Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

AA8C39

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N779UA · BOEING 777-200 · operated by UNITED AIRLINES INC

Hex
AA8C39
Octal
52506071
Decimal
11,177,017
Country
US
Tail
N779UA
Type
B772
No current signal · last broadcast Jul 26, 12:20 UTC
Flights observed
252
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 12:20 UTC

Last known position

Most recent position reported by Mode-S AA8C39.

Country allocation

The ICAO 24-bit address AA8C39 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
UAL1170 United Airlines 19 2026-07-25
UAL1169 United Airlines 14 2026-07-26
UAL300 United Airlines 13 2026-07-22
UAL1158 United Airlines 12 2026-07-19
UAL253 United Airlines 11 2026-07-23
UAL604 United Airlines 10 2026-07-20
UAL252 United Airlines 10 2026-07-23
UAL1157 United Airlines 10 2026-07-24
UAL1805 United Airlines 9 2026-07-25
UAL2610 United Airlines 8 2026-07-21
UAL2480 United Airlines 8 2026-07-20
UAL2358 - 8 2026-07-10
UAL383 - 7 2026-06-14
UAL1777 - 7 2026-06-22
UAL543 - 6 2026-06-22
UAL2475 - 6 2026-06-16
UAL1806 United Airlines 6 2026-07-25
UAL1736 United Airlines 6 2026-04-23
UAL384 United Airlines 5 2026-05-26
UAL368 - 5 2026-06-19

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL1169 BDL → ORD Jul 26, 11:35 UTCJul 26, 12:20 UTC45m
2026-07-26 UAL1169 BDL → ORD Jul 26, 07:55 UTCJul 26, 08:05 UTC10m
2026-07-25 UAL1805 LAS → EWR Jul 25, 22:50 UTCJul 26, 05:30 UTC6h 40m
2026-07-25 UAL1806 MCI → EWR Jul 25, 12:30 UTCJul 25, 18:15 UTC5h 45m
2026-07-25 UAL1170 LAX → HNL Jul 25, 05:31 UTCJul 25, 10:57 UTC5h 26m
2026-07-25 UAL1170 LAX → HNL Jul 25, 05:55 UTCJul 25, 10:50 UTC4h 55m
2026-07-24 UAL1157 BOS → IAD Jul 24, 23:20 UTCJul 24, 23:35 UTC15m
2026-07-24 UAL1157 BOS → IAD Jul 24, 23:20 UTCJul 25, 03:56 UTC4h 36m
2026-07-23 UAL253 IAH → HNL Jul 23, 15:45 UTCJul 23, 23:10 UTC7h 25m
2026-07-23 UAL252 HNL → IAH Jul 23, 06:15 UTCJul 23, 13:20 UTC7h 5m
2026-07-22 UAL300 SFO → HNL Jul 22, 22:37 UTCJul 23, 03:20 UTC4h 43m
2026-07-22 UAL300 SFO → HNL Jul 22, 22:30 UTCJul 22, 23:05 UTC35m
2026-07-22 UAL1147 IAD → SFO Jul 22, 14:45 UTCJul 22, 19:50 UTC5h 5m
2026-07-21 UAL1791 LAS → ORD Jul 21, 21:00 UTCJul 22, 01:30 UTC4h 30m
2026-07-21 UAL2610 IAD → PDX Jul 21, 14:20 UTCJul 21, 18:05 UTC3h 45m
2026-07-20 UAL2480 BOS → SFO Jul 20, 23:10 UTCJul 21, 02:45 UTC3h 35m
2026-07-20 UAL8185 LGA → YUL Jul 20, 19:00 UTCJul 20, 19:05 UTC5m
2026-07-20 UAL8185 LGA → YUL Jul 20, 15:55 UTCJul 20, 19:05 UTC3h 10m
2026-07-20 UAL8185 LGA → YUL Jul 20, 15:46 UTCJul 20, 18:45 UTC2h 59m
2026-07-20 UAL604 DEN → SYR Jul 20, 08:05 UTCJul 20, 11:20 UTC3h 15m
2026-07-20 UAL1818 - Jul 20, 00:20 UTCJul 20, 04:35 UTC4h 15m
2026-07-19 UAL1158 LAX → HNL Jul 19, 21:50 UTCJul 19, 22:10 UTC20m
2026-07-19 UAL1158 LAX → HNL Jul 19, 16:55 UTCJul 19, 17:55 UTC1h 0m
2026-07-19 UAL1169 - Jul 19, 07:50 UTCJul 19, 12:25 UTC4h 35m
2026-07-19 UAL1170 LAX → HNL Jul 19, 05:30 UTCJul 19, 05:55 UTC25m
2026-07-19 UAL1170 LAX → HNL Jul 19, 00:45 UTCJul 19, 01:15 UTC30m
2026-07-17 UAL1157 - Jul 17, 23:14 UTCJul 18, 03:50 UTC4h 36m
2026-07-16 UAL253 IAH → HNL Jul 16, 15:42 UTCJul 16, 23:29 UTC7h 47m
2026-07-16 UAL253 - Jul 16, 15:45 UTCJul 16, 23:25 UTC7h 40m
2026-07-16 UAL252 - Jul 16, 06:10 UTCJul 16, 13:20 UTC7h 10m
2026-07-16 UAL300 - Jul 16, 02:15 UTCJul 16, 02:35 UTC20m
2026-07-15 UAL300 - Jul 15, 21:50 UTCJul 15, 22:15 UTC25m
2026-07-13 UAL1147 - Jul 13, 12:55 UTCJul 13, 17:35 UTC4h 40m
2026-07-12 UAL1791 SFO → IAD Jul 12, 20:45 UTCJul 13, 01:15 UTC4h 30m
2026-07-12 UAL2610 - Jul 12, 14:30 UTCJul 12, 18:10 UTC3h 40m
2026-07-11 UAL2480 - Jul 11, 22:40 UTCJul 12, 02:10 UTC3h 30m
2026-07-11 UAL2610 - Jul 11, 15:05 UTCJul 11, 18:40 UTC3h 35m
2026-07-10 UAL2480 SFO → ORD Jul 10, 22:35 UTCJul 11, 02:05 UTC3h 30m
2026-07-10 UAL2358 - Jul 10, 16:00 UTCJul 10, 19:20 UTC3h 20m
2026-07-10 UAL604 - Jul 10, 08:10 UTCJul 10, 11:10 UTC3h 0m
2026-07-09 UAL2610 ORD → SFO Jul 9, 14:40 UTCJul 9, 18:45 UTC4h 5m
2026-07-09 UAL2480 SFO → ORD Jul 9, 07:35 UTCJul 9, 11:00 UTC3h 25m
2026-07-06 UAL3930 - Jul 6, 23:50 UTCJul 7, 03:50 UTC4h 0m
2026-07-06 UAL3930 ORD → SFO Jul 6, 23:43 UTCJul 7, 03:39 UTC3h 56m
2026-07-02 UAL2480 - Jul 2, 23:15 UTCJul 3, 03:00 UTC3h 45m
2026-07-02 UAL2610 - Jul 2, 15:35 UTCJul 2, 19:40 UTC4h 5m
2026-07-01 UAL2480 SFO → ORD Jul 1, 22:55 UTCJul 2, 02:25 UTC3h 30m
2026-07-01 UAL1147 - Jul 1, 13:25 UTCJul 1, 18:20 UTC4h 55m
2026-06-30 UAL1791 SFO → IAD Jun 30, 23:00 UTCJul 1, 03:30 UTC4h 30m
2026-06-30 UAL1791 SFO → IAD Jun 30, 22:07 UTCJul 1, 03:25 UTC5h 18m

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 N779UA page for operator, model, and routing details .

Mode-S AA8C39 frequently asked

What is Mode-S code AA8C39?
AA8C39 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N779UA.
Where is Mode-S AA8C39 registered?
Mode-S code AA8C39 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 AA8C39 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 12:20 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AA8C39, octal 52506071, decimal 11,177,017.
What flights does AA8C39 operate?
Mode-S AA8C39 has broadcast 20 distinct callsigns, including UAL1170, UAL1169, UAL300, UAL1158, UAL253.