NTSB Factual Report

HISTORY OF FLIGHT

On February 12, 1995, at 1046 hours Pacific standard time, a Bellanca 7GCBC, N53972, crashed at the Modesto Wastewater Treatment Plant, Modesto, California. The pilot was conducting a local visual flight rules personal flight. The airplane, registered to and operated by the pilot, was destroyed. The certificated private pilot, the sole occupant, sustained fatal injuries. Visual meteorological conditions prevailed. The flight originated at Souza Airstrip, a privately owned airstrip, Turlock, California, at 0930 hours.

The consensus of ground witnesses was that the airplane was traveling westbound at a low altitude. As the airplane approached the power lines, it entered into an abrupt climbing attitude. At the apex of the climb, the airplane left wing went down (the nose yawed to the left) followed by the nose going down. The airplane maintained this attitude until it crashed. One witness reported the airplane was above the power lines before it began climbing.

PILOT INFORMATION

The pilot held a private pilot certificate with an airplane single-engine land rating. He also held a third-class medical certificate; the medical certificate contained a "valid for 24 months following the month examined and a must have available glasses for near vision" limitations endorsement.

According to the pilot's Federal Aviation Administration (FAA) medical records, the pilot received an exemption for the third-class medical certificate from the FAA Medical Advisory Board on November 12, 1993. The exemption was required because of the pilot's medical history of high blood pressure, a myocardium infarction, and colon cancer.

National Transportation Safety Board investigators did not recover the pilot's flight hours logbook. The flight hours reflected on page 3 of this report were obtained from the pilot's last medical application form. The pilot indicated in the form that he had accrued 4,000 total flight hours.

The pilot's son told Safety Board investigators conducted on February 13, 1995, that his father often engaged in sport flying, which included aerobatics. He said his father received aerobatic instruction and was an avid aviation enthusiast.

AIRCRAFT INFORMATION

The airplane maintenance logbooks were not recovered. The pilot's son said that his father purchased the airplane sometime in June 1994. The facility that sold the airplane accomplished an annual inspection before it was delivered to the owner. According to the engine tachometer hourmeter, the airplane accrued 1,462.12 hours at the time of the accident.

WRECKAGE AND IMPACT INFORMATION

The airplane crashed in a waste water treatment plant next to a pond. The ground scars and the wreckage examination disclosed the airplane struck the ground in about a 70-degree nose-down, wings-level attitude; the top of the cabin was facing 032 degrees (all headings/bearings noted in this report are oriented toward magnetic north).

All of the airplane major components and flight controls were found at the main wreckage area. The wreckage was confined at the initial impact crater. Both wings remained attached at their respective upper wing-to-fuselage attach fittings. The upper attach fittings, however, were destroyed; the upper cabin area was demolished.

The flight controls remained attached at their respective attach fittings. Rescue personnel cut many of the flight control cables before Safety Board investigators arrived at the accident site. Continuity of the elevators and rudder flight controls to the cabin/cockpit area was established. Continuity of the aileron flight control cables to the ailerons from the inboard side of each wing was established. The flaps were found in the retracted position.

The engine was found imbedded about 3 feet in the ground. The propeller separated from the engine crankshaft. The fractured areas displayed extensive torsional overload characteristics. The propeller blades displayed symmetrical 60-degree bending toward the face side; the bending began at midspan of the blades.

One propeller blade displayed "S" twisting and chordwise scuff marks; the other blade displayed spanwise scuff marks.

The engine was examined at Plain Parts, Pleasant Grove, California, on February 28, 1995.

The carburetor throttle body upper housing separated from the carburetor. The throttle plate was found closed. The carburetor bowl contained a metal float and a single-piece venturi and was impacted with dirt. The inlet screen did not contain any contaminates; a strong fuel odor was present on the screen and its housing.

The left magneto distributor housing broke. The magneto remained attached to the accessory section.

The upper spark plugs displayed a dark, sooty appearance. The center electrodes displayed normal operating signatures.

The right magneto separated from the engine accessory section and sustained extensive impact damage. The magneto did not produce spark upon rotation of its drive shaft.

Continuity of the gear and valve train assembly was established. The crankshaft was rotated 360 degrees.

The oil pressure screen contained some dirt particles, but did not contain any metal.

The fuel gascolator micron screen contained minor dirt particles. The gascolator housing was impacted with dirt.

MEDICAL AND PATHOLOGICAL INFORMATION

The Modesto County Coroner's Office conducted the post mortem examination on the pilot. The pathologist noted in autopsy report, in part:

Of importance is the absence of tissue hemorrhages related to these multiple extreme blunt force injuries. There is no hemorrhage in the musculature or other shredded tissues. (These) findings suggest very low or absent cardiac output at the moment of impact.

Undoubtedly this is related to coronary atherosclerosis, and the likelihood of a lethal or potentially lethal incapacitating cardiac event. This should be correlated with the accident investigation to see if the pilot was indeed likely incapacitated. Of note is the previously described compound fracturing of the upper extremities suggesting that the hands were indeed in front of the body holding onto something at the moment of impact, rather than hanging loosely at the sides or relaxed in the lap.

The Federal Aviation Administration, Civil Aeromedical Institute (CAMI), Oklahoma City, Oklahoma, conducted toxicological examinations on the pilot. The examinations revealed that Labetalol, a hypertensive cardiovascular medication, was present in the pilot's system.

The CAMI toxicologist said in a telephone interview conducted on June 13, 1995, that the Labetalol levels were within the therapeutic range.

An FAA flight surgeon, CAMI, reviewed the toxicology and the accident factual findings and said, " . . . preliminary findings of a loss of control due to incapacitation from a lethal cardiac event. . . " are consistent with the circumstances of this accident.

ADDITIONAL INFORMATION

The Safety Board released the wreckage to the pilot's son on March 3, 1995. The wreckage was located at Plain Parts, Pleasant Grove, California.

NTSB Probable Cause

THE PILOT LOST CONTROL OF THE AIRPLANE FOR AN UNKNOWN REASON.