History of Flight
On August 18, 2018, at about 1040 eastern daylight time, a Quicksilver MXL II Sport light sport airplane, registered as N105SE, was substantially damaged when it impacted a field near Baugher's Orchard Airport (07MD) in Westminster, Maryland. The private pilot and a passenger sustained fatal injuries. The airplane was owned and operated by the pilot under 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed, and no flight plan was filed. The local flight originated from 07MD at about 1025.
Witnesses at the airport reported that the flight departed normally, flew north, then returned and entered the final approach for landing. The airport manager stated that when the airplane was about ¼ to ½ mile from the runway, a loud "bang" was heard. Another witness described the sound as a "high pitch crack of something under stress." An anonymous witness, looking directly at the airplane during approach, said the bang was followed by the "upward folding" of the right wing, after which the airplane rolled right and descended. Another witness indicated that the wing "broke" at an estimated altitude of 100 to 200 ft. The airport manager observed the airplane descending "straight down" while rotating right, and noted that the airframe parachute "blew" just before impact.
Two witnesses located about 2,100 ft south-southeast of the accident site heard a sound similar to a sputtering engine followed by a bang. One saw the airplane begin descending, and the other observed white/gray dust but could not discern the altitude.
Personnel Information
The pilot held a private pilot certificate with an airplane single-engine land rating and a third-class medical certificate issued on October 18, 2017, with the limitation "must wear corrective lenses for near and distant vision." On the medical certificate application, the pilot reported 1,200 hours of total flight experience. The pilot also held a repairman certificate for light sport aircraft, with a limitation for inspection of the accident airplane.
Aircraft Information
The high-wing, two-seat, tricycle gear airplane was built in 2006 and purchased by the pilot and his wife in August 2010. It was powered by a 65-horsepower Rotax 582 UL DCDI engine and equipped with a Warp Drive four-bladed 62-inch composite adjustable propeller. A BRS-5 model UL2 ballistic airframe parachute was mounted to the main axle tube behind the right seat.
The wing structure consisted of leading and trailing edge spars separated by a diagonal tube at the inboard end and four spanwise tubes. Eight support cables were attached to each wing at four attachment locations. The cables attached to the leading and trailing edge spars at the locations of the inboard and outboard middle chordwise tubes.
According to the Quicksilver Assembly, Maintenance, and Parts Manual, an AN5-30A bolt secures the upper and lower wing cables to the outboard attach point at the leading edge wing spar. The bolt head pointed downward; the lower leading edge outboard cable attached to the lower surface of the spar, while the anti-drag cable, bellcrank strut cable, and upper leading edge outboard cables attached to the upper surface. The manual specifies that AN quality bolts are used throughout for structural integrity and notes "NEVER USE SUBSTITUTES!" The manual did not provide a specific inspection interval for this bolt but indicated that the security of all bolts and nuts should be checked every 50 hours.
Available maintenance records spanned from January 6, 2010, to May 9, 2013. Entries included a condition inspection on January 6 and 7, 2010, for issuance of a Light Sport Aircraft Airworthiness Certificate. An entry dated July 21, 2010, documented removal of floats and amphibious landing gear and installation of standard wheels and brakes, at which time the airplane had accumulated 81 hours. No entries specified removal or replacement of the bolt securing the wing cables to the outboard attach point at the right wing leading edge spar.
Wreckage and Impact Information
The airplane crashed into a field about 1,500 ft and 003° from the approach end of the runway. The cockpit was inverted; the main wreckage was oriented along a magnetic heading of 124°. All components were within or near the main wreckage. No fire was evident, though black soot discolored the sheath of a cable attached to the BRS rocket near its exhaust.
The engine had separated and was found near its mount location. The right wing was beneath the inverted empennage; the outer section of the left wing lay over the top of the wreckage. A section of wing cable with a fractured attach bolt was found resting on the engine between the propeller and gearbox. The head of the bolt was not located.
Flight control continuity in roll and yaw axes was confirmed from cockpit to control surface. Pitch control continuity was confirmed through breaks consistent with overload and impact damage. The elevator trim tab was in a trailing-edge-down position. Multiple tailboom tubes were fractured consistent with bending overload.
Examination of the left wing showed the leading edge spar fractured about 61 3/8 inches from the root tube attachment, and the trailing edge spar fractured about 62 inches outboard. The lower forward inboard wing cable was fractured about 11 inches from its attach point; the upper aft inboard wing cable was fractured about 12 inches from the king post. All other cables remained attached. NTSB Materials Laboratory examination found the fracture surfaces of the spars on slant angles with matte gray color, consistent with ductile overstress fracture from aft bending loads on the leading edge spar and forward bending loads on the trailing edge spar. Individual wires in the inboard cable showed distributed fracture locations with necking and chisel-like features consistent with ductile overstress.
The right wing was fragmented. The leading edge spar had two creases about 6 and 7 inches outboard of the compression strut near the wing tie-down location. The spar was fractured about 62 inches outboard, coinciding with the inboard wing cable attachment; bending deformation was noted. The trailing edge spar was fractured into four pieces. Wing cables were intact except for the outboard forward upper and inboard aft upper cables; fractured wire strands showed necking and chisel-like features consistent with ductile overstress.
The four sections of the right wing trailing edge spar were examined; fracture surfaces were on slant angles with matte gray color consistent with ductile overstress. Deformation patterns indicated forward bending loads at the inboard location and torsion loads (clockwise rotation of outboard piece relative to inboard) at the outboard location.
The fractured bolt found on the engine was associated with hardware attaching the right wing outer upper and lower wing cables to the leading edge spar. Laboratory examination revealed chlorine branching cracks on the fracture surface, consistent with stress corrosion cracking. The cracking extended across about 95% of the bolt shank before final fracture. The bolt material was stainless steel.
Two AN43B-14A eyebolts with attached anchor nuts and fractured forkbolts were found near the wreckage, associated with the right aileron. Fracture surfaces showed evidence of overload; no pre-existing cracks were noted.
The left aft tri-bar downtube had separated from its fork, which was fractured. Fracture features were consistent with ductile overstress.
Examination of the ballistic parachute system revealed that the plastic cap of the rocket housing was on the ground about 50 ft east of the main wreckage. One-half of a fractured black plastic cap with a center hole (consistent with the inner canister cap) was recovered near the wreckage; the outer canister cap was not located. The parachute canister was securely mounted but displaced; as viewed from the right side, it was rotated clockwise with its long axis nearly parallel to the right seatback. Continuity was noted from the activation handle to the canister base. The pilot canopy, a portion of the parachute, and the rocket remained attached by cable. The rocket was discharged.
Further examination at the manufacturer's facility showed the canister and rocket launch tube with dents and scrapes; the inner canister cap damage was consistent with being in place during impact. Mounting brackets were "severely bent." The incremental bridle assembly was "fully intact, with no stitches broken." The suspension line attachment showed degradation consistent with prolonged wetness.
Examination of the Rotax engine found no evidence of preimpact failure or malfunction in the power train, fuel metering, air induction, ignition, exhaust, cooling, or lubrication systems. The cylinder head was removed; no carbon was noted on piston crowns. The gearbox was cracked on the left side; the power takeoff coupling was not fractured. Propeller attachment bolts damaged the gearbox exterior consistent with rotation at impact. Gearbox examination showed crankshaft gear teeth, propeller shaft, reduction gearbox crankshaft bearings, and gear teeth were satisfactory.
Propeller blades were secured in their clamps. One blade was full span with a deep gouge on the leading edge about 3.5 inches from the tip; blue paint was in the center. The other three blades were fractured at varying lengths from the hub.
Medical and Pathological Information
The Office of the Chief Medical Examiner, State of Maryland, performed an autopsy on the pilot. Cause of death was multiple injuries.
Toxicology testing by the FAA Forensic Sciences Laboratory detected acetaminophen in the pilot's urine, and bupropion (and its metabolite hydroxybupropion), tamsulosin, and diltiazem in the pilot's urine and cavity blood. No carbon monoxide or ethanol were detected.
Bupropion is an antidepressant marketed as Wellbutrin and is also the active drug in Zyban for smoking cessation. It can cause neuropsychiatric symptoms and seizures; prescribers advise that use may impair ability to perform tasks requiring judgment or motor and cognitive skills.
Tamsulosin is used to treat enlarged prostate symptoms; diltiazem treats blood pressure; acetaminophen is an over-the-counter analgesic. These three drugs are not considered impairing.