Do you mean for the 4Y flight with the erratic instruments on takeoff?
We did find the problem. Externally, nothing appeared amiss. On the ground on return, everything was matched up and working.
The takeoff involved an overrotation in an effort to get airborne before striking the trees, and in so doing, the captain struck the tail. Not the tail itself, but a tailskid that had once been retractable, but that was permanently welded down, in the airplane. It had a thick magnesium skid plate on the bottom. When that struck, the skid was thrust up into the belly of the airplane, and the magnesium ignited. It produced a fireball that enveloped the tail of the airplane, and ended up burning off the last 25' or so of the underside of the airplane...skin, stringers, etc.
The problem was caused by rain. The 4Y had fairly large static ports. Plugs were placed in the ports, but the plugs still allowed water, due to the design of the ports themselves. Because of the nature of the flying, pitot covers and static plugs, and other security devices were removed during the morning preflight. When heavy rains came, with strong winds, the rain was nearly horizontal, and entered both the pitot tubes and the static ports quite handily, as we later determined.
The cockpit indications were fairly nill, but weren't symmetrical or uniform throughout the system. In other words, what appeared to be an altimeter mismatch was part of a bigger problem.
We broke the static system in multiple places and blew the lines out through filters. Water was the culprit in some points, and low areas in the line, and in others we found a dead insect which swelled in the presence of water.
We also instituted a policy of keeping everything covered until the dispatch itself...at which time one person would remove and stow all the covers.