Apparatus

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sensors Mode-S transponder

A18D29

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N19986 · BOEING 787-9 Dreamliner · operated by UNITED AIRLINES INC

Hex
A18D29
Octal
50306451
Decimal
10,587,433
Country
US
Tail
N19986
Type
B789
Broadcasting now · callsign UAL62 · 37,000 ft
Flights observed
233
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 20:20 UTC

Current position

A18D29 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A18D29 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
UAL181 United Airlines 11 2026-04-15
UAL820 - 8 2026-06-29
UAL821 - 7 2026-06-30
UAL153 - 7 2026-07-12
UAL123 - 7 2026-06-27
UAL839 - 6 2026-07-14
UAL178 United Airlines 6 2026-04-27
UAL177 United Airlines 6 2026-04-26
UAL122 - 6 2026-06-26
UAL82 - 5 2026-06-22
UAL78 United Airlines 5 2026-05-17
UAL63 - 5 2026-07-09
UAL187 United Airlines 5 2026-07-26
UAL182 United Airlines 5 2026-04-15
UAL152 - 5 2026-07-11
UAL143 United Airlines 5 2026-04-30
UAL892 United Airlines 4 2026-06-03
UAL842 - 4 2026-07-14
UAL806 United Airlines 4 2026-07-25
UAL79 United Airlines 4 2026-05-16

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL187 JNB → EWR Jul 26, 20:00 UTCJul 26, 20:20 UTC20m
2026-07-26 UAL188 EWR → JNB Jul 26, 01:40 UTCJul 26, 16:00 UTC14h 21m
2026-07-25 UAL713 ORD → DEL Jul 25, 17:35 UTCJul 25, 22:15 UTC4h 40m
2026-07-25 UAL806 ICN → SFO Jul 25, 02:45 UTCJul 25, 13:10 UTC10h 25m
2026-07-25 UAL806 ICN → SFO Jul 25, 02:56 UTCJul 25, 13:04 UTC10h 8m
2026-07-24 UAL805 SFO → ICN Jul 24, 08:00 UTCJul 24, 19:10 UTC11h 10m
2026-07-23 UAL1757 PIT → DEN Jul 23, 23:40 UTCJul 24, 04:20 UTC4h 40m
2026-07-23 UAL1849 MCO → EWR Jul 23, 15:35 UTCJul 23, 19:55 UTC4h 20m
2026-07-22 UAL28 SIN → SFO Jul 22, 16:20 UTCJul 23, 04:45 UTC12h 25m
2026-07-22 UAL28 SIN → SFO Jul 22, 13:16 UTCJul 23, 04:50 UTC15h 34m
2026-07-21 UAL29 SFO → SIN Jul 21, 19:00 UTCJul 21, 19:30 UTC30m
2026-07-20 UAL949 LHR → SFO Jul 20, 12:25 UTCJul 20, 22:55 UTC10h 30m
2026-07-19 UAL923 LAX → LHR Jul 19, 23:10 UTCJul 20, 09:00 UTC9h 50m
2026-07-19 UAL2692 EWR → LAX Jul 19, 16:34 UTCJul 19, 21:04 UTC4h 30m
2026-07-19 UAL2692 - Jul 19, 16:30 UTCJul 19, 21:05 UTC4h 35m
2026-07-17 UAL1855 ORD → BOS Jul 17, 21:55 UTCJul 18, 02:35 UTC4h 40m
2026-07-16 UAL99 MEL → LAX Jul 16, 23:58 UTCJul 17, 13:57 UTC13h 59m
2026-07-16 UAL99 - Jul 16, 23:59 UTCJul 17, 01:15 UTC1h 15m
2026-07-16 UAL98 - Jul 16, 06:50 UTCJul 16, 21:40 UTC14h 50m
2026-07-16 UAL353 - Jul 16, 00:05 UTCJul 16, 04:40 UTC4h 35m
2026-07-15 UAL2096 - Jul 15, 16:35 UTCJul 15, 22:20 UTC5h 45m
2026-07-14 UAL842 SYD → LAX Jul 14, 23:55 UTCJul 15, 13:05 UTC13h 10m
2026-07-14 UAL839 - Jul 14, 06:55 UTCJul 14, 21:10 UTC14h 15m
2026-07-14 UAL839 LAX → SYD Jul 14, 06:09 UTCJul 14, 20:58 UTC14h 49m
2026-07-13 UAL935 - Jul 13, 12:35 UTCJul 13, 22:45 UTC10h 10m
2026-07-12 UAL923 LAX → LHR Jul 12, 22:55 UTCJul 13, 08:50 UTC9h 55m
2026-07-12 UAL153 HKG → LAX Jul 12, 05:08 UTCJul 12, 18:35 UTC13h 27m
2026-07-12 UAL153 - Jul 12, 05:10 UTCJul 12, 18:35 UTC13h 25m
2026-07-12 UAL153 - Jul 12, 02:15 UTCJul 12, 02:30 UTC15m
2026-07-11 UAL152 - Jul 11, 13:35 UTCJul 11, 13:45 UTC10m
2026-07-10 UAL152 LAX → HKG Jul 10, 20:35 UTCJul 11, 11:00 UTC14h 25m
2026-07-10 UAL152 LAX → HKG Jul 10, 20:18 UTCJul 11, 10:56 UTC14h 38m
2026-07-10 UAL33 - Jul 10, 08:25 UTCJul 10, 17:55 UTC9h 30m
2026-07-10 UAL33 NRT → LAX Jul 10, 08:15 UTCJul 10, 17:44 UTC9h 29m
2026-07-09 UAL7 - Jul 9, 16:00 UTCJul 10, 04:55 UTC12h 55m
2026-07-09 UAL63 - Jul 9, 01:05 UTCJul 9, 10:50 UTC9h 45m
2026-07-08 UAL62 - Jul 8, 00:15 UTCJul 8, 09:20 UTC9h 5m
2026-07-07 UAL6 - Jul 7, 08:10 UTCJul 7, 19:30 UTC11h 20m
2026-07-06 UAL32 - Jul 6, 18:05 UTCJul 6, 19:05 UTC1h 0m
2026-07-06 UAL32 LAX → NRT Jul 6, 18:15 UTCJul 7, 04:41 UTC10h 26m
2026-07-06 UAL842 - Jul 6, 00:05 UTCJul 6, 00:15 UTC10m
2026-07-05 UAL842 SYD → LAX Jul 5, 23:51 UTCJul 6, 13:09 UTC13h 18m
2026-07-05 UAL839 - Jul 5, 06:40 UTCJul 5, 07:10 UTC30m
2026-07-05 UAL839 LAX → SYD Jul 5, 06:41 UTCJul 5, 21:10 UTC14h 29m
2026-07-04 UAL199 PVG → LAX Jul 4, 06:20 UTCJul 5, 00:00 UTC17h 40m
2026-07-03 UAL198 - Jul 3, 20:30 UTCJul 4, 15:00 UTC18h 30m
2026-07-03 UAL153 HKG → LAX Jul 3, 05:08 UTCJul 3, 17:35 UTC12h 27m
2026-07-03 UAL153 HKG → LAX Jul 3, 05:00 UTCJul 3, 08:15 UTC3h 15m
2026-07-03 UAL153 HKG → LAX Jul 3, 02:30 UTCJul 3, 02:40 UTC10m
2026-07-03 UAL153 HKG → LAX Jul 3, 01:15 UTCJul 3, 01:35 UTC20m

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 N19986 page for operator, model, and routing details .

Mode-S A18D29 frequently asked

What is Mode-S code A18D29?
A18D29 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N19986.
Where is Mode-S A18D29 registered?
Mode-S code A18D29 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 A18D29 broadcasting right now?
Yes. Mode-S A18D29 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A18D29, octal 50306451, decimal 10,587,433.
What flights does A18D29 operate?
Mode-S A18D29 has broadcast 20 distinct callsigns, including UAL181, UAL820, UAL821, UAL153, UAL123.