Aviation Accident Summaries

Aviation Accident Summary DEN02LA055

Salt Lake City, UT, USA

Aircraft #1

N7338M

Cessna 175

Analysis

While in cruise flight at 5,600 feet msl, the tachometer indicated the engine had lost 100 to 200 rpm (revolutions per minute) and shortly thereafter, the oil temperature "pegged high" but oil pressure remained steady at 25 psi. The engine vibrated and the upper cowling broke off, exposing a breach in the top of the casing aft of #3 cylinder. White smoke filled the cockpit, the engine seized, and the propeller stopped in the vertical position. A forced landing in salt water ensued. The last annual inspection on the airplane had been performed 9 years before the accident.

Factual Information

On June 15, 2002, at 2012 mountain daylight time, a Cessna 175, N7338M, registered to and operated by the pilot, was destroyed when a forced landing was made in the Great Salt Lake, near Tooele, Utah. The pilot and one passenger received minor injuries, and the second passenger was not injured. Visual meteorological conditions prevailed, and no flight plan had been filed for the personal flight being conducted under Title 14 CFR Part 91. The flight originated in Ogden, Utah, approximately 2000, and was en route to Tooele, Utah. According to the pilot's accident report, the airplane was in cruise flight at 5,600 feet msl (mean sea level) when he and his son, an airplane mechanic, became concerned when the tachometer indicated the engine had lost 100 to 200 rpm (revolutions per minute). Shortly thereafter, they noticed the oil temperature was "pegged high." Oil pressure remained normal and steady at 25 pounds per square inch (psi). "Within seconds the engine started to self-destruct," the pilot wrote, resulting in "violent and high amplitude" vibrations that shook the airplane. "Then the engine exploded with a series of loud bangs and the upper engine cowl jumped wildly." The cowling broke off and they saw what they thought was one of the crankshaft counterweights blown through the top of the casing aft of the #3 cylinder. White smoke came out of the front of the engine cowling, up and over the windshield, and filled the cockpit. The engine seized and the propeller stopped in the vertical position. The pilot retarded the throttle and mixture, and turned the magnetos and fuel selector off. After making a distress call, the pilot ditched the airplane in the lake. Control tower personnel at Salt Lake City International Airport monitored the radio transmission and notified the Civil Air Patrol (CAP). A searching CAP airplane soon located the occupants swimming near the submerged airplane. At a later date, the pilot attempted to retrieve the airplane but before he could secure it on shore, high winds and heavy seas washed it back into the lake. The engine was not recovered. The pilot told a Teledyne Continental Motors investigator that all magnesium components had eroded away and the aluminum parts were "bubbling" in the salt water. From the decription given to him by the pilot, the investigator surmised that either a counterweight had separated, or the number 2 connecting rod may have broken off the crankshaft. According to an FAA inspector with the Salt Lake City Flight Standards District Office, the pilot did not have a current medical certificate and he did not have a current biennial flight review. In addition, the last annual inspection on the airplane had been performed 9 years ago.

Probable Cause and Findings

total mechanical loss of engine power for reasons undetermined. Contributing factors were the lack of an annual inspection and the (forced landing in) salt water.

 

Source: NTSB Aviation Accident Database

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