Aluminum from a broken air filter caused a small plane to lose power and crash in Penn Township last year, killing a pilot and three skydivers, the National Transportation Safety Board has ruled.
Pilot error also contributed to the June 16, 2003, crash at the Greensburg-Jeannette Regional Airport in Boquet, Penn Township, according to the federal agency. The investigation found that "a factor was the pilot's delayed decision to perform a forced landing after experiencing a partial loss of engine power."
But the agency offered no explanation as to why two pieces of aluminum from an air filter mount frame broke off before they were ingested into the combustion chamber of the Teledyne Continental Motor engine powering the Cessna 205, which crashed into a row of trees about 250 feet from the runway.
Victims included the pilot, Richard diPretoro, 54, of Pittsburgh, and three skydivers from Skydive Boquet, Charles Bryant, 61, the owner of the airplane; Terry Blanish, 52, of West Newton; and David Ray, 49, of Seward.
A fourth parachutist, Brian Fox, 31, also of Seward, was seriously injured. He was unable to help federal aviation investigators because he has no recollection of the accident.
"Examination of the engine cylinders revealed heavy black combustion deposits on the number 3 and number 6 cylinder chambers, exhibiting signatures of operation with a foreign material. Additionally, two pieces of aluminum material were found in the combustion chamber of the number 6 cylinder," the panel wrote in its report. "The aluminum pieces were identified to be the same material as the air filter mount frame from the airframe induction system."
The engine's manufacturer, Continental Teledyne, a subsidiary of Pittsburgh-based Allegheny Teledyne, assisted in the inquiry. The manufacturer's report indicated fragments entering the engine "can affect proper valve operation/timing and produce a combustion miss, thereby diminishing the engine power output."
Investigators said they also discovered that a compression ring in the engine was broken and severely worn.
According to an unidentified eyewitness to the crash, the airplane engine began "sputtering" during its initial climb from the airport runway. NTSB investigators said the witness was watching activity at the airfield from a motorcycle on the airport ramp. The witness told investigators the plane then turned around, apparently to land, but "then continued past the runway and it appeared that the engine had regained power" before beginning another climb.
"The witness then lost sight of the airplane behind a trailer, but immediately heard the engine stop producing power, then heard the sound of an impact with trees. The witness also noted that when the airplane initially turned back, it had sufficient altitude and airspeed to reach runway 20," investigators said in the report.
Reports indicate that diPretoro was an experienced pilot with a commercial pilot's certificate and 809 flight hours. He had compiled 10 hours in the type of aircraft that crashed.
Witnesses said the airplane had made several flights earlier that day without problems.
The crash report also noted that small amounts of fuel were recovered from the fuel pump and fuel lines and tested. Although the report noted the fuel samples contained some "black particulate matter with white suspended contamination," the panel did not determine that the particulates in the fuel contributed to the engine's failure.
Repeated attempts to reach federal officials for comment on the report Tuesday were unsuccessful.
