One tiny hole may have caused Golf Hammock crash

Why did the plane crash a year ago at Golf Hammock? An NTSB investigation is focusing on a single hole drilled into the wing structure.

"The origin of the breakup is in the vicinity of the hole," National Transportation Safety Board investigator Dennis Diaz said Thursday. "That's where it started to come apart."

On Dec. 13, 2008, an Ercoupe 415-D broke up in midflight over northwest Sebring. Parts of the plane were found over a half-mile long area. The seats landed in trees near the golf course clubhouse. The pilot, James Weener, 70, and passenger, James Ricker, 46, died.

The report

Why was it drilled, and why would one screw hole cause a plane to crash?

NTSB investigators are fact finders, Diaz said. The NTSB board itself will explain why in its Jan. 7 final report.

Diaz also hasn't determined who drilled the hole. His Nov. 13 factual report states that the factory drilled two holes into the wing spar - the I-beam which holds the weight of the wings.

Two holes were drilled by the factory into the top wing spar, the top of the I-beam. The Ercoupe 415-D seats two, a pilot and a passenger, side by side. They sit in two seats, which are mounted to the seat pan. The two holes are to fasten the seat pan to the wing spar.

"Three screw holes were observed in the spar cap with the tip of a broken self-tapping screw still in one of the holes," Diaz's report said. The third hole was located between and less than one inch from the two original seat-pan holes.

That single hole could have caused the crash, local pilot Jon Lowe agreed. He owns an antique aircraft restoration business at Sebring airport.

The crash

Witnesses on the ground at Golf Hammock saw a plane in trouble. The engine was over revving, it was dipping and turning and rolling. Dope chips - paint from the cloth-covered wings - were drifting to the ground like confetti. Ailerons, the hinged flaps on the control surfaces attached to the wing's trailing edge, fluttered at a high frequency.

That could remove the paint from the fabric, Lowe said.

"Flutter of a control surface is a catastrophic, and very, very rare thing," said Ed Burkhead, a former Ercoupe owner and contributor to the Ercoupe technical forum on the Internet. "The vibrations from control surface flutter can destroy an aircraft."

One witness, an airline transport pilot, saw the left wing of the plane fold back and separate from the fuselage. The plane pivoted in the air, and the right wing came off.

Along the flight path, the first pieces of wreckage found were the aft cabin windows, then dope chips, inspection panels, and personal effects from the cabin. Oddly, the left wing was found 900 feet farther ahead than the left wing.

The NTSB report says little about the pilot. Medical and toxicological information revealed no traces of carbon monoxide, cyanide, ethanol or drugs.

Likewise, the 62-year-old plane, which logged 2,588 hours in the air, passed its annual inspection on May 9, 2008.

Witnesses on the ground at Golf Hammock included two pilots. One witness saw the plane flying southwest. It made "a very slight dip and turned to the right."

According to Weener's friend, who was also an aircraft mechanic, he and Weener flew together in the airplane on a sightseeing flight immediately prior to the accident flight. The friend didn't note abnormalities with the performance of the airplane or the pilot.