ERA14LA006

The pilot’s failure to maintain airplane control due to spatial disorientation in low-visibility conditions while maneuvering during a missed approach. Contributing to the accident was the pilot’s ineffective use of the onboard GPS equipment.

The instrument-rated pilot was on a cross-country flight. According to air traffic control records, an air traffic controller provided the pilot vectors to an intersection to fly a GPS approach. Federal Aviation Administration radar data showed that the airplane tracked off course of the assigned intersection by 6 nautical miles and descended 800 ft below its assigned altitude before correcting toward the initial approach fix. The airplane then crossed the final approach fix 400 ft below the minimum crossing altitude and then continued to descend to the minimum descent altitude, at which point, the pilot performed a missed approach. The missed approach procedure would have required the airplane to make a climbing right turn to 2,500 ft mean sea level (msl) while navigating southwest back to the intersection; however, radar data showed that the airplane flew southeast and ascended and descended several times before leveling off at 2,800 ft msl. The airplane then entered a right 360-degree turn and almost completed another circle before it descended into terrain. Examination of the wreckage revealed no evidence of any preimpact mechanical malfunctions or failures. During the altitude and heading deviations just before impact, the pilot reported to an air traffic controller that adverse weather was causing the airplane to lose "tremendous" amounts of altitude; however, weather radar did not indicate any convective activity or heavy rain at the airplane's location. The recorded weather at the destination airport about the time of the accident included a cloud ceiling of 400 ft above ground level and visibility of 3 miles. Although the pilot reported over 4,000 total hours on his most recent medical application, the investigation could not corroborate those reported hours or document any recent or overall actual instrument experience. In addition, it could not be determined whether the pilot had experience using the onboard GPS system, which had been installed on the airplane about 6 months before the accident; however, the accident flight track is indicative of the pilot not using the GPS effectively, possibly due to a lack of proficiency or familiarity with the equipment. The restricted visibility and precipitation and maneuvering during the missed approach would have been conducive to the development of spatial disorientation, and the variable flightpath off the intended course was consistent with the pilot losing airplane control due to spatial disorientation. Toxicological tests detected ethanol and other volatiles in the pilot's muscle indicative of postmortem production.

Spatial Disorientation The FAA publication Medical Facts for Pilots (AM-400-03/1), described several vestibular illusions associated with the operation of aircraft in low visibility conditions. Somatogyral illusions, those involving the semicircular canals of the vestibular system, were generally placed into one of four categories, one of which was the "graveyard spiral." According to the text, the graveyard spiral, "…is associated with a return to level flight following an intentional or unintentional prolonged bank turn. For example, a pilot who enters a banking turn to the left will initially have a sensation of a turn in the same direction. If the left turn continues 20 seconds or more, the pilot will experience the sensation that the airplane is no longer turning to the left. At this point, if the pilot attempts to level the wings this action will produce a sensation that the airplane is turning and banking in the opposite direction (to the right). If the pilot believes the illusion of a right turn (which can be very compelling), he/she will reenter the original left turn in an attempt to counteract the sensation of a right turn. Unfortunately, while this is happening, the airplane is still turning to the left and losing latitude. " Pulling the control yoke/stick and applying power while turning would not be a good idea–because it would only make the left turn tighter. If the pilot fails to recognize the illusion and does not level the wings, the airplane will continue turning left and losing altitude until it impacts the ground." An autopsy was performed on the pilot on December 15, 2013, by the Commonwealth of Virginia, Office of the Chief Medical Examiner, Norfolk, Virginia. Forensic toxicology was performed on specimens from the pilot by the FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma. The toxicology report stated no drugs were detected in the muscle. Ethanol in concentrations of 73 (mg/dL, mg/hg), N-Butanol and N-Propanol were detected in the muscle. The recorded weather at the Chesapeake Regional Airport (CPK), Norfolk, Virginia, located 4.21 miles from the accident site at an elevation of 19 feet, at 1155, included calm wind, 7 statute miles visibility, light rain, a broken ceiling at 600 feet above ground level (agl), overcast skies at 1,100 feet agl, temperature of 21 degrees Celsius (C), dew point temperature of 20 degrees C, and an altimeter setting of 29.88 inches of mercury. The conditions at 1235 included calm wind, 5 statute miles visibility, light rain, an overcast ceiling at 600 feet agl, temperature of 21degrees C, dew point temperature of 21 degrees C, and an altimeter setting of 29.87 inches of mercury. The PVG reported weather conditions at 1135 located 6.58 miles from the accident site at an elevation of 28 feet, included wind from 360 degrees at 8 knots, varying in direction between 320 and 020 degrees, 3 statute miles visibility, an overcast ceiling at 400 feet agl, temperature of 19 degrees C, dew point temperature of 18 degrees C, and an altimeter setting of 29.92 inches of mercury. The PVG reported weather conditions at 1235 were winds from 360 degrees at 7 knots with gusts to 17 knots, wind variable between 330 and 030 degrees, 9 miles visibility, an overcast ceiling at 500 feet agl, temperature of 18 degrees C, dew point temperature of 17 degrees C, and an altimeter setting of 29.91 inches of mercury. A Meteorological Impact Statement (MIS) was issued at 0932 and was valid for the accident site at the accident time. The MIS warned of IFR ceilings, visibilities between 1 and 5 miles, rain, and mist for Virginia. It also warned of light to moderate turbulence below FL420 with thunderstorms along the Virginia and North Carolina coast Airmen's Meteorological Information Tango and Sierra issued at 1045, and valid at the accident time, forecasted IMC for the accident site with ceilings below 1,000 feet, visibilities below 3 statute miles in precipitation and mist, and moderate turbulence below 8,000 feet. ORF, located 14 miles northeast of the accident site, was the closest location with a terminal area forecast (TAF). The TAF issued at 0735 forecast for the time period from 1100, winds 040 degrees at 18 knots with gust 26 knots, 5 miles visibility, light rain and fog, overcast 600 feet agl; from 1400, wind from 060 at 14 knots with 21 knot gust, 5 miles visibility, drizzle and fog, overcast 900 feet agl; and from 1700, wind from 020 at 10 knots with 18 knots gust, 5 miles visibility, drizzle and fog, broken at 900 feet agl and overcast at 1,500 feet agl. There was no record of the pilot having received a preflight weather briefing from a Lockheed Martin Flight Service facility, nor was there a record of the pilot having received a briefing through the Direct User Access Terminal Service. According to first responders, the airplane came to rest on a northeast heading. The wreckage debris field was about 150 feet long. At the end of the debris field, there was an impact crater 8 feet wide, 30 feet long, and about 4 feet deep. All flight control surfaces, controls, and cable hardware were observed at the wreckage site and were impact-damaged. An examination of the airframe revealed that all of the trim settings were unreliable due to impact damage. The rudder remained attached to the vertical stabilizer and the rudder trim tab remained attached to the rudder. The left elevator was separated from the horizontal stabilizer. The right elevator remained attached to the horizontal stabilizer and the elevator trim tab remained attached to the elevator. The left aileron was separated into two sections, with the trim tab attached. The right aileron was separated into three sections. Examination of the fuel system revealed that only one fuel selector valve was found loose in the wreckage and it was in the "OFF" position and the strainer screen was free of debris. The fuel caps for both wing tip tanks and both aux fuel tanks were observed in place and latched. The aircraft was equipped with a left and right wing locker fuel tanks, and the wing locker tank fuel caps were not recovered. Examination of the left engine revealed that all of the cylinders were impact-damaged. The engine crankshaft was rotated by hand, and all cylinders displayed thumb compression. All cylinders were examined using a borescope and displayed varying amounts of mud impaction and normal operating signatures. The three blade, variable pitch propeller remained attached to the propeller flange; however, the propeller flange had sheered from the crankshaft. The spinner remained attached to the propeller and displayed signatures of impact damage. All three of the blades remained within the propeller hub and were locked in place. Two of the three blades displayed varying amounts of tip curling; the third blade displayed minor bending of the tip. All three of the propeller blades had minor bending deformation. Examination of the right engine revealed all cylinders were impact-damaged. All cylinders were examined using a borescope, and the cylinders displayed normal operating signatures. The crankcase displayed impact damage concentrated to the bottom portion of the crankcase. The crankshaft was unable to be rotated by hand, and it was noted that the crankshaft had shifted towards the rear of the case. There were no anomalies noted with the crankcase. The three blade, variable pitch propeller remained attached to the propeller flange; however, the propeller flange had broken free from the crankshaft. The propeller displayed damage consistent with impact damage and the spring and spring housing had separated from the propeller hub. All three blades remained within the propeller hub; however, all three blades were loose in the hub. One blade's tip had broken free from the rest of the blade; the blade also displayed twisting deformation. One blade was bent approximately 90-degrees and disp