Fuel tank mixup led to street landing, TSB report says
Failure to switch from empty outboard tanks to full ones behind 36 St. N.E. scare
Failure to switch from empty outboard fuel tanks to inboard tanks with adequate fuel led to the emergency landing of a small airplane on a northeast Calgary street in April, a Transportation Safety Board of Canada report has found.
The fact-gathering investigation details the incident on April 25, when the Piper PA-31-350 Navajo Chieftain owned by Super T Aviation made an emergency landing in the northbound lanes of 36th Street N.E. around 5:45 a.m. None of the crew members or passengers was injured.
After departing the Medicine Hat Airport, the aircraft climbed to a cruising altitude of 8,000 feet above sea level and the crew switched the fuel selectors from inboard to outboard fuel tanks.
Before the plane began its descent to the Calgary airport, the two-person crew went through a routine checklist. But when the aircraft was about 12 nautical miles south of its designated runway, the right engine started to surge. The first officer ran an engine failure inflight checklist, but a “cause check,” which directs the crew to check fuel flow, quantity and fuel selector position, was not completed, the report states.
Around 5:42 a.m. and at 5:43 a.m., the flight crew made two Mayday calls and informed the airport control tower they would be landing on a road.
“The crew is to monitor the fuel level in the outboard tanks and, either if they run low on fuel or as part of the checklist, they move the selectors to inboard,” said Jeremy Warkentin, regional senior technical investigator with the Transportation Safety Board of Canada.
“When we got to the scene of the aircraft and did our examination, there was no fuel in the outboard tanks at that point and ... approximately 40 gallons remained in the inboard tanks.”
The report states that Super T Aviation’s normal procedures checklist had two differences from the checklist published by the aircraft manufacturer, including a step in the manufacturer’s checklist to check that the fuel selectors are set to inboard before descent.
Warkentin said technically there were no problems with the engines, but that with the outboard tanks selected, fuel starvation to the engine led to the loss of power and emergency landing.
The investigator said the report did not involve a safety recommendation to the industry, but the board did communicate with the operator, which took multiple safety actions.
Those steps, according to the report, include changes to the normal procedures checklist, including the addition of a step to set a timer when the outboard tanks are selected, and transferring the direction to switch to inboard tanks from the company’s beforelanding checklist to its descent checklist. More details on procedures for rough-running engines and preparing passengers for an emergency landing have also been added.
The report indicates that when the flight crew determined the plane wouldn’t make it to the airport, “their prioritization of selecting a suitable alternate landing area and managing the energy state of the aircraft contributed to the success of the emergency landing.”
The operations manager of Super T Aviation could not be reached for comment Thursday.