Measuring for success

Measuring for Success A Calibration Overview By Michelle Garetson March 1999 From the time that we get up until the time we go to sleep, metrology affects our lives. Metrology -- the science of measurement, and calibration -- the...


Measuring for Success

A Calibration Overview

By Michelle Garetson

March 1999

From the time that we get up until the time we go to sleep, metrology affects our lives. Metrology -- the science of measurement, and calibration -- the comparison of measurement, are responsible for the ways that we gauge our present and future, as well as how we define our past.

We rely on our personal wristwatches and clocks to be within acceptable parameters of those wristwatches and clocks at the places where we conduct business and other pursuits. We trust that our car's speedometers are calibrated correctly when our peripheral vision spots the State Trooper's radar detector. If any or all of these items are out of sync with the accepted standards; missed deadlines, fines, and lost opportunities can result.

Why is Calibration Important?
For any business, not just aviation, having the proper tools is imperative to how business is accomplished and how customers perceive the tasks performed. However, having the proper tools isn't always enough. Many tools need to conform to industry standards in order to work properly and to be utilized specific to their design.

Proper calibration of tools such as torque wrenches, weighing scales, and non-destructive testing equipment is critical to the accuracy required in their respective functions.

Fluke Corporation, based in Everett, Washington, offers some insight on its web page (www.fluke.com) as to the importance of maintaining a calibration calendar, but the need for calibration is directly related to the specific tasks performed by your equipment.

According to Fluke, the "measuring instruments are the Ôheartbeat' of your company . . . they control the quality of your products and in the end, responsible for the success and the profitability of your business."

Further, "A regular check of your Ôheartbeat' with traceable calibration equipment is essential."

What this regular check does for your operation is to ensure the quality expected by your customers — this is especially important where ISO 9000 certification is involved.

Other benefits of regular calibration include:
• Establishment of a quality system
• Consistency of quality of your production output
• Meet production control criteria
• Lower operating costs due to enhanced reliability
• Organized records for quality audit and reviews
• Establishment of calibration traceability

"The calendar for calibration can vary," says Michael Thee, president of Continental Testing Inc. (CTI) in Watkins, Colorado. "But, most items, unless otherwise stated by the manufacturer of the equipment, is one year. FAA inspectors can require more frequent calibrations such as for pitot/static testers. Due to the sensitive nature and critical importance of that instrument, a six month calibration is recommended. Also, most NDT equipment is on a six month cycle."

Thee adds, "Customers can start a cal cycle that has all calibrations due at certain intervals at one time a year or two times per year, and so on. Instead of tracking tools at all different times a month, customers can have the bulk completed in one on-site calibration, which reduces tracking significantly."

Like the examples of the wristwatch and speedometer, Don York, metrologist for Midcoast Aviation in Cahokia, Illinois, stresses that operations need to be able to trust the measurements of their tools and machinery, regardless of where that tool lies on the calibration timeline.

"If there is doubt," says York, "then the calibration of that equipment should be checked. If a tool is dropped, if there is possible salt water contamination or excessive humidity in the environment of the equipment, a re-calibration would be warranted."

Environment is very important. Midcoast's calibration lab is constantly monitoring humidity and temperature levels in an effort to maintain consistency for calibration testing. Even the type of lighting used in labs has to be considered as different lamp categories vary in heat output.

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