Aviation Accident Summaries

Aviation Accident Summary LAX02LA275

Fresno, CA, USA

Aircraft #1

N394BL

Huene Velocity XL-RG

Analysis

The pilot reported that while descending in preparation for landing, he noticed an unusual sound from the engine and noted a loss of oil pressure, followed by a loud thud, a vibration, and a total loss of engine power. A forced landing was made to an open field. After the aircraft came to a stop and the pilot and passenger exited the aircraft, smoke and fire was noted coming from the engine area. Attempts to extinguish the fire were unsuccessful. The aircraft was consumed by the fire and destroyed. A witness reported observing the aircraft fly over his location when he heard a loud bang and debris was seen falling from the aircraft. Later, two propeller blades and the lower engine cowl were located in fields near the witnesses location. Examination of the cowling revealed heat distress near the right side, starting at the opening for the exhaust stack and emenating aft. An unusual amount of oil was noted on the inside of the cowling and a thin coat of oil was noted on the outside. The two propeller blades were also coated with a thin layer of oil. During the engine examination, it was found that the exhaust system was cracked at the welds at both exhaust outlets with the left side exhaust outlet missing just aft of the number six cylinder riser. Further inspection of the exhaust riser identified two additional cracks. No other mechanical failures or malfunctions were noted during the engine examination.

Factual Information

On September 6, 2002, approximately 1200 pacific daylight time, a Huene Velocity XL-RG single-engine experimental airplane, N394BL, was destroyed by a post-cash fire following a forced landing near Fresno, California. The private pilot and his passenger were not injured. The airplane was registered to Anatarius Inc., of Wilmington, Delaware. Visual meteorological conditions prevailed for the 14 Code of Federal Regulations Part 91 personal flight, and no flight plan was filed. The airplane departed the Apple Valley Airport at 1100, and was destined for the Skypark Airport, Fresno. During a telephone interview with the NTSB investigator-in-charge, and subsequent written statement, the pilot reported that while descending through 2,000 feet mean sea level in preparation for landing, he noticed an unusual sound from the engine and noted a loss of oil pressure, followed by a "loud thud," a vibration, and a total loss of power. The pilot elected to make a forced landing in a vacant field. After landing and safely egressing the airplane, the pilot and his passenger noticed a fire coming from the rear portion of the airplane where the engine is located. An attempt to extinguish the fire proved unsuccessful, and the airplane was destroyed when it was consumed by fire. A witness located about two miles east of the accident site reported that he observed the aircraft fly over his location when he heard a loud bang and saw debris fall from the rear of the aircraft. Smoke was also seen trailing from the rear of the aircraft. Two propeller blades were later located in a vineyard about .25 miles from the witnesses location. Later the lower engine cowling was found in the field adjacent to where the propeller blades were located. Documentation of the wreckage by a Federal Aviation Administration Inspector from the Fresno, California, Flight Standards District Office, reported that the airframe was completely consumed by fire. The rear mounted engine was equipped with an experimental three bladed propeller. The blades have a wooden core and carbon fiber sheathing. Two of the blades had separated in flight from the propeller hub. Both blades displayed leading edge and tip damage. Both blades had a thin coating of oil on their surface. The pilot reported that this coating was not present at the time of departure. The third blade remained attached to the hub assembly, however, due to the post-crash fire, was destroyed. The right side winglet displayed impact damage on its trailing edge. The semi-circular portion of the structure was missing approximately eight inches up from the wing surface. The rudder on the winglet was partially detached. The lower engine cowling which separated in flight was a fiber glass structure. Indications of heat distress were noted on the right side, starting at the opening for the exhaust stack and emenating aft. The interior side of the cowl contained an unusual amount of clean engine oil. The exterior side of the cowl had a thin coat of oil in excess of normal residual. The cowl separated with sufficient force to tear the attach structure from the fuselage. The Lycoming IO-540 engine had been modified to gain compatibility with the Velocity design. The engine had been assembled approximately two years prior to the accident and installed in the accident aircraft. During the engine teardown inspection on September 25, 2002, at an engine overhaul facility in Visalia, California, and in the presence of the FAA Inspector, it was found that the exhaust system was cracked at the welds at both exhaust outlets with the left side exhaust outlet missing just aft of the number six cylinder riser. Further inspection of the exhaust riser identified two additional cracks. No other mechanical failures or malfunctions were noted during the engine examination.

Probable Cause and Findings

An in-flight exhaust stack separation during descent for landing resulting in loss of engine power and a forced landing to an open field.

 

Source: NTSB Aviation Accident Database

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