When to upgrade engine test cells

Staying current with engine technology is key in the aerospace business, requiring up-to-date equipment capable of testing complex machines since companies want to keep equipment running as long as possible to get the most out of their investment. At the same time, they don’t want to wait until something breaks because shutting down a test facility is to be avoided at all costs.

Preventing shutdowns begins with a strategic upgrade plan.

Failing to plan

To keep repairs in house, a maintenance, repair, and overhaul (MRO) test facility owned by the parent airline company required an adapter for a legacy engine. The test cell was aging, and the engine would push the test cell to its airflow limitations. A successful upgrade could save the airline money.

The new engine was deemed feasible with a caveat: inconsistent test results from the old test cell. The MRO decided the risk of sporadic failed engine tests was worth the cost compared to a new test cell.

Many of the airline’s similar new aircraft were using a brand-new engine that was years in the making. The MRO shop also wanted an adapter for this engine, but the test cell couldn’t support the airflow required. In the years it’ll take to develop a new test cell, the airline will pay another MRO to perform service on the engine until it’s capable. Had the airline made a different decision when it originally needed new engines, it could have a test cell guaranteeing quality results for their entire engine portfolio. When to adapt, upgrade, and replace should be decided before the situation is critical.

Time to upgrade

Equipment that fails or shows wear must be upgraded. Typical engine designs last decades and include frequent improvements, adjustments, and fixes. Each time the physical design of the engine changes, the test facility must be evaluated to ensure it still meets the model’s testing needs.

Software updates may be required for small changes in engine design, whereas introducing a different engine requires software and structural or mechanical upgrades. Other quantitative indicators include periodic non-destructive testing (NDT) for equipment exposed to cyclic fatigue to monitor for potential equipment deterioration.

In aircraft testing, nearly all decisions are data driven. Seasoned professionals develop a gut feeling for how long a piece of equipment can last before it starts deteriorating or how long short-term fixes such as adapters can be relied upon.

What looks like a qualitative judgment represents years of past data compounding in the pro’s mind to form a natural predictive model. A recommendation that looks like an opinion is a complex mental calculation based on previous experience.

Companies can’t afford to stop testing while upgrading a facility. Typically, upgrades are performed in batches, with a secondary facility picking up the slack. In the case of an MRO test cell, this requires diverting engine repairs to facilities far away, adding time and cost to the process. Managing the timing and duration of upgrades without affecting testing schedules requires a plan backed by quantitative analysis.

Another MRO facility required a new adapter for an engine, which temporarily took the test cell out of commission to fit the adapter and troubleshoot. In this case, the specific engine was a major evolution of a legacy engine that required a new control and communication infrastructure.

Since this was a multi-day effort, the downtime was used to upfit the aging data acquisition (DAQ) system. The DAQ upgrade wasn’t necessary at that time, but the MRO facility knew the components had finite life remaining and took advantage of the scheduled downtime.

Upgrade planning

Testing facilities are a massive capital investment. The equipment must be durable and capable of modification. Facilities are built to last decades, but in many cases, they’ll need adaptations for new engine designs.

Engines are constantly becoming more complex and efficient. For example, the U.S. military is upgrading two test cells at Arnold Engineering Development Complex to accommodate new engine designs requiring test cells that can handle higher temperatures and greater air flow.

Such upgrades are an example of the science of upgrade planning. As technology evolves, it becomes harder for legacy test cells to deliver results to the same level of quality, but it’s uncommon for a test cell to become obsolete overnight. Planning for upgrades extends facilities’ lifespans.

In aerospace, the pressures of maintaining up-to-date facilities face a multiplier unmatched by other industries. Aerospace companies made futureproofing and upgrades hallmarks of facility planning. It’s critical both art and science are employed to develop and maintain facilities that perform whatever the future brings.

ACS Inc.

About the authors: Matt Thiel is the director of facility planning and integration and a principal. Joe Sweeney is the senior integration technical leader at ACS. For more information, call 608.663.1590.