Apparatus

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sensors Mode-S transponder

A9DCE9

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N73445 · BOEING 737-900 · operated by UNITED AIRLINES INC

Hex
A9DCE9
Octal
52356351
Decimal
11,132,137
Country
US
Tail
N73445
Type
B739
Broadcasting now · callsign UAL700 · 31,000 ft
Flights observed
379
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 22:15 UTC

Current position

A9DCE9 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A9DCE9 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
UAL2741 - 5 2026-06-30
UAL1653 - 5 2026-06-30
UAL1145 - 5 2026-06-30
UAL2163 - 4 2026-07-16
UAL2054 - 4 2026-07-18
UAL1997 - 4 2026-07-19
UAL1554 United Airlines 4 2026-07-22
UAL1516 - 4 2026-07-09
UAL1406 - 4 2026-07-18
UAL1014 - 4 2026-07-10
UAL664 - 3 2026-07-11
UAL651 - 3 2026-07-11
UAL538 - 3 2026-06-15
UAL433 United Airlines 3 2026-07-22
UAL2635 - 3 2026-07-11
UAL254 United Airlines 3 2026-07-20
UAL2322 - 3 2026-07-06
UAL1875 United Airlines 3 2026-05-21
UAL1718 United Airlines 3 2026-04-15
UAL1335 United Airlines 3 2026-04-16

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL2463 ORD → MCO Jul 26, 22:10 UTCJul 26, 22:15 UTC5m
2026-07-26 UAL2169 ORD → SFO Jul 26, 12:50 UTCJul 26, 14:50 UTC2h 0m
2026-07-25 UAL1379 ORD → EWR Jul 25, 22:15 UTCJul 26, 00:20 UTC2h 5m
2026-07-25 UAL2065 MCO → IAD Jul 25, 17:50 UTCJul 25, 19:25 UTC1h 35m
2026-07-25 UAL379 IAD → MCO Jul 25, 13:35 UTCJul 25, 15:15 UTC1h 40m
2026-07-25 UAL1083 EWR → JAX Jul 25, 07:25 UTCJul 25, 12:00 UTC4h 35m
2026-07-25 UAL1575 MSP → EWR Jul 25, 00:00 UTCJul 25, 05:45 UTC5h 45m
2026-07-24 UAL2431 FLL → EWR Jul 24, 16:10 UTCJul 24, 20:55 UTC4h 45m
2026-07-24 UAL717 MFR → SFO Jul 24, 13:00 UTCJul 24, 14:05 UTC1h 5m
2026-07-24 UAL548 BWI → DEN Jul 24, 05:00 UTCJul 24, 06:00 UTC1h 0m
2026-07-24 UAL2681 DEN → SFO Jul 24, 02:40 UTCJul 24, 03:35 UTC55m
2026-07-23 UAL1275 SFO → RNO Jul 23, 19:50 UTCJul 24, 00:10 UTC4h 20m
2026-07-23 UAL1198 LAS → ORD Jul 23, 14:55 UTCJul 23, 18:00 UTC3h 5m
2026-07-23 UAL307 SEA → EWR Jul 23, 11:15 UTCJul 23, 12:00 UTC45m
2026-07-23 UAL2005 DFW → SFO Jul 23, 01:20 UTCJul 23, 02:20 UTC1h 0m
2026-07-22 UAL433 BOS → SFO Jul 22, 21:05 UTCJul 22, 23:10 UTC2h 5m
2026-07-22 UAL1554 SJC → DEN Jul 22, 18:15 UTCJul 22, 19:40 UTC1h 25m
2026-07-22 UAL1733 PDX → SFO Jul 22, 14:25 UTCJul 22, 16:45 UTC2h 20m
2026-07-22 UAL1733 PDX → SFO Jul 22, 14:21 UTCJul 22, 16:23 UTC2h 2m
2026-07-22 UAL2443 MSN → ORD Jul 22, 00:20 UTCJul 22, 02:20 UTC2h 0m
2026-07-21 UAL2179 LGA → ORD Jul 21, 19:15 UTCJul 21, 21:40 UTC2h 25m
2026-07-21 UAL1850 IAH → SFO Jul 21, 15:50 UTCJul 21, 17:35 UTC1h 45m
2026-07-21 UAL656 - Jul 21, 13:05 UTCJul 21, 13:50 UTC45m
2026-07-21 UAL1923 IAH → LGA Jul 21, 03:00 UTCJul 21, 03:35 UTC35m
2026-07-20 UAL254 ORD → BOS Jul 20, 23:55 UTCJul 21, 00:45 UTC50m
2026-07-20 UAL254 ORD → BOS Jul 20, 22:50 UTCJul 20, 23:50 UTC1h 0m
2026-07-20 UAL2454 ORD → LGA Jul 20, 15:40 UTCJul 20, 18:50 UTC3h 10m
2026-07-20 UAL1712 EWR → DFW Jul 20, 11:00 UTCJul 20, 13:55 UTC2h 55m
2026-07-19 UAL1498 IAD → EWR Jul 19, 17:41 UTCJul 19, 19:08 UTC1h 27m
2026-07-19 UAL1498 IAD → EWR Jul 19, 17:45 UTCJul 19, 19:15 UTC1h 30m
2026-07-19 UAL1997 MCO → IAD Jul 19, 01:00 UTCJul 19, 02:40 UTC1h 40m
2026-07-18 UAL1101 IAD → MCO Jul 18, 21:40 UTCJul 18, 23:35 UTC1h 55m
2026-07-18 UAL2054 RSW → IAD Jul 18, 16:20 UTCJul 18, 18:20 UTC2h 0m
2026-07-18 UAL2054 RSW → IAD Jul 18, 16:12 UTCJul 18, 18:20 UTC2h 8m
2026-07-18 UAL1406 IAD → RSW Jul 18, 12:35 UTCJul 18, 14:40 UTC2h 5m
2026-07-18 UAL1997 MCO → IAD Jul 18, 00:55 UTCJul 18, 02:35 UTC1h 40m
2026-07-18 UAL1997 MCO → IAD Jul 18, 00:37 UTCJul 18, 02:41 UTC2h 4m
2026-07-17 UAL1101 IAD → MCO Jul 17, 21:20 UTCJul 17, 23:14 UTC1h 55m
2026-07-17 UAL2054 RSW → IAD Jul 17, 16:59 UTCJul 17, 19:00 UTC2h 0m
2026-07-17 UAL1406 IAD → RSW Jul 17, 13:43 UTCJul 17, 15:33 UTC1h 50m
2026-07-17 UAL1406 - Jul 17, 13:29 UTCJul 17, 14:15 UTC45m
2026-07-17 UAL2129 - Jul 17, 05:55 UTCJul 17, 10:20 UTC4h 25m
2026-07-17 UAL1343 - Jul 17, 02:59 UTCJul 17, 04:14 UTC1h 15m
2026-07-16 UAL2117 - Jul 16, 23:55 UTCJul 17, 01:05 UTC1h 10m
2026-07-16 UAL2163 IAD → SAN Jul 16, 17:31 UTCJul 16, 21:59 UTC4h 28m
2026-07-16 UAL2163 IAD → SAN Jul 16, 17:40 UTCJul 16, 22:05 UTC4h 25m
2026-07-15 UAL1373 - Jul 15, 23:45 UTCJul 16, 02:20 UTC2h 35m
2026-07-15 UAL2492 - Jul 15, 19:30 UTCJul 15, 22:15 UTC2h 45m
2026-07-15 UAL723 ORD → LAS Jul 15, 14:20 UTCJul 15, 17:20 UTC3h 0m
2026-07-15 UAL2672 - Jul 15, 10:40 UTCJul 15, 12:30 UTC1h 50m

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 N73445 page for operator, model, and routing details .

Mode-S A9DCE9 frequently asked

What is Mode-S code A9DCE9?
A9DCE9 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N73445.
Where is Mode-S A9DCE9 registered?
Mode-S code A9DCE9 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 A9DCE9 broadcasting right now?
Yes. Mode-S A9DCE9 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A9DCE9, octal 52356351, decimal 11,132,137.
What flights does A9DCE9 operate?
Mode-S A9DCE9 has broadcast 20 distinct callsigns, including UAL2741, UAL1653, UAL1145, UAL2163, UAL2054.