A single-engine airplane that took off from Long Beach Airport last month and crashed while trying to land at French Valley Airport, injuring the two pilots, experienced an engine failure while descending toward the runway for reasons still under investigation today.

The crash happened about 8:35 a.m. Jan. 27, roughly 2,000 feet short of the threshold for Runway 36, according to the National Transportation Safety Board.

The agency, which released its preliminary findings on the crash earlier this week, determined that the Cessna 210N Centurion, tail No. N4758C, had departed Long Beach Airport about 25 minutes prior to the accident.

”The pilot in command reported that he and his pilot-rated passenger were flying a short cross-country flight to have breakfast,” according to the NTSB.

The report stated that the pilot verified during his preflight inspection that he had sufficient fuel in both wing tanks. He relied on his left wing tank for half the journey, then switched to the right tank, according to the narrative.

”When they approached (French Valley) Airport, the PIC retarded the throttle to near idle, while descending and decreasing the airplane’s airspeed,” the report said. “On the downwind leg of the traffic pattern, about 1,000 feet above ground level, the PIC extended the landing gear, extended the flaps … trimmed the airplane, and made a right turn to the baseleg of the traffic pattern.”

The pilot attempted to add power to maintain altitude, “but the engine did not respond,” with the propeller only windmilling, according to the NTSB.

”He cycled the throttle to troubleshoot … and turned on the fuel pump. However, the engine still did not respond, and the airplane descended into a ravine,” the agency said.

The Cessna plowed into a rocky hillside along Sky Canyon Drive, near Borel Road, nosing over and flipping onto its back.

Both pilots were able to climb out of the wreckage, and there was no post-impact fire, according to the Riverside County Fire Department.

The flying pilot suffered minor injuries, but his co-pilot companion was seriously hurt, the NTSB said.

Both men were taken to a regional trauma center for treatment and are recovering.

Officials said the plane, which was manufactured in 1979, sustained major damage and was taken to a secure facility for further examination.

A final report on the crash was not expected to be released until sometime next year.