Aircraft Maintenance: Torque and Fasteners

What type of nuts typically require lower torque values?

Shear nuts

What is the purpose of a torque wrench?

To measure the amount of torque required to turn a fastener

Why is correct torquing important for bolts?

To ensure the bolt is subject to its metallic stress strain

How is the amount of torque calculated?

By multiplying the applied force and the lever arm Signup and view all the answers

How should a torque wrench (except dial type) be held to operate accurately?

At the knurled handle Signup and view all the answers

What type of torque wrench uses a beam that deflects under load?

Flexible beam type torque wrench Signup and view all the answers

What is a unique characteristic of PLI washers?

They can only be used once and must be replaced if slackened Signup and view all the answers

Why is accurate measurement essential in aircraft maintenance?

To ensure the correct functioning and reliability of engines Signup and view all the answers

What is the first step in using a precision measuring instrument?

Zero the instrument Signup and view all the answers

What is required to ensure precision measuring instruments are reliable?

Regular inspection, service, and calibration Signup and view all the answers

Why is it important to observe in-service limits?

To ensure wear limits are not exceeded Signup and view all the answers

What should a technician do if a precision measuring instrument does not zero correctly?

Calibrate the instrument Signup and view all the answers

What is the pitch of the spindle of the English micrometer?

1/40 Signup and view all the answers

What does each vertical line on the sleeve of the English micrometer designate?

1/40 or 0.025 in. Signup and view all the answers

What is the distance moved by the spindle longitudinally when the thimble is rotated from one division to the next?

0.001 in. Signup and view all the answers

What is the total distance represented by 25 divisions on the thimble?

0.025 in. Signup and view all the answers

What is the typical range increment of metric micrometers?

25 mm Signup and view all the answers

What is the purpose of the vernier scale on a micrometer?

To measure in 0.002 mm increments Signup and view all the answers

When using a micrometer other than 0–25 mm, what must be added to the reading on the scale?

The gap in the frame Signup and view all the answers

How do you read the metric Vernier micrometer scale?

By adding the normal reading to the vernier scale reading Signup and view all the answers

What type of micrometer gives a digital read-out of measurements?

Electronic micrometer Signup and view all the answers

What is the accuracy of measurements using a Vernier micrometer?

Two thousandths of a millimetre (0.002 mm) Signup and view all the answers

What is the primary purpose of the internal micrometer?

To measure internal dimensions Signup and view all the answers

What is the range of the sleeve scale on an internal micrometer?

1/2 inch Signup and view all the answers

What is the purpose of the collar on an internal micrometer?

To extend the measuring range Signup and view all the answers

What is used to lock the collar in place on an internal micrometer?

A locking screw Signup and view all the answers

What determines the measuring range of an internal micrometer?

The length of the extension rod Signup and view all the answers

What is the purpose of the extension rods on an internal micrometer?

To vary the measuring range Signup and view all the answers