Four passengers on a Continental Airlines jet that veered off a Denver runway Dec. 20 have filed lawsuits against the jet’s maker.

The lawsuits allege that Boeing Co. negligently designed and manufactured certain mechanisms on the plane, making it hard for the pilots to maintain runway heading while taking off.

The Houston-bound Boeing 737 veered sharply off the Denver International Airport runway and into a ravine, where it caught fire. The flight was carrying 115 people; 38 were injured.

The passengers who filed claims Wednesday in federal court in Denver were Julie Hart of Boulder County and Carey Scharfenstine of El Paso County. Scharfenstine also filed separate suits on behalf of her sons, Greyson and Lloyd Scharfenstine.

Boeing did not immediately return a call seeking comment Wednesday night.