# NTSB WPR24LA210: Lancair LC42-550FG, N141PB, Humboldt Bay, CA, June 20, 2024 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: June 20, 2024, 10:31 local (17:31 UTC) - Place: Humboldt Bay, CA · Marsh - Coordinates: 40.69524, -124.21173 - Nearby events: https://openairdocs.org/map.md?lat=40.6952&lon=-124.2117&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-climb to cruise: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Western Pacific Region - Parties: FAA FSDO - NTSB case key (mKey): 194542 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR24LA210 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/194542/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=194542 - Page: https://openairdocs.org/ntsb/WPR24LA210 ## Probable cause Maintenance personnel’s incorrect installation of an engine rocker cover gasket, which resulted in oil exhaustion and subsequent loss of engine power during the initial climb. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine (reciprocating): recip eng cyl section](https://openairdocs.org/ntsb-findings/01058530): Aircraft › Aircraft power plant · Incorrect service/maintenance (probable cause); cases with it: [Lancair LC42-550FG, 1 case](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=5150002), [All aircraft, 373 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md) - [Fluids: oil](https://openairdocs.org/ntsb-findings/01071020): Aircraft › Fluids/misc hardware · Fluid level (probable cause); cases with it: [Lancair LC42-550FG, 1 case](https://openairdocs.org/ntsb-findings/01071020/cases.md?model=5150002), [All aircraft, 174 cases](https://openairdocs.org/ntsb-findings/01071020/cases.md) - [Maintenance: scheduled/routine maintenance](https://openairdocs.org/ntsb-findings/02062010): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Lancair LC42-550FG, 1 case](https://openairdocs.org/ntsb-findings/02062010/cases.md?model=5150002), [All aircraft, 320 cases](https://openairdocs.org/ntsb-findings/02062010/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Prior to flight: Aircraft maintenance event](https://openairdocs.org/ntsb-events/040); cases with it: [Lancair LC42-550FG, 1 case](https://openairdocs.org/ntsb-events/040/sequence.md?model=5150002), [All aircraft, 484 cases](https://openairdocs.org/ntsb-events/040/sequence.md) - [Enroute-climb to cruise: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) (defining event); cases with it: [Lancair LC42-550FG, 1 case](https://openairdocs.org/ntsb-events/340/sequence.md?model=5150002), [All aircraft, 820 cases](https://openairdocs.org/ntsb-events/340/sequence.md) - [Enroute-climb to cruise: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341); cases with it: [Lancair LC42-550FG, 2 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=5150002), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Landing-flare/touchdown: Nose over/nose down](https://openairdocs.org/ntsb-events/096); cases with it: [Lancair LC42-550FG, 1 case](https://openairdocs.org/ntsb-events/096/sequence.md?model=5150002), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md) ## Analysis Shortly after takeoff, the engine lost most of its oil, resulting in a partial engine seizure and a total loss of engine power. During a forced landing to a soft field, the airplane nosed over, sustaining substantial damage to the vertical stabilizer, rudder, and fuselage. Postaccident examination of the engine revealed that a rocker cover gasket was misaligned before the accident. The gasket was unable to maintain an adequate seal and opened during the accident flight. Oil was then ejected out of the gap between the rocker cover and cylinder head, which resulted in oil exhaustion. Maintenance that was performed about 20 flight hours before the accident flight would have included installing the gasket. Maintenance instructions required a series of specific steps to install the gasket; based on the condition of the gasket after the accident, the instructions were likely not followed properly. ## Factual narrative On June 20, 2024, about 1031 Pacific daylight time, a Lancair LC42-550FG (Columbia 350), N141PB, was substantially damaged when it was involved in an accident near Humboldt Bay, California. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The airplane had just departed Murray Field Airport (EKA), Eureka, California, after receiving an instrument flight rules clearance to Napa County Airport (APC), Napa, California. During the initial climb, the airplane passed through a cloud layer, after which it broke out into visual meteorological conditions at an altitude of about 1,500 ft mean sea level (msl). As the airplane climbed through 2,300 ft msl, the pilot established communications with the Seattle Air Route Traffic Control Center. About one minute later, he noticed a change in engine noise, with an accompanying vibration. The engine monitor indicated the cylinder head temperature for cylinder No. 6 was rising, and a short time later the engine lost all power and appeared to seize. The pilot declared an emergency and was provided vectors back to EKA. While the airplane was turning toward the airport, it descended into the cloud layer. The airplane broke out into visual conditions about 700 ft msl over coastal marshland. The pilot maneuvered the airplane toward the flattest looking area, and on touchdown the airplane nosed over. The airplane sustained substantial damage to the vertical stabilizer and rudder, along with the forward cabin roof. Postaccident examination of the engine revealed that the engine had lost most of its oil in flight, with only 1 quart of oil remained in the sump (its capacity was 8 quarts). The entire belly of the airplane was coated in oil and, within the engine compartment, the lower inner surface of the lower cowling, along with the left side of the engine, was coated in a sheen of oil. Examination of the rocker covers revealed that the gasket for the exhaust rocker for cylinder No. 2 (on the left aft side of the engine) was misaligned in its lower right corner, such that a gap between the rocker cover and cylinder head was present (figure 1). The cover was removed, and a dark stain was present on the face of the gasket mating surface, which mirrored the misalignment of the gasket (figure 2). Figure 1. Misaligned gasket (left); gap in the gasket seal (right). Figure 2. Witness marks showing pre-existing misaligned gasket on rocker (left) and cover (right). The oil cooler and all oil lines were intact and showed no evidence of leaks. Both the oil sump drain plug and the quick drain plug were intact and locked. The outer surface of the oil filter, which was mounted behind the aft engine baffle and forward of the firewall, was clean, dry, and firmly attached to its adapter. The oil filter element was covered in fine metallic particles. Although the engine crankshaft could be rotated by hand at the propeller hub, its motion felt stiff, with more resistancethan typical. Other than the rocker cover gasket misalignment, the engine examination revealed no evidence of any preimpact mechanical malfunctions or failures that would have precluded normal operation. The most recent airplane maintenance was completed about 20 flight hours before the accident, on September 17, 2023. At that time, an annual inspection was performed, along with replacement of all six engine cylinder and valve assemblies. The logbook entry stated that ground operation checks were performed following the maintenance, and no leaks were noted. Continental Aerospace Technologies issued Service Information Letter SIL21-04B in August 2021, which was applicable to the accident engine. The letter provided instructions for installing an updated 100% silicone rocker cover gasket (part number 668893) in place of previous fiber and combination fiber/silicone bead gaskets. The letter stated that the new gasket “provides a more flexible seal than the previous gasket, when properly installed.” The letter included a caution that failure to adequately clean the rocker and rocker cover flanges will cause an oil leak. It also specified reduced torque values for attaching the cover fasteners than those used for the fiber-based gaskets and stated that if the lower values were not used, the gasket and cover would be damaged. The newer silicone gasket had been installed in the engine, and both it and the rocker cover were undamaged. Review of the Federal Aviation Administration’s service difficulty reporting system database did not find any reports of failures of the newer silicone gasket. ## Aircraft - Registration: [N141PB](https://openairdocs.org/aircraft/N141PB), registered now, S/N 42066 (OpenAirDocs) - Reported make and model: LANCAIR COMPANY LC42-550FG - Registry model: [Lancair LC42-550FG](https://openairdocs.org/model/lancair-lc42-550fg) (registry code 5150002) (OpenAirDocs) - Category: Airplane - Serial number: 42066 - Year built: 2005 - Airframe hours: 1176 - Engines: Continental Motors IO 550N 310 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, September 17, 2023, 20 hours before - Departed: EKA, Eureka, CA - Destination: APA, Napa, CA - Flight plan: IFR - Equipment: Onboard weather, Stall warning system, ADS-B, Auto-pilot, Electronic multifunction display, Electronic primary flight display ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 67; injuries: none; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3, with waivers/limitations; last flight review October 8, 2023; seat: left; restraint: 3-point; flight hours: 2,600 total, 600 in this make and model, 2,600 as pilot in command, 25 in the last 90 days, 4 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 340° at 5 knots - Visibility: 4 statute miles - Lowest ceiling: 300 ft overcast - Temperature: 50 °F, dew point 50 °F - Altimeter: 29.95 inHg - Observed at: KFOT, 9 nm away - METAR: METAR KFOT 201735Z AUTO 34005KT 4SM OVC003 10/10 A2995 RMK AO1= ## 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 20240620009269A](https://openairdocs.org/incident/20240620009269A), Jun 20, 2024: Lancair Company LC42-550FG, Fortuna, CA, Substantial damage. 06/20/2024 Filed for 10:30 IFR departure keka fot V27 eni sts sgd kapc. Remaining fuel 68 gallons equally distributed r and l tanks. Obtained telephone… ## Docket (5 files) The files NTSB released with the investigation on April 23, 2025, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=194542. 8.1 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 5.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17838435&FileExtension=pdf&FileName=r_6120_1-WPR24LA210%20NTSB%20report_Redacted-Rel.pdf - NTSB engine examination report (item 2, PDF, 7 pages, 7 photos, 1.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17843645&FileExtension=pdf&FileName=Engine%20Examination%20Report-WPR24LA210-Rel.pdf - Maintenance logbook excerpts (item 3, PDF, 1 page, 824 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17838539&FileExtension=pdf&FileName=r_Maint%20log%20excerpts_Redacted-Rel.pdf - SIL21-04B service information letter (item 4, PDF, 2 pages, 625 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17838181&FileExtension=pdf&FileName=SIL21-04B-Rel.pdf - Release of aircraft wreckage, NTSB form 6120.15 (item 5, PDF, 1 page, 124 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17838549&FileExtension=pdf&FileName=r_Release-of-Wreckage-WPR24LA210_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.