Investigators Blame Pilot for ’89 Plane Crash That Killed 5 : Report: Safety board said improper installation of a part on twin-engine craft contributed to death of Canadian family.

The National Transportation Safety Board has blamed pilot error and improper maintenance for a twin-engine plane crash here three years ago that killed all five members of a Canadian family heading home from a Disneyland holiday.

“The pilot failed to attain adequate airspeed before maneuvering back toward the airport, which resulted in a loss of aircraft control,” the safety board said in a report on the March 31, 1989, crash. A contributing factor, the agency said, was an improperly installed part that allowed contamination of fuel injectors and a loss of power in the right engine.

The agency’s findings, obtained by The Times in response to a Freedom of Information Act request, do not identify who was at fault for the improper installation. Agency investigators were unavailable for comment Friday because of the holiday weekend.

Previously, however, agency investigators had said they found traces in the engine of a foam rubberlike sealer material that had come from an air inlet door. An improperly installed fuel line modification kit failed to filter out the foreign material, the investigators had said, but the final NTSB findings released this week were the first to mention pilot error as the leading cause of the crash.

The aircraft, a twin-engine Aerostar, can be flown on one engine, but doing so requires a skilled pilot, according to aviation experts.

Two minutes after taking off from John Wayne Airport for a return trip to Canada, the plane went down in the Newport Beach neighborhood of Eastbluff, narrowly missing several people on the Newport Beach Tennis Club’s courts. No one on the ground was hurt, but several people were treated for shock.

The aircraft was flown by Anthony Deis, 35, an experienced pilot and millionaire owner of three jewelry stores in the Canadian province of Alberta. Deis, his wife, Marilyn Aletha, 34, and their daughters--Amanda Lynn, 10, Jaclyn Dawn, 7, and Kimberly Lisa, 5--flew from their home in Camrose, Alberta, on March 22 for a vacation in Southern California. During their stay in Orange County, the family visited Disneyland.

Witnesses on the ground said the plane’s right engine backfired and trailed black smoke during the takeoff ground roll, which lasted about 80% longer than normal. “Witnesses said the aircraft staggered off the ground, was slow and never got above 100 feet,” the safety board said.

Deis radioed the tower that he had to return to the runway and banked steeply to the left, a maneuver that apparently stalled the airplane, the safety board said.

The plane then nose-dived into two courts at the tennis club.