ERA12FA438

The non-instrument rated pilot’s decision to continue visual flight rules flight into instrument meteorological conditions, which resulted in his spatial disorientation, a loss of airplane control, and subsequent impact with trees and terrain.

The non-instrument rated pilot departed the airport in instrument meteorological conditions with no flight plan filed for the personal flight. Prior to the flight, an employee at the departure airport who talked to the pilot reported that the pilot stated he was in a "hurry to depart due to possible bad weather in the area." A review of radar data indicated that a radar target identified as the accident airplane flew for about 25 minutes after takeoff at a relatively constant altitude of about 1,000 feet mean sea level (msl). Then, the radar target began to climb at 0849:55 with intermittent descents of one to two hundred feet. The last radar return at 0852:27 indicated an altitude of 2,600 feet msl, which was in the vicinity of the accident location. Postaccident analysis of position information recovered from an enhanced ground proximity warning system (EGPWS) showed that last 10 seconds of recorded data exhibits a steadily increasing negative vertical speed rate. The last two seconds of data recorded a 5,000 foot per minute descent up to a 15,000 foot per minute descent. The roll rate of the airplane in the last 10 seconds of recorded data varied from a 24 degree roll to the right to a 28 degree roll to the left. During the final moments of the recorded flight data, ground speed peaked around 140 knots, and then decreases to 20 knots in two seconds. Examination of the wreckage revealed no evidence of any pre-impact mechanical malfunctions or failures. Analyses of weather information and witness statements were consistent in depicting conditions likely to have produced restricted visibility at the time of the accident. Therefore, it is likely that the restricted visibility conditions and  the airplane’s turning ground track would have been conducive to the development of spatial disorientation. Subsequently, the rapid descent and steep bank angle could have resulted from the pilot losing control of the airplane due to spatial disorientation.

The Office of the Chief Medical Examiner, Memphis, Tennessee, conducted an autopsy on the pilot on July 12, 2012. The autopsy findings included "multiple blunt traumatic injuries," and the report listed the specific injuries.   Forensic toxicology was performed on specimens from the pilot by the FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma. The toxicology report stated no ethanol or drugs were detected.     Multi-Function Display and Primary Function Display   A multi-function display (MFD) and primary flight display (PFD) were recovered from the cockpit and forwarded to the NTSB Vehicle Recorders Laboratory, Washington, DC, for data download. Due to the excessive damage and fragmentation of the memory devices, no viable data was extracted from the MFD or PFD.     Enhanced Ground Proximity Warning System   An enhanced ground proximity warning system (EGPWS) was also retained by the NTSB for data download. A review of the data revealed that heading, GPS position, GPS altitude, and vertical speed were recorded. Ground speed was derived from aircraft position information. The highest recorded altitude of the airplane was about 2700 feet msl, which was about 10 seconds prior to the end of the recording. In addition, the last 10 seconds of recorded data exhibits a steadily increasing negative vertical speed rate. The last two seconds of recorded data indicated a 5,000 foot per minute descent up to a 15,000 foot per minute descent. The roll rate of the airplane in the last 10 seconds of recorded data varied from a 24 degree roll to the right to a 28 degree roll to the left. The recorded ground speed peaks 2 seconds prior to the end of the recorded data around 140 knots, and then decreases to 20 knots in two seconds.   According to the downloaded data, the airplane experienced two EGPWS alerts during the accident sequence. A Mode 1 “Sink Rate” caution occurred at system time 511:53:35. A Mode 1 “Pull Up” warning occurred at system time 511:53:36. According to the manufacturer's pilot's guide:   “Initially, the voice alert “Sink Rate” will be heard, and the yellow caution alert annunciator lamp will illuminate. If the aircraft continues in the high rate of descent, the “Sink Rate-Sink Rate” voice alert will be repeated at an increasing frequency. Should the aircraft penetrate the warning boundary, the voice alert “Pull Up” will be heard continuously and the red warning annunciator lamp will illuminate. In both cases, as the pilot reacts to decrease the high rate of descent and the aircraft flight path exits the alerting/warning envelope, the annunciator lamp will extinguish and the voice alerts will cease.”   More details about the EGPWS examination can be found in the "EGPWS Factual Report" located in the public docket for this accident.   FAA Advisory Circular 60-4A Pilot's Spatial Disorientation According to FAA Advisory Circular 60-4A "Pilot's Spatial Disorientation," "Surface references and the natural horizon may at times become obscured, although visibility may be above visual flight rule minimums. Lack of natural horizon or surface reference is common on over-water flights, at night, and especially at night in extremely sparsely populated areas or in low visibility conditions. A sloping cloud formation, an obscured horizon, a dark scene spread with ground lights and stars, and certain geometric patterns of ground lights can provide inaccurate visual information for aligning the aircraft correctly with the actual horizon. The disoriented pilot may place the aircraft in a dangerous attitude." FAA's Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25)   The FAA's Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25), also states that under normal flight conditions, when there is a visual reference to the horizon and ground, the sensory system in the inner ear helps to identify the pitch, roll, and yaw movements of the airplane. When visual contact with the horizon is lost, the vestibular system becomes unreliable. Without visual references outside the airplane, there are many situations where combinations of normal motions and forces can create convincing illusions that are difficult to overcome. In a classic example, a pilot may believe the airplane is in level flight, when, in reality, it is in a gradual turn. If the airspeed increases, the pilot may experience a postural sensation of a level dive and pull back on the stick, which tightens the turn and creates increasing G-loads. If recovery is not initiated, a steep spiral will develop. This is sometimes called the graveyard spiral, because if the pilot fails to recognize that the airplane is in a spiral and fails to return the airplane to wings-level flight, the airplane will eventually strike the ground. If the horizon becomes visible again, the pilot will have an opportunity to return the airplane to straight-and-level flight, and continued visual contact with the horizon will allow the pilot to maintain straight-and-level flight. However, if contact with the horizon is lost again, the inner ear may fool the pilot into thinking the airplane has started a bank in the other direction, causing the graveyard spiral to begin all over again.   Around the time of departure, the NQA 0835 recorded weather observation indicated variable wind at 4 knots; visibility 6 statute miles, mist, overcast clouds at 900 feet above ground level (agl), temperature 24 degrees C; dew point 22 degrees C; altimeter 29.99.   The 0854 recorded weather observation at Memphis International Airport (MEM), located approximately 29 miles west of the accident location, included wind from 080 degrees at 7 knots, 9 miles visibility, overcast clouds at 600 feet agl, temperature 24 degrees C, dew point 22 degrees C; barometric altimeter 29.99 inches of mercury.   The GOES-13 infrared image for 0902 CDT image depicted a large area of low stratiform clouds over the accident site with cloud tops near 8,000 feet. In addition, the image depicted multiple layers of clouds over the area that produced an overcast cloud cover of stratiform clouds over the region and the accident site. Cumulus congestus type clouds associated with vertical development and rain showers can be identified east, with additional development southwest of Memphis.   There were a significant number of pilot reports made in the vicinity of McKellar-Sipes Regional Airport (MKL), Jackson, Tennessee, which was 41 nautical miles north east of the accident location, and reported overcast clouds with bases between 1,200 and 1,600 feet msl (or approximately 800 and 1,200 feet agl) with tops between 2,000 and 5,000 feet msl surrounding the period.     The aircraft struck trees and impacted terrain on the edge of an open meadow on an estimated 035-degree heading. The airplane’s initial collision was with the top of an approximately 40 foot tall tree, with a ground elevation of 498 feet msl. The airplane impacted terrain about 70 feet beyond the impacted tree. The descent angle between the tree and terrain equated to about 60-degrees. The initial ground impact crater measured approximately 6 feet square and consisted of a ground scar approximately 20-feet-wide by 15-feet-long, which were consistent in size and dimension to the right leading edge of the wing, the right main landing gear, and left main landing gear. This was also consistent with a right wing low attitude at impact. The debris field extended outward approximately 115 feet-wide by 480 feet-long from the crater.   The engine was encased in three individual cowling pieces. The upper engine cowling, which was located in the debris field, exhibited impact damage. The left and right engine cowl