Factual Report: Malibu turboprop mod breaks up in thunderstorms

 - October 8, 2007, 10:51 AM

PIPER PA-46-310P OSTEEN, FLA., JUNE 14, 2002–Flying in an area of thunderstorms, Piper Malibu N9143B, a JetProp turboprop conversion, lost its right wing and left horizontal stabilizer in flight. The private pilot and two passengers were killed when the airplane crashed at about 8:35 p.m. The turboprop single was en route from Raleigh, N.C., to Marco Island, Fla.

The pilot had received an FSS briefing at 4:52 p.m. and was provided a synopsis of a weather system over the Florida Gulf Coast, the briefer stating there were “looming thunderstorms” in that area. The NTSB report later revealed that the preflight briefing did not thoroughly address hazardous weather along N9143B’s route of flight. However, as the flight progressed, the pilot became aware of the weather conditions through other means.

According to the radar study, N9143B was cruising at FL260, heading toward heavy thunderstorms, when the pilot requested a deviation around bad weather. About two minutes later, the pilot reported seeing a hole and attempted to fly through it. Three minutes or so later, radar data showed the airplane descending rapidly in a left-hand turn, at a rate of 20,700 fpm, to a final altitude of 2,700 feet. The radar pod and wing panel separated at an altitude of 26,000 feet just before the airplane’s rapid descent.

Witnesses reported hearing the engine make a winding noise, then saw the airplane coming out of the clouds at about 300 feet agl in a nose-low spiral, with the right wing missing.

The fractures in the right wing and left horizontal stabilizer spar appeared to be caused by excessive upward aerodynamic loads. Initial failure was determined to be compression buckling along the upper surface of the wing.

The pilot had completed a 16-hour Piper Malibu PA-46T ground and flight recurrent course on May 24, 2002, and had 2,800 hours TT, of which 380 were in make and model. His flight instructor said the pilot “pushed himself dangerously close when making weather decisions in this class of airplane.” He seemed to “lack a healthy respect” for the destructive forces of thunderstorms and seemed to take “delight” in how far he could push the envelope. The CFI said he had cautioned him as late as “two weeks” before the accident that his decision-making in this respect was deficient and he needed to exercise “greater care” when flying his converted Malibu (equipped with a Pratt & Whitney Canada PT6A-34 turboprop engine) in and around “adverse weather systems.”