Test cell Airmen prep F-16 engines for flight

  • Published
  • By Senior Airman Jessica Lockoski
  • 35th Fighter Wing Public Affairs
MISAWA AIR BASE, Japan (AFNS) --  An F-16 Fighting Falcon engine testing facility, called the "hush house," is anything but what its name implies. Outside the soundproof structure, the decibels from roaring engines are hardly detectable. Inside, however, jet engines run at ear-splitting, full-volume afterburner, as 35th Maintenance Squadron aerospace propulsion test cell Airmen make sure the units are functionally safe and ready for flight.

"Hush house testing is the last line of defense before an engine goes back into an aircraft and on the flightline," said Staff Sgt. Danny Shaw, a 35th MXS aerospace propulsion craftsman. "To help support what goes on in the air, the Airmen must test run these engines."

Following engine maintenance, Airmen in the hush house can quickly power up standalone engine units. Additionally, they can also test engines fully installed in a restrained F-16.

Engines at Misawa AB are tested around the clock to support the 35th Fighter Wing's constant flying mission.

"An aircraft is often sent to the hush house during evening quiet hours, when the base adheres to local noise laws, or when the aircraft runs idle above 85 percent revolutions per minute," Sergeant Shaw said. "This prevents our host nation from having to bear with unbearable noises."

Airmen also test engines that need significant or complex maintenance and must wait for the engine units to be reassembled by their fellow maintainers. Engines are reconstructed at a different location before being tested on the reliability of maintenance.

Once an engine is in the hands of test cell Airmen, they secure it or the entire aircraft to the floor, aligning its exhaust directly in front of a long, metal tunnel more than 120 feet long. As the engine runs, the tunnel absorbs expelled gas and flames from the exhaust.

The Airmen test an average of six engines each week, half of which are standalone units, Sergeant Shaw said.

An engine test can last anywhere between 45 minutes to a couple days, depending on the amount of work done on the engine, he added.

For the test, Airmen use a three-part component system that runs through two separate rooms of the hush house. A test stand supports the engine in place and a junction box connects electrical circuits from the engine to a sound-proof test cab in the next room, where Airmen perform function tests on the engine, Sergeant Shaw said.

From the testing cab, Airmen power-up an engine and monitor the unit, both via dash board indicators and observing through a window into the main room. Although it is quiet in the testing cab, Sergeant Shaw said Airmen near the running engine are not as lucky due to the blaring sound.

"Out on the testing floor, the noise will jar your teeth," he added, referring to ground inspectors who circle the running engine.

The ground inspectors check for leaks and physical discrepancies and listen to engine pitch.

"If something is minor, such as a leak, we can shut the engine down and fix it on the spot, Sergeant Shaw said. "For major problems, we will shut down testing."

The Airmen look for anything inside and outside the engine that may malfunction.

"The testing equipment can detect if these parts (need) further maintenance," Sergeant Shaw said. "It gives us readings such as the throttle position, exhausts and inlet temperature, fuel and oil pressure and vibration level in the motor."

Airman 1st Class Christopher Backers, a 35th AMXS aerospace propulsion apprentice, often observes engines at a close proximity as the ground inspector -- without the dangers associated with other hush houses across the Air Force.

"This uniquely Japanese designed hush house found here has an air intake on its ceiling that provides cool airflow to the engine," Airman Backers said. "Most other hush houses have inlet baffles on the sides of the building. The airflow could create so much suction, if someone is working near the engine, he could be sucked into the tunnel and seriously injured. Since the air stays above us in this facility, a person can stand right next to the engine in full burner."

Soon, test cell Airmen will be able to run more than one engine at a time. A second hush house facility next door is currently being refurbished during a $4.7 million project that will encompass both buildings.

For now, Airmen work with the 139-decibel roar in the single structure, drowning out nearly everything else.