026-07-26
UAL979 - 5 2026-07-06
UAL978 - 5 2026-07-06
UAL351 - 5 2026-07-02
UAL350 - 5 2026-07-01

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL274 RDU → EWR Jul 26, 18:45 UTCJul 26, 22:45 UTC4h 0m
2026-07-26 UAL1095 MYR → EWR Jul 26, 10:50 UTCJul 26, 16:00 UTC5h 10m
2026-07-25 UAL229 BZN → SFO Jul 25, 11:40 UTCJul 25, 18:50 UTC7h 10m
2026-07-25 UAL228 IAD → DUB Jul 25, 03:10 UTCJul 25, 09:30 UTC6h 20m
2026-07-24 UAL311 BOS → LAX Jul 24, 08:10 UTCJul 24, 15:15 UTC7h 5m
2026-07-24 UAL310 EWR → SFO Jul 24, 00:30 UTCJul 24, 06:30 UTC6h 0m
2026-07-23 UAL229 BZN → SFO Jul 23, 11:45 UTCJul 23, 18:55 UTC7h 10m
2026-07-23 UAL317 IAH → PHL Jul 23, 03:40 UTCJul 23, 09:45 UTC6h 5m
2026-07-23 UAL3902 TPA → ORD Jul 23, 00:05 UTCJul 23, 00:55 UTC50m
2026-07-22 UAL3902 TPA → ORD Jul 22, 23:22 UTCJul 23, 00:50 UTC1h 28m
2026-07-22 UAL229 BZN → SFO Jul 22, 12:00 UTCJul 22, 19:25 UTC7h 25m
2026-07-22 UAL228 IAD → DUB Jul 22, 03:45 UTCJul 22, 05:25 UTC1h 40m
2026-07-21 UAL419 BNA → EWR Jul 21, 13:35 UTCJul 21, 19:05 UTC5h 30m
2026-07-21 UAL1558 SNA → IAH Jul 21, 03:55 UTCJul 21, 09:05 UTC5h 10m
2026-07-20 UAL2759 IAD → EWR Jul 20, 19:20 UTCJul 20, 20:55 UTC1h 35m
2026-07-20 UAL2759 IAD → EWR Jul 20, 18:59 UTCJul 20, 20:51 UTC1h 52m
2026-07-20 UAL289 EWR → RDU Jul 20, 08:55 UTCJul 20, 09:30 UTC35m
2026-07-20 UAL289 EWR → RDU Jul 20, 08:57 UTCJul 20, 16:23 UTC7h 26m
2026-07-20 UAL288 DCA → ORD Jul 20, 00:32 UTCJul 20, 06:55 UTC6h 23m
2026-07-20 UAL288 DCA → ORD Jul 20, 00:10 UTCJul 20, 07:00 UTC6h 50m
2026-07-19 UAL2788 EWR → ORD Jul 19, 19:50 UTCJul 19, 22:00 UTC2h 10m
2026-07-19 UAL139 EWR → KEF Jul 19, 12:00 UTCJul 19, 17:40 UTC5h 40m
2026-07-19 UAL912 KEF → ORD Jul 19, 03:45 UTCJul 19, 09:30 UTC5h 45m
2026-07-18 UAL913 KEF → ORD Jul 18, 12:25 UTCJul 18, 18:30 UTC6h 5m
2026-07-18 UAL912 KEF → ORD Jul 18, 08:05 UTCJul 18, 08:25 UTC20m
2026-07-18 UAL912 KEF → ORD Jul 18, 03:00 UTCJul 18, 05:30 UTC2h 30m
2026-07-17 UAL661 EWR → ORD Jul 17, 22:37 UTCJul 18, 00:07 UTC1h 30m
2026-07-17 UAL661 EWR → ORD Jul 17, 22:25 UTCJul 18, 00:19 UTC1h 55m
2026-07-17 UAL2743 - Jul 17, 14:10 UTCJul 17, 19:05 UTC4h 55m
2026-07-16 UAL2191 - Jul 16, 20:45 UTCJul 17, 01:39 UTC4h 55m
2026-07-16 UAL419 SFO → EWR Jul 16, 13:45 UTCJul 16, 18:34 UTC4h 50m
2026-07-15 UAL1340 - Jul 15, 22:35 UTCJul 16, 04:30 UTC5h 55m
2026-07-15 UAL2743 - Jul 15, 14:55 UTCJul 15, 19:50 UTC4h 55m
2026-07-13 UAL2641 - Jul 13, 22:15 UTCJul 14, 03:00 UTC4h 45m
2026-07-13 UAL419 SFO → EWR Jul 13, 13:40 UTCJul 13, 18:50 UTC5h 10m
2026-07-12 UAL8111 - Jul 12, 21:55 UTCJul 13, 03:40 UTC5h 45m
2026-07-12 UAL1149 SFO → EWR Jul 12, 14:25 UTCJul 12, 19:30 UTC5h 5m
2026-07-10 UAL1340 - Jul 10, 22:55 UTCJul 11, 04:25 UTC5h 30m
2026-07-10 UAL634 - Jul 10, 11:00 UTCJul 10, 11:55 UTC55m
2026-07-10 UAL634 BIO → EWR Jul 10, 10:53 UTCJul 10, 18:41 UTC7h 48m
2026-07-10 UAL633 - Jul 10, 02:10 UTCJul 10, 08:40 UTC6h 30m
2026-07-09 UAL2171 - Jul 9, 21:35 UTCJul 9, 23:50 UTC2h 15m
2026-07-09 UAL2053 EWR → ORD Jul 9, 17:25 UTCJul 9, 19:20 UTC1h 55m
2026-07-09 UAL2301 ORD → EWR Jul 9, 14:10 UTCJul 9, 15:16 UTC1h 6m
2026-07-09 UAL2301 - Jul 9, 13:45 UTCJul 9, 13:50 UTC5m
2026-07-08 UAL913 KEF → ORD Jul 8, 12:10 UTCJul 8, 18:30 UTC6h 20m
2026-07-08 UAL398 IAD → KEF Jul 8, 03:00 UTCJul 8, 08:30 UTC5h 30m
2026-07-07 UAL229 DUB → IAD Jul 7, 13:10 UTCJul 7, 20:15 UTC7h 5m
2026-07-07 UAL229 DUB → IAD Jul 7, 12:46 UTCJul 7, 20:10 UTC7h 24m
2026-07-07 UAL228 IAD → DUB Jul 7, 04:50 UTCJul 7, 11:05 UTC6h 15m

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 N17128 page for operator, model, and routing details .

Mode-S A11FA3 frequently asked

What is Mode-S code A11FA3?
A11FA3 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N17128.
Where is Mode-S A11FA3 registered?
Mode-S code A11FA3 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 A11FA3 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 22:45 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A11FA3, octal 50217643, decimal 10,559,395.
What flights does A11FA3 operate?
Mode-S A11FA3 has broadcast 20 distinct callsigns, including UAL317, UAL316, UAL229, UAL1758, UAL2115.