PMEL - Setting Standards for Metrology and Calibration

In the test and measurement equipment industry, PMELs (Precision Measurement Equipment Laboratories) are renown for working to some of the highest standards available when it comes to metrology and the calibration of test and measurement equipment. For good reason. As one PMEL instructor describes it, “Everything we do has to be precise… It can affect thousands of people if we make a little mistake.”

What Is a Precision Measurement Equipment Laboratory (PMEL)?

A Precision Measurement Equipment Laboratory (PMEL) is a United States Air Force (USAF) facility that calibrates and repairs test and measurement equipment. There are PMEL labs throughout the Air Force, overseen by AFMETCAL (Air Force METrology and CALibration) Program Office, located in Heath, Ohio.

PMEL technicians are responsible for the calibration and preventative and corrective maintenance of all the avionic, navigational, radar, test and intelligence equipment used by the USAF. They maintain, calibrate and certify the equipment in coordination with AF Primary Standards Laboratory, and to the National Institute of Standards and Technology (NIST) and other AFMETCAL-approved standards.

The test equipment is worked on in different calibration sections (K-Sections). The three most common sections are: K1/K8, K5/K6 and K3/K4. A K1/K8 section maintains equipment such as digital multimeters, high voltage probes and resistance standards. A K5/K6 section handles truck scales, pressure gauges, optics and micrometers. And a K3/K4 section maintains frequency counters, oscilloscopes, synthesized signal generators and power sensors.

PMEL has its roots in the United States Air Force

PMEL came about as an effort to provide a uniform set of standards and policies to ensure accurate, reliable, traceable and repeatable measurements of increasingly sophisticated equipment in use throughout the USAF. Prior to its establishment, aircraft manufacturers, equipment suppliers and military operators managed their own testing and maintenance, leading to varied and non-traceable results.

The USAF calibration standards program can trace its origins to 1952, when the Dayton Air Force Depot (DAFD), located at Gentile Air Force Station in Dayton, OH, developed and implemented a plan to ensure traceability to national standards, applied to all measurements made in the Air Force on any weapon system. In 1957, the Air Force took this one step further and set up a “Test Shop” program at March AFB, CA. The Test Shop program success led to the commitment to build additional base-level PMEL laboratories. In 1959, Westover Air Force Base, MA received the first PMEL, and by early 1960 there were 136 Air Force bases with PMEL capability.

Overseeing the PMEL program from 1961-1962 was the division known as the USAF Standardization and Calibration Division, which became the Directorate of Metrology in 1968. During this period, a new facility housing more than 10 highly specialized primary calibration labs, the Air Force Measurement Standards Laboratories (AFMSL), was constructed in Heath, OH. The new AFMSL occupied four levels underground and contained 20,000 square feet of laboratory area, complete with the most sophisticated and advanced testing equipment available. [The AFMSL was re-named as the Air Force Primary Standards Laboratory (AFPSL) in 1995.]

Organizational changes came to the AFMETCAL program with the 1993 Base Realignment and Closure Commission (BRAC). Base closures led to the 1996 privatization of two major Metrology functions - the calibration services performed by the AFPSL and the generation of calibration technical orders. Management of the AFMETCAL Program remained (and remains today) an Air Force function. AFMETCAL responsibilities include calibration procedure management, laboratory certification, equipment budgeting and acquisition for both the AFPSL and PMELs, Foreign Military Sales management, and metrology research and development management.

Day-to-Day Operations of a PMEL technician

In this brief video, PMEL technicians provide some insights into the work they do and the important role it plays in today’s need for precise, accurate and traceable calibration and repair.

The experience and training a PMEL technician receives is unparalleled in the industry. That’s why you’ll find that nearly all technicians in the MATsolutions lab are US-military trained. This, in addition to our ISO/IEC 17025:2005 Accreditation, ISO 9001:2015  Certification and 6,000 sq ft state-of-the-art Lab and Repair Facility with accredited 68-degree Cold Room, helps assure the quality of our calibration and repair work. Because accuracy, precision and traceability is important for any test and measurement equipment – in military and non-military situations alike.




  • AFMETCAL - Air Force Metrology and Calibration - Retains engineering authority for all calibrations performed in the PMEL labs throughout the Air Force, and oversees the contractor-managed and -operated Air Force Primary Standards Lab.
  • PMEL - Precision Measurement Equipment Laboratory - USAF facility where calibration, repair and testing of test equipment takes place (Not to be confused with NOAA's Pacific Marine Environmental Laboratory (PMEL))
  • AFMSL - Air Force Measurement Standards Laboratories (became AFPSL)
  • AFPSL - The Air Force Primary Standards Laboratory - the highest echelon metrology and calibration laboratory in the Air Force