The families of two U.S. soldiers who were in a fatal helicopter crash in Afghanistan in 2013 have filed a lawsuit against a company that makes a key piece of the aircraft involved, saying the aviation firm is responsible for the crash.

Army Chief Warrant Officer 3 James E. Groves III, 37, was killed in the crash of the Kiowa Warrior OH-58D on March 16, 2013. His co-pilot, 1st Lt. Jonathon K. Kohl, 25, suffered severe spine and head trauma, and has undergone numerous surgeries, said an attorney for the two families, Timothy Loranger. Kohl remains confined to a wheelchair with a long list of medical ailments.

The wrongful death and personal injury lawsuit names Goodrich Pump and Engine Control Systems Inc., of Charlotte, N.C., and the parent company that acquired it around the time of the crash, Triumph Group Inc., of Berwyn, Pa. The suit cites the failure of a component in the aircraft’s Full Authority Digital Electronic Control (FADEC), a digital device that makes sure there is enough fuel going to the helicopter’s engine.

Triumph could not be reached immediately for comment. The lawsuit alleges the company’s design of the engine control unit in the FADEC was “defective and unreasonably dangerous,” and accuses Goodrich and Triumph of concealing defects in it while continuing to supply parts to companies and the U.S. government.

“The defendants knew that the consequences of these failures were and are serious injury and death, including the death of Plaintiffs’ decedent Groves and permanent physical injuries suffered by Kohl,” the lawsuit said.

“This problem is related to a design issue and also a manufacturing defect,” Loranger said in a phone interview Tuesday. “When it came off the line, it had problems.”

The lawsuit seeks compensatory damages of at least $100,000, attorney fees and other legal bills for both families, along with “any other relief” the court deems appropriate. The suit was filed in the Philadelphia County Court of Common Pleas.

Army officials declined to comment, citing the pending litigation. It is unclear how many other allegedly defective parts may be i use in military aircraft.

Loranger, of the firm Baum, Hedlund, Aristei & Goldman in Los Angeles, said the failure of the company’s engine control unit has been cited in other crashes, including one that killed Army Capt. John David Hortman and Chief Warrant Officer 3 Steven B. Redd in August 2011 at Fort Benning, Ga. They were flying an AH-6M Little Bird helicopter for the 160th Special Operations Aviation Regiment, which flies missions in support of Army Rangers, Navy SEALs, and other elite U.S. troops.

As Checkpoint reported in September, the crash that killed Groves and injured Kohl occurred after a test-fire exercise north of Kandahar Airfield in Afghanistan. Military investigators said the crash likely occurred because the digital electronic engine control did not automatically send more fuel to the engine when the helicopter’s rotor slowed down, putting the aviators in a situation from which they could not recover, according to documents obtained through the Freedom of Information Act.

The crash occurred nine seconds after the warning alarm in the helicopter sounded. Witness statements included in the investigation’s report outline a frantic effort to get to the “ball of twisted aluminum” that was the wreckage. At least three other helicopters landed to help, running toward the crash site even though it was unclear whether ammunition on board the Kiowa Warrior might explode.

Groves was widely respected as a veteran aviator by his fellow soldiers, the report said. His wife, Katie, and their two children live in Port Wentworth, Ga.

Kohl is married, and now has a full-time medical assistant. He lives at a rehabilitation center in Germantown, Md., and his wife Aileen lives a few miles away in Washington.