# NTSB ANC23LA054: Dehavilland DHC-2 MK. I(L20A), N302BL, Twin Hills, AK, July 13, 2023 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Class 3 · Limited · Final report - Date: July 12, 2023, 16:30 local (Jul 13, 2023, 00:30 UTC) - Place: Twin Hills, AK · lake - Coordinates: 58.926762, -160.17477 - Nearby events: https://openairdocs.org/map.md?lat=58.9268&lon=-160.1748&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Defining event: [Initial climb: Unknown or undetermined](https://openairdocs.org/ntsb-events/000) - Highest injury: Serious injuries - Injuries: 2 serious, 2 minor, 1 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Alaska Regional Office - Parties: Federal Aviation Administration (FAA) - NTSB case key (mKey): 192671 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC23LA054 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/192671/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=192671 - Page: https://openairdocs.org/ntsb/ANC23LA054 ## Probable cause The pilot’s loss of control during initial climb for reasons that could not be determined. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Performance/control parameters: lateral/bank control](https://openairdocs.org/ntsb-findings/01062023): Aircraft › Aircraft oper/perf/capability · Unknown/Not determined (probable cause); cases with it: [Dehavilland DHC-2 MK. I(L20A), 1 case](https://openairdocs.org/ntsb-findings/01062023/cases.md?model=2808002), [All aircraft, 390 cases](https://openairdocs.org/ntsb-findings/01062023/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Initial climb: Unknown or undetermined](https://openairdocs.org/ntsb-events/000) (defining event); cases with it: [Dehavilland DHC-2 MK. I(L20A), 2 cases](https://openairdocs.org/ntsb-events/000/sequence.md?model=2808002), [All aircraft, 1,703 cases](https://openairdocs.org/ntsb-events/000/sequence.md) - [Initial climb: Loss of control in flight](https://openairdocs.org/ntsb-events/240); cases with it: [Dehavilland DHC-2 MK. I(L20A), 3 cases](https://openairdocs.org/ntsb-events/240/sequence.md?model=2808002), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) ## Analysis The pilot stated that moments after takeoff from a lake he heard a loud bang, and the airplane impacted the water. The passengers stated that after takeoff there was a sound similar to a cable snap or a hammer hitting metal. The airplane made a hard left turn, and the left wing impacted the water. Postaccident examination of the engine and airframe revealed no evidence of any preimpact mechanical malfunctions or failures that would have precluded normal operation. The airplane came to rest fragmented in a lake and the floats were not recovered; therefore, the fly wires and floats could not be examined, and the reason for the loss of control could not be determined. ## Factual narrative On July 12, 2023, about 1630 Alaska daylight time, a DeHavilland DHC-2 airplane, N302BL, was substantially damaged when it was involved in an accident near Twin Hills, Alaska. The pilot was not injured, two passengers sustained minor injuries, and two passengers sustained serious injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 business flight. The pilot stated that just after takeoff from the water, he heard a “bang” and then the airplane impacted the water. The passengers reported hearing a sound similar to a “cable snap” or “hitting a hammer on a piece of metal.” The airplane made a hard left turn, the left wing dipped into the water, and the airplane pivoted around that point. The airplane came to rest mostly submerged and fragmented. Postaccident examination of the airplane revealed the left wing was separated from the fuselage, consistent with impact damage; the right wing was removed to facilitate recovery. Flight control continuity was confirmed from the cockpit inputs to the recovery cuts. The left flap attachment arm remained attached to the flap and was bent and twisted. The right flap attachment arm was undamaged. The fuel selector was set to the aft tank. The floats and fly wires were not recovered from the lake and therefore were not available for examination. The throttle control was near the closed position, and the mixture was at idle. The spark plug attachments and cylinder base nuts were all intact and tight. When the propeller was manually rotated, thumb compression was obtained on all cylinders. The cylinders were examined using a lighted borescope and no anomalies were noted. All magneto leads produced a spark when spun with an electric drill. A review of the maintenance logbooks revealed that the engine had accumulated 66 hours since an overhaul that was completed about 6 months before the accident. ## Aircraft - Registration: [N302BL](https://openairdocs.org/aircraft/N302BL), registered now, S/N 613, built 1954 (OpenAirDocs) - Reported make and model: DEHAVILLAND DHC-2 MK. I(L20A) - Registry model: [Dehavilland DHC-2 MK. I(L20A)](https://openairdocs.org/model/dehavilland-dhc-2-mk-i-l20a) (registry code 2808002) (OpenAirDocs) - Registry engine: [Pratt & Whitney R-985 series](https://openairdocs.org/engine/pratt-whitney-r-985-series) (registry code 52008, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 613 - Year built: 1954 - Airframe hours: 17631.6 - Engines: Pratt & Whitney R985-14B 450 horsepower reciprocating - Damage: Substantial damage - Flight: Other work use, Part 91 - Operator: Bristol Bay Lodge - Registered owner: D&B Aircraft Leasing LLC - Airworthiness certificate: Standard, Normal - Last inspection: Annual, January 28, 2023 - Destination: Dillingham, AK - Equipment: Handheld GPS, Stall warning system ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 76; injuries: none; flight engineer, airline transport; airplane ratings: multi-engine land, single-engine sea, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review May 14, 2022; seat: left; flight hours: 40,000 total, 10,000 in this make and model, 200 in the last 90 days, 50 in the last 30 days, 4 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 66 °F, dew point 50 °F - Altimeter: 30.31 inHg - Observed at: ATG - METAR: PATG 122356Z AUTO 10SM CLR 19/10 A3031 RMK AO2 SLP262 T01940100 10194 20156 58004 $ ## 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 20230712011719A](https://openairdocs.org/incident/20230712011719A), Jul 12, 2023: Dehavilland DHC-2 MK. I(L20A), Togiak, AK, Substantial damage. Pilot stated that shortly after a normal take-off on floats, aircraft was approx 10FEET in the air and there was a loud "pop" and aircraft lost power and… ## Docket (4 files) The files NTSB released with the investigation on August 20, 2025, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=192671. 7.3 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 6.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16832783&FileExtension=pdf&FileName=NTSB%206120%20form_Redacted-Rel.pdf - Witness statements (item 2, PDF, 2 pages, 72 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18993920&FileExtension=pdf&FileName=Witness%20Statements-Rel.pdf - Wreckage examination (item 3, PDF, 6 pages, 260 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=19047732&FileExtension=pdf&FileName=Wreckage%20Exam-Rel.pdf - Photos (item 4, PDF, 4 pages, 423 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16832164&FileExtension=pdf&FileName=Photos-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.