Apparatus

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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 DAL236 · 39,000 ft
Flights observed
326
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 18:35 UTC

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
DAL143 Delta Air Lines 14 2026-07-24
DAL242 Delta Air Lines 13 2026-06-03
DAL243 Delta Air Lines 11 2026-07-25
DAL240 Delta Air Lines 11 2026-07-25
DAL257 Delta Air Lines 10 2026-06-01
DAL223 Delta Air Lines 10 2026-07-26
DAL162 Delta Air Lines 10 2026-05-29
DAL142 Delta Air Lines 10 2026-07-24
DAL220 - 9 2026-07-17
DAL165 Delta Air Lines 9 2026-07-08
DAL125 Delta Air Lines 9 2026-05-16
DAL57 - 8 2026-07-17
DAL124 Delta Air Lines 8 2026-05-16
DAL81 - 7 2026-07-14
DAL225 - 7 2026-07-18
DAL144 Delta Air Lines 7 2026-06-01
DAL17 Delta Air Lines 6 2026-07-23
DAL16 Delta Air Lines 6 2026-07-22
DAL156 - 6 2026-06-15
DAL137 Delta Air Lines 6 2026-06-07

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 DAL223 ATH → ATL Jul 26, 07:00 UTCJul 26, 10:50 UTC3h 50m
2026-07-26 DAL223 ATH → ATL Jul 26, 07:00 UTCJul 26, 18:25 UTC11h 25m
2026-07-25 DAL240 BOS → ATH Jul 25, 20:05 UTCJul 25, 21:20 UTC1h 15m
2026-07-25 DAL240 BOS → ATH Jul 25, 20:00 UTCJul 26, 04:18 UTC8h 18m
2026-07-25 DAL243 TLV → BOS Jul 25, 09:45 UTCJul 25, 11:25 UTC1h 40m
2026-07-25 DAL243 TLV → BOS Jul 25, 09:44 UTCJul 25, 16:39 UTC6h 55m
2026-07-24 DAL142 SEA → AMS Jul 24, 21:10 UTCJul 25, 06:00 UTC8h 50m
2026-07-24 DAL142 SEA → AMS Jul 24, 21:15 UTCJul 25, 05:30 UTC8h 15m
2026-07-24 DAL143 FRA → DTW Jul 24, 08:37 UTCJul 24, 18:10 UTC9h 33m
2026-07-24 DAL143 FRA → DTW Jul 24, 08:37 UTCJul 24, 18:09 UTC9h 32m
2026-07-24 DAL143 FRA → DTW Jul 24, 08:40 UTCJul 24, 13:30 UTC4h 50m
2026-07-23 DAL134 DTW → AMS Jul 23, 22:40 UTCJul 24, 05:35 UTC6h 55m
2026-07-23 DAL17 LHR → DTW Jul 23, 10:15 UTCJul 23, 11:30 UTC1h 15m
2026-07-23 DAL17 LHR → DTW Jul 23, 10:11 UTCJul 23, 17:52 UTC7h 41m
2026-07-22 DAL16 DTW → LHR Jul 22, 23:05 UTCJul 23, 06:10 UTC7h 5m
2026-07-22 DAL17 - Jul 22, 11:10 UTCJul 22, 17:55 UTC6h 45m
2026-07-21 DAL16 DTW → LHR Jul 21, 23:35 UTCJul 22, 05:25 UTC5h 50m
2026-07-21 DAL135 - Jul 21, 10:20 UTCJul 21, 18:30 UTC8h 10m
2026-07-20 DAL134 DTW → AMS Jul 20, 22:45 UTCJul 21, 06:00 UTC7h 14m
2026-07-20 DAL17 LHR → DTW Jul 20, 10:20 UTCJul 20, 17:50 UTC7h 30m
2026-07-19 DAL16 DTW → LHR Jul 19, 23:05 UTCJul 20, 06:25 UTC7h 20m
2026-07-19 DAL16 DTW → LHR Jul 19, 23:03 UTCJul 20, 06:15 UTC7h 12m
2026-07-19 DAL133 - Jul 19, 07:35 UTCJul 19, 09:15 UTC1h 40m
2026-07-19 DAL133 AMS → DTW Jul 19, 07:34 UTCJul 19, 15:22 UTC7h 48m
2026-07-18 DAL256 BOS → AMS Jul 18, 21:00 UTCJul 19, 03:15 UTC6h 15m
2026-07-18 DAL225 - Jul 18, 10:10 UTCJul 18, 17:00 UTC6h 50m
2026-07-17 DAL220 SLC → CDG Jul 17, 21:44 UTCJul 18, 06:56 UTC9h 12m
2026-07-17 DAL220 - Jul 17, 21:44 UTCJul 18, 07:00 UTC9h 16m
2026-07-17 DAL57 AMS → SLC Jul 17, 09:26 UTCJul 17, 19:12 UTC9h 46m
2026-07-17 DAL57 AMS → SLC Jul 17, 09:26 UTCJul 17, 19:16 UTC9h 50m
2026-07-17 DAL57 - Jul 17, 09:30 UTCJul 17, 11:00 UTC1h 30m
2026-07-16 DAL142 SEA → AMS Jul 16, 21:56 UTCJul 17, 06:52 UTC8h 56m
2026-07-16 DAL142 - Jul 16, 22:00 UTCJul 17, 05:30 UTC7h 30m
2026-07-15 DAL21 - Jul 15, 16:55 UTCJul 16, 02:25 UTC9h 30m
2026-07-15 DAL21 LHR → SEA Jul 15, 16:50 UTCJul 16, 02:22 UTC9h 32m
2026-07-15 DAL20 - Jul 15, 05:05 UTCJul 15, 14:10 UTC9h 5m
2026-07-14 DAL81 CDG → SEA Jul 14, 14:30 UTCJul 15, 00:30 UTC9h 59m
2026-07-14 DAL81 CDG → SEA Jul 14, 14:30 UTCJul 15, 00:25 UTC9h 55m
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

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 DAL143, DAL242, DAL243, DAL240, DAL257.