CEN10FA063

A loss of aircraft control for undetermined reasons.

Shortly after takeoff in the pressurized twin-engine airplane, the pilot was cleared to climb and maintain 16,000 feet. The pilot reported passing through instrument conditions with heavy snow and that he cleared the tops of the clouds at 7,000 feet. The pilot was then cleared to climb and maintain flight level (FL) 230. Radar data showed the airplane's altitude and course varied throughout the flight after having reached FL 230. Several times during the flight the air traffic controller questioned the pilot regarding his altitude and/or course. Each time the pilot responded that he was at the correct altitude and/or course. The radar data showed that after each of these conversations, the airplane would return to the assigned altitude and/or course. The controller then informed the pilot that, because radar showed the airplane’s altitude fluctuating between FL 224 and FL 237, he was going to have to descend out of positive controller airspace. The pilot acknowledged this transmission. The controller instructed the pilot to descend to 17,000 feet. The last transmission from the pilot was when he acknowledged the descent. Radar data showed that one minute later the airplane was at FL 234. During the last minute and 12 seconds of radar data, the airplane reversed its course and descended from FL 233 to FL 214, at which time radar data was lost. Witnesses reported hearing loud engine sounds and seeing the airplane in a spiraling descent until ground impact. Postaccident inspection of the engines did not identify any anomalies that would have precluded normal operation. Most of the fuselage was consumed by fire; however, flight control continuity was established. Given the pilot’s experience and the flight’s altitude and course variations the investigation considered that the pilot may have suffered from hypoxia; however, due to the postimpact fire the functionality of the airplane’s pressurization system could not be observed and no conclusive determination could be made that the pilot was impaired.

HISTORY OF FLIGHT On December 4, 2009, at 1845 eastern standard time, a Piper PA-31T2, N85EM, collided with the terrain following an in flight loss of control in Harrison, Michigan. The airline transport rated pilot suffered fatal injuries. The airplane was destroyed by impact forces and a post impact fire. Visual meteorological conditions prevailed and an instrument flight rules (IFR) flight plan was filed. The business flight was being operated under 14 Code of Federal Regulations Part 91. The flight departed the Charlevoix Municipal Airport (CVX), Charlevoix, Michigan, at 1811, en route to the Seneca County Airport (16G), Tiffin, Ohio. The pilot departed from 16G earlier in the evening and flew to CVX to drop off a passenger. He was returning to 16G when the accident occurred. Another pilot who knew the pilot of N85EM stated he landed at CVX approximately 5 minutes before N85EM. According to the times provided by this pilot, N85EM was on the ground at CVX for approximately 30 minutes. He stated N85EM was on the other side of the airport from where he was so he did not see the pilot of N85EM, but they conversed on the aircraft radio while on the ground. He stated that the pilot of N85EM did not mention having any problems with the airplane. He departed CVX about 5 minutes after N85EM, en route to Toledo, Ohio. The pilot stated the cloud tops were around 8,000 feet with a trace of rime ice in the clouds. He stated he overheard radio conversation between the pilot of N85EM and air traffic control. He stated the pilot responded accordingly to the radio transmissions and that there were no "signs of distress." The pilot of N85EM picked up his IFR clearance while on the ground at CVX. At 1816:13, he contacted the Minneapolis Air Route Traffic Control Center (ARTCC) stating that he was out of 1,800 feet climbing to 6,000 feet. The controller then cleared N85EM to climb and maintain 16,000 feet. Radar contact with N85EM was established at 1817:35. At this time the pilot reported climbing out of 5,600 feet and being in solid IFR conditions with heavy snow. At 1838:19, the pilot reported being on top of the clouds in clear weather at 7,000 feet. At 1820:58, N85EM was cleared to climb to and maintain flight level (FL) 230. The pilot acknowledged this clearance. Radar data indicated that during the climb to FL 230 there were slight variations in the aircraft course, but overall the aircraft maintained a south-southeasterly course of about 170 degrees. Around 1828, the aircraft turned to a south-southwesterly course of about 190 degrees and entered a descent. At 1829:13, the controller asked the pilot what altitude he was at. The pilot reported being at FL 230 feet to which the controller responded that radar was showing him as being at FL 224. The pilot acknowledged this transmission. The radar data showed the airplane began to climb and at 1830:18, the controller stated that the radar was now showing the airplane back level at FL 230. At 1831:36, the controller asked the pilot how the ride was at FL 230. The pilot responded that the ride was smooth and there was no ice. Around 1834, the airplane again turned to a south-southwesterly course of about 230 degrees, entering a descent. At 1834:46, the controller contacted the pilot informing him that the radar was showing him as being on a southwesterly course. The controller asked the pilot if he was showing himself as being on course, to which the pilot answered "yes sir." The controller then stated that the radar was showing that he was 300 feet below his assigned altitude. The pilot responded, "we’re shown twenty three hundred twenty three thousand ah twenty nine ninety two." The radar showed the airplane then turned back to a course of about 170 degrees. The course of the airplane gradually changed back to a heading of about 190 degrees as the airplane climbed to FL 242. The radar track indicates that around 1838, the airplane’s course changed to about 130 degrees and the altitudes continued to fluctuate. At 1838:37, the controller stated that the mode C readout was showing the airplane's altitude fluctuating between FL 224 and FL 237. The pilot responded that he would get it checked when he got on the ground. The controller then informed the pilot that because the altitude readout was fluctuating, he could not let him fly in positive control airspace. The controller instructed the pilot to descend and maintain 17,000 feet. The pilot responded, "okay ah stop the altitude squawk for (unintelligible)." At 1838:53, the controller again instructed the pilot to descend and maintain 17,000 feet. At 1839:15, the pilot replied, "(unintelligible) leaving two four --- (for one seven thousand)." This was the last transmission from N85EM. The radar data showed the airplane was at FL 242 when this last transmission occurred. The airplane maintained an altitude between FL 242 and FL 240 until 1839:48. The radar data indicated that at 1840, the airplane was on a southerly course at FL 234. At 1840:12, the course was about 140 degrees at an altitude of FL 233. The airplane maintained this course until 1840:24 when it switched to a northerly course. At 1840:51, the course changed to a track of about 070 degrees and the altitude data indicated an altitude of FL 223. Nine seconds later, the course changed to one of about 015 degrees. The last recorded radar was at 1841:24 at an altitude of FL 214. The location of the last radar contact was approximately 0.7 miles northwest of the accident site. There were four witnesses identified who heard and saw the airplane prior to the accident. All of the witnesses reported that they heard the airplane prior to seeing it and it was the sound of the engines that caught their attention. Three of the witnesses reported hearing loud engine sounds. One of which reported that the only change in engine sound was from the change in the airplane's direction and not from a change in engine operation. The fourth witness reported hearing the engines, followed by silence, which was followed by more engine sounds. Two of the witnesses reported seeing the airplane spiraling in a "flat" attitude prior to the nose dropping and the airplane impacting the terrain. Another of the witnesses reported seeing the lights on the airplane as it made approximately 10 spirals while descending. This witness stated the airplane was not in a "flat" spin. The fourth witness stated that it sounded as if the airplane was flying back and forth over her house. She stated the airplane was flying level prior to it nosing down and impacting the terrain. The witnesses reported that they did not see smoke or flames coming from the airplane prior to it impacting the terrain. PERSONNEL INFORMATION The pilot, age 58, held an airline transport pilot (ATP) certificate with an airplane multi-engine land rating. The certificate contained commercial pilot privileges with an airplane single-engine land rating. The pilot's ATP certificate also contained a type rating for Cessna CE-500 airplanes. The pilot's last Federal Aviation Administration medical examination was completed on October 16, 2009, when he was issued a second-class medical certificate. The medical certificate contained the limitation, "Must wear corrective lenses." The application for this medical examination indicated that the pilot did not take any medications. The pilot's previous application for a medical certificate dated October 6, 2008, indicated that the pilot was taking the medication Crestor. On this application, the pilot indicated that he had 13,000 hours of flight time. The pilot's logbooks were not located during the investigation. An application for insurance dated October 14, 2009, indicated that the pilot’s last biennial flight review and instrument check was completed on August 20, 2009. The application indicated that the pilot had 4,00