Primary finding
Probable cause
The pilot's inadequate preflight route planning and in-flight route and altitude selection, which resulted in an in-flight collision with a communications tower in possible instrument meteorological conditions. Contributing to the accident were the pilot's improper use of the enhanced ground proximity warning system's terrain inhibit switch and the air traffic controller's failure to issue a safety alert regarding the proximity of the tower.
Investigator assessment
Analysis narrative
The airplane climbed to 3,100 feet mean sea level (msl) on an approximate direct heading for the destination airport. When the airplane was about 9 miles east of the airport, the air traffic controller advised the pilot that he had "radar contact," verified the altitude of 3,100 feet msl, and instructed him to maintain visual flight rules (VFR). The airplane then descended to 3,000 feet msl, and, about 1 minute later, struck a communications tower with an overall height of about 3,089 feet msl. Examination of the airplane and engines revealed no evidence of any preimpact malfunction or failure that would have precluded normal operation. Review of the airplane's flight route indicated that the pilot had chosen a direct flight route near rising terrain and obstructions within a designated mountainous area at his selected cruise altitude of 3,100 feet msl, which was below the published maximum elevation figure of 3,500 feet msl depicted on the VFR sectional chart for the area. The pilot should have taken into account terrain elevation, obstructions, and weather when planning his route. If he had chosen a route that avoided obstructions and terrain and planned to fly at a higher altitude, he may have been able to safely complete the short flight. The airplane was equipped with a cockpit voice recorder (CVR) and an enhanced ground proximity warning system (EGPWS). The EGPWS had a terrain inhibit switch, which, when engaged by the pilot, inhibits all EGPWS visual and aural alerts and warnings to allow aircraft to operate without nuisance or unwanted warnings. However, the pilot's guide cautioned that the terrain inhibit switch should "NOT" be engaged for normal operations. CVR and EGPWS data revealed that the terrain inhibit switch was engaged before departure. As a result, although the EGPWS calculated an obstacle alert for terrain 3 minutes after takeoff, the alert was not annunciated. Review of previous flights revealed that the pilot routinely engaged the terrain inhibit switch while flying into the departure airport for this flight and would then disengage it after departure. This indicated that the pilot's normal habit was to disengage the terrain inhibit switch after departure, but, on this flight, his normal habit pattern may have been interrupted, he may have become distracted, or he may have simply forgotten to shut it off. Regardless, aeronautical charts found on board the airplane depicted the tower hazard, so the pilot should have had some awareness of the tower's presence. As noted previously, the controller identified the airplane and verified the observed and reported altitude. At the time that the airplane was identified, it was about 3.8 miles from the communications tower and its altitude was indicating that its trajectory was below the top of the tower. The tower's location was depicted on the controller's radar map as an obstruction to flight. Under the circumstances, the controller should have been aware that the airplane was flying 400 feet below the highest obstruction in the area and was nearing the tower, and he should have provided the pilot with a safety alert about the proximity of the antenna. Although the controller had other traffic, his workload at the time was not excessive. Although the weather conditions at the destination airport were conducive to landing under VFR, the pilot would have encountered reduced visibility and possibly instrument meteorological conditions east of the airport around the area of the accident due to haze and cumuliform-type clouds from 1,500 to 3,000 feet above ground level, which may have affected his ability to see the tower.
Source record
Factual narrative
HISTORY OF FLIGHT On June 22, 2012, at 1001 eastern daylight time a Raytheon Aircraft Company, C90GT, N508GT, operated by Oz Gas Aviation LLC, was substantially damaged when it struck a communications tower near Morgantown, West Virginia. The certificated airline transport pilot was fatally injured. No flight plan had been filed for the positioning flight from Nemacolin Airport (PA88), Farmington, Pennsylvania, to Morgantown Municipal Airport (MGW), Morgantown, West Virginia conducted under Title14 Code of Federal Regulations (CFR) Part 91. At 0924 on the morning of the accident, the airplane departed from Rigrtona Airport (13PA), Tidioute, Pennsylvania for PA88 with the pilot and three passengers onboard. The airplane landed on runway 23 at PA88 at 0944. The pilot then parked the airplane; shutdown both engines, and deplaned the three passengers. He advised them that he would be back on the following day to pick them up. After the passengers got on a shuttle bus for the Nemacolin Woodlands Resort, the pilot started the engines. He idled for approximately 2 minutes, and then back taxied on runway 23 for takeoff. At 0957, he departed from runway 23 for the approximately 19 nautical mile positioning flight to MGW, where he was going to refuel and spend the night. After departure from PA88, the airplane climbed to 3,100 feet above mean sea level (msl) on an approximately direct heading for MGW. The pilot then contacted Clarksburg Approach Control and was given a discrete code of 0130. When the airplane was approximately nine miles east of the Morgantown airport, the air traffic controller advised the pilot that he had "radar contact" with him. The airplane then descended to 3,000 feet, and approximately one minute later struck the communications tower on an approximate magnetic heading of 240 degrees. According to a witness who was cutting timber across the road from where the accident occurred; the weather was cloudy with lighting and thunder, and it had just started "sprinkling". He then heard a loud "bang", turned, and observed the airplane descending upside down, and then impact. About 20 minutes later it stopped "sprinkling". He advised that he could still see the top of the tower when it was "sprinkling". PERSONNEL INFORMATION The pilot was self-employed and flew and managed the airplane for Oz Gas Aviation LLC. He also flew for a training organization that provided ground and flight instruction in customer's airplanes. According to Federal Aviation Administration (FAA) records, the pilot held an airline transport pilot certificate with ratings for airplane single-engine land and airplane multi-engine land, and type ratings for the CE-500, DA-10, IA-JET, LR-JET, N-265, and CE-525S. He also held commercial privileges for rotorcraft-helicopter, and instrument helicopter, and a flight instructor certificate with ratings for airplane single-engine, airplane multi-engine, rotorcraft-helicopter, instrument airplane, and instrument helicopter. He held a special issuance FAA second-class medical certificate which was issued on August 1, 2011 and was not valid for any class of certificate after August 31, 2012. Review of FAA and pilot records revealed that the pilot had reported to the FAA during the application of his special issuance medical certificate that he had accrued 22,000 total hours of flight experience, 150 hours of which were in the previous 6 months. He had completed C90GT initial training on February 4, 2008, and C90GT recurrent training on February 9, 2009. No other records of training, or record of completion of an FAA flight review within the two years preceding the accident were discovered during the course of the investigation. AIRCRAFT INFORMATION The accident aircraft was a low wing, pressurized, twin engine airplane, of conventional metal construction equipped with retractable landing gear. It was powered by two Pratt & Whitney Canada PT6A-135A turbopropeller engines capable of producing 550 shaft horsepower, each equipped with a Hartzell 4-bladed, fully reversing, constant speed propeller. It could cruise at 270 knots true airspeed and could operate at altitudes up to 30,000 feet. Its range with full fuel was 1,068 nautical miles. According to FAA and maintenance records, the airplane was manufactured in 2006. The airplane's most recent phase inspection was completed on May 11, 2011. At the time of the inspection the airplane had accrued 1,305 hours of operation. At the time of the accident the airplane had accrued 1439.2 hours of operation and was overdue for its next phase inspection. METEOROLOGICAL INFORMATION Destination Weather The reported weather at MGW at 0953, included: winds 220 degrees at 5 knots, 9 miles visibility, a few clouds at 1,700 feet, temperature 24 degrees C, dew point 20 degrees C, and an altimeter setting of 29.95 inches of mercury. There were clouds around 1,500 to 2,000 feet above ground level (agl) with a slight reduction in visibility due to haze. With the haze that was present there was likely more reduced visibility in the horizontal direction than the vertical direction and though 9 miles visibility was reported, it was likely slightly less than that, looking up or down at an angle, but nothing below 7 miles visibility. The clouds would have likely been most prominent near the mountainous terrain given the weather in the Mid-Atlantic region, and mountain and valley breeze circulations present during the morning hours. Accident Area From 0900 to 1100, there was an increase in mid- level clouds as satellite images of the area taken at 0945, 1045, and 1145 showed an increase in cloud cover, indicating that the pilot would have had reduced visibility and possibly instrument meteorological conditions from clouds at 1,500 to 3,000 feet agl. A witness statement also indicated that light rain and thunder was present at the time of the accident, and review of a photograph taken of the communications tower at 1130, revealed the presence of cumulus clouds in close proximity to the top of the communications tower. FLIGHT RECORDERS Per federal regulation, because the aircraft was certificated to be operated by one pilot, it was not required to be equipped with a cockpit voice recorder (CVR). The aircraft, however, was equipped with a solid-state CVR that recorded the last 30 minutes of aircraft operation; this was accomplished by recording over the oldest audio data. When a CVR is deactivated or removed from the airplane, it retains only the most recent 30 minutes of CVR operation. This model CVR, the L-3/Fairchild FA2100-1010, recorded 30 minutes of digital audio, which was stored in solid-state memory modules. Four channels of audio information were retained: one channel for each flight crew and one channel for the cockpit area microphone (CAM). The CVR had sustained only minor physical damage. The audio information was extracted from the recorder normally, without difficulty. The recording consisted of two channels of audio information. One of the channels contained audio information from the pilot's audio panel. The quality of this channel was good. One channel contained audio information from the CAM. The quality of this channel was also good. The third and fourth channel did not contain audio, nor was it required by regulation to do so. The quality of these channels was unknown. The following is a summary of the recorded audio information: At 9:24:28.7, recording started. At 9:25:00.3, the airplane was in a VFR climb to 8,000 feet msl, destined for PA88 talking to Cleveland Air Route Traffic Control Center (ARTCC). At 9:26:48.4, the pilot can be heard talking to a male passenger about the destination. At 9:27:28.9, the pilot advises Cleveland ARTCC that he was descending to 6,000 feet msl. At 9:27:51.5, unintelligible background conversation of passenger can be heard during most of the flight. At