Aviation Accident Summaries

Aviation Accident Summary NYC07FA217

Syria, VA, USA

Aircraft #1

N6493W

PIPER PA-28-140

Analysis

The accident airplane was on a direct course to its destination airport during dark night with mountainous terrain off its left side. The pilot had accumulated approximately 140 total hours of flight experience and was not instrument-rated. While descending to 3,500 feet above mean sea level (msl), the airplane turned off its established course to the east. When queried by the approach controller, the pilot responded he was heading 045 degrees. When asked again to say his heading, he responded he was on a 107-degree heading, but should be on a 025-degree heading, and was making a left turn "towards my course." He then was told to proceed on course and advised to maintain "Ground avoidance, obstacle avoidance as you are in a 5,600 foot minimum vectoring altitude area." No further transmissions were received and moments later radar contact lost by the approach control facility. Review of radar data also revealed that the accident airplane’s ground speed and ground track had begun to fluctuate just prior to the controller’s query and that after the airplane turned back to the left, altitude decreased, airspeed increased, and radar contact was then lost. The wreckage was discovered on the side of a mountain at 2,848 feet msl. No evidence of any preimpact malfunction of the airplane or engine was discovered. A report from another pilot to the approach controller revealed that there was no visible horizon or visible ground lighting in the area where the accident airplane went off radar. The FAA's Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25) stated, "Unless a pilot has many hours of training in instrument flight, flight in reduced visibility or at night when the horizon is not visible should be avoided."

Factual Information

HISTORY OF FLIGHT On September 6, 2007, about 2033 eastern daylight time, a Piper PA-28-140, N6493W, was destroyed when it impacted trees about 4 nautical miles west of Syria, Virginia. The certificated private pilot and two passengers were killed. Night visual meteorological conditions prevailed, and a visual flight rules flight plan had been air filed for the flight, which departed Hartsville Regional Airport (HVS), Hartsville, South Carolina, destined for Winchester Regional Airport (OKV), Winchester, Virginia. The personal flight was conducted under 14 Code of Federal Regulations Part 91. According to data provided by the Federal Aviation Administration (FAA), the flight originated at Brunswick Golden Isles Airport (BQK) Brunswick, Georgia, at 1500. It then proceeded to Sumter Airport (SMS), Sumter, South Carolina, and then HVS. After departing from HVS, the airplane climbed to 5,500 feet mean sea level (msl) while in the vicinity of Chapel Hill, North Carolina, and the pilot "air-filed" a visual flight rules flight plan with OKV as the destination. The flight continued uneventfully on a direct course to OKV until shortly after the pilot contacted Potomac Approach and began to descend to 3,500 feet msl. The airplane then turned off the established course to the east. When queried by the approach controller, the pilot responded that he was heading 045 degrees. When asked to say his heading a second time, he responded that he was on a 107-degree heading, but should be on a 025-degree heading and he was making a left turn back "towards my course." He then was told to proceed on course and advised to maintain "ground avoidance, obstacle avoidance as you are in a 5,600 foot minimum vectoring altitude area." No further transmissions were received and moments later at 20:32:24, the approach controller stated "November nine three whiskey radar contact lost." The accident occurred during the hours of night. After a search by multiple local, state, and federal agencies, the wreckage was discovered on September 7, 2007, on the northeast side of Fork Mountain. PERSONNEL INFORMATION The pilot, age 46, held a private pilot certificate with a rating for airplane single-engine land. The pilot did not hold an instrument rating. His most recent FAA third-class medical certificate was issued on August 13, 2007. He reported 140 total hours of flight experience on that date. Review of the pilot's logbook revealed that he had accumulated approximately 3.6 hours of night experience and 5.5 hours of simulated instrument experience. AIRCRAFT INFORMATION According to FAA and maintenance records, the airplane was manufactured in 1964. The airplane's most recent annual inspection was completed on March 6, 2007. At the time of the inspection, the airplane had accrued 3,832.54 total hours of operation. METEOROLOGICAL INFORMATION The reported weather at Orange County Airport (OMH), Orange, Virginia, approximately 22 nautical miles southeast of the accident site, at 2040, included: wind 140 degrees at 3 knots, visibility 10 miles, sky clear, temperature 27 degrees Celsius, dew point 21 degrees Celsius, and an altimeter setting of 30.20 inches of mercury. According to the United States Naval Observatory, sunset occurred at 1935, and the end of civil twilight occurred at 2002. Moonrise did not occur until 0122 on the following day. WRECKAGE AND IMPACT INFORMATION Examination of the accident site revealed that the airplane had come to rest inverted, perpendicular to the face of the mountain, which sloped downward about 45 degrees. The elevation of the accident site was 2,848 feet msl. The wreckage path was about 30 feet long, and the main wreckage had come to rest on a magnetic heading of 300 degrees. A tree, located at the beginning of the wreckage path, exhibited impact damage and was broken off approximately 30 feet above ground level. Broken limbs and branches existed throughout the accident site. Further examination of some of the limbs and branches revealed multiple breaks and cuts consistent with propeller strikes. The wreckage displayed varying degrees of damage; however, examination revealed no evidence of any preimpact malfunction of the engine, airframe, or flight controls. Multiple breaks in the fuselage structure existed, and the aft fuselage was partially severed from the main cabin. The left side of the stabilator had been shredded, was separated from the airplane, and portions of its structure were discovered at the beginning of the wreckage path. The right side of the stabilator remained intact. The left wing was stripped of the majority of its structure and the right wing had separated at its attachment fittings. The wing flap actuating mechanism was in the flaps up position, and the pitch trim was approximately neutral. Control continuity was established from the stabilator control mechanism, rudder panel, and ailerons to the cockpit. The engine was discovered approximately 20 feet down slope of, and to the right of the main wreckage. Examination of the engine revealed that it exhibited impact damage to the front of the case, and the oil sump was sheared off. The propeller flange was bent back against the engine case and the front of the case was cracked. All four cylinders remained in place and residual oil was present. All spark plugs were removed and their electrodes were intact and light gray in color. Both magnetos displayed impact damage, but rotated freely and produced spark from three of the eight towers. The propeller was separated from the propeller flange and had come to rest approximately 10 feet forward of the main wreckage. Both propeller blades exhibited leading edge gouging, polishing, chordwise scratching, twisting, and S-bending. Examination of the vacuum pump revealed that the vanes were intact and no anomalies were noted. MEDICAL AND PATHOLOGICAL INFORMATION A postmortem examination was performed on the pilot by the State of Virginia's Office of the Chief Medical Examiner. The cause of death was reported as "multiple blunt force injuries." Toxicological testing of the pilot was conducted at the FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma. The testing revealed the presence of ethanol, propanol, and acetaldehyde; however, putrefaction was noted as yes. The testing was negative for drugs. TESTS AND RESEARCH Review of FAA-provided radar data revealed that at 20:29:17, the accident airplane’s ground speed and ground track began to fluctuate. At 20:30:17, the airplane’s ground track eventually reached a heading of 106 degrees. The airplane then began to turn to the left, altitude decreased, airspeed increased, and at 20:30:46, the reported altitude went into "coast." Additional Weather Information According to a witness who lived in the local area, and heard the accident airplane pass over the top of "double top," it was very dark on the evening of the accident. No moon was visible and he could not see "the Blue Ridge," even though it was approximately 2 miles from where he lived. A report from a pilot to Potomac Approach also revealed that there was no visible horizon or visible ground lighting in the area where the accident airplane went off radar. Pilot’s Handbook of Aeronautical Knowledge According to the FAA's Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25), 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. The Handbook also advised, that prevention is usually the best remedy for spatial disorientation, and "Unless a pilot has many hours of training in instrument flight, flight in reduced visibility or at night when the horizon is not visible should be avoided."

Probable Cause and Findings

The pilot's inadvertent flight into instrument meteorological conditions and his failure to maintain aircraft control. Contributing to the accident was the dark night conditions.

 

Source: NTSB Aviation Accident Database

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