Aviation Accident Summaries

Aviation Accident Summary LAX01FA253

Palm Springs, CA, USA

Aircraft #1

N25063

McDougall VERI EZE

Analysis

The airplane collided with a wind turbine following an in-flight separation of the majority of the right canard and all of the right elevator. The accident occurred in an area that commonly had turbulent conditions. The airplane fragmented; the right canard and elevator were not in the main debris field, and were found about 1/2 mile from the main wreckage. The canard and elevator damage was not symmetrical. The left side remained intact and attached to the fuselage while the right side separated near the fuselage attachment points. All that remained of the right canard was the top skin, which had scattered patches of paint missing. The owner and the pilot built the airplane together. They acquired pieces for the airplane from different sources, and assembled the airplane. The owner did not recall who actually built the elevator. They obtained advice and technical suggestions from various builders of the model at their home field. They did not contact the kit manufacturer during construction. The kit manufacturer maintained close contact with builders through newsletters and a company website. They designed an improvement to the elevator, which incorporated a wider chord. They recommended that owners make the change if they had not flown their airplane. The manufacturer provided a full size diagram so that builders could physically place their piece on top of the drawing to insure that their manufactured piece conformed to the drawing. The accident elevator did not conform to the kit manufacturer's instructions. In a newsletter to builders, the manufacturer informed them that the airplanes would be difficult or even dangerous to fly if the elevators did not have the correct cross section. The kit manufacturer repeatedly stressed the importance of the correct shape, weight, and balance of the elevators in their newsletters. On two occasions, once in 1979 and again in 1988, they noted that builders had installed balance weights in improper locations. In one case the builder experienced flutter, and investigation determined that he added weight to balance a reconstructed elevator. Instead of dividing the added weight between inboard and outboard mass balance points, he placed them all on the inboard point. The manufacturer noted that this was incorrect, and that the balance weights should not all be installed inboard. They stated that any variance of weight, stiffness, or shape from recommended design specifications should be considered dangerous, and builders should discard elevators that did not conform. The accident airplane had a large number of balance weights, and all of them were at the inboard mass balance point.

Factual Information

HISTORY OF FLIGHT On July 20, 2001, at 1901 Pacific daylight time, an experimental McDougall VERI EZE, N25063, collided with a wind turbine in the Banning Pass area near Palm Springs, California. The owner was operating the airplane under the provisions of 14 CFR Part 91, and lent it to the pilot for the flight. The private pilot and one passenger sustained fatal injuries; the airplane was destroyed. The personal cross-country flight departed Chino, California, about 1830, en route to Palm Springs. Visual meteorological conditions prevailed, and no flight plan had been filed. The first identified point of contact (FIPC) was at 34 degrees 54.646 minutes north latitude and 116 degrees 34.893 minutes west longitude. PERSONNEL INFORMATION A review of Federal Aviation Administration (FAA) airman records revealed that the pilot held a private pilot certificate with an airplane single engine land rating. The pilot held a third-class medical certificate issued on October 5, 2000. It had the limitations that the pilot must wear corrective lenses. An examination of the pilot's logbook indicated an estimated total flight time of 350 hours. The owner stated that the pilot had about 25 hours in the VERI EZE, all in the accident airplane. AIRCRAFT INFORMATION The operator submitted a written report. He reported that the airplane was a McDougall VERI EZE, serial number MM320. He estimated a total airframe time of 150 hours. He completed the last condition inspection on July 14, 2001. The airplane accumulated about 5 hours between the inspection and the accident. The engine was a Teledyne Continental Motors O-200-A, and according to the owners statement, the serial number was 72-JAEH-A-48. Total time on the engine was 400 hours. METEOROLOGICAL INFORMATION A National Transportation Safety Board meteorologist prepared a factual report. The Surface Analysis Chart depicted a low pressure system and associated troughs with warm air east of the accident site, which indicated a thermal low. There were no frontal systems across California. The Weather Depiction Chart reported visual flight rules (VFR) conditions. The Radar Summary Chart did not depict any echoes over southern California for the time of the accident. The report noted that the Banning Pass commonly has turbulent conditions. Upper air soundings indicated that the wind speed was 10 knots or less through 8,000 feet. The only pilot report in the region was from the pilot of a Cessna 172 who was 3 miles west of Palm Springs at 2046 PDT. He reported moderate turbulence at 2,300 feet. The Area Forecast was for clear skies with unrestricted visibility. COMMUNICATIONS The airplane was in contact with the Palm Springs air traffic control tower. It did not report any difficulties. WRECKAGE AND IMPACT The FAA accident coordinator examined the wreckage on site. The wreckage covered an area about 200 feet wide and out to a distance of 400 feet from the FIPC. The airplane was highly fragmented, and the debris field encompassed a wind turbine and its stanchion. The right canard and elevator were not in the main debris field, and recovery personnel did not recover them with the main wreckage. A deputy sheriff found them about 1/2 mile from the main wreckage several days after the accident on a follow-up search requested by the Safety Board investigator-in-charge (IIC). MEDICAL AND PATHOLOGICAL INFORMATION The Riverside County Coroner completed an autopsy. The FAA Toxicology and Accident Research Laboratory performed toxicological testing of specimens of the pilot. They did not test for carbon monoxide or cyanide, and detected none of the listed drugs. The report contained the following results for volatiles: 15 (mg/dL, mg/hg) ethanol detected in muscle, 2 (mg/dL, mg/hg) acetaldehyde detected in muscle. The report stated that the ethanol found in this case might potentially be from postmortem ethanol formation, and not from the ingestion of ethanol. TESTS AND RESEARCH Investigators from the Safety Board, the FAA, and Scaled Composites, Inc., examined the wreckage at Eastman Aircraft, Corona, California, on August 8, 2001. The engine separated from the airframe and sustained mechanical damage. The carburetor and magnetos separated from the engine. The exhaust was crushed and buckled, but not cracked. Investigators removed the top spark plugs and inspected the interior of the cylinders with a flashlight. They did not observe any mechanical damage on the piston faces. The spark plugs did not display any mechanical damage, and were black and sooty. Investigators inspected the fuel selector valve, which separated from the airframe structure. It was about halfway to the ON position. The flight control system sustained multiple disconnects. Investigators measured the recovered pieces, and they approximated the total length of the control system. All fracture surfaces were irregular in shape. Both trim springs were stretched and deformed. The rear control stick remained connected; the recovery team did not locate the front control stick. The left wing separated into two pieces. The canard and elevator damage was not symmetrical. The left canard and elevator remained intact while most of the right canard and the entire elevator separated near the fuselage attachment points. All that remained of the right canard was the top skin, which had scattered patches of paint missing. ADDITIONAL INFORMATION The owner/builder reported that he and the pilot built the airplane together. They acquired pieces for the airplane from different sources, and assembled the airplane. The original inboard elevator hinges were misaligned, and they had removed them and replaced them with the current configuration. He was unsure who built the original elevator. They built the new airfoil over the old one, as indicated in the drawings that he had. He said that they added weight to the bell horn and balanced according to the specifications that they had. They obtained advice and technical suggestions from various builders of the model at their home field. They did not contact the kit manufacturer during construction. The kit manufacturer representative reported that they sell the kits with a serial number. The serial number for the airplane did not match their records. They require builders to join their association, and they maintain close contact with their builders through newsletters and a company website. The kit manufacturer designed an improvement to the elevator, which incorporated a wider chord. They recommended that owners make the change if they had not flown their airplane. The manufacturer provided a diagram; builders could physically place their piece on top of the drawing to insure that their manufactured piece conformed to the drawing. Investigators examined the accident elevator, and found that it did not conform to the kit manufacturer's instructions. It had a wider chord than specified. In a newsletter to builders, the manufacturer informed them that their airplane would be difficult or even dangerous to fly if the elevators did not have the correct cross section. The kit manufacturer repeatedly stressed the importance of the correct shape, weight, and balance of the elevators in their newsletters. On two occasions, once in 1979 and again in 1988, they noted that builders had installed balance weights in improper locations. One case noted that the builder experienced flutter. He added weight to balance a reconstructed elevator. Instead of dividing the added weight between inboard and outboard mass balance points, he placed them all on the inboard point. The manufacturer emphatically noted that this was incorrect. The articles emphasized that the balance weights should not be installed inboard. They stated that any variance of weight, stiffness, or shape from recommended design specifications should be considered dangerous, and builders should discard elevators that did not conform. The accident airplane had a large number of balance weights, and all of them were at the inboard mass balance point. The investigator-in-charge released the wreckage to the owner's representative.

Probable Cause and Findings

the failure of the builder to balance the elevators per the kit manufacturer's instructions resulting in flutter and in-flight separation of the right elevator.

 

Source: NTSB Aviation Accident Database

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