Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

AC491D

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N891AT · BOEING 717-200 · operated by DELTA AIR LINES INC

Hex
AC491D
Octal
53044435
Decimal
11,290,909
Country
US
Tail
N891AT
Type
B712
No current signal · last broadcast Jul 26, 21:15 UTC
Flights observed
629
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 21:15 UTC

Last known position

Most recent position reported by Mode-S AC491D.

Country allocation

The ICAO 24-bit address AC491D 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
DAL3173 Delta Air Lines 12 2026-07-26
DAL3108 Delta Air Lines 9 2026-07-23
DAL1186 Delta Air Lines 9 2026-07-19
DAL1182 - 9 2026-07-15
DAL3193 Delta Air Lines 7 2026-06-03
DAL3083 - 7 2026-07-04
DAL3077 Delta Air Lines 7 2026-07-20
DAL3051 Delta Air Lines 7 2026-06-05
DAL2944 Delta Air Lines 7 2026-07-24
DAL2780 Delta Air Lines 7 2026-07-26
DAL2467 Delta Air Lines 7 2026-06-09
DAL1021 - 7 2026-06-19
DAL441 - 6 2026-06-24
DAL3096 - 6 2026-07-18
DAL2681 - 6 2026-07-10
DAL1289 - 6 2026-07-08
DAL3180 - 5 2026-07-18
DAL3117 Delta Air Lines 5 2026-07-23
DAL3095 Delta Air Lines 5 2026-06-04
DAL3078 Delta Air Lines 5 2026-04-26

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 DAL2780 LGA → MIA Jul 26, 20:55 UTCJul 26, 21:15 UTC20m
2026-07-26 DAL1347 TPA → LGA Jul 26, 18:40 UTCJul 26, 19:45 UTC1h 5m
2026-07-26 DAL1347 TPA → LGA Jul 26, 16:35 UTCJul 26, 17:30 UTC55m
2026-07-26 DAL3173 ATL → GSO Jul 26, 14:40 UTCJul 26, 15:30 UTC50m
2026-07-26 DAL3173 ATL → GSO Jul 26, 12:30 UTCJul 26, 13:25 UTC55m
2026-07-26 DAL1393 LAX → SEA Jul 26, 03:45 UTCJul 26, 04:55 UTC1h 10m
2026-07-26 DAL1393 LAX → SEA Jul 26, 01:40 UTCJul 26, 02:50 UTC1h 10m
2026-07-25 DAL880 SLC → MSO Jul 25, 22:35 UTCJul 25, 23:50 UTC1h 15m
2026-07-25 DAL880 SLC → MSO Jul 25, 19:50 UTCJul 25, 21:10 UTC1h 20m
2026-07-25 DAL1704 DTW → FLL Jul 25, 16:50 UTCJul 25, 18:30 UTC1h 40m
2026-07-25 DAL1704 DTW → FLL Jul 25, 16:48 UTCJul 25, 18:25 UTC1h 37m
2026-07-25 DAL1704 DTW → FLL Jul 25, 13:50 UTCJul 25, 15:45 UTC1h 55m
2026-07-25 DAL1255 TPA → SLC Jul 25, 10:50 UTCJul 25, 12:20 UTC1h 30m
2026-07-25 DAL1283 YWG → MSP Jul 25, 02:10 UTCJul 25, 03:35 UTC1h 25m
2026-07-25 DAL1283 YWG → MSP Jul 25, 02:08 UTCJul 25, 03:30 UTC1h 22m
2026-07-24 DAL2857 MSP → ORD Jul 24, 23:35 UTCJul 25, 01:00 UTC1h 25m
2026-07-24 DAL2857 MSP → ORD Jul 24, 23:30 UTCJul 25, 00:57 UTC1h 27m
2026-07-24 DAL2857 MSP → ORD Jul 24, 20:45 UTCJul 24, 22:30 UTC1h 45m
2026-07-24 DAL2944 SAV → MSP Jul 24, 18:05 UTCJul 24, 18:50 UTC45m
2026-07-24 DAL2944 SAV → MSP Jul 24, 18:03 UTCJul 24, 18:51 UTC48m
2026-07-24 DAL2944 SAV → MSP Jul 24, 16:20 UTCJul 24, 16:55 UTC35m
2026-07-24 DAL3011 SAV → ATL Jul 24, 14:10 UTCJul 24, 14:45 UTC35m
2026-07-24 DAL3011 SAV → ATL Jul 24, 12:25 UTCJul 24, 13:10 UTC45m
2026-07-24 DAL2823 SLC → SEA Jul 24, 00:00 UTCJul 24, 00:45 UTC45m
2026-07-23 DAL2823 SLC → SEA Jul 23, 18:00 UTCJul 23, 18:35 UTC35m
2026-07-23 DAL3108 ATL → DAY Jul 23, 15:30 UTCJul 23, 16:45 UTC1h 15m
2026-07-23 DAL3108 ATL → DAY Jul 23, 15:27 UTCJul 23, 16:41 UTC1h 14m
2026-07-23 DAL3108 ATL → DAY Jul 23, 13:15 UTCJul 23, 14:15 UTC1h 0m
2026-07-23 DAL3041 JAN → ATL Jul 23, 10:45 UTCJul 23, 11:30 UTC45m
2026-07-23 DAL3117 ATL → JAN Jul 23, 03:05 UTCJul 23, 03:35 UTC30m
2026-07-22 DAL2837 SLC → JAC Jul 22, 23:40 UTCJul 23, 01:10 UTC1h 30m
2026-07-22 DAL2837 SLC → JAC Jul 22, 21:15 UTCJul 22, 22:45 UTC1h 30m
2026-07-22 DAL1195 - Jul 22, 18:10 UTCJul 22, 19:45 UTC1h 35m
2026-07-22 DAL1195 - Jul 22, 15:20 UTCJul 22, 16:55 UTC1h 35m
2026-07-22 DAL1085 JFK → LAX Jul 22, 12:45 UTCJul 22, 13:35 UTC50m
2026-07-22 DAL1085 JFK → LAX Jul 22, 12:40 UTCJul 22, 13:28 UTC48m
2026-07-21 DAL3017 ATL → GSO Jul 21, 22:00 UTCJul 21, 22:45 UTC45m
2026-07-21 DAL1060 ATL → COS Jul 21, 18:50 UTCJul 21, 20:30 UTC1h 40m
2026-07-21 DAL1060 ATL → COS Jul 21, 16:00 UTCJul 21, 17:45 UTC1h 45m
2026-07-21 DAL1158 OKC → ATL Jul 21, 13:15 UTCJul 21, 14:55 UTC1h 40m
2026-07-21 DAL2784 ORD → LGA Jul 21, 00:05 UTCJul 21, 01:45 UTC1h 40m
2026-07-20 DAL2094 - Jul 20, 19:35 UTCJul 20, 21:10 UTC1h 35m
2026-07-20 DAL2094 ATL → DSM Jul 20, 16:30 UTCJul 20, 18:10 UTC1h 40m
2026-07-20 DAL3077 ATL → AVL Jul 20, 14:45 UTCJul 20, 15:15 UTC30m
2026-07-20 DAL3077 ATL → AVL Jul 20, 12:30 UTCJul 20, 13:45 UTC1h 15m
2026-07-20 DAL1537 - Jul 20, 10:10 UTCJul 20, 10:45 UTC35m
2026-07-20 DAL1596 - Jul 20, 02:50 UTCJul 20, 03:30 UTC40m
2026-07-19 DAL1186 MSP → BOS Jul 19, 23:00 UTCJul 20, 00:40 UTC1h 40m
2026-07-19 DAL1186 MSP → BOS Jul 19, 22:58 UTCJul 20, 00:35 UTC1h 37m
2026-07-19 DAL1186 MSP → BOS Jul 19, 20:05 UTCJul 19, 21:35 UTC1h 30m

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 N891AT page for operator, model, and routing details .

Mode-S AC491D frequently asked

What is Mode-S code AC491D?
AC491D is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N891AT.
Where is Mode-S AC491D registered?
Mode-S code AC491D 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 AC491D broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 21:15 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AC491D, octal 53044435, decimal 11,290,909.
What flights does AC491D operate?
Mode-S AC491D has broadcast 20 distinct callsigns, including DAL3173, DAL3108, DAL1186, DAL1182, DAL3193.