NTSB Factual Report

HISTORY OF FLIGHT

On August 20, 2011, at 1341 central daylight time, a Vertical Unlimited LLC model 12 airplane, N2BJ, was substantially damaged when it impacted terrain at the Charles B. Wheeler Downtown Airport (MKC), Kansas City, Missouri. The pilot was performing an aerobatic routine at the Kansas City Aviation Expo at the time of the accident. The pilot was fatally injured. The airplane was registered to Vertical Unlimited LLC and operated by the pilot. The aerobatic exhibition (air show) flight was being conducted under the provisions of 14 Code of Federal Regulations Part 91 and a Certificate of Waiver issued for the air show. Visual meteorological conditions prevailed for the flight, which was not operated on a flight plan. The local exhibition flight originated from MKC about 1336.

The air show performance appeared to proceed normally until shortly before the accident. A review of video footage of the final portion of the accident routine indicated that the pilot appeared to have exited a Lomcevak maneuver into a right, inverted spin. Upon recovery from the inverted spin, as the airplane began to pitch up from a nose-down attitude, it rolled to the left and the nose dropped. The airplane appeared to yaw to the left (counterclockwise) during the final descent, completing about one and one-half revolutions before impacting the ground. The resolution of the video did not permit any assessment of flight control surface deflections.

A series of six photographs taken at approximately one-second intervals immediately before the accident depicted the airplane in a nose low pitch attitude. It was upright, with the wings level to a slight left bank angle. The consecutive sequence of photos suggested that the airplane was yawing to the left (counter-clockwise) as it descended. The airshow/aerobatic performance smoke was on at the time. In the fifth photograph in the series, the smoke stream was oriented approximately vertically in the frame. The angle between the wing chord and the smoke orientation appeared to be about 30 degrees.

The airplane appeared intact, with no anomalies apparent in any of the photos. The elevator control surfaces appear to be deflected upward relative to the airframe. The right ailerons appeared to be deflected upward/left ailerons downward. The rudder appeared to be neutral or deflected slightly right in the first and second photos. It is deflected to the left in the third and fourth photos; and appeared to be deflected left in the fifth photo. The airshow smoke obscured the rudder in the final photo. All control surfaces appeared to be intact and deflected within the normal range of travel; however, the exact deflection angles were not determined.

A friend and colleague of the pilot stated that a Lomcevak maneuver was initiated on an inverted 45-degree up-line, followed by full forward elevator and then full left rudder control inputs. He added that most of the time recovery from the maneuver would be straight ahead, but occasionally recovery from an inverted spin would be necessary. He noted that the pilot appeared to initiate the maneuver more aggressively in the accident performance than he had seen during previous airshow performances.

A second friend and colleague of the pilot, who had trained with him and was familiar with his routine, reported that the Lomcevak maneuver completed during the accident flight included an extra rotation. The airplane subsequently exited the maneuver into an inverted spin, which was not unusual.

PERSONNEL INFORMATION

The accident pilot held an Airline Transport Pilot certificate with single and multi-engine land airplane ratings. The certificate also included type ratings for A-320, B-747-4, DC-9, and SA-227 airplanes. The single-engine airplane class rating was limited to commercial pilot privileges. He also held a current Acrobatic Competency card with a minimum altitude limitation of 250 feet above ground level (agl).

The pilot was issued a first class airman medical certificate on March 1, 2011, with a restriction for corrective lenses. On the application for that certificate, he reported an estimated 22,000 hours total flight time and 300 hours of that flight time within the previous 6 months.

The pilot had reportedly been flying aerobatics for 15 years, with experience in Christen Eagle, Laser 200, Pitts S1S, and Extra 300L airplanes. The pilot was reportedly involved in the development and construction of the accident airplane. He had signed the registration and airworthiness documents submitted to the FAA to support certification.

AIRCRAFT INFORMATION

The accident airplane, an amateur-built Vertical Unlimited model 12, serial number 297, was a modified single-place, aerobatic biplane. The airplane was based on the 2-place Pitts model 12 airplane design. The front cockpit position was removed, and smoke and auxiliary fuel tanks were installed in that location. The wing fuel tank was also eliminated. In addition, the ailerons were lengthened and another aileron hinge point was added.

The airplane was powered by a 412-horsepower modified Vedeneyev M14P radial engine, and a 3-bladed MT Propellers model MTV-9-K-C propeller assembly. The airplane was issued an experimental exhibition category airworthiness certificate on March 5, 2009.

Maintenance records indicated that the most recent condition inspection was completed on February 1, 2011, at 196.1 hours total airframe time. Testing of the transponder and altitude encoder was conducted on March 8, 2011. The records indicated that the engine oil and filter were changed on June 16, 2011, at 207.0 hours. There were no subsequent entries in the aircraft maintenance logbooks.

METEOROLOGICAL CONDITIONS

The MKC Automated Surface Observation System (ASOS), at 1354, recorded the following weather conditions: calm wind; 10 miles visibility with light rain; clear skies; temperature 24 degrees Celsius; dew point 20 degrees Celsius; altimeter 29.97 inches of mercury. According to documentation provided by the National Weather Service, ASOS will not report cloud heights greater than 12,000 feet above ground level.

A friend and colleague of the pilot noted that the accident airplane was moved into a hangar briefly when it began to rain shortly before his scheduled performance. After about 15 minutes, the rain has stopped. The airplane was removed from the hangar and the pilot began his performance. She noted that the cloud cover was high enough not to have affected the pilot's air show routine.

AIRPORT INFORMATION

The Charles B. Wheeler Downtown Airport (MKC) is a publicly-owned facility, located along the Missouri River, adjacent to downtown Kansas City, at an elevation of 757 feet. It is served by two hard surfaced runways: runway 1-19 is 6,827 feet by 150 feet; and runway 3-21 is 5,050 feet by 100 feet. Air traffic services in the immediate vicinity of MKC are provided by the Airport Traffic Control Tower (ATCT). The surrounding airspace is controlled by the Kansas City Terminal Radar Approach Control (TRACON) facility located at the Kansas City International Airport (MCI), about 12 miles north-northwest of MKC.

The airport was hosting the Kansas City Aviation Expo at the time of the accident. Air show operations were being conducted under a Certificate of Waiver issued by the Federal Aviation Administration (FAA) for the event. The waiver authorized day and night aerobatic demonstrations, high speed flight, and parachute demonstrations within 5 miles of the airport and up to 16,000 feet msl.

WRECKAGE AND IMPACT INFORMATION

The accident site was located on the airport in the grass infield area about 280 feet west of the runway 1-19 and 3-21 intersection. The airplane came to rest upright and all major airframe components were observed in place relative to the overall airframe. The fuselage, engine, and wings exhibited damage consistent with impact forces. The forward fuselage, engine, cockpit, and the inboard portion of the upper and lower wings were consumed by a postimpact fire. The aft fuselage and empennage remained intact; the majority of that portion of the airframe structure was unaffected by the postimpact fire. The engine and propeller assembly were partially embedded into the ground. The main landing gears had collapsed and were located under the airframe.

A postaccident airframe examination was conducted at MKC by Federal Aviation Administration (FAA) inspectors. A subsequent engine teardown examination was conducted under the direct supervision of an FAA inspector. No anomalies consistent with a preimpact failure or malfunction were observed.

The flight controls remained attached to their mating airframe structure. The upper and lower ailerons were partially compromised by the postimpact fire. Aileron control continuity was confirmed from the cockpit control stick to the lower ailerons; however, the push-pull control tube rod end at the left lower aileron bellcrank was separated. The fracture surface appeared consistent with an overstress failure. The left wing aileron slave strut was separated at the lower aileron rod end. The fracture surface appeared consistent with an overstress failure. The right wing aileron slave strut remained attached to both the upper and lower aileron. The elevators and rudder remained attached to the horizontal and vertical stabilizers, respectively. Each control surface appeared intact. Elevator and rudder control continuity was confirmed from each control surface to their respective cockpit controls; although, the elevator push-pull control tube and the rudder cables had been cut to facilitate recovery. The elevator trim tabs remained attached to the elevators; however, the trim cables were separated in a manner consistent with an overload failure.

Engine mixture and propeller control continuity was confirmed from the cockpit controls to the throttle body and propeller governor, respectively. The throttle cable was separated at the throttle body; however, the separation appeared consistent with impact forces. The throttle cable remained attached to the cockpit throttle control.

The engine assembly exhibited damage consistent with impact forces. The nose case and no. 6 cylinder were displaced, but remained attached to the engine. The reduction gear was removed with the nose case. The reduction gearing appeared intact and rotated freely. Once the crankcase was parted, the crankshaft rotated freely. The case halves appeared undamaged. The master rod and articulated rods rotated freely on the crankpin. The no. 6 cylinder articulated connecting rod was bent consistent with the damage to that cylinder. The master rod bearing appeared intact. The pistons did not exhibit any scoring. The cylinder rocker boxes were deformed consistent with impact; however, the rocker arms appeared to be intact. The front sparkplugs were damaged. The rear spark plugs were removed; they exhibited normal combustion signatures and proper electrode gaps. The oil pump rotated freely; the oil screen did not contain any foreign material. The accessory gears appeared intact and the rotated freely. The supercharger rotated freely by hand. The supercharger contained ingested soil and appeared to contain residual fuel.

The propeller assembly remained attached to the engine. Two propeller blades had separated at the blade root; the third blade separated about mid-span. The separation of all three propeller blades appeared consistent with overstress/impact forces.

The Data Acquisition Unit (DAU) and Electronic Flight Information System (EFIS) installed in the accident airplane were recovered and sent to the NTSB recorders lab for examination. Data recovered from the EFIS was not relevant to the accident flight. No data was recovered from the DAU.

MEDICAL AND PATHOLOGICAL INFORMATION

An autopsy of the pilot was performed by the Jackson County Medical Examiner's Office, Kansas City, Missouri, on August 21, 2011. The autopsy report attributed the pilot's death to blunt force traumatic injuries sustained in the accident.

The FAA Civil Aerospace Medical Institute forensic toxicology report stated:

Nordiazepam detected in urine;

Nordiazepam NOT detected in Blood (Cavity);

Oxazepam NOT detected in Blood (Cavity);

0.021 (ug/ml, ug/g) Oxazepam detected in Urine;

Temazepam detected in Urine;

Temazepam NOT detected in Blood (Cavity).

Nordiazepam, oxazepam, and temazepam are metabolites of diazepam, which is commonly marketed under the trade name Valium.

According to the pilot's medical records, he had sought treatment for vertigo in March 2010. He reported feeling off-balance and nauseated while conducting aerobatics. In addition, he had fallen after getting out of the airplane. The pilot independently obtained some treatment information and reported feeling better; however, the dizziness returned when he flew a few days later. During a subsequent office evaluation, a physical therapist was able to reproduce some of the vertigo sensations and prescribed further treatment. According to the records, the pilot never returned to the therapist.

A colleague of the pilot noted that he had initially experienced the vertigo condition during an aerobatic practice session. The pilot abruptly terminated the practice session. Ultimately, the pilot ceased flying for about three months following the initial event and had completed treatment for the condition. Based on her observations at the time of the accident, the pilot showed absolutely no signs of impairment and appeared to be completely healthy.

The autopsy report noted the presence of atherosclerotic disease with one coronary artery occluded up to 99-percent. In addition, the autopsy revealed that the pilot's heart was enlarged and exhibited a congenital anomaly of the aortic valve. Histology of the right and left ventricle walls revealed the presence of transmural hypereosinophilic myocytes, many of which exhibited contraction bands. The left ventricle exhibited an interstitial edema in the wall of the heart.

The pilot's available medical records did not contain any record related to a diagnosis of heart disease.

TESTS AND RESEARCH

A Garmin 496 GPS unit was recovered from the accident airplane. The data was successfully downloaded from the unit and a copy of the data file is included with the docket material associated with this investigation. The recorded data included date, time, position, and GPS altitude. Calculated ground speed and ground track information was also recorded in the data file.

The data appeared to be associated with two flights. The first portion of the data was dated August 19, 2011, the day before the accident, beginning about 1326 and ending about 1411. The position data originated and terminated at MKC. An increase in ground speed, consistent with takeoff, began about 1348. A decrease in ground speed, consistent with landing, occurred about 1408.

The second portion of the data was dated August 20, 2011, the day of the accident. The initial data point was recorded at 1333:35 (hhmm:ss) and the final data point was recorded at 1341:40. Based on the recorded groundspeed information, the takeoff began about 1336. Variations in the altitude, ground speed, and ground track data appeared consistent with aerobatic flight maneuvers.

ADDITIONAL INFORMATION

The FAA Airplane Flying Handbook describes a spin as an aggravated aerodynamic stall that results in the airplane following a downward corkscrew path. Spin recovery is completed by reducing the throttle to idle, holding a neutral aileron position, applying full rudder opposite the direction of spin rotation, and applying forward movement of the elevator control in order to break the stalled condition. Once rotation has stopped, the rudder control should be neutralized and the airplane recovered to level flight. The handbook notes that excessive use of the elevator on recovery can cause a secondary aerodynamic stall and result in another spin.

NTSB Probable Cause

The pilot's impairment during an aerobatic airshow performance for reasons that could not be determined based on available information, which resulted in an in-flight loss of airplane control.