Apparatus

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sensors Mode-S transponder

A9DC5E

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N73406 · BOEING 737-900 · operated by UNITED AIRLINES INC

Hex
A9DC5E
Octal
52356136
Decimal
11,131,998
Country
US
Tail
N73406
Type
B739
No current signal · last broadcast Jul 26, 21:25 UTC
Flights observed
439
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 21:25 UTC

Last known position

Most recent position reported by Mode-S A9DC5E.

Country allocation

The ICAO 24-bit address A9DC5E 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
UAL1936 United Airlines 12 2026-07-01
UAL1563 - 12 2026-07-01
UAL2662 United Airlines 10 2026-06-26
UAL2304 United Airlines 10 2026-07-24
UAL1927 United Airlines 10 2026-07-26
UAL1872 - 10 2026-07-04
UAL1571 United Airlines 10 2026-05-19
UAL1361 United Airlines 10 2026-07-23
UAL2833 United Airlines 9 2026-07-23
UAL1752 - 9 2026-07-16
UAL1127 United Airlines 9 2026-07-24
UAL1898 United Airlines 8 2026-07-25
UAL1795 United Airlines 8 2026-07-25
UAL1345 - 8 2026-07-16
UAL740 United Airlines 7 2026-07-26
UAL2406 United Airlines 7 2026-07-25
UAL2310 United Airlines 7 2026-07-25
UAL1950 - 7 2026-07-15
UAL1687 United Airlines 7 2026-05-26
UAL468 United Airlines 6 2026-05-19

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL1927 ORD → EWR Jul 26, 20:10 UTCJul 26, 21:25 UTC1h 15m
2026-07-26 UAL740 SEA → DEN Jul 26, 14:50 UTCJul 26, 18:30 UTC3h 40m
2026-07-26 UAL2399 MCO → IAH Jul 26, 11:30 UTCJul 26, 13:15 UTC1h 45m
2026-07-25 UAL2846 ORD → ABQ Jul 25, 22:15 UTCJul 26, 00:05 UTC1h 50m
2026-07-25 UAL2406 LAX → SFO Jul 25, 18:20 UTCJul 25, 20:05 UTC1h 45m
2026-07-25 UAL2310 MIA → EWR Jul 25, 15:00 UTCJul 25, 16:55 UTC1h 55m
2026-07-25 UAL2310 MIA → EWR Jul 25, 15:04 UTCJul 25, 16:55 UTC1h 51m
2026-07-25 UAL1898 DEN → ORD Jul 25, 10:15 UTCJul 25, 12:45 UTC2h 30m
2026-07-25 UAL1898 DEN → ORD Jul 25, 10:12 UTCJul 25, 12:44 UTC2h 32m
2026-07-25 UAL1795 DEN → CLE Jul 25, 00:10 UTCJul 25, 02:45 UTC2h 35m
2026-07-24 UAL2237 ORD → EWR Jul 24, 19:15 UTCJul 24, 22:05 UTC2h 50m
2026-07-24 UAL2491 SFO → DEN Jul 24, 15:00 UTCJul 24, 17:35 UTC2h 35m
2026-07-24 UAL2491 SFO → DEN Jul 24, 15:00 UTCJul 24, 17:34 UTC2h 34m
2026-07-24 UAL1127 ORD → SFO Jul 24, 12:30 UTCJul 24, 13:40 UTC1h 10m
2026-07-24 UAL2304 SFO → PSP Jul 24, 01:40 UTCJul 24, 02:40 UTC1h 0m
2026-07-24 UAL2304 SFO → PSP Jul 24, 01:32 UTCJul 24, 02:35 UTC1h 3m
2026-07-23 UAL2833 EWR → IAH Jul 23, 21:45 UTCJul 23, 23:55 UTC2h 10m
2026-07-23 UAL1361 SNA → IAH Jul 23, 17:30 UTCJul 23, 19:40 UTC2h 10m
2026-07-23 UAL2863 SFO → DTW Jul 23, 12:25 UTCJul 23, 15:50 UTC3h 25m
2026-07-23 UAL1148 DEN → BOS Jul 23, 02:15 UTCJul 23, 05:35 UTC3h 20m
2026-07-22 UAL1927 ORD → EWR Jul 22, 20:35 UTCJul 23, 00:35 UTC4h 0m
2026-07-22 UAL1927 ORD → EWR Jul 22, 20:12 UTCJul 23, 00:31 UTC4h 19m
2026-07-22 UAL740 SEA → DEN Jul 22, 14:45 UTCJul 22, 18:25 UTC3h 40m
2026-07-22 UAL1859 IAD → BTV Jul 22, 11:10 UTCJul 22, 12:55 UTC1h 45m
2026-07-22 UAL1591 - Jul 22, 01:10 UTCJul 22, 03:35 UTC2h 25m
2026-07-21 UAL2833 EWR → IAH Jul 21, 21:10 UTCJul 21, 23:15 UTC2h 5m
2026-07-21 UAL2833 EWR → IAH Jul 21, 21:20 UTCJul 21, 23:17 UTC1h 57m
2026-07-21 UAL1361 SNA → IAH Jul 21, 17:35 UTCJul 21, 19:45 UTC2h 10m
2026-07-21 UAL2863 - Jul 21, 12:25 UTCJul 21, 15:50 UTC3h 25m
2026-07-21 UAL1148 DEN → BOS Jul 21, 01:55 UTCJul 21, 05:10 UTC3h 15m
2026-07-20 UAL1444 SFO → IAH Jul 20, 21:10 UTCJul 20, 23:30 UTC2h 20m
2026-07-20 UAL315 FLL → IAD Jul 20, 17:10 UTCJul 20, 19:35 UTC2h 25m
2026-07-20 UAL1318 EWR → MSY Jul 20, 13:20 UTCJul 20, 15:35 UTC2h 15m
2026-07-20 UAL2432 SFO → LAS Jul 20, 03:25 UTCJul 20, 05:40 UTC2h 15m
2026-07-20 UAL2432 SFO → LAS Jul 20, 03:32 UTCJul 20, 05:33 UTC2h 1m
2026-07-20 UAL2215 FLL → EWR Jul 20, 00:20 UTCJul 20, 02:10 UTC1h 50m
2026-07-19 UAL496 EWR → SFO Jul 19, 19:55 UTCJul 19, 22:00 UTC2h 5m
2026-07-19 UAL1493 IAH → DEN Jul 19, 16:25 UTCJul 19, 18:15 UTC1h 50m
2026-07-19 UAL2245 - Jul 19, 12:40 UTCJul 19, 14:40 UTC2h 0m
2026-07-19 UAL2245 IAH → MCO Jul 19, 12:39 UTCJul 19, 14:36 UTC1h 57m
2026-07-18 UAL2474 - Jul 18, 23:50 UTCJul 19, 01:55 UTC2h 5m
2026-07-18 UAL462 EWR → PBI Jul 18, 19:45 UTCJul 18, 21:45 UTC2h 0m
2026-07-18 UAL2253 - Jul 18, 17:00 UTCJul 18, 17:40 UTC40m
2026-07-18 UAL575 BOS → ORD Jul 18, 14:50 UTCJul 18, 15:40 UTC50m
2026-07-18 UAL1898 - Jul 18, 10:25 UTCJul 18, 12:55 UTC2h 30m
2026-07-18 UAL1795 - Jul 18, 00:00 UTCJul 18, 02:40 UTC2h 40m
2026-07-17 UAL2457 RTB → IAH Jul 17, 18:40 UTCJul 17, 21:04 UTC2h 24m
2026-07-17 UAL2457 - Jul 17, 15:00 UTCJul 17, 21:10 UTC6h 10m
2026-07-17 UAL1127 ORD → SFO Jul 17, 12:25 UTCJul 17, 13:29 UTC1h 5m
2026-07-17 UAL2304 - Jul 17, 02:25 UTCJul 17, 03:25 UTC1h 0m

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 N73406 page for operator, model, and routing details .

Mode-S A9DC5E frequently asked

What is Mode-S code A9DC5E?
A9DC5E is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N73406.
Where is Mode-S A9DC5E registered?
Mode-S code A9DC5E 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 A9DC5E broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 21:25 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A9DC5E, octal 52356136, decimal 11,131,998.
What flights does A9DC5E operate?
Mode-S A9DC5E has broadcast 20 distinct callsigns, including UAL1936, UAL1563, UAL2662, UAL2304, UAL1927.