Transcontinental and Western Air's Star of Lisbon Crashes

The Constellation, named "Star of Lisbon" departed Reading Airport at 11:21, for a local instrument training flight. The aircraft climbed to an altitude of 3,000 feet to an area approximately four miles east of the Reading Airport at which time it leveled off to begin practice of instrument approach procedures. Shortly thereafter, the flight crew detected an odor resembling burning insulation, but did not immediately determine the source. At approximately 11:37, the slight engineer went aft in order to determine the origin of the smoke. Upon opening the galley door, he observed that the entire cabin was filled with a very dense smoke. The crew immediately attempted to combat the fire with the cockpit fire-extinguisher but were unable to enter the cabin because of the dense smoke and intense heat. The smoke quickly filled the cockpit through the open galley door, rendering visibility extremely poor and making it difficult for the pilots to observe the instruments. The student flight engineer opened the cockpit crew hatch in an attempt to clear the cockpit of smoke, however, the opening of the hatch increased the flow of smoke from the cabin toward the cockpit and shortly thereafter it became impossible to observe any of the instruments or to see through the windshield.

http://aviation-safety.net/database/record.php?...