ANC94FA106

The airplane was on a part 135 on-demand air taxi flight, when physical separation of the no. 3 cylinder and piston occurred and an in-flight fire ensued. Subsequently, the airplane crash landed on terrain near the shoreline of a body of water. One of the four occupants survived the crash, but the surviving passenger could not recall events that led to the accident. Maintenance records indicated that the #3 and #4 cylinder assemblies were installed about 220 flight hours before the accident. This maintenance was performed without removing the engine from the airplane. No problem with the airframe or engine was recorded subsequent to the cylinder change. Inspection of the engine revealed fatigue cracks in the case under the no. 3 cylinder. Magnified inspection of the case revealed wear and deformation damage, where the holding flange and inner skirt of the cylinder would normally be positioned, which was consistent with the cylinder moving in relation to the case. Also, mechanical damage was evident on the threads of the studs and both through-bolts.

History of flight

On August 14, 1994, at approximately 0927 Alaska daylight time (ADT), a wheel equipped Piper PA-32-260 Cherokee Six airplane, registration No. 4839S, owned and operated by Lake Clark Air, Inc., of Port Alsworth, Alaska, collided with terrain near the mouth of Lake Clark Pass, about 40 nautical miles northwest of Kenai, Alaska. The site of the accident is in the Big River Lakes region. The airline transport certificated pilot-in-command and two passengers received fatal injuries and the remaining passenger sustained serious injuries. The airplane was destroyed. At the time of the accident, the flight was being operated under the on-demand rules of 14 Code of Federal Regulation (CFR) Part 135. The flight last departed the Merrill Field Airport in Anchorage, Alaska at about 0808 on the morning of the fourteenth on a company visual flight rules (VFR) flight plan. The intended destination was Port Alsworth, Alaska, located about 140 miles to the southwest. Visual meteorological conditions prevailed at the time of the mishap. An emergency locator transmitter (ELT) signal associated with the crash site was initially picked up by civilian search aircraft at 1008. The crash site was located at about 1200 ADT.

Communication information

The pilot did not report any problems with the airplane, either prior to or during the en route portion of the accident flight.

Meteorological information

The Kenai Automated Flight Service Station 1046 ADT Record Observation for Big River Lakes, Alaska on August 14, 1994, was clear, visibility 70 miles, temperature 63F, dewpoint 50F, wind 150@4, altimeter 30.10Hg.

Passenger/witness information

The surviving passenger sustained serious injuries in the accident and has no recall of the events leading up to or immediately after the mishap. Aside from the surviving passenger, there were no additional witnesses to the accident.

Flightcrew information

The pilot was the holder of Airline Transport Pilot Certificate No. 2102759, with the ratings of airplane multi-engine land, and commercial privileges for airplane single engine land and sea, and multi-engine sea, latest issue date May 02, 1994. He also possessed flight and ground instructor certificates. His most recent flight medical examination occurred on June 30, 1994, at which time he was issued a 2nd Class Medical Certificate with the limitation that he possess corrective glasses for near vision. He completed his most recent 14 CFR Part 135 proficiency check on July 13, 1994. At the time of the accident, Mr. Reynolds had accrued a total flight time of 12,500 hours of which 500 hours were in the Cherokee Six aircraft. His total flight time and (time in the Cherokee Six) follows: last 90 days 300 hours (25 hours), last 30 days 100 hours (10 hours), last 24 hours 6.9 hours (0.6 hours).

Medical and pathological information

The autopsy on the pilot was performed by the Alaska State Medical Examiner, Doctor Michael T. Propst. The forensic toxicology was performed by the Federal Aviation Administration's Toxicology and Accident Research Laboratory in Oklahoma City, Oklahoma. Toxicological testing on the pilot were negative.

Aircraft information

The airplane, a Piper PA-32-260 Cherokee Six, having registration number N4839S, and serial number 32-1268, was manufactured in 1969 by the Piper Aircraft Corporation. At the time of the accident, the airframe had accrued 4702.5 hours. The airframe received its most recent 100 hour inspection on August 6, 1994, at which time it was found to be in airworthy condition.

Powerplant information

The airplane was powered by an Avco Lycoming Corporation normally aspirated horizontally opposed reciprocating engine, model O-540-E4B5, serial number L-6329-48C, with a power rating of 260 horsepower. The engine was installed on N4839S on February 10, 1993, at which time the engine had accrued 319 hours since major overhaul (SMOH). At the time of the accident, the engine had accrued 4071.7 operating hours since manufacture, 1266.7 hours SMOH, and 23.1 hours since its most recent 100 hour inspection on August 6, 1994, at which time it was found to be in airworthy condition. Factory new No. 3 (SN:5988-2) and No. 4 (SN:5988-1) cylinder assembles were installed with the engine on the airplane on June 11, 1994, 220 hours prior to the accident. The maintenance records did not indicate the reason for the cylinder changes. There was no indication in the maintenance entry concerning the cylinder work performed that any inspection, other than visual, was associated with the work activity.

Propeller information

Coupled to the engine was a Hartzell two blade propeller, model HC-C24K-1BF/F8477-2, serial number CH21213. The propeller underwent its most recent inspection on August 6, 1994, at which time it was found to be in airworthy condition.

Aircraft flight log review

At the request of the Safety Board's investigator-in-charge (IIC), the airline provided the aircraft flight log record for N4839S covering the period March 17, 1994 to August 11, 1994. The log pages were not numbered sequentially. The only means of identifying any particular log page was by calendar date. The log pages covering the period August 11, 1994 up to the time of the accident were reportedly still in the aircraft flight log on board the airplane and were not recovered. No aircraft discrepancies concerning engine roughness or performance were found in the maintenance log during the aforementioned period.

On scene wreckage and impact information

Alaska State Trooper (AST) recovery personnel arrived at the scene of the accident at approximately 1700 on the afternoon of the fourteenth. Further damage to aircraft by the AST's included folding the cabin roof back, tearing out the pilot seat, and cutting seat belts.

The Safety Board's IIC arrived at the accident site on August 17, 1994 to begin the on scene investigation. The site investigation was delayed by inclement weather and transportation logistics. The wreckage of the white and blue aircraft was located near the mouth of Lake Clark Pass, 40 miles northwest of Kenai, Alaska. The coordinates of the accident site were 60.51.14 north and 152.17.80 west.

On scene exterior observations

The plane was partially submerged on the south side of a waterway, known locally as Big River, and was resting against the river bank. The bank was about six feet in height and was covered on top with a thicket of alder trees. Pieces of wing skin, fiberglass material, a fuel tank, and the left side of the engine cowling were found among the trees. The main structure of the airplane was in the water partially submerged. The left wing and landing gear were separated from the aircraft and were about 75 feet down river adjacent to the bank. The right wing was twisted inverted and the landing gear was still attached. The wing appeared to be still connected to the fuselage. The engine was submerged and could not be examined. The nose gear, minus the tire, was protruding through the forward part of the cabin floor. The upper and lower halves of the right side of the fiberglass engine cowling were burned. The exterior paint along the right side of the airplane was burned, scorched, and discolored, beginning at the engine cowling traversing rearward to the forward portion of the main cabin/cockpit door.

On scene interior observations

The right upper interior portion of the right main door seal was discolored and there were pieces of suet along the right cabin wall and ceiling. The interior side of the main cabin door window on the right side of the airplane was covered with a thin grayish colored film.

The cockpit and cabin floor was buckled upward. The engine and flight control panel was not structurally secured to the aircraft