Kansas City, Mo ? An airplane parts manufacturer knew for 20 years that one of its products was causing airplanes to crash but did nothing about it, an attorney for the family of the late Gov. Mel Carnahan said Wednesday.

The part, called a vacuum pump, is at the center of a lawsuit filed against Parker Hannifin Corp., of Cleveland, by Carnahan’s widow, Jean, and her three adult children, Russell, Thomas and Robin Carnahan. All four family members were in Jackson County Circuit Court Wednesday to hear opening statements in the case.

Randy Carnahan, the governor’s son and the pilot, also died in the plane crash south of St. Louis, along with the governor’s longtime aide, Chris Sifford. The plane crashed Oct. 16, 2000, while Mel Carnahan campaigned for a U.S. Senate seat held by John Ashcroft, now the U.S. attorney general.

Carnahan won the race posthumously and Jean Carnahan was named to the seat, which she lost two years later to Republican Jim Talent.

In a three-hour opening statement Wednesday, attorney Gary Robb detailed evidence he said would show Parker Hannifan knew the vacuum pump, which powered the directional gyroscope and attitude indicator — instruments critical to showing a plane’s position in the air — had caused crashes that resulted 46 deaths.

In his opening statement, Parker Hannifan’s attorney, Wayne Taff, countered the case was not about the vacuum pump failing. He said evidence would show the crash occurred after Randy Carnahan, “through no fault of his own,” suffered spatial disorientation, which left him unable to tell where he was going or control the airplane.

Taff and Robb both likened spatial disorientation to the feeling one has after someone spins them very quickly on a chair 30 or 40 times.

“(Spatial disorientation) is the most horrifying experience a pilot can experience,” Taff said.

Robb said the pump’s failure left Randy Carnahan “flying blind” and disoriented on the night of the crash.

Robb played the tape of a discussion between the airport and Randy Carnahan, which included Carnahan saying the attitude indicator had failed and asking for directions.

The younger Carnahan reported problems with the primary attitude indicator, also known as an artificial horizon, shortly after takeoff from a suburban St. Louis airport en route to New Madrid. The primary attitude indicator tells a pilot whether the plane is banking and whether the nose is high or low.

The National Transportation Safety Board reported the primary attitude indicator was not working properly when the Cessna 335 crashed in fog, rain and darkness.