SPOKANE, Wash. – The family of a pilot who died from his injuries in a Spokane plane crash after the wrong fuel was filled into his plane has filed a wrongful death lawsuit against the refueling company.

Monday marked one year since the crash at Spokane's Hamilton Street overpass.

Michael Clements, 61, from Alberta was on his way to California and stopped at Felts Field to refuel.

His plane crashed shortly after takeoff. He died at the hospital two days later from severe injuries.

The NTSB investigation later confirmed his Piper Malibu was filled with Jet A fuel, instead of the AV gas the aircraft required.

Watch 2015 story: Alberta pilot crashes near Hamilton Street exit

The lawsuit claimed it was a Western Aviation employee who filled the plane full of the wrong fuel, pumping 52 gallons of Jet A into the two tanks over the wings.

The lawsuit also claimed that employee ignored and disregarded numerous safety measures designed to avoid that type of error.

Aviation experts said pump nozzles for the two types of fuel are supposed to be different, but in this case, the lawsuit stated the fuel attendant used a "rogue nozzle," allowing the plane to be filled with the wrong fuel.

The lawsuit also stated the employee ignored labels on the aircraft itself that warned to only fill the plane with AV gas.

The attorney handling the case for Clements family said the family is deeply saddened on the one year anniversary of his death.

The attorney added the family’s experts continue to independently and thoroughly investigate the accident and identify the responsible parties.

Western Aviation did not return calls seeking comment on whether the company had changed its refueling regulations.

The FAA and NTSB said the investigation into what happened is still in the preliminary stage. Neither agency said when it expected to complete the investigation.