Lorenz Jessen, Manager, Bell Intermediate Product Support Engineering
Brian Jenkins, Bell Intermediate Product Support Engineering
In today’s helicopter operations, aircraft availability is so important that it is imperative that operators are able to maintain their aircraft in a safe and efficient manner. Helicopter maintenance is expensive, so the ability to develop an inspection schedule that will reduce direct maintenance costs substantially has become a priority among helicopter OEMs. The Bell Helicopter 429 and the Eurocopter EC 175 are leading the charge by using the MSG-3 process to develop their maintenance programs.
What is MSG-3?
... A little history lesson first. With the advent of commercial airline jet service in the early 1960s, it became clear quickly that for the airlines to stay profitable, their maintenance philosophy would have to evolve. The level of maintenance called for was creating too much downtime, was too expensive and even created failures in taking components apart too often. The Air Transport Association (ATA) then decided to create a “maintenance steering group” (MSG) task force whose mandate would be to analyze the current state of how maintenance was being performed and look for opportunities to increase aircraft availability and reduce maintenance costs, while not compromising safety. That effort resulted in the MSG-1 recommendations put forth in 1968. This process eventually led to MSG-3 recommendations, which were published in 1980 and whose latest version was produced in 2009. To keep it simple, MSG-3 introduced the reliability-centered maintenance (RCM) approach. RCM is a task-oriented program which uses a “top down” approach, by analyzing a system to determine failure modes which may cause a functional failure and develops maintenance tasks as necessary.
So what do airliner inspection methods have to do with my helicopter? A lot, especially if you consider availability and reliability important to your operation. During the MSG-3 analysis, a team consisting of the OEM, operators and the regulatory authorities analyzed every aircraft system, including airframe structure and wiring installation, to determine the failure modes, their criticality, the ease of their detection, the level of inspection required and the ideal recurrence of inspection. This is where the varied experience of the team comes into play. AME/A&Ps used their many years of experience in aircraft operations and engineers provided input as to system detailed functions. From this results a maintenance schedule that can see up to 30 percent less maintenance work hours versus a comparable aircraft not using MSG-3 guidelines.
Why have you not heard of this before in the helicopter industry? Bell Helicopter was the first OEM to use this method in the creation of the maintenance schedule for the Bell 429 helicopter.
The major aviation authorities, Transport Canada, the Federal Aviation Administration (FAA) and the European Aviation Safety Agency (EASA) supported Bell in pioneering this approach. Eurocopter has now joined Bell in this pioneering approach to maintenance development by using the MSG-3 process to develop the maintenance schedule for the EC 175 helicopter.
The main difficulty the helicopter OEMs experience in using MSG-3 is that the MSG-3 standard was developed for fixed-wing aircraft, so the process has had to be adapted for use on helicopters. Therefore, in order to develop a common methodology that is applicable to the rotorcraft world, Bell Helicopter, Eurocopter, Sikorsky and Agusta/Westland are now working together to modify/adapt the existing MSG-3 process, and make it more rotorcraft friendly. The working group has now had three meetings and the way forward is to develop a purely rotorcraft version of MSG-3.
Even though the use of MSG-3 is still new to the helicopter world, Transport Canada, the FAA and EASA all recommend that MSG-3 be used to develop the maintenance programs. In fact, Transport Canada and the FAA have already released guidance material requiring the use of an RCM process on all twin-engine helicopters. EASA will release its guidance material very shortly.
So what is MSG-3 to us, the helicopter maintenance professionals? It is the new way that maintenance tasks are defined and how often they are anticipated to be performed. Maintenance determination for the twenty-first century is in the works now.