On September 14, 1994, at 0846 eastern daylight time (EDT), a Piper PA-60-602P, Canadian registry, C-FSMO, registered to FCF Bowers, Incorporated of Stratford, Ontario, Canada, and piloted by a Canadian private pilot, was destroyed when it collided with trees and terrain during a power off forced landing. The 14 CFR Part 91 flight was operating on an IFR flight plan. Instrument meteorological conditions prevailed at the time of the accident. The pilot and three passengers were seriously injured. The flight originated from Stratford, Ontario, Canada, at 0805 EDT. According to the pilot, he departed Stratford with 165 gallons of fuel on board. He encountered "Fairly solid IMC from 3,000 to 18,000 feet... ." During the last 1,000 feet of climb the pilot said he noted "...a slight power loss and [he] began scanning instruments, gauges, and switches." The pilot continued, "Before reaching 22,000 feet the right engine stopped--within seconds the left engine quit." He said the airplane descended 18,000 feet in three minutes. He said he attempted to restart the engines two or three times. The pilot said the airplane broke out of the clouds at 3,000 feet into rain, fog, and one mile visibility. C-FSMO collided with trees and brush before coming to rest against a large tree. Witnesses said that the airplane exploded when it struck the trees. The airplane's center fuselage, inboard wing sections, including the inboard sections of the fuel tank, and engines burned during the post crash fire. During an interview with the pilot he stated a total loss of power occurred 30 to 40 minutes after takeoff. He said he couldn't recall if the fuel tank gauges were showing low fuel or empty. He said he could not recall if the fuselage center tank's low fuel warning light had illuminated. The on-scene investigation was conducted by a Federal Aviation Administration (FAA) Principal Maintenance Inspector (PMI). An examination of the engines revealed no mechanical anomalies that would prevent them from producing power. The PMI said he had not found fuel in the left and right fuel filter elements, fuel supply lines, and injector lines. He said he had found traces of fuel in the left and right engine's fuel injector servos and flow dividers. The fuel distribution manifold that is located within the fuselage center tank was fire damaged. The main fuel solenoid valves on the manifold were found in the open position. The PMI said the open solenoid valves matched the fuel selector switch position. Examination of the airplane's left and right wing fuel tank caps revealed "O" rings that were hardening with flat spots on them. The fuel tank caps opening tabs could be moved with eight and three pounds of pressure respectively. According to the airplane's manufacturer, the fuel cap tabs should require 16 pounds of force (+/- three pounds) to place them in the open position. The left fuel tank cap's "O" ring was collapsed. According to the airplane's present type certificate holder, a wing surface negative pressure of 0.57 pounds per square (psi) inch could prevent the wing tanks from feeding the fuselage center tank. The manufacturer's representative said that it would take less pressure than 0.57 psi to create the same situation when the fuel tanks were less than full. Airplane service bulletins and an FAA Airworthiness Directive were issued for the negative fuel tank pressure problem as it pertained to the 601 model of the airplane. The present type certificate holder said that the 602P model had not been produced when these modifications had been published. He said the 602P had the fuel cap changes made before it was introduced into the marketplace. The 602P maintenance manual said that the fuel cap tab tension must be checked during each annual inspection. This inspection was not found in C-FSMO's airframe logbook. The pilot's operating handbook shows that the tabs must be hand checked for stiffness during the pilot's preflight inspection.