Which statement about cold straightening of aluminum propeller blades is correct?

• A. It is allowed for shipping to a repair facility.
• B. It is prohibited because it can cause hidden damage rendering the blade nonrepairable.
• C. It is recommended to straighten before transport.
• D. Only with manufacturer approval.

Answer: (B)

Cold straightening aluminum propeller blades is avoided because bending at room temperature can introduce or propagate hidden damage that isn’t visible in surface inspections. This can create microcracks or other flaws that undermine the blade’s structural integrity. Once such damage exists, the blade may be beyond repair, meaning it would have to be replaced. That safety risk is why the practice is prohibited: straightening can mask defects and leave a blade that cannot be reliably repaired in service. In practice, damaged blades are removed and evaluated under approved procedures, often requiring replacement or manufacturer-approved repair, rather than attempting cold straightening.