Imperial Oil said in early March that it intended to resume making 100 LL avgas after it resolved quality control issues that resulted in an interrupted supply to Canadian customers for much of February and March.

The company ordered a quarantine on all fuel shipped between Dec. 28 and Feb. 13 after tests revealed it might not meet conductivity standards which could lead to issues with capacitance-type fuel gauge sensors on aircraft and ground storage fuel tanks.

Imperial Oil said it had identified and tested all fuel in the field by March 8 and that 70 percent was fit for use. It had earlier said that the deficient fuel was unlikely to damage any aircraft or fuel dispensing equipment.

As those tests proceeded, the company was arranging for alternative sources until it could resume manufacturing and predicted that fuel supplies would return to normal by the end of March.

“This has been a challenging situation and we appreciate all of the patience, understanding and cooperation we have received from our customers, their resellers and from end users, said Imperial Vice President Jon Wetmore. “We recognize this situation has significantly disrupted the avgas flying community and we apologize for this.”

The affected fuel was shipped from the company’s Strathcona refinery in Edmonton to wholesalers supplying customers throughout Western Canada and in Eastern Ontario.

Many of the affected areas were in the grip of severe winter weather that minimized the impact on piston-engine customers but B.C.’s coastal areas were significantly affected. Several airports around Vancouver ran out of fuel and that grounded flight schools and other GA businesses. Some businesses arranged for fuel to be shipped from the U.S. but it was priced about 25 percent higher than the Esso product.