Inter-Canadian flight 1678 departed Val D’Or Airport, Canada, at 09:57 local time en route to Montreal’s Dorval Airport. The co-pilot was flying the aircraft. The ATR 42 was cleared to climb to flight level 210 and proceed on airway V372 to the Mirabel VOR. Shortly after take-off, the crew engaged the autopilot (A/P) at 3000 feet above sea level (asl). The climb was routine up to about 17000 feet asl, when a violent explosion rocked the aircraft and the cabin depressurized. The CONTINUOUS REPETITIVE CHIME warning sounded in the cockpit, and at the same time the master warning light and cabin excessive altitude light illuminated. The crew observed that the right engine parameters indicated a total loss of power. Nine seconds after the depressurization, the pilot-in-command assumed control of the aircraft and disengaged the A/P. He aborted the climb, commenced a descent, and maintained speed. The engine failure procedure and single engine checklist were completed during the descent. The co-pilot contacted Montreal Area Control Centre (ACC) and advised the controller that the aircraft had experienced an engine failure and requested clearance to descend to 15,000 feet, then to 11,000 feet. The co-pilot pulled fire handle No. 2 after visually confirming the damage to the engine and observing a fuel leak. The cabin excessive altitude checklist was then completed. Three minutes after the occurrence, the crew declared an emergency with the Montreal ACC. About seven minutes after the cabin depressurization, the co-pilot visually confirmed the structural damage in the cabin. The pilot-in-command felt it was preferable to minimize the number of turns in order to reduce the risk of further structural damage. After noting the damage and assessing the situation, the pilot-in-command decided to continue the flight to Dorval. At that time, the aircraft was 36 minutes flying time from Val D’Or, 39 minutes from Mirabel and 44 minutes from Dorval. At 10:28, the aircraft initiated a descent toward 9000 feet asl and maintained that altitude, which was above the cloud layer, until it entered the Montreal terminal zone. The aircraft was aligned with the ILS for Dorval runway 06L by radar vectors. It landed without further incident at 11:16. An investigation showed that the top of the No. 2 blade had failed and punctured the fuselage as the blade passed on its trajectory toward and beneath the aircraft. A vertical cut measuring 104 cm by 2.5 cm was observed between stations 9157 and 9333 on the right side of the fuselage. The seat adjacent to the vertical cut was partially cut. Two landing gear hydraulic lines mounted under the floor were slightly bent. Causes: “Corrosion pitting had occurred on the surface of the taper bore of the No. 2 blade as a result of water combining with chlorine deposits on the cork in the taper bore. The chlorine was associated with the bleaching of the corks during their manufacture. One of the corrosion pits was the point of origin of the fatigue cracks that caused the propeller blade to fracture.”