Zero mistakes. That's the standard the precision measurement equipment laboratory (PMEL) technicians are held to on a daily basis. One mistake in their shop could mean the difference between a guided weapons system firing on target or missing by several feet.

The 31st Maintenance Squadron PMEL shop has a heavy weight of dependence resting on their shoulders and accuracies are corrected to the thousandth of an inch. Their job is to calibrate and repair measurement and diagnostic equipment to provide customers with reliable, safe and accurate equipment that meets and exceeds expectations.  

"We work in a production environment, but our work is meticulous and painstakingly slow to ensure we're meeting the criteria and being safe about it," said Staff Sgt. Brian Coleman, a 31st MXS PMEL craftsman. "Everyone in maintenance can tell you attention to detail is pivotal, but in this case, we cannot make mistakes. We are literally allowed zero errors -- everything has to be done exactly right."

For instance, the 20 mm cannon on an F-16 Fighting Falcon is aligned to the head-up display (HUD) using fixtures that are calibrated at PMEL. A pilot needs to be able to rely on the accuracy of his HUD's targeting system when he fires or his life could be in danger.

The PMEL troops support 5,200 different types of equipment on base for 84 different work centers. Fifteen laboratory personnel work on approximately 18-24 items per day, adding up to 360-480 maintenance work orders per month. This equipment includes torque wrenches, spectrum analyzers, pressure gauges, and missile guidance control systems.

According to Coleman, the PMEL maintainers must calibrate and fine tune this equipment with four criteria in mind: accuracy, reliability, traceability and safety.

"We support everyone on base -- if it takes a measurement, we calibrate equipment for them," Coleman said.  “That way, every time one of our clients is making a measurement, they can be sure it's accurate.”

The Air Force Metrology and Calibration Program mandates that all measurements performed by any PMEL technicians must be traceable to the National Institute of Standards and Technology. Traceability is an established written record of standards, helping ensure quality measurements, and in turn, reliable instruments.

The equipment they receive typically falls under two different categories. The first category involves electrical standards, which deals with voltage, current and resistance-type measurements or the wave-form generation and analysis section.  The second category deals with the physical dimension sciences, including pressure, torque, tension, weight, optics and temperature.

Even with what seems as an arduous tolerance level for mistakes, these Airmen have a 97 percent sustained equipment availability rate -- three percent above the mandated Air Force standard. This means out of the 5,200 pieces of equipment on base, there are approximately 5,044 available because of their exhaustive effort.

"The work we have here is ongoing," Coleman said. "Every unit on base has a list of equipment that needs to be inspected and calibrated on a regular basis and we make sure they adhere to our standards."

While the work may seem meticulous, Coleman finds the positive side of the work he does every day.

"I love what I do," he said. "It requires me to think critically on a consistent basis. There's a lot of problem solving that goes into what we do and it's constantly different."