Apparatus

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sensors Mode-S transponder

A71AAD

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N557NW · BOEING 757-200 · operated by DELTA AIR LINES INC

Hex
A71AAD
Octal
51615255
Decimal
10,951,341
Country
US
Tail
N557NW
Type
B752
Broadcasting now · callsign DAL498 · 37,000 ft
Flights observed
473
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 21:15 UTC

Current position

A71AAD is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A71AAD 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
DAL391 - 15 2026-07-13
DAL1902 Delta Air Lines 12 2026-06-09
DAL755 - 9 2026-07-15
DAL348 Delta Air Lines 9 2026-07-21
DAL955 - 8 2026-07-16
DAL502 - 8 2026-07-20
DAL929 - 7 2026-07-21
DAL2076 Delta Air Lines 7 2026-05-22
DAL1336 - 7 2026-07-05
DAL1150 Delta Air Lines 7 2026-05-27
DAL777 Delta Air Lines 6 2026-07-23
DAL689 - 6 2026-07-06
DAL1089 - 6 2026-06-29
DAL1070 Delta Air Lines 6 2026-05-21
DAL824 Delta Air Lines 5 2026-06-03
DAL748 Delta Air Lines 5 2026-06-26
DAL570 Delta Air Lines 5 2026-05-27
DAL423 Delta Air Lines 5 2026-05-04
DAL377 Delta Air Lines 5 2026-07-26
DAL366 - 5 2026-06-27

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 DAL555 LAS → ATL Jul 26, 21:10 UTCJul 26, 21:15 UTC5m
2026-07-26 DAL555 LAS → ATL Jul 26, 14:05 UTCJul 26, 19:30 UTC5h 25m
2026-07-26 DAL377 JFK → SFO Jul 26, 06:35 UTCJul 26, 11:20 UTC4h 45m
2026-07-25 DAL377 JFK → SFO Jul 25, 23:30 UTCJul 26, 04:50 UTC5h 20m
2026-07-25 DAL2272 SFO → LAX Jul 25, 19:20 UTCJul 25, 22:00 UTC2h 40m
2026-07-25 DAL2272 SFO → LAX Jul 25, 19:16 UTCJul 25, 21:59 UTC2h 43m
2026-07-25 DAL497 JFK → LAX Jul 25, 12:45 UTCJul 25, 17:50 UTC5h 5m
2026-07-25 DAL2614 ORD → LGA Jul 25, 01:20 UTCJul 25, 03:40 UTC2h 20m
2026-07-25 DAL2614 ORD → LGA Jul 25, 01:20 UTCJul 25, 03:30 UTC2h 10m
2026-07-24 DAL2272 SFO → LAX Jul 24, 19:50 UTCJul 24, 22:25 UTC2h 35m
2026-07-24 DAL497 JFK → LAX Jul 24, 12:10 UTCJul 24, 17:15 UTC5h 5m
2026-07-23 DAL430 JFK → LAS Jul 23, 18:10 UTCJul 23, 22:45 UTC4h 35m
2026-07-23 DAL777 BOS → ORD Jul 23, 12:45 UTCJul 23, 16:15 UTC3h 30m
2026-07-22 DAL2345 - Jul 22, 22:50 UTCJul 23, 00:15 UTC1h 25m
2026-07-22 DAL2345 ATL → FLL Jul 22, 19:45 UTCJul 22, 21:10 UTC1h 25m
2026-07-22 DAL317 - Jul 22, 15:05 UTCJul 22, 17:55 UTC2h 50m
2026-07-21 DAL317 - Jul 21, 23:20 UTCJul 22, 17:55 UTC18h 35m
2026-07-21 DAL315 JFK → SLC Jul 21, 22:32 UTCJul 22, 01:50 UTC3h 18m
2026-07-21 DAL315 JFK → SLC Jul 21, 22:35 UTCJul 22, 01:30 UTC2h 55m
2026-07-21 DAL348 PHX → ATL Jul 21, 17:35 UTCJul 21, 20:55 UTC3h 20m
2026-07-21 DAL348 PHX → ATL Jul 21, 12:25 UTCJul 21, 15:40 UTC3h 15m
2026-07-21 DAL929 PHX → ATL Jul 21, 07:05 UTCJul 21, 10:20 UTC3h 15m
2026-07-21 DAL842 PBI → LGA Jul 21, 02:10 UTCJul 21, 05:40 UTC3h 30m
2026-07-20 DAL466 LAS → ATL Jul 20, 20:30 UTCJul 21, 00:15 UTC3h 44m
2026-07-20 DAL466 ATL → LAS Jul 20, 15:25 UTCJul 20, 18:55 UTC3h 30m
2026-07-20 DAL965 DTW → ATL Jul 20, 11:35 UTCJul 20, 13:00 UTC1h 25m
2026-07-20 DAL502 LAS → DTW Jul 20, 06:30 UTCJul 20, 10:10 UTC3h 40m
2026-07-20 DAL502 LAS → DTW Jul 20, 06:30 UTCJul 20, 09:57 UTC3h 27m
2026-07-20 DAL916 - Jul 20, 01:15 UTCJul 20, 04:50 UTC3h 35m
2026-07-19 DAL492 LGA → ATL Jul 19, 19:05 UTCJul 19, 23:05 UTC4h 0m
2026-07-19 DAL492 LGA → ATL Jul 19, 13:15 UTCJul 19, 17:05 UTC3h 50m
2026-07-18 DAL334 - Jul 18, 18:50 UTCJul 18, 22:25 UTC3h 35m
2026-07-18 DAL497 BOS → LAS Jul 18, 12:10 UTCJul 18, 17:20 UTC5h 10m
2026-07-17 DAL430 LAS → BOS Jul 17, 18:10 UTCJul 17, 22:49 UTC4h 40m
2026-07-17 DAL607 JFK → LAS Jul 17, 11:15 UTCJul 17, 15:49 UTC4h 35m
2026-07-16 DAL624 - Jul 16, 20:49 UTCJul 17, 01:29 UTC4h 40m
2026-07-16 DAL625 JFK → MEX Jul 16, 14:05 UTCJul 16, 18:19 UTC4h 15m
2026-07-16 DAL498 LAS → JFK Jul 16, 06:45 UTCJul 16, 11:15 UTC4h 30m
2026-07-16 DAL498 LAS → JFK Jul 16, 06:44 UTCJul 16, 11:11 UTC4h 27m
2026-07-16 DAL955 ATL → LAS Jul 16, 01:30 UTCJul 16, 05:15 UTC3h 45m
2026-07-15 DAL1101 ORF → ATL Jul 15, 22:45 UTCJul 16, 00:00 UTC1h 15m
2026-07-15 DAL1101 ATL → ORF Jul 15, 19:30 UTCJul 15, 20:50 UTC1h 20m
2026-07-15 DAL755 LAS → ATL Jul 15, 13:15 UTCJul 15, 16:55 UTC3h 40m
2026-07-15 DAL755 LAS → ATL Jul 15, 13:14 UTCJul 15, 16:51 UTC3h 37m
2026-07-15 DAL825 ATL → LAS Jul 15, 02:05 UTCJul 15, 05:40 UTC3h 35m
2026-07-15 DAL825 ATL → LAS Jul 15, 02:02 UTCJul 15, 05:34 UTC3h 32m
2026-07-14 DAL1101 ORF → ATL Jul 14, 23:00 UTCJul 15, 00:20 UTC1h 20m
2026-07-14 DAL1101 ATL → ORF Jul 14, 20:30 UTCJul 14, 21:35 UTC1h 5m
2026-07-14 DAL1726 TPA → ATL Jul 14, 10:25 UTCJul 14, 11:30 UTC1h 5m
2026-07-14 DAL1560 ATL → TPA Jul 14, 03:30 UTCJul 14, 04:35 UTC1h 5m

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 N557NW page for operator, model, and routing details .

Mode-S A71AAD frequently asked

What is Mode-S code A71AAD?
A71AAD is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N557NW.
Where is Mode-S A71AAD registered?
Mode-S code A71AAD 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 A71AAD broadcasting right now?
Yes. Mode-S A71AAD is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A71AAD, octal 51615255, decimal 10,951,341.
What flights does A71AAD operate?
Mode-S A71AAD has broadcast 20 distinct callsigns, including DAL391, DAL1902, DAL755, DAL348, DAL955.