# NTSB WPR16LA107: Cessna 208B, N1114A, Acampo, CA, May 12, 2016 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: May 12, 2016, 14:13 local (21:13 UTC) - Place: Acampo, CA - Coordinates: 38.203334, -121.255279 - Nearby events: https://openairdocs.org/map.md?lat=38.2033&lon=-121.2553&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-climb to cruise: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: Minor injuries - Injuries: 1 minor, 17 uninjured - Status: Completed, report March 19, 2018 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Adminsitration, P&W Canada, Cessna Aircraft, Blackhawk Modifications Inc - NTSB case key (mKey): 93159 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR16LA107 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/93159/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=93159 - Page: https://openairdocs.org/ntsb/WPR16LA107 ## Probable cause A total loss of engine power due to a fatigue fracture of the fuel pressure line that connected the fuel control unit and the fuel flow transducer due to vibration as the result of a fatigue fracture of an associated support clamp. Contributing to the accident was the mechanic’s inadequate inspection of the fuel line support clamp during the previous replacement of the fuel line. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine fuel and control: fuel distribution](https://openairdocs.org/ntsb-findings/01057310): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Cessna 208B, 1 case](https://openairdocs.org/ntsb-findings/01057310/cases.md?model=2073701), [All aircraft, 55 cases](https://openairdocs.org/ntsb-findings/01057310/cases.md) - [Inspection](https://openairdocs.org/ntsb-findings/02061500): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Cessna 208B, 2 cases](https://openairdocs.org/ntsb-findings/02061500/cases.md?model=2073701), [All aircraft, 29 cases](https://openairdocs.org/ntsb-findings/02061500/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute-climb to cruise: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Cessna 208B, 11 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=2073701), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Landing: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Cessna 208B, 7 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=2073701), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Cessna 208B, 20 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=2073701), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) - [Landing: Nose over/nose down](https://openairdocs.org/ntsb-events/096); cases with it: [Cessna 208B, 3 cases](https://openairdocs.org/ntsb-events/096/sequence.md?model=2073701), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md) ## Analysis The commercial pilot reported that, after takeoff on the local skydiving flight, the engine experienced a total loss of power. He initiated a turn toward the airport, but realized the airplane would not reach the runway and chose to perform a forced landing to an open field. During the landing roll, the airplane exited the field, crossed a road, impacted a truck, and continued into a vineyard, where it nosed over. Postaccident examination of the engine revealed that the fuel pressure line that connects the fuel control unit to the airframe fuel pressure transducer was fractured below the fuel control unit fitting's swaged seat. In addition, a supporting clamp for the fuel pressure fuel line was fractured and separated. The operator reported that the fractured fuel line had been replaced the night before the accident and had accumulated about 4 hours of operational time. The previously-installed line had also fractured. Metallurgical examination of the two fractured fuel lines revealed that both fuel lines fractured due to reverse bending fatigue through the tube wall where a ferrule was brazed to the outside of the tube. There were no apparent anomalies or defects at the crack initiation sites. Examination of the supporting clamp determined that it fractured due to unidirectional bending fatigue where one of the clamp's tabs met the clamp loop, with the crack initiating along the inward-facing side of the clamp. The orientation of the reverse bending fatigue cracks and the spacing of the fatigue striations on the tube fracture surfaces were consistent with high-cycle bending fatigue due to a vibration of the tube. The cushioned support clamp is designed to prevent such vibrations from occurring. However, if the clamp tab is fractured, it cannot properly clamp the tube and will be unable to prevent the vibration. The presence of the fractured clamp combined with the fact that the two pressure tubes failed in similar modes in short succession indicated that the clamp most likely failed first, resulting in the subsequent failure of the tubes. Since the clamp was likely fractured when the first fractured fuel pressure line was replaced, the clamp was either not inspected or inadequately inspected at the time of the maintenance. ## Factual narrative On May 12, 2016, about 1413 Pacific daylight time, a Cessna 208B, N1114A, was substantially damaged during a forced landing near Acampo, California. The airplane was registered to Flanagan Enterprises (Nevada) INC., and operated by the Parachute Center under the provisions of 14 Code of Federal Regulations Part 91. The commercial pilot sustained minor injuries and his 17 passengers were not injured. Visual meteorological conditions prevailed and no flight plan was filed for the skydiving flight. The local flight originated about 1 minute prior to the accident. The pilot reported that following takeoff from runway 26, he made a right turn and continued his climb for the skydive drop, however, as the airplane passed 1,000 ft above ground level (agl), the engine lost power. The pilot initiated a turn toward the airport, however, realized he was unable to make it, and landed in an open field. During the landing roll, the airplane exited the field, crossed a road, impacted a truck, continued into a vineyard, and nosed over. Examination of the airplane by a Federal Aviation Administration inspector revealed that the fuselage and left wing were substantially damaged. The wreckage was recovered to a secure location for further examination. Examination of the recovered wreckage was conducted on May 17 and 18, 2016. The engine remained partially attached to the fuselage. The fuel pressure line that connects the fuel control unit to the airframe fuel pressure transducer, Pratt & Whitney Canada (PWC) part number 3033981, was fractured below the fuel control unit fitting swaged seat. The supporting clamp, PWC part number 3006614, was fractured and was separated from its mating fuel pressure fuel line, PWC part number 3032010. In addition, the airframe P3 air line that provides air to the vacuum system exhibited a hole within the tube. The operator reported that they had replaced the fuel line, PWC part number 3033981, the night before the accident due to the original fuel line being fractured. They stated that the new fuel line had about 4 hours of operational time since the installation. Review of the maintenance logbooks revealed that an entry regarding the replacement of the fuel line was dated April 11, 2016, with no airframe, engine, or HOBBS meter times listed. The operator was further questioned about what manual they used regarding engine maintenance and they replied they used the manufacturers manual for all engine related maintenance. When questioned about the supporting clamp, PWC part number 3006614, the operator stated that the clamp was attached at the time of the fuel line replacement. Both the new and old fuel lines and separated clamp were sent to the National Transportation Safety Board Materials Laboratory for further examination. A Senior Materials Engineer examined the fuel lines and clamp and reported that the fuel line fracture surfaces were examined with the aid of a digital optical microscope and a scanning electron microscope andboth fractured tubes were found to exhibit features consistent with crack initiation due to reverse bending fatigue. The metal band of the clamp was fractured near the intersection of the tab and the loop portion of the clamp. The fracture surfaces were examined and exhibited features consistent with crack initiation at the inward-facing side of the tab due to bending fatigue. The fracture surface exhibited a comparatively flat appearance with curved crack progression marks on the fracture surface consistent with the crack initiating on the inward-facing side of the tab. For further information, see the Materials Laboratory Factual Report within the public docket for this accident. ## Aircraft - Registration: [N1114A](https://openairdocs.org/aircraft/N1114A), registered now, S/N 208B0309 (OpenAirDocs) - Reported make and model: CESSNA 208B (B) - Registry model: [Cessna 208B](https://openairdocs.org/model/cessna-208b) (registry code 2073701) (OpenAirDocs) - Registry engine: [Pratt & Whitney PT6A series](https://openairdocs.org/engine/pratt-whitney-pt6a-series) (registry code 52032, turbo-prop) (OpenAirDocs) - Category: Airplane - Serial number: 208B0309 - Year built: 1992 - Airframe hours: 12848.9 - Engines: P&W PT6A SER turbo prop - Damage: Substantial damage - Flight: Skydiving, Part 91 - Operator: Parachute Center - Registered owner: Flanagan Enterprises (Nevada) Inc - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, February 10, 2016, 69 hours before - Departed: 1O3, Acampo, CA - Destination: 1O3, Acampo, CA - Airport: 1O3, Lodi ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 64; injuries: minor; commercial; airplane ratings: single-engine sea, single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review March 2, 2015; seat: left; restraint: 3-point; flight hours: 7,050 total, 253 in this make and model, 6,680 as pilot in command, 80 in the last 90 days, 25 in the last 30 days, 4 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 88 °F, dew point 54 °F - Altimeter: 29.95 inHg - Observed at: KSAC, 21 nm away ## 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 20160512007799A](https://openairdocs.org/incident/20160512007799A), May 12, 2016: Cessna 208B, Acampo, CA, Destroyed. A parachute operations aircraft was destroyed with an off field landing accident from the Lodi Airport (1O3), Acampo, California. Aircraft took off from runway… ## Docket (7 files) The files NTSB released with the investigation on November 21, 2017, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=93159. 11.0 MB in all. - Materials Laboratory Factual Report 17-028 (item 1, .PDF, 12 photos, 6.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40458258&FileExtension=.PDF&FileName=Materials%20Laboratory%20Factual%20Report%2017-028-Master.PDF - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 2, .PDF, 3.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40458259&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Record of Conversation - Operator (item 3, .PDF, 53 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40458260&FileExtension=.PDF&FileName=Record%20of%20Conversation%20-%20Operator-Master.PDF - NTSB Airframe and Engine Examination Summary (item 4, .PDF, 51 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40458261&FileExtension=.PDF&FileName=NTSB%20Airframe%20and%20Engine%20Examination%20Summary-Master.PDF - Statement of Party Representatives to NTSB Investigation - Blackhawk Modifications (item 5, .PDF, 506 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40458262&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation%20-%20Blackhawk%20Modifications-Master.PDF - Statement of Party Representatives to NTSB Investigation - Cessna (item 6, .PDF, 464 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40458263&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation%20-%20Cessna-Master.PDF - Release of Aircraft Wreckage, NTSB Form 6120.15 (item 7, .PDF, 251 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40458264&FileExtension=.PDF&FileName=Release%20of%20Aircraft%20Wreckage,%20NTSB%20Form%206120.15-Master.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.