# NTSB WPR14LA377: Piper PA 28, N5948W, Lone Pine, CA, September 15, 2014 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: September 15, 2014, 12:30 local (19:30 UTC) - Place: Lone Pine, CA - Coordinates: 36.45222, -118.339721 - Nearby events: https://openairdocs.org/map.md?lat=36.4522&lon=-118.3397&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-cruise: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338) - Highest injury: Serious injuries - Injuries: 1 serious - Status: Completed, report February 13, 2017 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Hartzell Propeller Inc, Federal Aviation Administration - NTSB case key (mKey): 90083 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR14LA377 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/90083/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=90083 - Page: https://openairdocs.org/ntsb/WPR14LA377 ## Probable cause The fatigue failure of a propeller blade due to a propeller strike by/of an unidentified object at an unknown time. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Propeller system: propeller blade section](https://openairdocs.org/ntsb-findings/01046111): Aircraft › Aircraft propeller/rotor · Damaged/degraded (probable cause); cases with it: [Piper PA-28-150, 1 case](https://openairdocs.org/ntsb-findings/01046111/cases.md?model=7102804), [All aircraft, 51 cases](https://openairdocs.org/ntsb-findings/01046111/cases.md) - [Propeller system: propeller blade section](https://openairdocs.org/ntsb-findings/01046111): Aircraft › Aircraft propeller/rotor · Fatigue/wear/corrosion (probable cause); cases with it: [Piper PA-28-150, 1 case](https://openairdocs.org/ntsb-findings/01046111/cases.md?model=7102804), [All aircraft, 51 cases](https://openairdocs.org/ntsb-findings/01046111/cases.md) - [Propeller system: propeller blade section](https://openairdocs.org/ntsb-findings/01046111): Aircraft › Aircraft propeller/rotor · Failure (probable cause); cases with it: [Piper PA-28-150, 1 case](https://openairdocs.org/ntsb-findings/01046111/cases.md?model=7102804), [All aircraft, 51 cases](https://openairdocs.org/ntsb-findings/01046111/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute-cruise: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338) (defining event); cases with it: [Piper PA-28-150, 1 case](https://openairdocs.org/ntsb-events/338/sequence.md?model=7102804), [All aircraft, 563 cases](https://openairdocs.org/ntsb-events/338/sequence.md) - [Enroute-cruise: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Piper PA-28-150, 3 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=7102804), [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: [Piper PA-28-150, 5 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=7102804), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The private pilot reported that, 2 hours into the personal cross-country flight, he observed a "flash of something" depart the front of the airplane and that the airplane instantly began violently shuddering and vibrating. The pilot immediately landed the airplane in a clearing, and he observed that almost half of one of the propeller blades was missing. A postaccident examination of the propeller assembly revealed that the propeller blade was fractured about 24 inches from the blade butt. Examination of the fracture surface revealed characteristics of fatigue failure that originated in a stress raiser located about 1.25 inches from the leading edge on the lower blade surface. A witness mark, in the form of a distinct score line, was present, indicating that the blade experienced a strike, which created a flaw of critical size at the fatigue origin site that ultimately propagated to failure. The investigation could not determine whether an object struck the blade or the blade struck an object or when the strike occurred. ## Factual narrative On September 15, 2014, about 1230 Pacific daylight time, a Piper PA-28-150, N5948W, experienced severe vibrations and the pilot initiated a forced landing onto a meadow about 15 miles southwest of Lone Pine, California. The pilot was seriously injured, and the airplane sustained substantial damage to both wings. The airplane was registered to and operated by the pilot as a personal flight under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed, and no flight plan was filed for the flight which departed from Reid-Hillview Airport of Santa Clara County, San Jose, California at 1040. The pilot reported that two hours into the flight he observed a "flash of something" depart the front of the airplane; the airplane instantly began shuddering and vibrating violently. The pilot immediately reduced the throttle to idle and found a clear spot to land. With the engine at idle the pilot could see that about half of one of the propeller blades was missing. He also observed considerable movement of the front of the airplane. He descended the airplane rapidly to the clearing; as he approached the clearing, he observed large rocks that the airplane barely cleared. He held the nose of the airplane up as long as possible; the left landing gear touched the ground first and separated from the airplane followed by the right landing gear. As the nose wheel touched down it also collapsed and the airplane slid on its belly until it impacted a rock and came to a rest. The propeller assembly was taken to Hartzell Propeller Inc for examination with a Hartzell Propeller representative. The examination revealed that both propeller blades appeared to be in a high pitch position. One of the two blades was intact and exhibited extensive spanwise scoring, along with chordwise/rotational scoring near the blade tip. The other blade was fractured about 24 inches from the blade butt. The propeller hub was disassembled and the blades were removed. The pitch change knob on the fractured blade was bent, and the pitch change knob on the intact blade was fractured. The fracture surface of the fractured propeller blade was examined and it exhibited fatigue failure characteristics that originated in a stress raiser located about 1.25 inches from the leading edge on the lower blade surface. A witness mark, in the form of a distinct score line, was present at the fatigue origin site. The airplane's most recent maintenance was an annual/100 hour inspection that occurred on August 21, 2014 at a tach time of 2,096 hours, and a propeller total time in service of 2,049 hours. During the inspection, the leading edges of the propeller blade were filed. ## Aircraft - Registration: [N5948W](https://openairdocs.org/deregistered/N5948W-2018-06-01), registration cancelled 2018-06-01, S/N 28-3636, built 1966 (OpenAirDocs) - Reported make and model: PIPER PA 28 (150) - Registry model: [Piper PA-28-150](https://openairdocs.org/model/piper-pa-28-150) (registry code 7102804) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 28-3636 - Year built: 1966 - Airframe hours: 7082 - Engines: LYCOMING O-320 SERIES 180 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, August 21, 2014, 6 hours before - Departed: RHV, San Jose, CA - Destination: PVT, Darwin, CA - Equipment: Unknown ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 65; injuries: serious; private; airplane ratings: single-engine land; medical: class 2, with waivers/limitations; last flight review October 16, 2012; seat: left; restraint: 3-point; flight hours: 1,052 total, 1,001 in this make and model, 975 as pilot in command, 9 in the last 90 days, 6 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 190° at 6 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 91 °F, dew point 41 °F - Altimeter: 30.04 inHg - Observed at: BIH, 52 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 20140915016459A](https://openairdocs.org/incident/20140915016459A), Sep 15, 2014: Piper PA-28-150, Lone Pine, CA, Destroyed. [privacy data omitted] Said that when he was at 13,000 feet headed to his destination he noticed that a shiny object seemed to fly from the propeller arc and… ## Docket (7 files) The files NTSB released with the investigation on December 22, 2016, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=90083. 5.0 MB in all. - Metallurgical Laboratory Report - American Testing Services, Ltd. (item 1, .PDF, 1.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40447794&FileExtension=.PDF&FileName=Metallurgical%20Laboratory%20Report%20-%20American%20Testing%20Services,%20Ltd.-Master.PDF - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 2, .PDF, 249 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40447795&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Propeller Assembly Examination Summary (item 3, .PDF, 5 photos, 639 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40447796&FileExtension=.PDF&FileName=Propeller%20Assembly%20Examination%20Summary-Master.PDF - Maintenance Records (item 4, .PDF, 907 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40447797&FileExtension=.PDF&FileName=Maintenance%20Records-Master.PDF - Statement of Party Representatives to NTSB Investigation (item 5, .PDF, 113 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40447798&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation-Master.PDF - Release of Aircraft Wreckage, NTSB Form 6120.15 (item 6, .PDF, 33 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40447799&FileExtension=.PDF&FileName=Release%20of%20Aircraft%20Wreckage,%20NTSB%20Form%206120.15-Master.PDF - On Scene Photographs - Courtesy of the National Park Service (item 7, .PDF, 4 photos, 2.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40447800&FileExtension=.PDF&FileName=On%20Scene%20Photographs%20-%20Courtesy%20of%20the%20National%20Park%20Service-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.