Federal safety investigators have concluded that a problem with a carburetor part led to engine failure and the crash of a vintage airplane piloted by actor Harrison Ford in California.

The National Transportation Safety Board said Thursday that the part known as a main metering jet likely came loose over the years since the plane was restored. The problem allowed too much fuel to flow, resulting in a loss of engine power.

Ford had just taken off from Santa Monica Airport on March 5 when he reported engine failure and requested an immediate return.

The single-engine Ryan Aeronautical ST3KR struck a tree, however, and crashed on a golf course, injuring the actor.

The NTSB also found that an improperly installed shoulder harness likely contributed to the severity of his injuries.