Apparatus

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sensors Mode-S transponder

ADD66C

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N991AT · BOEING 717-200 · operated by DELTA AIR LINES INC

Hex
ADD66C
Octal
53353154
Decimal
11,392,620
Country
US
Tail
N991AT
Type
B712
No current signal · last broadcast 1d ago
Flights observed
653
Distinct callsigns
20
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S ADD66C.

Country allocation

The ICAO 24-bit address ADD66C 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
DAL2364 Delta Air Lines 10 2026-06-19
DAL3045 - 9 2026-07-10
DAL3096 Delta Air Lines 8 2026-05-27
DAL2681 Delta Air Lines 7 2026-05-15
DAL2577 Delta Air Lines 7 2026-05-24
DAL2232 - 7 2026-06-23
DAL3092 - 6 2026-06-23
DAL3063 - 6 2026-07-07
DAL3010 Delta Air Lines 6 2026-05-16
DAL2481 Delta Air Lines 6 2026-06-11
DAL1704 Delta Air Lines 6 2026-06-08
DAL1618 - 6 2026-07-05
DAL1549 Delta Air Lines 6 2026-06-04
DAL3199 Delta Air Lines 5 2026-05-07
DAL3089 Delta Air Lines 5 2026-06-06
DAL3052 Delta Air Lines 5 2026-06-09
DAL3031 Delta Air Lines 5 2026-05-26
DAL3026 Delta Air Lines 5 2026-05-30
DAL2837 - 5 2026-06-19
DAL2793 Delta Air Lines 5 2026-06-07

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-13 DAL9950 ATL → MLB Jul 13, 02:43 UTCJul 13, 03:51 UTC1h 8m
2026-07-13 DAL9950 ATL → MLB Jul 13, 02:45 UTCJul 13, 03:50 UTC1h 5m
2026-07-12 DAL1186 - Jul 12, 23:45 UTCJul 13, 01:01 UTC1h 15m
2026-07-12 DAL1186 TUL → ATL Jul 12, 23:41 UTCJul 13, 01:15 UTC1h 34m
2026-07-12 DAL1186 ATL → TUL Jul 12, 21:05 UTCJul 12, 22:35 UTC1h 30m
2026-07-12 DAL1085 - Jul 12, 17:45 UTCJul 12, 18:40 UTC55m
2026-07-10 DAL1604 - Jul 10, 23:20 UTCJul 11, 00:20 UTC1h 0m
2026-07-10 DAL3045 ECP → ATL Jul 10, 16:45 UTCJul 10, 17:25 UTC40m
2026-07-10 DAL3045 ECP → ATL Jul 10, 16:42 UTCJul 10, 17:27 UTC45m
2026-07-10 DAL3045 ATL → ECP Jul 10, 14:55 UTCJul 10, 15:40 UTC45m
2026-07-10 DAL2802 - Jul 10, 12:55 UTCJul 10, 13:40 UTC45m
2026-07-10 DAL3002 ATL → BNA Jul 10, 02:17 UTCJul 10, 03:00 UTC43m
2026-07-10 DAL3002 ATL → BNA Jul 10, 02:20 UTCJul 10, 03:00 UTC40m
2026-07-09 DAL1186 - Jul 9, 22:30 UTCJul 10, 00:00 UTC1h 30m
2026-07-09 DAL1186 - Jul 9, 20:00 UTCJul 9, 21:30 UTC1h 30m
2026-07-09 DAL1290 - Jul 9, 16:20 UTCJul 9, 16:45 UTC25m
2026-07-09 DAL1290 - Jul 9, 14:40 UTCJul 9, 15:10 UTC30m
2026-07-09 DAL1160 - Jul 9, 11:00 UTCJul 9, 12:45 UTC1h 45m
2026-07-09 DAL2144 - Jul 9, 01:40 UTCJul 9, 03:20 UTC1h 40m
2026-07-08 DAL1728 MDW → ATL Jul 8, 22:20 UTCJul 8, 23:50 UTC1h 30m
2026-07-08 DAL1728 ATL → MDW Jul 8, 19:25 UTCJul 8, 20:50 UTC1h 25m
2026-07-08 DAL1509 - Jul 8, 15:55 UTCJul 8, 17:30 UTC1h 35m
2026-07-08 DAL1509 - Jul 8, 12:50 UTCJul 8, 14:20 UTC1h 30m
2026-07-08 DAL3030 - Jul 8, 03:45 UTCJul 8, 04:30 UTC45m
2026-07-08 DAL3030 GNV → ATL Jul 8, 03:40 UTCJul 8, 04:28 UTC48m
2026-07-08 DAL3079 - Jul 8, 01:45 UTCJul 8, 02:35 UTC50m
2026-07-07 DAL3063 - Jul 7, 23:25 UTCJul 8, 00:25 UTC1h 0m
2026-07-07 DAL3063 GPT → ATL Jul 7, 23:19 UTCJul 8, 00:34 UTC1h 15m
2026-07-07 DAL3063 - Jul 7, 21:20 UTCJul 7, 22:10 UTC50m
2026-07-07 DAL731 - Jul 7, 18:50 UTCJul 7, 19:55 UTC1h 5m
2026-07-07 DAL731 - Jul 7, 16:20 UTCJul 7, 17:10 UTC50m
2026-07-07 DAL1290 - Jul 7, 14:35 UTCJul 7, 15:05 UTC30m
2026-07-07 DAL1290 ATL → TYS Jul 7, 13:00 UTCJul 7, 13:30 UTC30m
2026-07-07 DAL3140 - Jul 7, 10:15 UTCJul 7, 11:30 UTC1h 15m
2026-07-07 DAL3167 ATL → DAY Jul 7, 03:15 UTCJul 7, 04:10 UTC55m
2026-07-07 DAL3167 ATL → DAY Jul 7, 03:11 UTCJul 7, 04:09 UTC58m
2026-07-07 DAL1093 - Jul 7, 01:20 UTCJul 7, 02:05 UTC45m
2026-07-06 DAL1093 - Jul 6, 23:25 UTCJul 7, 00:05 UTC40m
2026-07-06 DAL3078 - Jul 6, 21:00 UTCJul 6, 22:10 UTC1h 10m
2026-07-06 DAL3078 - Jul 6, 19:05 UTCJul 6, 19:50 UTC45m
2026-07-06 DAL932 - Jul 6, 16:05 UTCJul 6, 16:45 UTC40m
2026-07-06 DAL3054 ATL → SAV Jul 6, 13:50 UTCJul 6, 14:50 UTC1h 0m
2026-07-06 DAL3054 ATL → SAV Jul 6, 13:46 UTCJul 6, 14:34 UTC48m
2026-07-06 DAL1868 - Jul 6, 01:40 UTCJul 6, 02:20 UTC40m
2026-07-05 DAL1868 - Jul 5, 19:45 UTCJul 5, 20:15 UTC30m
2026-07-05 DAL1637 - Jul 5, 16:25 UTCJul 5, 18:20 UTC1h 55m
2026-07-05 DAL1637 - Jul 5, 13:30 UTCJul 5, 15:05 UTC1h 35m
2026-07-05 DAL1618 - Jul 5, 11:25 UTCJul 5, 11:55 UTC30m
2026-07-05 DAL3202 - Jul 5, 00:40 UTCJul 5, 01:05 UTC25m
2026-07-04 DAL3195 SDF → ATL Jul 4, 20:40 UTCJul 4, 21:40 UTC1h 0m

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 N991AT page for operator, model, and routing details .

Mode-S ADD66C frequently asked

What is Mode-S code ADD66C?
ADD66C is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N991AT.
Where is Mode-S ADD66C registered?
Mode-S code ADD66C 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 ADD66C broadcasting right now?
No active broadcast right now. Last signal was 1d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex ADD66C, octal 53353154, decimal 11,392,620.
What flights does ADD66C operate?
Mode-S ADD66C has broadcast 20 distinct callsigns, including DAL2364, DAL3045, DAL3096, DAL2681, DAL2577.