Apparatus

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sensors Mode-S transponder

A609D4

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N4888U · AIRBUS A-319 · operated by BANK OF UTAH TRUSTEE

Hex
A609D4
Octal
51404724
Decimal
10,881,492
Country
US
Tail
N4888U
Type
A319
No current signal · last broadcast Jul 26, 21:25 UTC
Flights observed
496
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 21:25 UTC

Last known position

Most recent position reported by Mode-S A609D4.

Country allocation

The ICAO 24-bit address A609D4 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
UAL1818 United Airlines 9 2026-04-17
UAL2476 United Airlines 8 2026-04-17
UAL1856 - 7 2026-06-25
UAL425 - 6 2026-07-17
UAL581 - 5 2026-06-24
UAL2808 - 5 2026-06-25
UAL1813 - 5 2026-06-22
UAL1608 - 5 2026-06-27
UAL1030 United Airlines 5 2026-07-17
UAL481 United Airlines 4 2026-06-07
UAL2343 United Airlines 4 2026-06-20
UAL1451 - 4 2026-07-13
UAL1410 - 4 2026-06-24
UAL1371 United Airlines 4 2026-05-15
UAL1317 United Airlines 4 2026-06-07
UAL1025 - 4 2026-07-17
UAL693 United Airlines 3 2026-05-17
UAL676 - 3 2026-06-30
UAL657 - 3 2026-06-14
UAL622 United Airlines 3 2026-05-06

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL1531 ORD → CMH Jul 26, 20:30 UTCJul 26, 21:25 UTC55m
2026-07-26 UAL283 DFW → EWR Jul 26, 16:10 UTCJul 26, 19:10 UTC3h 0m
2026-07-26 UAL717 MFR → SFO Jul 26, 13:15 UTCJul 26, 14:20 UTC1h 5m
2026-07-26 UAL548 BWI → DEN Jul 26, 06:05 UTCJul 26, 06:15 UTC10m
2026-07-26 UAL548 BWI → DEN Jul 26, 05:12 UTCJul 26, 05:49 UTC37m
2026-07-26 UAL548 BWI → DEN Jul 26, 05:05 UTCJul 26, 06:15 UTC1h 10m
2026-07-26 UAL1508 IAD → EWR Jul 26, 03:00 UTCJul 26, 03:50 UTC50m
2026-07-25 UAL2764 IAD → EWR Jul 25, 23:41 UTCJul 26, 00:19 UTC38m
2026-07-25 UAL2764 IAD → EWR Jul 25, 23:25 UTCJul 26, 00:25 UTC1h 0m
2026-07-25 UAL1453 SJD → IAH Jul 25, 21:30 UTCJul 25, 22:25 UTC55m
2026-07-25 UAL2154 ORD → TPA Jul 25, 17:35 UTCJul 25, 19:35 UTC2h 0m
2026-07-25 UAL1045 DEN → IAD Jul 25, 14:00 UTCJul 25, 15:35 UTC1h 35m
2026-07-25 UAL1351 FLL → EWR Jul 25, 00:25 UTCJul 25, 01:40 UTC1h 15m
2026-07-24 UAL2671 IAD → SAT Jul 24, 20:40 UTCJul 24, 22:30 UTC1h 50m
2026-07-24 UAL1188 RDM → DEN Jul 24, 17:52 UTCJul 24, 19:13 UTC1h 21m
2026-07-24 UAL1188 RDM → DEN Jul 24, 17:45 UTCJul 24, 19:15 UTC1h 30m
2026-07-24 UAL1235 DEN → DFW Jul 24, 13:10 UTCJul 24, 15:40 UTC2h 30m
2026-07-24 UAL1235 DEN → DFW Jul 24, 13:18 UTCJul 24, 15:33 UTC2h 15m
2026-07-24 UAL1228 CVG → ORD Jul 24, 00:30 UTCJul 24, 02:35 UTC2h 5m
2026-07-23 UAL498 PDX → EWR Jul 23, 20:35 UTCJul 23, 22:35 UTC2h 0m
2026-07-23 UAL1112 BOS → DEN Jul 23, 17:20 UTCJul 23, 19:05 UTC1h 45m
2026-07-23 UAL1376 RDU → EWR Jul 23, 13:10 UTCJul 23, 15:25 UTC2h 15m
2026-07-23 UAL1541 IAH → LGA Jul 23, 04:37 UTCJul 23, 06:40 UTC2h 3m
2026-07-23 UAL1541 IAH → LGA Jul 23, 04:25 UTCJul 23, 06:45 UTC2h 20m
2026-07-22 UAL2128 SLC → SFO Jul 22, 18:10 UTCJul 23, 03:00 UTC8h 50m
2026-07-22 UAL1610 ORD → LGA Jul 22, 14:20 UTCJul 22, 15:55 UTC1h 35m
2026-07-22 UAL8142 DFW → YYZ Jul 22, 00:40 UTCJul 22, 02:00 UTC1h 20m
2026-07-21 UAL1510 - Jul 21, 20:10 UTCJul 21, 22:30 UTC2h 20m
2026-07-21 UAL1479 - Jul 21, 16:10 UTCJul 21, 18:15 UTC2h 5m
2026-07-21 UAL340 SFO → DEN Jul 21, 11:40 UTCJul 21, 14:20 UTC2h 40m
2026-07-21 UAL1305 EWR → RDU Jul 21, 00:45 UTCJul 21, 03:10 UTC2h 25m
2026-07-20 UAL1728 SFO → IAH Jul 20, 21:20 UTCJul 20, 22:25 UTC1h 5m
2026-07-20 UAL792 LAX → EWR Jul 20, 18:30 UTCJul 20, 19:40 UTC1h 10m
2026-07-19 UAL1376 MSY → DEN Jul 19, 15:25 UTCJul 19, 17:35 UTC2h 10m
2026-07-19 UAL2140 SFO → IAH Jul 19, 02:35 UTCJul 19, 03:25 UTC50m
2026-07-19 UAL404 - Jul 19, 00:30 UTCJul 19, 01:05 UTC35m
2026-07-18 UAL515 EWR → SAT Jul 18, 20:10 UTCJul 18, 23:40 UTC3h 30m
2026-07-18 UAL2233 SNA → EWR Jul 18, 11:35 UTCJul 18, 15:10 UTC3h 35m
2026-07-18 UAL2233 SNA → EWR Jul 18, 11:39 UTCJul 18, 15:07 UTC3h 28m
2026-07-18 UAL2198 - Jul 18, 02:55 UTCJul 18, 03:30 UTC35m
2026-07-17 UAL1025 - Jul 17, 23:05 UTCJul 18, 00:50 UTC1h 45m
2026-07-17 UAL1025 MEX → IAH Jul 17, 22:58 UTCJul 18, 00:48 UTC1h 50m
2026-07-17 UAL1090 - Jul 17, 19:30 UTCJul 17, 21:20 UTC1h 50m
2026-07-17 UAL425 - Jul 17, 15:49 UTCJul 17, 17:25 UTC1h 35m
2026-07-17 UAL425 ATL → IAH Jul 17, 15:55 UTCJul 17, 17:25 UTC1h 30m
2026-07-17 UAL1030 SAT → EWR Jul 17, 12:35 UTCJul 17, 14:15 UTC1h 40m
2026-07-16 UAL2376 - Jul 16, 23:44 UTCJul 17, 01:20 UTC1h 35m
2026-07-16 UAL1211 - Jul 16, 19:55 UTCJul 16, 21:35 UTC1h 40m
2026-07-16 UAL1211 IAH → ATL Jul 16, 20:00 UTCJul 16, 21:31 UTC1h 31m
2026-07-16 UAL2190 - Jul 16, 15:10 UTCJul 16, 17:49 UTC2h 40m

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 N4888U page for operator, model, and routing details .

Mode-S A609D4 frequently asked

What is Mode-S code A609D4?
A609D4 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N4888U.
Where is Mode-S A609D4 registered?
Mode-S code A609D4 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 A609D4 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 A609D4, octal 51404724, decimal 10,881,492.
What flights does A609D4 operate?
Mode-S A609D4 has broadcast 20 distinct callsigns, including UAL1818, UAL2476, UAL1856, UAL425, UAL581.