Engine fire leads to crash of Piper Navajo in Sanikiluaq

Casualties unknown • Sanikiluaq, Northwest Territories, CA

A Piper Navajo Chieftain crashed during takeoff in the Northwest Territories after an engine fire caused by improper exhaust system maintenance.

What happened

During a night flight from Sanikiluaq to Iqaluit, a Piper Navajo Chieftain carrying two pilots and two passengers experienced an engine fire shortly after takeoff. While performing the takeoff roll on runway 2-7 under instrument meteorological conditions, the pilot observed flames emerging from the right engine cowl.

In response to the fire, the pilot shut down the right engine. However, the aircraft was unable to maintain a sufficient rate of climb and struck the snow-covered ground approximately one mile from the end of the runway. The aircraft sustained substantial damage, but all four occupants were able to evacuate through the left front door and walk to the airport terminal. There were no injuries reported.

The investigation

Investigators examined the wreckage and found that the fire was concentrated on the right engine cowl, where intense heat had melted holes through the fiberglass skin. The investigation revealed that the exhaust muffler had become disconnected from the exhaust pipe for cylinders 1, 3, and 5. This disconnection was caused by the improper installation of two stainless steel collars on the No. 5 cylinder exhaust pipe, a modification that did not follow manufacturer instructions or approved procedures. This misalignment caused exhaust gases to be projected directly onto the engine cowling.

Further scrutiny of the operator's maintenance records revealed significant systemic issues. The investigation found that the company's record-keeping was inadequate, with many documents lacking dates, signatures, or aircraft registration numbers. Additionally, the maintenance department had experienced high turnover, with three different Directors of Maintenance in 1997, and the position was vacant at the time of the accident. The investigation also noted that the aircraft had been operated despite uncorrected mechanical deficiencies.

Findings

  • The aircraft could not maintain a positive rate of climb after the right engine was shut down because the engine failure occurred at the most critical phase of flight, between rotation and acceleration.
  • An improper modification to the exhaust system caused the exhaust pipe to disconnect, leading to the engine fire.
  • The installation of stainless steel collars was inconsistent with the manufacturer's instructions and contributed to the fire risk.
  • The pilot's decision not to request Community Aerodrome Radio Station (CARS) services after hours meant there was no active flight monitoring, which could have facilitated a more rapid rescue.
  • Maintenance oversight was compromised by frequent leadership changes and incomplete aircraft records.

Safety action

Following the investigation, Transport Canada suspended the Aircraft Maintenance Organization certificate of the operator.

Probable cause

An improper modification to the cabin heating unit, which deviated from manufacturer recommendations, caused an engine fire in the right engine cowl. The subsequent shutdown of the engine during the critical climb phase left the aircraft unable to maintain altitude, resulting in the crash.

Frequently asked questions

What happened in the 1998-01-20 Piper PA31-350 Navajo Chieftain C-FDNF accident near Sanikiluaq, Northwest Territories, CA?

A Piper Navajo Chieftain crashed during takeoff in the Northwest Territories after an engine fire caused by improper exhaust system maintenance.

What aircraft was involved and where did it happen?

The accident on 1998-01-20 involved a Piper PA31-350 Navajo Chieftain C-FDNF, operated by Air Nunavut Ltd., at Sanikiluaq, Northwest Territories, CA.

What was the probable cause of the accident?

An improper modification to the cabin heating unit, which deviated from manufacturer recommendations, caused an engine fire in the right engine cowl. The subsequent shutdown of the engine during the critical climb phase left the aircraft unable to maintain altitude, resulting in the crash.

Loading the flight search…