Preventative Measures: Maintaining special tool calibration records

Preventative Measures Maintaining special tool calibration records By John Goglia July 1999 John Goglia is a member of the National Transportation Safety Board (NTSB). He has 30 years experience as an aircraft technician. Mechanics...


Preventative Measures

Maintaining special tool calibration records

By John Goglia

July 1999

John Goglia

Mechanics who work within a 145 repair station can find themselves at risk if they don't understand the relationship between internally accepted manuals or procedures and the Federal Aviation Regulations. One area that we, as mechanics, are exposed to on a regular basis is in the use of special tools or precision testing equipment.

How many times have you heard of someone making a tool because the one called for by the manual is not available? Although the locally-manufactured tool may work fine, in some cases it may not function exactly the same.

Additionally, the FAA may ask you for the data you used to manufacture the tool/test equipment. We are not talking about bending wrenches here, but more complicated tooling. You may be surprised to learn that one of the most common tools that causes us problems is a torque wrench that is either past its calibration date or one that doesn't have a record of when the next calibration is due. Every torque wrench that is used on an aircraft or component must be calibrated in order to insure accuracy. Air carriers and repair stations must have procedures to ensure that the torque wrenches that are used in the performance of maintenance are accurate.

Note the words "used in the performance of maintenance." This means if you use a torque wrench on an aircraft, it must be checked to ensure that it is accurate. This also means if you use a torque wrench that you have in your toolbox, it also must be checked. So, if you use your own torque wrench, you will need to be able to explain to an FAA inspector how you determined that the torque wrench is accurate. Your employer is also subject to a violation if you are found to be using tools that are out of calibration or have no record of torque wrenches being checked for accuracy.

FAA inspectors tell me that out-of-date calibration on tools and test equipment is probably the number one violation they find in both air carriers and repair stations. Since the procedures manuals require that tooling be checked, how does out of calibration tooling find its way into maintenance operations? The only way is from maintenance people who fail to pay attention to the date on the calibration tags. When we go to the tool area to get special tools, including torque wrenches, the first thing we should look for is the calibration tag and check the date. If it is out of date, don't use it and store it in the area for unserviceable tools.

If you think I'm exaggerating, think again. I actually had an FAA inspector show up in the hangar one day for what was normally an uneventful visit. He found us using a personal torque wrench and asked to see it. It did not have any tag on it that would indicate that it was calibrated, and this led us into a very interesting discussion in tool control and responsibilities. Under a different set of circumstances this could have easily resulted in at least two violations — one for the mechanic and one for the employer.

We were fortunate in that this hangar had a torque wrench calibration fixture mounted on a wall in a secured area. With this device, you could verify the setting on the torque wrench and what this torque-measuring device indicated. If you were calibrating the torque wrench, you would then adjust the settings so that they agreed. In this case, we were able to demonstrate to the FAA inspector not only that the torque wrench was accurate, but that we actually had set the torque wrench, but by the actual reading of torque as indicated on this calibrated testing device.

Given the tone of our discussions with this inspector, it was clear to me that a violation was in the works, but we were able to save lots of problems because this calibration device was available.

This content continues onto the next page...

We Recommend