Precision measurements for a precision aircraft

By Staff Sgt. Jason McCasland 2nd Bomb Wing Public Affairs

A single office is solely responsible for maintaining the precision tools required to keep the B-52H Stratofortress flying its precision mission.

The Precision Measurement Equipment Laboratory supports more than 7,500 items of test measurement and equipment used daily on the flightline and in maintenance backshops.

"We calibrate equipment for aircraft maintenance units, civil engineers, communications squadrons, security police, hospitals and different federal agencies," said David Bordelon, 2nd Maintenance Squadron PMEL site manager. "If a tool or equipment can measure something, our PMEL technicians ensure it is accurate."

PMEL's primary mission is to guarantee weapons and weapons systems operate at the right time and place. Their strict adherence and attention to detail, joined with highly-trained technicians provide the PMEL customers with precision calibrated tools and equipment to accomplish their daily duties. The five different sections of PMEL include: electrical standards, RF and frequency, temperature and humidity, physical dimensional test equipment and automated test equipment section.

"We see all types of precision measurement equipment here," said Douglas Smith, 2 MXS PMEL lead technician. "From torque wrenches to night vision goggle testers, we ensure each item gives the most accurate measurements for the job at hand."

The PMEL office supports more than 120 work centers to include Barksdale Air Force Base, the Reserves, Navy and Air National Guard. They use the standards from the Air Force Metrology and Calibration Program in conjunction with the National Institute of Standards and Technology, which helps to keep all Air Force Bases on the same page.

PMEL calibrates engine Jet Cals which take readings from barometric pressure, fuel flow, engine gas temperature and engine pressure ratio readings so the jet engine shop is able adjust the fuel control to achieve the desired output of engines.

"Without PMEL, we can't be sure that our measurement tools such as: slide calipers, depth gauges, torque wrenches, jet cals, vibration analyzers and more, that we use daily are giving us the correct information to do our jobs," said Tech. Sgt. Jason Richards, 96th Aircraft Maintenance Unit propulsion element lead. "They calibrate all of our vibration analyzers, which are placed in three different areas of the engine and indicate unwanted or out of limit vibrations that can cause catastrophic engine failures. They help us put the plane in the air, save lives, and save on costly engine replacements."

To ensure the highest quality of calibrations, the PMEL office has its own internal quality assurance inspector selected from within the lab. This QA inspector is responsible for ensuring the TMDE items certified by PMEL are safe, accurate, reliable and traceable. The inspector is also responsible for monitoring the laboratory environment to make sure temperature, humidity and airflow are within the limits set by the standards of the AF METCAL program.

"Some of our equipment has environmental standards that requires our lab to be within a certain temperature range," said Smith. "Our QA inspector has to monitor what the humidity and temperature are within the office constantly; METCAL takes readings to ensure our lab falls within these acceptable limits."

Additionally, the PMEL lab helps the 2nd Maintenance Group decide what types of tools to purchase when it comes to TMDE items such as torque wrenches or multimeters.

"We try to talk with the PMEL monitors of each shop to help them decide which type of TMDE would better suit their needs," said Smith. "At PMEL we are experts in the calibration field. We know the different manufacturers tools, and we know which ones are better suited for accuracy and longevity."

This partnership saves the Air Force from spending money on multiple replacements for TMDE equipment.

By working closely with more than 120 different shops, the PMEL lab keeps the quality of maintenance and accuracy of measurements of the 2 MXG within the limits. This dedicated team of technicians strive for the perfection that maintainers rely on to put planes in the air, and complete the mission of the Air Force.