What happened
On February 20, 2008, a Kamov KA-32 helicopter, registration CS-HMN, was conducting maritime search and rescue training approximately two nautical miles south of Vilamoura, Portugal. The mission, operated by EMA – Empresa de Meios Aéreos, S.A., involved training a new hoist operator and rescue swimmers.
During the operation, the crew attempted to recover a rescue swimmer and a simulated victim suspended from the aircraft's Goodrich hoist. As the hoist began to lift the individuals, the cable unexpectedly stopped ascending and began descending at a normal speed, pulling the personnel into the water. The crew attempted to regain control, but the malfunction recurred when the individuals were hoisted to an altitude of approximately 20 meters, causing them to fall into the sea a second time. The incident concluded when the hoist ceased functioning entirely due to an overheating warning, leaving approximately ten meters of cable suspended.
No injuries were reported, and there was no damage to the aircraft or third parties. The personnel were recovered by a support vessel.
The investigation
The GPIAAF investigation examined the hoist, the aircraft, and the operational procedures. Technical examinations of the Goodrich hoist (model 4/4311-10-2) by the manufacturer revealed that the hoist's braking system had experienced a significant reduction in performance. Tests indicated that the braking system was unable to hold a load exceeding half of its rated capacity.
Investigators also analyzed the environmental conditions, noting that the hoist was positioned in an area of high heat exposure, receiving hot air from the engine exhausts and the transmission cooling system. This heat, combined with the use of non-recommended cleaning and maintenance products, likely affected the elasticity of the internal components. Furthermore, the investigation found that the operator lacked a formal flight operations manual following JAR-OPS 3 standards, and specific procedures for hoist operations were not clearly defined.
Findings
- The primary cause was the reduced braking capacity of the hoist's cable retention system, which failed to support loads even at half of its nominal capacity.
- Contributing factors included the exposure of the hoist to extreme temperatures, which compromised component elasticity, and the operation of the equipment under loads and conditions exceeding its design limits.
- The crew's decision to continue attempting recoveries after the initial malfunction increased the risk to the personnel.
- There was a lack of standardized operational procedures and training programs specifically for the use of this hoist model.
- Maintenance deficiencies were noted, including the use of improper cleaning products and inadequate preparation for hoist maintenance.