What aircraft was involved and where did it happen?

The accident on 2002-02-05 involved a Bell 212, at Helipuerto, EC.

Loss of Power Leads to Bell 212 Crash in Napo Province

On February 5, 2002, a Bell 212 was involved in an aviation accident near Helipuerto, EC. Investigators recorded the probable cause as: The probable cause of the accident was the loss of lubrication in the helicopter's transmission shaft couplings, leading to overheating and subsequent fracture of the transmission gears. This summary draws on records from the Ecuadorian Civil Aviation Directorate (DGAC Ecuador).

A Bell 212 helicopter experienced a sudden loss of power during takeoff from the Ishpingo 3 helipad, resulting in an impact with the terrain and four injuries.

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 was carrying two crew members and 11 passengers.

During the takeoff phase from the Ishpingo 3 helipad in Napo Province, the helicopter climbed to an altitude of approximately 8 to 15 meters when it suddenly experienced a loss of power. Witnesses and crew reported hearing a loud metallic noise, described by some as an explosion or the sound of a tire deflating. Following this noise, the aircraft underwent a sharp leftward turn of approximately 97 to 120 degrees before impacting the outer edge of the helipad. The impact caused the helicopter to tilt onto its left side, leading the main rotor blades to strike the ground.

While there were no fatalities, four passengers sustained serious injuries during the accident. All occupants were able to evacuate the aircraft on their own.

The investigation

The investigation focused on the mechanical failure of the transmission system and the flight dynamics during the loss of power. Investigators examined the wreckage, noting significant damage including detached skids, a broken main rotor blade, and structural damage to the tail rotor gearbox, vertical stabilizer, and cabin.

Technical inspections of the transmission and couplings revealed evidence of corrosion, deformation, and discoloration. The investigation also reviewed maintenance records, noting discrepancies in the logging of certain Airworthiness Directives (AD) and inconsistencies in the numerical sequencing of some logbooks. Meteorological conditions at the time of the accident were reported as favorable with good visibility.

Findings

The primary cause of the mechanical failure was a loss of lubrication within the transmission shaft couplings.
This lack of lubrication led to overheating, which caused the gears in the transmission and the male coupling of the transmission shaft to fracture due to excessive stress.
While the loss of lubrication was identified as the trigger for the component failure, the specific source or reason for the lubrication loss could not be determined.
The aircraft's main rotor blades struck the terrain upon impact, causing significant structural damage and a partial separation of one blade.

Probable cause

The probable cause of the accident was the loss of lubrication in the helicopter's transmission shaft couplings, leading to overheating and subsequent fracture of the transmission gears.

2002-02-05: Bell 212 — Helipuerto, EC