S. S Khezrpour - M.S of Aerospace Engineering
A Fayazi - M.S of Management, Reliability and Maintainability Research Office, Center of Design, Modify and Renewal Helicopters, PANHA Company, Tehran, Iran.

Blades are highly sensitive dynamic parts and one of the most important of their applications is used as a helicopter main rotor. In the present paper, blades of helicopters of Bell 212 type are analyzed from reliability and maintainability viewpoint. By paying attention to the matter that reliability is one of the significant factors in safety assurance and effectivity of aviation systems and acceleration in compliance of this industry in different fields. Attention to this issue lead to reduction of lifecycle cost, reduction of inspections and supporting processes, and also reduction of damage ability and eventual failures. Statistical activities and maintenance issue are directly linked to the reliability. Based on this, above matters confirm the applicability of this research. Statistical analysis is based on real data and obtained from conditions of this type of blades in two categories of climate conditions, including: hot-dry (Semi-desert) and hot-wet (gulf) in the country of Iran. It is considerable that our used statistical population is taken Iran Bell 212 helicopter fleet used in civil segment, and the time limit is assumed last 25 years. Sampling has been random and accomplished by means of Morgan's table.

Blade; Helicopter; Mean time between failures; Maintenance; Reliability