# NTSB WPR26LA056: Rotorway Exec, Lake Havasu City, AZ, December 8, 2025 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 4 · Limited · Final report - Date: December 8, 2025, 10:30 local (18:30 UTC) - Place: Lake Havasu City, AZ - Coordinates: 34.528889, -114.43197 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=34.5289&lon=-114.4320&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report March 19, 2026 - Report: Approved by Office Director - Investigation class: Class 4 - Basic report with no Prelim publish - NTSB office: Western Pacific Region - Parties: FAA - NTSB case key (mKey): 202144 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR26LA056 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/202144/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=202144 - Page: https://openairdocs.org/ntsb/WPR26LA056 ## Probable cause The pilot’s improper securing hardware installation, which resulted in a loss of throttle control and a loss of engine power. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine fuel and control: fuel control/carburetor](https://openairdocs.org/ntsb-findings/01057322): Aircraft › Aircraft power plant · Incorrect service/maintenance (probable cause); cases with it: [All aircraft, 195 cases](https://openairdocs.org/ntsb-findings/01057322/cases.md) - [Maintenance: modification/alteration](https://openairdocs.org/ntsb-findings/02062030): Personnel issues › Task performance · Owner/builder; cases with it: [All aircraft, 69 cases](https://openairdocs.org/ntsb-findings/02062030/cases.md) - [Personnel issues](https://openairdocs.org/ntsb-findings/02060000): Personnel issues › Task performance · Pilot (probable cause); cases with it: [All aircraft, 137 cases](https://openairdocs.org/ntsb-findings/02060000/cases.md) - [Engine fuel and control](https://openairdocs.org/ntsb-findings/01057300): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [All aircraft, 49 cases](https://openairdocs.org/ntsb-findings/01057300/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Autorotation: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342); cases with it: [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Autorotation: Hard landing](https://openairdocs.org/ntsb-events/092); cases with it: [All aircraft, 2,102 cases](https://openairdocs.org/ntsb-events/092/sequence.md) ## Analysis The pilot/owner of an amateur-built helicopter reported that, while transitioning through translational lift for landing at about 30 ft above ground level with near-zero forward airspeed, the engine experienced a loss of power. The pilot/owner attempted to perform an autorotative landing by increasing collective and applying left pedal, and the helicopter subsequently experienced a hard landing, bounced, and came to rest on the edge of the runway at an 45° angle. The helicopter then rocked backward, resulting in substantial damage to the tailboom and tail rotor blades. The pilot’s post-accident examination of the engine revealed that it started normally during a test run; however, the engine would not accelerate above idle power. Further examination determined that the throttle cable was disconnected due to a missing retaining nut. The pilot reported that he had installed a nyloc self-locking nut, but the bolt threads did not extend sufficiently into the nut to engage the nylon insert and secure the nut. As a result, the nut separated in flight, which allowed the throttle to move to the idle position and resulted in a loss of engine power. ## Aircraft - Registration: C-GBZD (not matched to a registry record) - Reported make and model: ROTORWAY EXEC (162F) - Category: Helicopter, amateur-built - Serial number: 6614 - Year built: 2010 - Airframe hours: 290 - Engines: Rotorway International RI 162F 150 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Special flight (Special) - Last inspection: Annual, January 10, 2025 - Departed: HII, Lake Havasu City, AZ - Destination: 49X, Lake Havasu City, AZ - Airport: 49x, Chemehuevi Valley, runway 16, 5,000 × 75 ft, asphalt - Equipment: None ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 74; injuries: none; private, foreign; airplane ratings: single-engine land, single-engine sea; medical: class 3, with waivers/limitations; seat: left; restraint: 4-point; flight hours: 1,103 total, 11 in this make and model, 1,062 as pilot in command, 0 in the last 90 days, 0 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 63 °F, dew point 34 °F - Altimeter: 30.26 inHg - Observed at: EED, 17 nm away - METAR: METAR KEED 081756Z AUTO 34007KT 10SM CLR 17/01 A3026 RMK AO2 SLP234 T01670011 10167 20089 50009 ## Docket (4 files) The files NTSB released with the investigation on March 19, 2026, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=202144. 3.3 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 10 pages, 1.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=19711427&FileExtension=pdf&FileName=WPR26LA056%206120.1_Redacted-Rel.pdf - Photos (item 2, PDF, 5 pages, 1.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=20024314&FileExtension=pdf&FileName=Photographs-Rel.pdf - Pilot statement (item 3, PDF, 2 pages, 96 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=20082381&FileExtension=pdf&FileName=WPR26LA051%20Record%20of%20Conversation%20with%20Pilot%20Dec%2011%2025_Redacted-Rel.pdf - Memorandum for record a�� telephone interview, pilot (item 4, PDF, 1 page, 94 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=20025629&FileExtension=pdf&FileName=WPR26LA051%20Record%20of%20Conversation%20with%20Pilot%20Mar%203%202026_Redacted-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.