# NTSB WPR24LA314: Cessna U206G, N6522Z, West Sacramento, CA, September 19, 2024 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Class 3 · Limited · Final report - Date: September 19, 2024, 08:19 local (15:19 UTC) - Place: West Sacramento, CA · open field - Coordinates: 38.54, -121.519 - Nearby events: https://openairdocs.org/map.md?lat=38.5400&lon=-121.5190&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed, report August 26, 2026 - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration, Continental Aerospace Technologies - NTSB case key (mKey): 195224 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR24LA314 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/195224/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=195224 - Page: https://openairdocs.org/ntsb/WPR24LA314 ## Probable cause Failure of the No. 4 cylinder fuel injection assembly tube and subsequent total loss of engine power. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Terrain: rough terrain](https://openairdocs.org/ntsb-findings/03021015): Environmental issues › Physical environment · Contributed to outcome; cases with it: [Cessna U206G, 4 cases](https://openairdocs.org/ntsb-findings/03021015/cases.md?model=2073356), [All aircraft, 442 cases](https://openairdocs.org/ntsb-findings/03021015/cases.md) - [Engine fuel and control: fuel distribution](https://openairdocs.org/ntsb-findings/01057310): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Cessna U206G, 1 case](https://openairdocs.org/ntsb-findings/01057310/cases.md?model=2073356), [All aircraft, 55 cases](https://openairdocs.org/ntsb-findings/01057310/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 (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Cessna U206G, 10 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=2073356), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Landing-landing roll: Nose over/nose down](https://openairdocs.org/ntsb-events/096); cases with it: [Cessna U206G, 9 cases](https://openairdocs.org/ntsb-events/096/sequence.md?model=2073356), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md) ## Analysis While the airplane was en route to a local airport, the engine suddenly lost power and the airplane began to shake. The pilot noted rapidly decreasing cylinder head temperature readings on most cylinders and the loss of the temperature reading for the No. 4 cylinder. He turned the airplane toward the nearest airport, and the engine then lost all power. The pilot realized that the airplane would not glide to the nearest airport and selected a field to land in. He initiated an emergency landing to the field and the airplane nosed over, coming to rest inverted. Postaccident examination of the engine revealed that the No. 4 fuel injection assembly tube was not contained in its retention clamp, and the elastomer sleeve that cushions the clamped tube was displaced from its normal position. Examination of the tube during disassembly revealed a fracture where it intersected the shank of the ferrule that had been brazed onto the inboard end of the tube. Further examination of the fracture at the NTSB laboratory revealed that the fracture surfaces were consistent with fatigue and that the elastomer sleeve displayed wear marks consistent with previous clamping. The engine’s fuel flow divider was tested with the five intact fuel injection assembly tubes from the accident engine and one surrogate tube for the No. 4 position. The flow test failed when the No. 4 tube was removed to simulate the fracture. The investigation could not determine how long the No. 4 fuel injection assembly tube had been displaced from the retention clamp before the tube’s in-flight failure and subsequent engine failure. ## Factual narrative Review of maintenance records showed that the most recent annual inspection was completed on November 25, 2023. The most recent maintenance of any type was an oil change, completed on August 29, 2024. On July 6, 2022, the accident engine was installed on the accident airframe. On September 19, 2024, about 0819 Pacific daylight time, a Cessna U206G airplane, N6522Z, was substantially damaged when it was involved in an accident near West Sacramento, California. The pilot sustained minor injuries. The airplane was operated as a title 14 Code of Federal Regulations Part 91 other work use flight. According to the pilot, he was enroute from Sacramento Mather Airport, (MHR), Sacramento, California, to Watts-Woodland Airport (O41), Woodland, California. The engine exhibited an abrupt decrease in power and began to shake violently. The pilot observed engine monitor alarms for rapid cooling and noted that the No. 4 cylinder head temperature reading was no longer being displayed on the engine data management display; all other cylinder temperatures were rapidly decreasing. The pilot turned the airplane toward the nearest airport, Sacramento Executive Airport (SAC), and declared an emergency. Subsequently, the engine lost all power and the pilot determined that SAC was outside of the airplane’s glide range. The pilot initiated a forced landing to a field; during the landing roll the airplane nosed over, then came to rest inverted. Postaccident examination of the airplane revealed substantial damage to both wings, the fuselage, the horizontal stabilizer, and the rudder. Examination of the engine at the manufacturer’s facilities revealed that the elastomer sleeve on the fuel injector assembly tube for cylinder No. 4 was displaced outboard of the tube’s retaining clamp, and the tube was unclamped. Disassembly of the fuel injector assembly tube revealed a fracture separation where it intersected the shank of the ferrule that was brazed onto the inboard end of the tube. The fuel injector assembly tube and elastomer sleeve were examined by the NTSB materials laboratory. The fracture surfaces on the assembly tube were consistent with fatigue that originated at the lower forward quadrant of the tube’s outer diameter. A circumferential area of wear was observed on the elastomer sleeve. The fuel manifold was flow-tested using the 5 intact fuel injection assembly tubes from the accident engine, and one surrogate tube for the No. 4 position. The first test was conducted with all 6 lines connected. The first test was normal until the 150 pounds per hour (pph) test point, when it failed due to high pressure. The second test was conducted with the No. 4 line removed and the line open. The second test failed due to low pressures at the 50, 100, and 150 pph test points. ## Aircraft - Registration: [N6522Z](https://openairdocs.org/deregistered/N6522Z-2026-07-07), registration cancelled 2026-07-07, S/N U20606307, built 1981 (OpenAirDocs) - Reported make and model: CESSNA U206G - Registry model: [Cessna U206G](https://openairdocs.org/model/cessna-u206g) (registry code 2073356) (OpenAirDocs) - Registry engine: [Continental IO-520 series](https://openairdocs.org/engine/continental-io-520-series) (registry code 17032, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: U20606307 - Year built: 1981 - Airframe hours: 7006 - Engines: Continental IO-550-F21B 300 horsepower reciprocating - Damage: Substantial damage - Flight: Other work use, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, November 25, 2023, 250 hours before - Departed: KMHR, Mather, CA - Destination: O41, Woodland, CA - Airport: KSAC, Sacramento Executive Airport - Equipment: Stall warning system, ADS-B, Electronic flight bag or handheld device, Auto-pilot ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 48; injuries: minor; flight engineer, commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, with waivers/limitations; last flight review July 15, 2024; seat: left; restraint: 3-point; flight hours: 5,000 total, 1,500 in this make and model, 5,000 as pilot in command, 100 in the last 90 days, 40 in the last 30 days, 4 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 180° at 3 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 59 °F, dew point 55 °F - Altimeter: 29.85 inHg - Observed at: KSAC, 2 nm away - METAR: KSAC 191453Z AUTO 18003KT 10SM CLR 15/13 A2985 ## Docket (8 files) The files NTSB released with the investigation on August 26, 2026, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=195224. 10.8 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 2.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18806765&FileExtension=pdf&FileName=Pilot%206120%20flat_Redacted-Rel.pdf - Maintenance records (item 2, PDF, 4 pages, 722 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=20660322&FileExtension=pdf&FileName=Maintenance%20Log%20Excerpt_Redacted-Rel.pdf - Investigation photographs (item 3, PDF, 6 pages, 1.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=20660878&FileExtension=pdf&FileName=Investigation%20Photographs-Rel.pdf - Engine exam summary report (item 4, PDF, 14 pages, 3.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=20688383&FileExtension=pdf&FileName=Engine%20Exam%20Summary%20Report-Rel.pdf - Fuel flow bench test (item 5, PDF, 3 pages, 738 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=20660486&FileExtension=pdf&FileName=Bench%20Test%20Results-Rel.pdf - Materials laboratory factual report 25-043 (item 6, PDF, 6 pages, 5 photos, 825 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18967802&FileExtension=pdf&FileName=25-043-Rel.pdf - Party form (item 7, PDF, 1 page, 808 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=20663874&FileExtension=pdf&FileName=Continental%20Party%20Form%20signed_Redacted-Rel.pdf - Wreckage release (item 8, PDF, 1 page, 107 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=20657024&FileExtension=pdf&FileName=NTSB%20Wreckage%20Release%20Form%20N6522Z_signed_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.