WTT Blade Inspection & Maintenance 3

Question 1

What is the minimum personal fall arrest system (PFAS) anchor point strength required by OSHA when performing blade maintenance at height?

Accepted Answer

5,000 lbs (22.2 kN)

Answer

OSHA 1926.502 requires fall arrest anchor points to support at least 5,000 lbs (22.2 kN) per attached worker.

Question 2

During a blade inspection, a technician identifies a crack at the trailing edge bond line near mid-span. The FIRST action should be to:

Accepted Answer

Document the damage with photographs and measurements before any repair

Answer

Proper damage assessment requires thorough documentation — photos, dimensions, and location data — before any repair action is taken.

Question 3

Which type of blade erosion is caused primarily by repeated impact of airborne particles such as rain, dust, and insects at high tip speeds?

Accepted Answer

Leading edge erosion

Answer

Leading edge erosion occurs when high-velocity impacts from rain, sand, and insects progressively erode the blade's leading edge coating and laminate.

Question 4

A 'bond line read-through' on the blade exterior surface most likely indicates:

Accepted Answer

The adhesive joint beneath has caused a surface print-through

Answer

Bond line read-through (print-through) is a surface imperfection caused by the structural adhesive bond joint telegraphing through the skin laminate.

Question 5

When grinding a blade surface for a repair patch, what is the minimum feathering ratio (taper ratio) typically required to achieve adequate bond strength?

Accepted Answer

30:1 (30 mm taper per 1 mm depth)

Answer

A 30:1 taper ratio is the standard minimum for composite blade repairs, ensuring adequate load transfer through the stepped laminate overlap.

(WTT) Wind Turbine Technician Certification Practice Test

(WTT) Wind Turbine Technician Certification Practice Test

WTT Blade Inspection & Maintenance 3