What happened
On February 5, 2002, at approximately 20:10 UTC, a Bell 212 helicopter was performing its fifth flight of the day on a route between Ishpingo and Tiputini. The aircraft, carrying two crew members and 11 passengers, was conducting a vertical takeoff from the Ishpingo 3 helipad in the Napo province of Ecuador.
As the helicopter reached an altitude of approximately 8 to 15 meters, the crew and passengers reported hearing a loud metallic noise or a sound similar to a tire deflating. Immediately following this noise, the aircraft suffered a sudden loss of power and experienced a sharp leftward turn of approximately 97 to 120 degrees. The helicopter struck the outer edge of the helipad's earthen base, causing it to tilt heavily to the left. During the impact, the main rotor blades struck the ground, resulting in structural damage including the detachment of a portion of one blade.
All occupants successfully evacuated the aircraft on their own. While there were no fatalities, four passengers sustained serious injuries during the descent and impact.
The investigation
The investigation focused on the mechanical failure following the audible noise heard by the crew and ground personnel. Investigators examined the transmission components, including the gears and couplings, noting evidence of corrosion, deformation, and discoloration.
Technical analysis revealed that the transmission gears and the male coupling of the transmission shaft had fractured. The physical state of these components indicated they had been subjected to extreme overstress caused by overheating. While the investigation confirmed that the overheating was a direct result of a loss of lubrication, the specific origin of the lubrication failure could not be determined.