NYC84FFA03

A witness noted that, on takeoff, the acft appeared to be out of control. It entered a nose high attitude, then 'fell.' The plt recovered before the acft hit the ground, but the airplane 'oscillated in altitude until out of line of sight.' Subsequently, the acft collided with rocky terrain on arpt property about 1/4 mi from the end of the rwy and was destroyed. An investigation revealed that the plt had 2 cardboard boxes full of honey jars aboard. There was evidence that both boxes had been located on the right seat next to the plt. One box was still fastened to the seat by the seat belt, but the other box had been thrown forward. The investigator was unable to determine whether the latter box had shifted prior to or after impact.