Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

A4491F

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N3753 · BOEING 737-800 · operated by DELTA AIR LINES INC

Hex
A4491F
Octal
51044437
Decimal
10,766,623
Country
US
Tail
N3753
Type
B738
Broadcasting now · callsign DAL2018 · 20,350 ft
Flights observed
429
Distinct callsigns
20
Country
US
Last broadcast
2h ago

Current position

A4491F is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A4491F 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
DAL1734 Delta Air Lines 7 2026-05-15
DAL760 - 6 2026-06-28
DAL2377 - 6 2026-07-05
DAL1872 Delta Air Lines 6 2026-05-28
DAL609 Delta Air Lines 5 2026-06-15
DAL511 Delta Air Lines 5 2026-05-20
DAL3015 Delta Air Lines 5 2026-05-24
DAL2957 Delta Air Lines 5 2026-05-15
DAL2835 Delta Air Lines 5 2026-05-15
DAL2474 - 5 2026-07-02
DAL2407 Delta Air Lines 5 2026-05-26
DAL2197 Delta Air Lines 5 2026-05-01
DAL1985 Delta Air Lines 5 2026-05-13
DAL1679 Delta Air Lines 5 2026-06-07
DAL909 Delta Air Lines 4 2026-05-03
DAL861 Delta Air Lines 4 2026-05-03
DAL846 - 4 2026-06-20
DAL678 Delta Air Lines 4 2026-06-17
DAL3098 Delta Air Lines 4 2026-05-16
DAL3072 Delta Air Lines 4 2026-05-24

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 DAL758 DEN → JFK Jul 14, 06:05 UTCJul 14, 09:35 UTC3h 30m
2026-07-14 DAL1667 - Jul 14, 03:15 UTCJul 14, 04:15 UTC1h 0m
2026-07-13 DAL2468 YYZ → SLC Jul 13, 22:15 UTCJul 14, 01:35 UTC3h 20m
2026-07-13 DAL2477 SLC → YYZ Jul 13, 16:55 UTCJul 13, 20:20 UTC3h 25m
2026-07-13 DAL2477 SLC → YYZ Jul 13, 16:52 UTCJul 13, 20:16 UTC3h 24m
2026-07-13 DAL2142 - Jul 13, 11:35 UTCJul 13, 14:50 UTC3h 15m
2026-07-13 DAL2230 SLC → CMH Jul 13, 00:10 UTCJul 13, 03:15 UTC3h 5m
2026-07-13 DAL2230 SLC → CMH Jul 13, 00:09 UTCJul 13, 03:13 UTC3h 4m
2026-07-12 DAL1452 GEG → SLC Jul 12, 21:30 UTCJul 12, 22:55 UTC1h 25m
2026-07-12 DAL1452 SLC → GEG Jul 12, 18:50 UTCJul 12, 20:01 UTC1h 10m
2026-07-12 DAL2290 - Jul 12, 12:25 UTCJul 12, 15:05 UTC2h 40m
2026-07-11 DAL2515 - Jul 11, 19:50 UTCJul 11, 22:25 UTC2h 35m
2026-07-11 DAL1447 PHX → SLC Jul 11, 17:25 UTCJul 11, 18:35 UTC1h 10m
2026-07-11 DAL1447 - Jul 11, 15:00 UTCJul 11, 16:15 UTC1h 15m
2026-07-11 DAL1239 - Jul 11, 03:15 UTCJul 11, 04:40 UTC1h 25m
2026-07-10 DAL922 ANC → SEA Jul 10, 22:15 UTCJul 11, 01:25 UTC3h 10m
2026-07-10 DAL922 SEA → ANC Jul 10, 17:55 UTCJul 10, 20:50 UTC2h 55m
2026-07-10 DAL2041 MSP → IND Jul 10, 12:10 UTCJul 10, 15:50 UTC3h 40m
2026-07-10 DAL1634 - Jul 10, 01:00 UTCJul 10, 05:20 UTC4h 20m
2026-07-10 DAL1634 LAX → ORD Jul 10, 00:58 UTCJul 10, 05:19 UTC4h 21m
2026-07-09 DAL2725 HAF → LAX Jul 9, 22:50 UTCJul 9, 23:45 UTC55m
2026-07-09 DAL2725 SFO → LAX Jul 9, 22:46 UTCJul 9, 23:38 UTC52m
2026-07-09 DAL2725 LAX → SFO Jul 9, 19:50 UTCJul 9, 20:45 UTC55m
2026-07-09 DAL1421 - Jul 9, 16:40 UTCJul 9, 17:35 UTC55m
2026-07-09 DAL1421 - Jul 9, 14:15 UTCJul 9, 15:10 UTC55m
2026-07-09 DAL2861 SEA → LAX Jul 9, 02:30 UTCJul 9, 04:40 UTC2h 10m
2026-07-08 DAL2817 SLC → SEA Jul 8, 21:35 UTCJul 8, 23:15 UTC1h 40m
2026-07-08 DAL1265 SEA → SLC Jul 8, 18:25 UTCJul 8, 20:05 UTC1h 40m
2026-07-08 DAL1265 SEA → SLC Jul 8, 18:24 UTCJul 8, 19:55 UTC1h 31m
2026-07-08 DAL1570 PHX → SEA Jul 8, 14:05 UTCJul 8, 16:40 UTC2h 35m
2026-07-08 DAL2698 SEA → PHX Jul 8, 01:55 UTCJul 8, 04:20 UTC2h 25m
2026-07-08 DAL2698 SEA → PHX Jul 8, 01:54 UTCJul 8, 04:17 UTC2h 23m
2026-07-07 DAL2880 LAS → SEA Jul 7, 21:55 UTCJul 7, 23:50 UTC1h 55m
2026-07-07 DAL2880 SEA → LAS Jul 7, 18:30 UTCJul 7, 20:30 UTC2h 0m
2026-07-07 DAL2606 - Jul 7, 01:20 UTCJul 7, 03:20 UTC2h 0m
2026-07-06 DAL2769 SEA → LAX Jul 6, 18:30 UTCJul 6, 20:55 UTC2h 25m
2026-07-06 DAL2874 LGA → MSY Jul 6, 14:15 UTCJul 6, 15:50 UTC1h 35m
2026-07-06 DAL1239 SEA → SLC Jul 6, 02:55 UTCJul 6, 04:25 UTC1h 30m
2026-07-05 DAL1564 PHL → ATL Jul 5, 20:25 UTCJul 6, 00:20 UTC3h 55m
2026-07-05 DAL2247 - Jul 5, 13:55 UTCJul 5, 16:35 UTC2h 40m
2026-07-05 DAL2377 - Jul 5, 01:45 UTCJul 5, 04:30 UTC2h 45m
2026-07-05 DAL2377 ORD → SLC Jul 5, 01:43 UTCJul 5, 04:28 UTC2h 45m
2026-07-04 DAL2240 GRB → ORD Jul 4, 23:35 UTCJul 5, 00:30 UTC55m
2026-07-04 DAL2240 LGA → GRB Jul 4, 19:15 UTCJul 4, 21:30 UTC2h 15m
2026-07-04 DAL2633 - Jul 4, 16:15 UTCJul 4, 17:50 UTC1h 35m
2026-07-03 DAL2377 - Jul 3, 22:25 UTCJul 4, 01:20 UTC2h 55m
2026-07-03 DAL1447 - Jul 3, 16:55 UTCJul 3, 18:10 UTC1h 15m
2026-07-03 DAL1447 SLC → PHX Jul 3, 14:10 UTCJul 3, 15:20 UTC1h 10m
2026-07-02 DAL2149 - Jul 2, 22:00 UTCJul 3, 01:15 UTC3h 15m
2026-07-02 DAL1603 PBI → ATL Jul 2, 16:15 UTCJul 2, 18:10 UTC1h 55m

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 N3753 page for operator, model, and routing details .

Mode-S A4491F frequently asked

What is Mode-S code A4491F?
A4491F is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N3753.
Where is Mode-S A4491F registered?
Mode-S code A4491F 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 A4491F broadcasting right now?
Yes. Mode-S A4491F is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A4491F, octal 51044437, decimal 10,766,623.
What flights does A4491F operate?
Mode-S A4491F has broadcast 20 distinct callsigns, including DAL1734, DAL760, DAL2377, DAL1872, DAL609.