Most aviation maintenance professionals understand that equipment should be checked for accuracy and safety. However they don’t always know when this needs to occur. The key to calibration testing is that it is performed regularly. But what does regular mean? It can be difficult to determine when to calibrate aviation equipment with all of the differing information. The best place to begin when defining a calibration interval is the manufacturer recommendation.
Follow the Manufacturer Recommendation
There are two reasons to start with the manufacturer’s recommendation. The FAA procedures for part 145 repair stations include manufacturer guidance in part of the SAS (safety assurance system) requirements. “All MTE are calibrated and traceable to a standard acceptable to the Federal Aviation Administration (FAA), to include those recommended by the manufacturer, and the National Institute of Standards and Technology (NIST) or other national authority.” The manufacturer will have the most insight into how quickly parts on the instrument may lose accuracy. Their recommendations are often supported by industry standards.
Use the manufacturer recommendation when you first choose intervals to calibrate aviation equipment. This will contribute to quality compliance and safety assurance systems. In general, stick with the manufacturer interval for at least three cycles before considering changing intervals.
Review Historic Calibration Data
One of the best sources of information is past calibration data. Take a more in depth look than just whether an identical item passed or failed. What was the “as found” condition? If the instrument was found out of tolerance, investigate to what degree. Try to determine if instruments of this type are commonly found out of tolerance.
Determine Actual Service History
Most types of equipment will have recommended preventative maintenance. This can range from daily cleaning to a nine month overhaul. How often will the preventative maintenance be performed? This is the time to be realistic. If AMTs are thorough with tool maintenance, tooling accuracy can be sustained for a longer time. In an environment where tooling is shared amongst many technicians, it can be very difficult to determine if preventative maintenance is occurring regularly. If preventative maintenance and tool care are lacking, tooling may require calibration at shorter intervals.
Calibration may occur at irregular times if the instrument sustains damage or it is found to be out of tolerance. If the instrument can impact overall safety or contains sensitive parts, it will be sent for calibration immediately. If this happens, the following calibration cycles can be shifted to occur at the next interval from the new date.
If you have any questions about when to calibrate aviation equipment, contact the team at ISO 17025 accredited laboratory, e2b calibration.