# NTSB ANC24LA005: Diamond Aircraft Ind DA 40, N691YW, Kapolei, HI, December 4, 2023 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Class 3 · Limited · Final report - Date: December 4, 2023, 12:50 local (22:50 UTC) - Place: Kapolei, HI · Dirt field - Coordinates: 21.32, -158.1 - Nearby events: https://openairdocs.org/map.md?lat=21.3200&lon=-158.1000&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) - Highest injury: Serious injuries - Injuries: 1 serious, 1 minor - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Alaska Regional Office - Parties: FAA - NTSB case key (mKey): 193475 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC24LA005 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/193475/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=193475 - Page: https://openairdocs.org/ntsb/ANC24LA005 ## Probable cause A partial loss of engine power due to lose baffling from the muffler, which resulted in an obstruction of the exhaust system. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine exhaust: collector/nozzle](https://openairdocs.org/ntsb-findings/01057810): Aircraft › Aircraft power plant · Damaged/degraded (probable cause); cases with it: [Diamond Aircraft Ind DA 40, 1 case](https://openairdocs.org/ntsb-findings/01057810/cases.md?model=2990002), [All aircraft, 3 cases](https://openairdocs.org/ntsb-findings/01057810/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [Diamond Aircraft Ind DA 40, 1 case](https://openairdocs.org/ntsb-events/342/sequence.md?model=2990002), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Landing: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Diamond Aircraft Ind DA 40, 2 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=2990002), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing-landing roll: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Diamond Aircraft Ind DA 40, 12 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=2990002), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis 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. ## Factual narrative On December 04, 2023, about 1250 Hawaii-Aleutian standard time, a Diamond DA-40 airplane, N691YW, sustained substantial damage when it was involved in an accident in Kapolei, Hawaii. The pilot sustained minor injuries, and the designated pilot examiner sustained serious injuries. The airplane was operated by the pilot as a Title 14 Code of Federal Regulations Part 91 flight test. The pilot reported that an engine run-up inspection was completed without any issues of concern before departure. They departed from Danial K Inouye International Airport (PHNL) Honolulu, Hawaii, about 1235. After departure they leveled off at 1,500 ft mean sea level and proceeded to the practice area to conduct an evaluation for an airplane instrument rating. The pilot configured the airplane for the first maneuver. When he moved the throttle control lever forward, they 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 runway 11 at Kalaeloa Airport (PHJR), Kapolei, Hawaii, for an emergency landing. They scanned the ignition, control levers, fuel selector, and multi-function display. The pilot confirmed that the mixture control lever was full forward, the propeller control lever was full forward, and the throttle control lever was about 3/4 full forward. The ignition was positioned on "BOTH", the fuel selector knob was positioned directly over the right tank, and the multi-function display showed no discrepancies in engine instrument readings that would indicate a need for immediate corrective action. The airplane started a descent without any manual pitch adjustments. They increased the throttle lever to the full forward position, but this did not provide any additional thrust from the engine. They declared an emergency; the designated pilot examiner took the flight controls, and they began to look for a suitable area for a forced landing. They performed a forced landing to a flat area of land that was covered with dirt. After initial touchdown, the airplane continued to roll straight down the dirt path until it impacted a dirt hill, resulting in substantial damage to the fuselage and both wings. A postaccident examination conducted by a Federal Aviation Administration inspector and a certified airframe and powerplant mechanic revealed no internal failure of the engine. The fuel injection servo control was in the full throttle position and the mixture control was in the full rich position; neither cable could be moved in the cockpit due to impact damage. The fuel injection servo was removed for inspection, and it revealed that the throttle/butterfly did not move and was in the full-throttle position. The valve covers and lower sparkplugs were removed; no anomalies were noted. No obstructions were observed in the fuel system. The air filter was removed with no obstructionobserved. Internal baffling in the exhaust muffler had broken loose and had blocked about 3/4 of the opening. The last 100-hour inspection was completed on November 15, 2023, with the engine total time of 2,290.5 hours ## Aircraft - Registration: [N691YW](https://openairdocs.org/aircraft/N691YW), registered now, S/N 40.690, built 2006 (OpenAirDocs) - Reported make and model: DIAMOND AIRCRAFT IND INC DA 40 - Registry model: [Diamond Aircraft Ind DA 40](https://openairdocs.org/model/diamond-aircraft-ind-da-40) (registry code 2990002) (OpenAirDocs) - Registry engine: [Lycoming IO-360-M1A+](https://openairdocs.org/engine/lycoming-io-360-m1a-plus) (registry code 41869, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 40.690 - Year built: 2006 - Airframe hours: 9015.1 - Engines: LYCOMING IO-360-M1A+ 180 horsepower reciprocating - Damage: Substantial damage - Flight: Flight test, Part 91 - Registered owner: George'S Aviation Services Inc - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, November 15, 2023 - Departed: PHNL, Honolulu, HI - Destination: PHJR, Kapolei, HI - Airport: PHJR, Kalaeloa (John Rodgers Field) - Equipment: Electronic multifunction display, Electronic primary flight display, Stall warning system, ADS-B, Auto-pilot, Electronic flight bag or handheld device ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 25; injuries: minor; private; airplane ratings: single-engine land; medical: class 3, with waivers/limitations; last flight review September 23, 2022; seat: left; restraint: 3-point; flight hours: 141 total, 72 in this make and model, 84 as pilot in command, 30 in the last 90 days, 1 in the last 30 days, 0 in the last 24 hours - Other flight crew; age 77; injuries: serious; airline transport, flight engineer; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review November 9, 2023; seat: right; restraint: 3-point; flight hours: 16,800 total, 150 in this make and model, 15,000 as pilot in command, 35 in the last 90 days, 35 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Temperature: 81 °F, dew point 66 °F - Altimeter: 30.05 inHg - Observed at: HJR, 2 nm away - METAR: METAR PHJR 042153Z 05007G15KT 10SM BKN037 BKN048 27/19 A3005 RMK AO2 SLP181 T02720189 ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20231204020659A](https://openairdocs.org/incident/20231204020659A), Dec 4, 2023: Diamond Aircraft Ind Inc DA 40, Kapolei, HI, Destroyed. On Monday, December 4, 2023, at approximately 1245 HST, following a loss of power, an aircraft attempted to make an emergency landing at kalaeloa airport… ## Docket (6 files) The files NTSB released with the investigation on April 2, 2025, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=193475. 13.2 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 10 pages, 3.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16775177&FileExtension=pdf&FileName=ANC24LA005%206120%20combined_Redacted-Rel.pdf - Pilot interviews - FAA (item 2, PDF, 4 pages, 82 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16775478&FileExtension=pdf&FileName=ANC24La005%20Pilot%20Interviews%20combined-Rel.pdf - Engine exam (item 3, PDF, 1 page, 62 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18497788&FileExtension=pdf&FileName=ANC24LA005%20Engine%20exam%20FAA_Redacted-Rel.pdf - Aircraft and engine logbooks (item 4, PDF, 4 pages, 8.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16775187&FileExtension=pdf&FileName=Airframe%20and%20engine%20logbook%20ANC24LA005_Redacted-Rel.pdf - Release of aircraft wreckage, NTSB form 6120.15 (item 5, PDF, 1 page, 20 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16801700&FileExtension=pdf&FileName=ANC24LA005%20Wreckage%20Release_Redacted-Rel.pdf - Photos (item 6, PDF, 4 pages, 1.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16774931&FileExtension=pdf&FileName=ANC24LA005%20Photo%20array-Rel.pdf From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.