Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

A4F239

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N418DX · AIRBUS A-330-900 · operated by DELTA AIR LINES INC

Hex
A4F239
Octal
51171071
Decimal
10,809,913
Country
US
Tail
N418DX
Type
A339
Broadcasting now · callsign DAL223 · 40,000 ft
Flights observed
306
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 22:15 UTC

Current position

A4F239 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A4F239 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
DAL145 Delta Air Lines 17 2026-07-23
DAL80 Delta Air Lines 15 2026-07-24
DAL21 Delta Air Lines 15 2026-07-25
DAL56 - 14 2026-07-10
DAL81 Delta Air Lines 13 2026-07-24
DAL20 Delta Air Lines 13 2026-07-25
DAL57 - 11 2026-06-27
DAL142 Delta Air Lines 11 2026-07-26
DAL227 - 9 2026-07-14
DAL163 Delta Air Lines 9 2026-05-23
DAL221 - 8 2026-07-10
DAL164 Delta Air Lines 8 2026-07-23
DAL165 - 7 2026-07-12
DAL220 Delta Air Lines 6 2026-06-27
DAL67 Delta Air Lines 5 2026-06-06
DAL243 - 5 2026-07-09
DAL226 - 5 2026-06-22
DAL225 - 5 2026-06-28
DAL224 - 5 2026-07-09
DAL223 Delta Air Lines 5 2026-06-05

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 DAL142 SEA → AMS Jul 26, 21:15 UTCJul 26, 22:15 UTC1h 0m
2026-07-25 DAL21 LHR → SEA Jul 25, 17:30 UTCJul 25, 20:00 UTC2h 30m
2026-07-25 DAL21 LHR → SEA Jul 25, 17:27 UTCJul 26, 02:51 UTC9h 24m
2026-07-25 DAL20 SEA → LHR Jul 25, 05:20 UTCJul 25, 06:15 UTC55m
2026-07-25 DAL20 SEA → LHR Jul 25, 05:15 UTCJul 25, 13:46 UTC8h 31m
2026-07-24 DAL81 CDG → SEA Jul 24, 14:25 UTCJul 24, 21:15 UTC6h 50m
2026-07-24 DAL81 CDG → SEA Jul 24, 14:22 UTCJul 25, 00:05 UTC9h 43m
2026-07-24 DAL80 SEA → CDG Jul 24, 01:51 UTCJul 24, 11:12 UTC9h 21m
2026-07-24 DAL80 SEA → CDG Jul 24, 01:55 UTCJul 24, 05:20 UTC3h 25m
2026-07-23 DAL145 AMS → SEA Jul 23, 13:30 UTCJul 23, 23:05 UTC9h 35m
2026-07-23 DAL145 AMS → SEA Jul 23, 13:27 UTCJul 23, 22:57 UTC9h 30m
2026-07-23 DAL164 MSP → AMS Jul 23, 03:00 UTCJul 23, 10:50 UTC7h 50m
2026-07-22 DAL299 JFK → SFO Jul 22, 13:05 UTCJul 22, 14:15 UTC1h 10m
2026-07-22 DAL299 JFK → SFO Jul 22, 13:01 UTCJul 22, 23:07 UTC10h 6m
2026-07-22 DAL298 JFK → LOS Jul 22, 01:35 UTCJul 22, 02:55 UTC1h 20m
2026-07-22 DAL298 JFK → LOS Jul 22, 01:32 UTCJul 22, 10:38 UTC9h 6m
2026-07-21 DAL9 LHR → ATL Jul 21, 12:30 UTCJul 21, 20:40 UTC8h 10m
2026-07-21 DAL3 JFK → LHR Jul 21, 03:35 UTCJul 21, 09:49 UTC6h 14m
2026-07-21 DAL3 JFK → LHR Jul 21, 03:35 UTCJul 21, 05:20 UTC1h 45m
2026-07-20 DAL213 ATH → JFK Jul 20, 13:54 UTCJul 21, 00:01 UTC10h 7m
2026-07-20 DAL213 - Jul 20, 13:55 UTCJul 20, 18:00 UTC4h 5m
2026-07-20 DAL212 JFK → ATH Jul 20, 02:30 UTCJul 20, 11:30 UTC9h 0m
2026-07-20 DAL212 JFK → ATH Jul 20, 02:30 UTCJul 20, 11:30 UTC9h 0m
2026-07-19 DAL939A IAD → JFK Jul 19, 20:30 UTCJul 19, 21:15 UTC45m
2026-07-18 DAL939 - Jul 18, 18:55 UTCJul 19, 00:40 UTC5h 45m
2026-07-18 DAL713 JFK → LAX Jul 18, 11:30 UTCJul 18, 16:30 UTC5h 0m
2026-07-17 DAL972 BDL → ATL Jul 17, 20:55 UTCJul 18, 02:00 UTC5h 5m
2026-07-17 DAL972 BDL → ATL Jul 17, 20:52 UTCJul 18, 01:41 UTC4h 49m
2026-07-17 DAL742 JFK → LAX Jul 17, 14:10 UTCJul 17, 19:00 UTC4h 50m
2026-07-17 DAL742 JFK → LAX Jul 17, 14:06 UTCJul 17, 19:14 UTC5h 8m
2026-07-16 DAL972 BDL → ATL Jul 16, 21:15 UTCJul 17, 02:15 UTC5h 0m
2026-07-16 DAL972 BDL → ATL Jul 16, 21:13 UTCJul 17, 02:13 UTC5h 0m
2026-07-16 DAL742 JFK → LAX Jul 16, 11:40 UTCJul 16, 16:30 UTC4h 50m
2026-07-15 DAL9888 - Jul 15, 18:25 UTCJul 16, 03:50 UTC9h 25m
2026-07-14 DAL227 - Jul 14, 03:00 UTCJul 14, 11:20 UTC8h 20m
2026-07-14 DAL227 - Jul 14, 02:25 UTCJul 14, 02:55 UTC30m
2026-07-14 DAL227 JFK → GRU Jul 14, 02:23 UTCJul 14, 11:14 UTC8h 51m
2026-07-13 DAL4 - Jul 13, 16:25 UTCJul 13, 23:25 UTC7h 0m
2026-07-13 DAL4 LHR → JFK Jul 13, 16:22 UTCJul 13, 23:19 UTC6h 57m
2026-07-13 DAL10 MSP → LHR Jul 13, 04:17 UTCJul 13, 11:57 UTC7h 40m
2026-07-13 DAL10 - Jul 13, 04:20 UTCJul 13, 06:05 UTC1h 45m
2026-07-12 DAL165 - Jul 12, 12:55 UTCJul 12, 14:15 UTC1h 20m
2026-07-12 DAL165 AMS → MSP Jul 12, 12:54 UTCJul 12, 21:09 UTC8h 15m
2026-07-12 DAL136 - Jul 12, 02:45 UTCJul 12, 10:05 UTC7h 20m
2026-07-12 DAL136 DTW → AMS Jul 12, 02:42 UTCJul 12, 10:09 UTC7h 27m
2026-07-11 DAL137 - Jul 11, 13:00 UTCJul 11, 20:55 UTC7h 55m
2026-07-10 DAL56 SLC → AMS Jul 10, 22:55 UTCJul 11, 08:05 UTC9h 10m
2026-07-10 DAL221 - Jul 10, 09:30 UTCJul 10, 10:15 UTC45m
2026-07-10 DAL221 CDG → SLC Jul 10, 09:29 UTCJul 10, 19:31 UTC10h 2m
2026-07-09 DAL224 - Jul 9, 23:30 UTCJul 10, 05:50 UTC6h 20m

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 N418DX page for operator, model, and routing details .

Mode-S A4F239 frequently asked

What is Mode-S code A4F239?
A4F239 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N418DX.
Where is Mode-S A4F239 registered?
Mode-S code A4F239 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 A4F239 broadcasting right now?
Yes. Mode-S A4F239 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A4F239, octal 51171071, decimal 10,809,913.
What flights does A4F239 operate?
Mode-S A4F239 has broadcast 20 distinct callsigns, including DAL145, DAL80, DAL21, DAL56, DAL81.