Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

A544EE

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N439DX · AIRBUS A-330-900 · operated by DELTA AIR LINES INC

Hex
A544EE
Octal
51242356
Decimal
10,831,086
Country
US
Tail
N439DX
Type
A339
Broadcasting now · callsign DAL81 · 36,000 ft
Flights observed
288
Distinct callsigns
20
Country
US
Last broadcast
4h ago

Current position

A544EE is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A544EE 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
DAL242 Delta Air Lines 13 2026-06-03
DAL143 Delta Air Lines 11 2026-06-04
DAL257 Delta Air Lines 10 2026-06-01
DAL162 Delta Air Lines 10 2026-05-29
DAL243 - 9 2026-07-04
DAL240 Delta Air Lines 9 2026-07-04
DAL165 Delta Air Lines 9 2026-07-08
DAL125 Delta Air Lines 9 2026-05-16
DAL223 - 8 2026-07-05
DAL124 Delta Air Lines 8 2026-05-16
DAL220 Delta Air Lines 7 2026-06-28
DAL144 Delta Air Lines 7 2026-06-01
DAL225 - 6 2026-06-29
DAL156 - 6 2026-06-15
DAL142 Delta Air Lines 6 2026-07-03
DAL137 Delta Air Lines 6 2026-06-07
DAL81 Delta Air Lines 5 2026-06-26
DAL80 - 5 2026-07-14
DAL57 - 5 2026-06-28
DAL221 - 5 2026-07-07

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 DAL80 - Jul 14, 01:55 UTCJul 14, 11:00 UTC9h 5m
2026-07-13 DAL145 - Jul 13, 13:30 UTCJul 13, 23:20 UTC9h 50m
2026-07-13 DAL164 - Jul 13, 03:05 UTCJul 13, 04:00 UTC55m
2026-07-13 DAL164 MSP → AMS Jul 13, 03:05 UTCJul 13, 10:54 UTC7h 49m
2026-07-12 DAL299 - Jul 12, 13:10 UTCJul 12, 15:30 UTC2h 20m
2026-07-12 DAL299 FCO → MSP Jul 12, 13:09 UTCJul 12, 22:56 UTC9h 47m
2026-07-12 DAL298 - Jul 12, 01:35 UTCJul 12, 10:40 UTC9h 5m
2026-07-11 DAL117 - Jul 11, 12:30 UTCJul 11, 13:30 UTC1h 0m
2026-07-11 DAL117 CPH → MSP Jul 11, 12:25 UTCJul 11, 20:54 UTC8h 29m
2026-07-11 DAL116 MSP → CPH Jul 11, 01:45 UTCJul 11, 09:35 UTC7h 50m
2026-07-10 DAL9 LHR → MSP Jul 10, 13:08 UTCJul 10, 21:06 UTC7h 58m
2026-07-10 DAL9 - Jul 10, 13:10 UTCJul 10, 14:30 UTC1h 20m
2026-07-10 DAL3 JFK → LHR Jul 10, 03:15 UTCJul 10, 09:35 UTC6h 20m
2026-07-09 DAL4 - Jul 9, 15:40 UTCJul 9, 23:00 UTC7h 20m
2026-07-09 DAL4 LHR → JFK Jul 9, 15:39 UTCJul 9, 22:57 UTC7h 18m
2026-07-09 DAL10 MSP → LHR Jul 9, 04:40 UTCJul 9, 12:05 UTC7h 25m
2026-07-08 DAL165 AMS → MSP Jul 8, 13:10 UTCJul 8, 15:50 UTC2h 40m
2026-07-08 DAL165 AMS → MSP Jul 8, 13:05 UTCJul 8, 21:21 UTC8h 16m
2026-07-08 DAL165 AMS → MSP Jul 8, 13:05 UTCJul 8, 21:23 UTC8h 18m
2026-07-07 DAL56 SLC → AMS Jul 7, 22:45 UTCJul 8, 07:45 UTC9h 0m
2026-07-07 DAL221 - Jul 7, 09:35 UTCJul 7, 15:25 UTC5h 50m
2026-07-07 DAL221 CDG → SLC Jul 7, 09:33 UTCJul 7, 19:55 UTC10h 22m
2026-07-06 DAL224 - Jul 6, 23:50 UTCJul 7, 06:10 UTC6h 20m
2026-07-06 DAL63 - Jul 6, 14:10 UTCJul 6, 21:05 UTC6h 55m
2026-07-06 DAL108 - Jul 6, 02:40 UTCJul 6, 11:10 UTC8h 30m
2026-07-05 DAL223 - Jul 5, 16:35 UTCJul 5, 18:20 UTC1h 45m
2026-07-05 DAL223 - Jul 5, 06:55 UTCJul 5, 16:30 UTC9h 35m
2026-07-05 DAL223 ATH → ATL Jul 5, 06:52 UTCJul 5, 18:15 UTC11h 23m
2026-07-04 DAL240 BOS → ATH Jul 4, 19:59 UTCJul 5, 04:20 UTC8h 21m
2026-07-04 DAL240 BOS → ATH Jul 4, 20:00 UTCJul 5, 01:30 UTC5h 30m
2026-07-04 DAL243 AMS → BOS Jul 4, 09:45 UTCJul 4, 17:10 UTC7h 25m
2026-07-03 DAL142 SEA → AMS Jul 3, 21:10 UTCJul 4, 06:25 UTC9h 15m
2026-07-03 DAL903 ATL → SEA Jul 3, 03:10 UTCJul 3, 07:50 UTC4h 40m
2026-07-02 DAL85 - Jul 2, 14:45 UTCJul 2, 16:10 UTC1h 25m
2026-07-02 DAL85 CDG → ATL Jul 2, 14:41 UTCJul 2, 23:40 UTC8h 59m
2026-07-02 DAL84 ATL → CDG Jul 2, 02:10 UTCJul 2, 10:10 UTC8h 0m
2026-07-01 DAL223 ATH → ATL Jul 1, 07:00 UTCJul 1, 18:30 UTC11h 30m
2026-06-30 DAL240 BOS → ATH Jun 30, 19:33 UTCJul 1, 04:00 UTC8h 27m
2026-06-30 DAL240 BOS → ATH Jun 30, 19:35 UTCJul 1, 03:30 UTC7h 55m
2026-06-30 DAL243 - Jun 30, 09:55 UTCJun 30, 11:15 UTC1h 20m
2026-06-30 DAL243 AMS → BOS Jun 30, 09:55 UTCJun 30, 16:50 UTC6h 55m
2026-06-29 DAL256 - Jun 29, 21:14 UTCJun 30, 03:30 UTC6h 16m
2026-06-29 DAL225 - Jun 29, 10:34 UTCJun 29, 17:49 UTC7h 15m
2026-06-28 DAL220 SLC → CDG Jun 28, 21:36 UTCJun 29, 06:39 UTC9h 3m
2026-06-28 DAL220 SLC → CDG Jun 28, 21:40 UTCJun 29, 06:44 UTC9h 5m
2026-06-28 DAL57 - Jun 28, 09:34 UTCJun 28, 10:50 UTC1h 15m
2026-06-28 DAL57 AMS → SLC Jun 28, 09:32 UTCJun 28, 18:49 UTC9h 17m
2026-06-27 DAL142 SEA → AMS Jun 27, 21:34 UTCJun 28, 06:49 UTC9h 15m
2026-06-27 DAL142 SEA → AMS Jun 27, 21:33 UTCJun 28, 06:50 UTC9h 17m
2026-06-26 DAL81 CDG → SEA Jun 26, 15:15 UTCJun 26, 15:29 UTC15m

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 N439DX page for operator, model, and routing details .

Mode-S A544EE frequently asked

What is Mode-S code A544EE?
A544EE is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N439DX.
Where is Mode-S A544EE registered?
Mode-S code A544EE 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 A544EE broadcasting right now?
Yes. Mode-S A544EE is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A544EE, octal 51242356, decimal 10,831,086.
What flights does A544EE operate?
Mode-S A544EE has broadcast 20 distinct callsigns, including DAL242, DAL143, DAL257, DAL162, DAL243.