Most people are careful to maintain their cars and keep the engine clean and out of the repair shop. However, this week a joint NASA, government and industry project team seeks to purposely feed volcanic ash into an engine to create problems.

That's one way to see if a new engine health monitoring system can detect failures before they happen. If the tests are successful, the system capable of predicting engine challenges and improving fuel economy could become available for the next generation of commercial airline engines.

A July 9 panel discussion at NASA Armstrong Flight Research Center on Edwards Air Force Base, California, detailed the Vehicle Integrated Propulsion Research (VIPR) project. The concept is to test and evaluate a system that incorporates smart sensors and advanced diagnostic techniques. Speakers included Paul Krasa, VIPR project manager, John Lekki, VIPR principal investigator, Jack Hoying, U.S. Air Force volcanic ash environment principal investigator and Cheng Moua, Armstrong VIPR project manager.

"The ash will degrade the engine and allow us to see in real time what's happening and how well the health monitoring system works," said Lekki, who is based at NASA's Glenn Research Center in Cleveland.

Volcanic ash was chosen for the final of a three-phase research project because atmospheric particulates have become of interest to military and civil aviation authorities that have to assess the airworthiness of engines that have encountered the ash.

Eruptions in Iceland over the last five years, especially in 2010, disrupted air traffic worldwide and cost airline companies more than $1 billion due to cancelled or rerouted flights. The new sensors are expected to detect the degradation caused by the volcanic ash, quantify the significance of the event, and aid in identifying which components might require maintenance.

The Air Force Test Center at Edwards Air Force Base provides the C-17 military transport and NASA Armstrong contributes two F-117 engines for this research. The engines are a variant of an engine used in a Boeing Company commercial aircraft.

A rig called the spider will blow the ash into the engine for the tests. Researchers hope to gain a better understanding of how ash degrades an engine using the new system to observe low levels of ash blowing into the engine that can't be seen with the human eye and then feeding the power plant more moderate levels of ash with particulates that can be seen.

The engine health monitoring system's sensors also will measure emissions and combustion and can detect the effect of the ash on the engine in real time and research the prognostic capabilities that could predict how long it will take for an issue to emerge, Lekki said.

The sensors include a sensor that evolved from one that was used for the space shuttle main engines, high-temperature fiber optics, high-temperature thin film sensors and acoustic microphone arrays. Also included is a microwave tip clearance sensor developed through the Small Business Innovative Research program that measures the complex gap from the outer wall of the turbine to the tips of the blades, he explained.

"Compressor blade erosion and turbine ash deposits are what is damaging the engine," added Hoying, who is based at the Air Force Research Laboratory at Wright-Patterson Air Force Base in Ohio. "The tests can answer questions about how close we can fly to these volcanic plumes."

After the tests are over, the investigation will continue as the research engine is taken apart and evaluated, Moua added.

Improved sensors also could identify changes in vibration, speed, temperature and emissions that are symptomatic of engine problems before they become serious safety concerns. Notifications would be provided to ground crews of potential problems that could be fixed by preventive maintenance or alert pilots to changes in engine health thereby allowing time to prevent engine damage in flight.

To reduce risk, all such testing is conducted on the ground under controlled conditions.

The VIPR project began in 2011 with a baseline test to lay the groundwork for more complex experiments. The engine detected simulated faults, including an oil leak. A second test in early 2013 verified that sensors could detect actuator faults over a range of operating conditions.

"It will be a huge benefit economically and provide new diagnostic technologies to foster engine innovation in reliability," Lekki said.

In addition to the Air Force and the Federal Aviation Administration, NASA's partners on the project include Boeing Research and Technology, Pratt and Whitney, General Electric Aviation and Rolls-Royce Liberty Works, with assistance from the U.S. Geological Survey. Researchers from four NASA aeronautics centers - Armstrong, Glenn, Langley Research Center in Hampton, Virginia and Ames Research Center at Moffett Field, California - are involved in research and testing.