Sunday, February 26, 2017

Piper PA-28-140, N5948W: Accident occurred September 15, 2014 in Lone Pine, Inyo County, California

Pilot Tim Cassell
~




The National Transportation Safety Board did not travel to the scene of this accident.

Additional Participating Entities:
Federal Aviation Administration / Flight Standards District Office; Fresno, California 
Hartzell Propeller Inc; Piqua, Ohio

Aviation Accident Final Report -  National Transportation Safety Board: https://app.ntsb.gov/pdf

Docket And Docket Items -  National Transportation Safety Board: https://dms.ntsb.gov/pubdms

Aviation Accident Data Summary - National Transportation Safety Board: https://app.ntsb.gov/pdf

http://registry.faa.gov/N5948W 

NTSB Identification: WPR14LA377
14 CFR Part 91: General Aviation
Accident occurred Monday, September 15, 2014 in Lone Pine, CA
Probable Cause Approval Date: 02/13/2017
Aircraft: PIPER PA 28, registration: N5948W
Injuries: 1 Serious.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

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.

The National Transportation Safety Board determines the probable cause(s) of this accident as follows:
The fatigue failure of a propeller blade due to a propeller strike by/of an unidentified object at an unknown time.






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. 



NTSB Identification: WPR14LA377
14 CFR Part 91: General Aviation
Accident occurred Monday, September 15, 2014 in Lone Pine, CA
Aircraft: PIPER PA 28, registration: N5948W
Injuries: 1 Serious.

This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed. NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

On September 15, 2014, about 1115 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 it is unknown if a flight plan was filed for the flight which departed from Reid-Hillview Airport of Santa Clara County, San Jose, California.

The pilot reported to first responders that while he was in cruise flight part of the propeller blade separated from the airplane. The airplane vibrated so violently that the only thing he could do was to land immediately.

The airplane has been recovered to a secure location for further examination.

No comments: