Page:CAB Accident Report, Pennsylvania Central Airlines Flight 19.pdf/27

 around the shaft. The supercharger impeller was badly damaged and practically all of the blades had been broken off. The thrust bearing was badly broken, apparently due to impact.

The condition of the left engine was very similar to that of the right engine. In fact, the condition of the master rod bearings, the crankshafts, knuckle pins, impellers, and gears from the two engines were so nearly identical that it would be almost impossible to distinguish between them.

Both engines showed metal to metal contact between the master rod bearings and the crank pins, the oil film usually separating them apparently having broken down. The National Bureau of Standards, after examination of the engine parts sent to it, reported that no evidence of mechanical, structural, or fatigue failure or lightning strike prior to impact had been found.

Upon disassembly of the right propeller it was found that the dome section was not badly damaged, except that the breather cap had been broken off. The piston and rotating cam assembly was intact and not badly broken. The gear segments of all three blades had been split at a point near the 4th, 5th, and 6th teeth from the low pitch end. The condition of the bevel blade races indicated that heavy loads had been applied. Several of the rollers still remaining in the retainers were split. Cracks were apparent in the micarta barrel blocks at the shoulders. The blade butts from which the two blades had been broken off were intact at the hub. These two blades had also been fractured near the tips, apparently by impact. The one blade remaining with the hub was not fractured but showed indications of power bends.