Occurrence
The Piper Navajo Chieftain PA31-350, serial number 31-8252042, was on an instrument flight rules (IFR) flight from Sanikiluaq to Iqaluit, Northwest Territories, with two pilots and two passengers on board. After checking runway conditions and weather, the pilot commenced the take-off run on runway 27. Following take-off, the pilot observed flames emanating from the right engine cowl. The right engine was shut down, but the aircraft could not maintain a sufficient rate of climb and crashed on flat, snow-covered ground approximately one mile from the end of the runway. The aircraft sustained substantial damage upon landing. After the aircraft came to a stop, the occupants evacuated via the left front door and walked back to the airport terminal for shelter and assistance. No injuries were reported. The occurrence happened at night in instrument meteorological conditions.
Weather and Airport
The weather at the time of the accident was: wind 310 degrees true at 20 knots, visibility one and a half miles in light snow and blowing snow, temperature minus 22 degrees Celsius, dew point minus 24 degrees Celsius, altimeter 30.04. The Sanikiluaq aerodrome, operated by the government of the Northwest Territories, consists of one gravel runway 3,800 feet long by 100 feet wide. The airport is equipped with a Community Aerodrome Radio Station (CARS). At the time of the accident, the CARS employee (observer/communicator) was not on duty because the flight was after usual business hours. The pilot had elected not to call the CARS employee. However, the employee heard that an aircraft had landed and came to the airport on his own initiative to help prepare the flight. When the aircraft took off, he left the CARS and did not monitor the aircraft. The pilot had not officially requested monitoring. There are no aviation regulations requiring that an observer/communicator be present in the CARS when an aircraft lands at or takes off from the aerodrome.
Occupants and Crew
Records revealed that the pilot was certified and qualified for the flight under existing regulations. He had approximately 2,800 flying hours, including approximately 1,400 hours on multi-engine aircraft and 1,000 on type. A trainee pilot was seated in the right-hand seat. On this flight, the pilot-in-command had decided that the trainee pilot would observe.
Findings
The crew reported that the engines were producing maximum power on take-off and that the accident occurred when the right engine was shut down because of the engine fire. The pilot said he observed that the propeller was not feathered after the accident, although he thought it should have been because he had carried out the feathering procedure. Visual examination of the right propeller revealed one blade bent backward over 100 degrees at a point approximately 15 inches from the hub; the other two blades were bent backward approximately 70 degrees about 12 inches from the tip. The right propeller pitch was not determined but was estimated to be high. The observed damage was consistent with a propeller that was feathered but still turning at impact.
The manufacturer's Pilot's Operating Handbook contains a warning that as much as 100 feet may be lost during gear and flap retraction and transition to best single-engine angle of climb speed (104 knots), and that negative climb performance may result from an engine failure after lift-off before gear and flaps are retracted, the failed engine propeller feathered, cowl flap closed, and a speed of 106 knots attained. Based on the climb chart, with weight configuration and ambient conditions, the aircraft could have achieved a rate of climb of approximately 1,400 feet per minute on two engines with gear and flaps retracted, dropping to 230 feet per minute on one engine with gear and flaps retracted, engine cowl flap closed, and aircraft inclined five degrees toward the operating engine, maintaining 106 knots. According to the pilot, the aircraft had attained a speed in excess of 85 knots when he initiated rotation. About 100 feet above ground level, while retracting the landing gear, he saw flames and immediately started the emergency procedure to shut down the right engine. During the engine shutdown procedure, the aircraft lost altitude and crashed.
The wreckage was found approximately one mile beyond the end of runway 27 and a few hundred feet left of the runway center line. Visible damage was limited to the two propellers and the upper cowl of the right engine. No evidence of a system malfunction was found. The left engine was developing full power at impact. The right engine exhibited severe fire damage to the outboard half of the engine cowl, with flames melting through the upper outboard half. Examination revealed fire damage limited mainly to the engine cowl and the flexible air intake duct to the heat exchanger for the cabin auxiliary heating unit. The exhaust muffler was found disconnected from the exhaust pipe for cylinders Nos. 1, 3, and 5, butted up against each other with only about half their respective diameters connecting. Two stainless steel collars were found on the far aft side of the No. 5 cylinder exhaust pipe, preventing the exhaust muffler from being inserted more than one-quarter inch over the pipe, whereas the parts were designed to overlap by more than an inch and a half. The installation was not in accordance with existing requirements.
Maintenance and Regulatory Issues
A review of the aircraft log-books indicated that the aircraft was maintained in accordance with the inspection schedule approved by Transport Canada and the manufacturer's progressive inspection program. However, inspection of the aircraft files revealed several deficiencies in records management. Most documents could not be identified as relating to a specific aircraft; no dates, signatures, or aircraft registration numbers were indicated. Records were incomplete and inadequate. A review of the log-book revealed that the persons in charge of maintenance had authorized the aircraft to be used while some deficiencies had not been corrected, including an unserviceable fuel regulator shut-off. The company was monitored by Transport Canada, with limited oversight. In 1997, at least three different persons held the position of Director of Maintenance. On 22 December 1997, the Director of Maintenance went on vacation, and on 31 December 1997, he resigned, effective 22 December 1997. At the time of the accident, the position was vacant. A post-occurrence review by Transport Canada from 9 to 11 February 1998 confirmed the findings, and the company operating certificates were temporarily suspended.