Forecasting Parts Needs

By By Ernie Stephens | March 1, 2016
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An aircraft arriving for unscheduled repairs could throw an MRO off balance if it arrives to a hangar full of scheduled work. RSG Aviation, Inc. of Forth Worth, Texas, tries to save room for such scenarios. Photo courtesy of Keith Moreland / RSG Aviation, Inc.

It wasn’t raining when Noah built the ark. The thrust of that proverb is simply that you should plan far in advance of potential trouble.

Planning is something with which all helicopter operators have an intimate relationship, particularly when it comes to maintenance. It begins with an aircraft manufacturer’s direct operating cost projection and continues with a complicated maintenance schedule that must be adhered to. Interspersed between those date, time and dollar projections are issues that require unscheduled service and parts replacement. Some truly appear out of nowhere, while others may actually be foreseeable.


The operator most vulnerable to a maintenance-driven catastrophe is the small one—the company or public-service provider that only has one to five helicopters. If an aircraft goes down, there is rarely a spare that can pick up the slack for an extended period. If no spare exists, missions cannot be flown, and flight crews may be left sitting idle. On-call operations have it even rougher, because clients may have to be turned away and could end up on the doorstep of a competitor.

Even rotor blades can be the subject of unscheduled maintenance.  
Photo by Ernie Stephens

A helicopter maintenance, repair and overhaul (MRO) operation understands the problems faced by its smaller customers. Many do their best to handle scheduled and unscheduled maintenance issues as quickly as possible without cutting corners that could affect safety. An MRO also has the headache of trying to get parts from the manufacturer sooner rather than later, especially when the part is in short supply in the first place. A mega-customer—like the military or a private company with hundreds of aircraft—is going get priority attention from parts providers.

So how can the administrators and managers of small operations sidestep the land mines that accompany unscheduled maintenance issues?

Veterans of maintenance management offered some suggestions for ensuring parts are available to support prompt maintenance, repair or overhaul of your aircraft.

The first and most important is to develop a good working relationship with your maintenance provider.

Be sure to alert that provider when the pace or scope of your aircraft’s operation changes or when you begin flying in a different environment.

Get comfortable sharing data in advance with your maintenance provider.

Inform that provider of all issues that you have observed or experienced with your aircraft, because not every single one will recur during testing.

Difficult to Respond Quickly

Photo courtesy of Metro Aviation

Terry Reininger’s aviation career spans 45 years. He has worked in flight operations, maintenance, research and development, and the overhaul business (including serving as manager of a major rotor blade repair MRO). He has been a fixed-wing and helicopter pilot and is a certified U.S. Defense Dept. acquisition specialist. Today he owns of Reininger Aviation Services in Richland, Texas.

Reininger understands the issues that face both the small operator and its MRO provider. He also appreciates the weight that an unscheduled repair carries. The reason is because he has been on both sides of a repair order.

“It is difficult for most MRO facilities to respond to the small operators as quickly as needed,” said Reininger. “First, most MROs do not have the luxury of having teams standing by to respond. If an operator, large or small, stops by for drop-in maintenance, the technicians must be pulled from other jobs to respond.”

If small operators bring in an aircraft for heavy maintenance without prior planning, they may have to wait days or weeks to be accommodated. They even may have to consider finding another provider.

The secret to customer satisfaction is for the MRO and the operator to develop a great working relationship, according to Reininger. “It is important for the operator to share flight operations tempo with the MRO.” That tempo is the frequency of missions carried out by a unit or organization.

It isn’t enough for an MRO to know that its customer provides air ambulance services at an average of 100 flight hours a month. The maintenance provider needs the management of the flight operation to warn it when that operations tempo is going to change. For example, if the operator knows it will be transferring a large number of patients from an old hospital to a new one, its management should make a call to the MRO to let that outfit know that some aircraft will be building hours faster than normal. That means those will be coming in for maintenance that much sooner.

“Advanced knowledge will allow the MRO to order parts and have the correct technicians available for the job,” explained Reininger.

In addition to notifying the MRO of an increase in operations tempo, it is critical for a customer to alert the maintenance provider of any changes in the place or the way its aircraft are being used. For example, a change from a noncorrosive environment to a corrosive one could alter the kind of work a helicopter will need and when it will need it.

“If you plan to take your machine on an extended deployment, let the MRO know so they can evaluate possible overhaul issues,” warned Reininger. “If you have been operating at higher gross weights and higher speeds, let the maintenance facility know, so they can pay close attention for structural defects.”

If the heart of a helicopter is its powerplant, a close working relationship with the engine shop is vitally important.

“Most customers never supply advance information on a regular basis,” said Chuck Hurdleston, customer and support program manager at Keystone Turbine Services in Coatesville, Pennsylvania. “Which means we must always be ready at a moment’s notice to react when something goes wrong.”

Maintenance Options

Some maintenance shops, such as Keystone Turbine Services, try to have loaner engines on hand for customers who fall victim to unscheduled powerplant repairs. Photo by Ernie Stephens

A former U.S. Army pilot, Hurdleston has been in the small turbine repair business for nearly 30 years.

Keystone Turbine Services, like many other engine repair depots, will try to turn the customer’s engine around quickly. If the needed repair is a limited one, technicians will start working on it immediately. If, however, it looks like the repair will take longer, the customer has three options.

First, manage flight operations around the out-of-service aircraft until it has been returned. Second, exchange the troublesome engine with one of the MRO’s spares. Third, have a rental engine installed on a pay-by-the-hour basis.

Keystone’s 50 or so technicians service all Rolls-Royce M250 series engines, Honeywell accessories for the M250 and Honeywell’s LTS-101, Pratt & Whitney Canada PT6 series powerplants and Turbomeca Arriel 1 and 2 series products. To stay out in front of unscheduled maintenance on all of those units as much as possible, said Hurdleston, Keystone relies on business software.

“We track the amount of our business that’s considered ‘unscheduled’ versus ‘scheduled,’” said Hurdleston. “In other words, how much of our total business was based upon work we were not aware was going to be coming to us until a problem occurred.”

Look at History

Currently, Keystone Engine Services uses on-demand customer relationship management software provider Salesforce.com to track projected unit deliveries based upon annual hours flown and other predictors. According to its figures, more than 40% of Keystone’s engine support business is unscheduled.

“It’s hard to plan materially for these episodes, so the best you can do is look back on historical averages and plan accordingly,” said Hurdleston.

Reininger said he believes surprise maintenance issues can be reduced using what amounts to an early detection system.

“Pre-maintenance inspection visits to the customer’s facility can provide advanced notice of the extent of upcoming maintenance,” he said. “Advanced knowledge will allow the MRO to order parts and have the correct technicians available for the job.”

He also suggested that the operator provide the MRO with a complete list of issues before it delivers one of its aircraft to the maintenance facility. Technicians may not always find all issue if they are not alerted to them. If there were an intermittent problem, like a strange sound or vibration that isn’t reflected in an instrument reading, do not assume that the maintainer would discover it.

Reininger and Hurdleston were asked whether there was anything that small operators could do to ease the impact of unscheduled maintenance on their MRO, considering the advantages both parties could reap.

“In a perfect maintenance world, operators and maintainers would develop a relationship, which includes total transparency in sharing data and concerns,” said Reininger. “The MRO and operator have the same goal, and that is to keep a safe machine in the air the greatest number of hours on a continuous basis.”

He added that he recognizes that the concept of “total transparency” sends chills up the spines of some managers in the highly competitive aviation industry. They just aren’t programmed to let current and future flight operational plans leak past their own offices and hangars. Reininger, however, suggested one possible fix.

Operators and MROs “need to execute a non-disclosure agreement if there are concerns,” said Reininger. “If one or both of the parties are worried that their information will be leaked, maybe they are dealing with the wrong partner.”

Sikorsky has gotten way out in front of detecting maintenance issues before they can become an unscheduled repair problem.

S-76Ds and S-92s are equipped with a data collection system that allows Sikorsky engineers to monitor the health of the two lines.

For example, if engine No. 1 aboard aircraft serial No. 0050 in the worldwide S-92 fleet were experiencing a transient compressor problem, that would be detected at Sikorsky’s 360 Live Support Center in Connecticut. There, an engineer would query the system to see whether any other aircraft were experiencing the same problem.

If the problem were isolated to that one aircraft, the center would notify the operator, recommend a course of action, and keep an eye over it.

If a fleet-wide check reveals that more than one aircraft were experiencing the same issue, points of commonality would be assessed to better pinpoint the cause of the problem. Sikorsky claims this process can detect a problem long before a pilot or mechanic could perceive it and address it before a catastrophic surprise catches everyone off guard. (Think of it as a heavy, near-constant inspection that limits surprises.)

Lessening the Impact

Once an aircraft or engine arrives at a facility for unscheduled maintenance, there are several things the MRO could do to lessen the impact to the customer.

First, Reininger said, the MRO needs a software package that will help conduct incoming inspections, schedule work and track completed tasks. Secondly, the shop needs to have a clear understanding of the time to complete each task and the skills required. Third, a system must be in place to track the quality of work performed, since poorly trained technicians (or inept ones) can cost the MRO time and money in the form of rework.

“Finally, they need to have an accounting system that quickly and accurately bills the customer,” said Reininger. “There is nothing that frustrates a customer more than to receive multiple invoices that are incorrect.”

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