Apparatus

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sensors Mode-S transponder

ACA99C

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N915DU · BOEING 737-900 · operated by DELTA AIR LINES INC

Hex
ACA99C
Octal
53124634
Decimal
11,315,612
Country
US
Tail
N915DU
Type
B739
No current signal · last broadcast 1h ago
Flights observed
432
Distinct callsigns
20
Country
US
Last broadcast
1h ago

Last known position

Most recent position reported by Mode-S ACA99C.

Country allocation

The ICAO 24-bit address ACA99C 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
DAL1422 - 8 2026-07-14
DAL2078 Delta Air Lines 6 2026-04-17
DAL1244 - 6 2026-07-11
DAL1082 Delta Air Lines 6 2026-06-08
DAL442 Delta Air Lines 5 2026-05-10
DAL2587 Delta Air Lines 5 2026-05-03
DAL2196 Delta Air Lines 5 2026-04-17
DAL2129 - 5 2026-06-21
DAL1715 Delta Air Lines 5 2026-05-29
DAL1419 - 5 2026-07-15
DAL772 Delta Air Lines 4 2026-06-09
DAL690 Delta Air Lines 4 2026-04-14
DAL478 Delta Air Lines 4 2026-05-18
DAL2696 Delta Air Lines 4 2026-06-22
DAL2462 - 4 2026-07-03
DAL1730 Delta Air Lines 4 2026-06-19
DAL1619 Delta Air Lines 4 2026-05-25
DAL1401 Delta Air Lines 4 2026-04-16
DAL1004 - 4 2026-06-26
DAL935 - 3 2026-07-10

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-15 DAL1419 - Jul 15, 00:05 UTCJul 15, 02:30 UTC2h 25m
2026-07-14 DAL1419 JFK → FLL Jul 14, 19:50 UTCJul 14, 22:05 UTC2h 15m
2026-07-14 DAL1422 - Jul 14, 15:25 UTCJul 14, 18:00 UTC2h 35m
2026-07-14 DAL1422 FLL → JFK Jul 14, 15:23 UTCJul 14, 17:54 UTC2h 31m
2026-07-14 DAL1422 JFK → FLL Jul 14, 11:15 UTCJul 14, 13:40 UTC2h 25m
2026-07-14 DAL1643 AUS → JFK Jul 14, 03:15 UTCJul 14, 06:30 UTC3h 15m
2026-07-13 DAL1233 - Jul 13, 22:20 UTCJul 14, 01:25 UTC3h 5m
2026-07-13 DAL1575 ATL → JFK Jul 13, 18:40 UTCJul 13, 20:20 UTC1h 40m
2026-07-13 DAL3196 - Jul 13, 15:10 UTCJul 13, 16:20 UTC1h 10m
2026-07-13 DAL3196 ATL → SRQ Jul 13, 12:30 UTCJul 13, 13:35 UTC1h 5m
2026-07-13 DAL2966 ORF → ATL Jul 13, 09:25 UTCJul 13, 10:40 UTC1h 15m
2026-07-13 DAL2966 ORF → ATL Jul 13, 09:25 UTCJul 13, 10:46 UTC1h 21m
2026-07-13 DAL2731 ATL → ORF Jul 13, 03:20 UTCJul 13, 04:45 UTC1h 25m
2026-07-13 DAL2731 ATL → ORF Jul 13, 03:19 UTCJul 13, 04:29 UTC1h 10m
2026-07-13 DAL2199 - Jul 13, 00:50 UTCJul 13, 02:01 UTC1h 10m
2026-07-13 DAL2199 CVG → ATL Jul 13, 00:47 UTCJul 13, 01:59 UTC1h 12m
2026-07-12 DAL558 SEA → CVG Jul 12, 18:40 UTCJul 12, 22:30 UTC3h 50m
2026-07-12 DAL814 - Jul 12, 12:05 UTCJul 12, 16:20 UTC4h 15m
2026-07-12 DAL814 DTW → SEA Jul 12, 12:05 UTCJul 12, 16:18 UTC4h 13m
2026-07-11 DAL1432 BOS → DTW Jul 11, 23:45 UTCJul 12, 01:25 UTC1h 40m
2026-07-11 DAL1171 - Jul 11, 20:10 UTCJul 11, 21:45 UTC1h 35m
2026-07-11 DAL1171 DTW → BOS Jul 11, 20:06 UTCJul 11, 21:39 UTC1h 33m
2026-07-11 DAL2399 - Jul 11, 12:45 UTCJul 11, 16:35 UTC3h 50m
2026-07-11 DAL2399 LAX → DTW Jul 11, 12:41 UTCJul 11, 16:33 UTC3h 52m
2026-07-11 DAL1197 SLC → LAX Jul 11, 05:40 UTCJul 11, 07:05 UTC1h 25m
2026-07-11 DAL1244 PDX → SLC Jul 11, 00:45 UTCJul 11, 02:15 UTC1h 30m
2026-07-11 DAL1244 PDX → SLC Jul 11, 00:45 UTCJul 11, 02:08 UTC1h 23m
2026-07-10 DAL1244 SLC → PDX Jul 10, 22:10 UTCJul 10, 23:35 UTC1h 25m
2026-07-10 DAL935 - Jul 10, 16:35 UTCJul 10, 19:45 UTC3h 10m
2026-07-10 DAL935 DTW → SLC Jul 10, 16:30 UTCJul 10, 19:45 UTC3h 15m
2026-07-10 DAL808 TPA → DTW Jul 10, 12:35 UTCJul 10, 14:50 UTC2h 15m
2026-07-10 DAL2433 LGA → TPA Jul 10, 01:35 UTCJul 10, 04:10 UTC2h 35m
2026-07-09 DAL2195 TPA → LGA Jul 9, 20:50 UTCJul 9, 23:45 UTC2h 55m
2026-07-09 DAL2195 LGA → TPA Jul 9, 16:50 UTCJul 9, 19:20 UTC2h 30m
2026-07-09 DAL2387 - Jul 9, 10:30 UTCJul 9, 13:15 UTC2h 45m
2026-07-09 DAL2387 MIA → LGA Jul 9, 10:29 UTCJul 9, 12:59 UTC2h 30m
2026-07-09 DAL1428 - Jul 9, 00:25 UTCJul 9, 02:50 UTC2h 25m
2026-07-08 DAL532 DEN → JFK Jul 8, 18:20 UTCJul 8, 21:40 UTC3h 20m
2026-07-08 DAL532 JFK → DEN Jul 8, 12:55 UTCJul 8, 16:25 UTC3h 30m
2026-07-08 DAL2500 - Jul 8, 00:25 UTCJul 8, 02:45 UTC2h 20m
2026-07-07 DAL2500 JFK → MIA Jul 7, 19:40 UTCJul 7, 22:10 UTC2h 30m
2026-07-07 DAL732 TPA → JFK Jul 7, 15:30 UTCJul 7, 17:55 UTC2h 25m
2026-07-07 DAL732 TPA → JFK Jul 7, 15:28 UTCJul 7, 17:58 UTC2h 30m
2026-07-07 DAL2042 JFK → TPA Jul 7, 11:30 UTCJul 7, 13:50 UTC2h 20m
2026-07-06 DAL2398 ATL → JFK Jul 6, 23:50 UTCJul 7, 01:40 UTC1h 50m
2026-07-06 DAL2398 ATL → JFK Jul 6, 23:47 UTCJul 7, 01:37 UTC1h 50m
2026-07-06 DAL2894 ORD → ATL Jul 6, 19:20 UTCJul 6, 20:45 UTC1h 25m
2026-07-06 DAL2894 ATL → ORD Jul 6, 16:15 UTCJul 6, 17:50 UTC1h 35m
2026-07-06 DAL2988 YYZ → ATL Jul 6, 12:30 UTCJul 6, 14:10 UTC1h 40m
2026-07-06 DAL2669 ATL → YYZ Jul 6, 01:00 UTCJul 6, 02:40 UTC1h 40m

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 N915DU page for operator, model, and routing details .

Mode-S ACA99C frequently asked

What is Mode-S code ACA99C?
ACA99C is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N915DU.
Where is Mode-S ACA99C registered?
Mode-S code ACA99C 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 ACA99C broadcasting right now?
No active broadcast right now. Last signal was 1h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex ACA99C, octal 53124634, decimal 11,315,612.
What flights does ACA99C operate?
Mode-S ACA99C has broadcast 20 distinct callsigns, including DAL1422, DAL2078, DAL1244, DAL1082, DAL442.