Eastern Provincial Airways Flight 102

Investigation

During the medical examination of the crash victims, traces of carbon monoxide were found, initially leading to the hypothesis that the crew might have become incapacitated in flight. This hypothesis was later rejected when clinical tests revealed that the concentration of carbon monoxide in the victims' blood was not high enough to cause incapacitation. Ultimately, a heating pipe that had been hung on the cabin door at Halifax Airport to prevent the cockpit from cooling down while the aircraft was on the ground was identified as the likely source of the carbon monoxide.

The examination of the wreckage revealed that the underside of the fuselage had been subject to progressive internal corrosion for an extended period. During flight, the underside of the fuselage ripped open along the 32nd stringer, which runs along the centerline of the fuselage underside, starting approximately at the transition from the cockpit to the cabin area and proceeding aft. The structural failure in flight progressed from front to rear. The fuselage skin deformed so severely that it was ultimately struck by one of the propellers.

The report of vibrations in the tail section was also thoroughly investigated, especially since it was discovered that the left horizontal stabilizer had broken off from the aircraft ahead of the vertical stabilizer and the fuselage, behind the rear pressure bulkhead. It was therefore initially assumed that the structural failure originated in the tail section. However, since no small pieces of wreckage from the tail area were found at the beginning of the debris field, this theory was ultimately rejected.

The exact cause and type of corrosion could ultimately not be determined.

The maximum cabin operating pressure for Herald series 200/400 aircraft was reduced from 4.2 to 3.0 psi as a precautionary measure.