Diamond Aircraft Ind INC DA 40 accident near Kapolei, Hawaii, December 4, 2023
On December 4, 2023 at about 10:50 pm local time, a 2006 Diamond Aircraft Ind INC DA 40, registered N691YW, was substantially damaged in an accident during enroute near Kapolei, Hawaii (Kalaeloa (John Rodgers Field)). It was a flight test under general aviation rules (Part 91). 1 person was seriously injured and 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A partial loss of engine power due to lose baffling from the muffler, which resulted in an obstruction of the exhaust system.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- December 4, 2023 · about 10:50 pm local time
- Place
- Kapolei, Hawaii · Kalaeloa (John Rodgers Field) · map
- Type
- Accident
- Injuries
- 1 person was seriously injured and 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Diamond Aircraft Ind INC DA 40, built 2006
- Registration
- N691YW · registry record · serial 40.690
- Damage
- Substantial damage
- Flight
- Flight test · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
While enroute the pilot moved the throttle control lever forward and heard a “pop” sound come from the engine, followed by a rumbling noise and an airplane vibration. The pilot pulled the throttle back to its original position in an attempt to stop the rumbling and vibrations and turned the airplane back toward the runway for an emergency landing. Engine power was not restored, and the airplane began to lose altitude, so the pilot performed a forced landing, which resulted in substantial damage to the fuselage and both wings. Postaccident examination revealed that baffling from the exhaust muffler had broken loose, blocking about 3/4 of the opening. The blocked exhaust reduced the volumetric efficiency of the engine cylinders, resulting in the partial loss of engine power.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Loss of engine power (partial) during enroute defining event
- Off-field or emergency landing during landing
- Collision with terrain or object (not controlled flight into terrain) during landing (landing roll)
The NTSB's findings
- Aircraft › Aircraft power plant › Engine exhaust › Collector/nozzle › Damaged/degraded
Pilot
- Certificate: private
- Ratings: single-engine land
- Flight time: 141 hours in all; 72 in this make and model; 30 in the last 90 days; 1 in the last 30 days; 84 as pilot in command
- Last flight review: September 23, 2022
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: left
- Injury: minor injuries
Other crew
- Certificate: airline transport pilot, flight engineer
- Ratings: multi-engine land; single-engine land; instructor: airplane multi-engine; instructor: airplane single-engine; instrument: airplane
- Flight time: 16,800 hours in all; 150 in this make and model; 35 in the last 90 days; 35 in the last 30 days; 15,000 as pilot in command; 5,900 on instruments
- Last flight review: November 9, 2023
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: rgt
- Injury: serious injuries
The aircraft
- Airframe total time: 9,015.1 hours
- Last inspection: 100-hour inspection, November 15, 2023
- Maximum gross weight: 2,646 lb
- Seats: 4
- Landing gear: fixed
- Engine: Lycoming IO-360-M1A+ (piston); 2,290 hours total
The flight
- Departed from: PHNL Honolulu HI at 10:35 pm
- Destination: PHJR Kapolei HI
- Flight plan: none
- A second pilot was aboard
Weather at the time
- Light: daylight
- Temperature: 81°F (27°C), dew point 66°F (19°C)
- Altimeter: 30.05 inHg
- Observation at 11:53 am from HJR, 2 miles away
Weather report (METAR): METAR PHJR 042153Z 05007G15KT 10SM BKN037 BKN048 27/19 A3005 RMK AO2 SLP181 T02720189
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
6 documents, released by the NTSB on April 2, 2025. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
| # | Document | What it is | |
|---|---|---|---|
| 1 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 | PDF, 10 pages | View Download |
| 2 | Pilot Interviews - FAA | PDF, 4 pages | View Download |
| 3 | Engine Exam | PDF, 1 page | View Download |
| 4 | Aircraft and Engine Logbooks | PDF, 4 pages | View Download |
| 5 | Release of Aircraft Wreckage, NTSB Form 6120.15 | PDF, 1 page | View Download |
| 6 | Photos | PDF, 4 pages | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.