Apparatus

Try JFK, AAL1290, BAW, or N225AN.

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 Jul 26, 22:20 UTC
Flights observed
499
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 22:20 UTC

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
DAL361 Delta Air Lines 5 2026-07-19
DAL2587 Delta Air Lines 5 2026-05-03
DAL2196 Delta Air Lines 5 2026-04-17
DAL2129 - 5 2026-06-21
DAL1879 Delta Air Lines 5 2026-07-26
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
DAL1801 Delta Air Lines 4 2026-07-26
DAL1730 Delta Air Lines 4 2026-06-19
DAL1619 Delta Air Lines 4 2026-05-25

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 DAL1800 MBJ → ATL Jul 26, 20:20 UTCJul 26, 22:10 UTC1h 50m
2026-07-26 DAL1801 ATL → MBJ Jul 26, 15:35 UTCJul 26, 17:58 UTC2h 23m
2026-07-26 DAL1801 ATL → MBJ Jul 26, 15:35 UTCJul 26, 17:05 UTC1h 30m
2026-07-26 DAL1879 MSP → ORD Jul 26, 11:50 UTCJul 26, 13:30 UTC1h 40m
2026-07-26 DAL1879 MSP → ORD Jul 26, 10:10 UTCJul 26, 10:25 UTC15m
2026-07-26 DAL1861 ATL → SJU Jul 26, 02:05 UTCJul 26, 02:25 UTC20m
2026-07-25 DAL1861 ATL → SJU Jul 25, 23:15 UTCJul 26, 00:30 UTC1h 15m
2026-07-25 DAL1928 MBJ → ATL Jul 25, 18:30 UTCJul 25, 20:58 UTC2h 28m
2026-07-25 DAL1997 ATL → MBJ Jul 25, 14:30 UTCJul 25, 21:00 UTC6h 30m
2026-07-25 DAL1524 BOS → ORD Jul 25, 11:10 UTCJul 25, 12:35 UTC1h 25m
2026-07-25 DAL1403 RSW → MSP Jul 25, 03:25 UTCJul 25, 04:45 UTC1h 20m
2026-07-24 DAL2206 JAX → LGA Jul 24, 21:25 UTCJul 25, 01:35 UTC4h 10m
2026-07-24 DAL2206 JAX → LGA Jul 24, 21:24 UTCJul 25, 01:30 UTC4h 6m
2026-07-24 DAL2206 JAX → LGA Jul 24, 15:10 UTCJul 24, 19:40 UTC4h 30m
2026-07-24 DAL1247 HPN → ATL Jul 24, 12:05 UTCJul 24, 13:30 UTC1h 25m
2026-07-24 DAL1247 HPN → ATL Jul 24, 12:03 UTCJul 24, 13:25 UTC1h 22m
2026-07-24 DAL1199 FLL → DTW Jul 24, 02:55 UTCJul 24, 04:40 UTC1h 45m
2026-07-23 DAL1987 MBJ → ATL Jul 23, 22:40 UTCJul 24, 00:20 UTC1h 40m
2026-07-23 DAL1949 ATL → MBJ Jul 23, 17:55 UTCJul 23, 19:20 UTC1h 25m
2026-07-23 DAL1949 ATL → MBJ Jul 23, 17:51 UTCJul 23, 20:11 UTC2h 20m
2026-07-23 DAL1688 ABQ → ATL Jul 23, 13:15 UTCJul 23, 15:50 UTC2h 35m
2026-07-23 DAL1531 IAH → LGA Jul 23, 01:05 UTCJul 23, 03:45 UTC2h 40m
2026-07-23 DAL1531 IAH → LGA Jul 23, 01:04 UTCJul 23, 03:44 UTC2h 40m
2026-07-22 DAL1978 SAL → ATL Jul 22, 20:05 UTCJul 22, 23:00 UTC2h 55m
2026-07-22 DAL1910 ATL → SAL Jul 22, 15:15 UTCJul 22, 17:55 UTC2h 40m
2026-07-22 DAL2554 BDL → ATL Jul 22, 11:15 UTCJul 22, 13:15 UTC2h 0m
2026-07-22 DAL1011 ATL → BDL Jul 22, 01:55 UTCJul 22, 04:40 UTC2h 45m
2026-07-21 DAL1978 SAL → ATL Jul 21, 20:10 UTCJul 21, 23:15 UTC3h 5m
2026-07-21 DAL1978 SAL → ATL Jul 21, 19:56 UTCJul 21, 23:09 UTC3h 13m
2026-07-21 DAL1910 - Jul 21, 15:05 UTCJul 21, 18:00 UTC2h 55m
2026-07-21 DAL1910 ATL → SAL Jul 21, 15:03 UTCJul 21, 18:10 UTC3h 7m
2026-07-21 DAL1396 - Jul 21, 12:05 UTCJul 21, 13:00 UTC55m
2026-07-21 DAL1396 LIT → ATL Jul 21, 12:00 UTCJul 21, 13:12 UTC1h 12m
2026-07-21 DAL2701 - Jul 21, 02:30 UTCJul 21, 03:30 UTC1h 0m
2026-07-20 DAL1758 PTY → ATL Jul 20, 21:35 UTCJul 21, 00:40 UTC3h 5m
2026-07-20 DAL1758 PTY → ATL Jul 20, 20:52 UTCJul 21, 00:37 UTC3h 45m
2026-07-20 DAL1759 - Jul 20, 15:25 UTCJul 20, 18:10 UTC2h 45m
2026-07-20 DAL1759 ATL → PTY Jul 20, 15:21 UTCJul 20, 19:02 UTC3h 41m
2026-07-20 DAL3001 BNA → ATL Jul 20, 11:35 UTCJul 20, 12:20 UTC45m
2026-07-20 DAL2126 - Jul 20, 02:55 UTCJul 20, 04:00 UTC1h 5m
2026-07-19 DAL361 DTW → SFO Jul 19, 19:05 UTCJul 19, 22:55 UTC3h 50m
2026-07-19 DAL361 DTW → SFO Jul 19, 19:02 UTCJul 19, 22:54 UTC3h 52m
2026-07-19 DAL361 DTW → SFO Jul 19, 13:00 UTCJul 19, 17:15 UTC4h 15m
2026-07-19 DAL651 DTW → PHL Jul 19, 03:30 UTCJul 19, 05:00 UTC1h 30m
2026-07-18 DAL1800 MBJ → ATL Jul 18, 20:35 UTCJul 18, 22:05 UTC1h 30m
2026-07-18 DAL1800 MBJ → ATL Jul 18, 19:46 UTCJul 18, 22:09 UTC2h 23m
2026-07-18 DAL1801 - Jul 18, 15:30 UTCJul 18, 17:00 UTC1h 30m
2026-07-18 DAL1801 ATL → MBJ Jul 18, 15:28 UTCJul 18, 17:58 UTC2h 30m
2026-07-18 DAL1879 MSP → ORD Jul 18, 12:00 UTCJul 18, 13:35 UTC1h 35m
2026-07-18 DAL1879 MSP → ORD Jul 18, 10:15 UTCJul 18, 10:25 UTC10m

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 Jul 26, 22:20 UTC.
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.