| There can be
significant differences in the experience level of technicians, and the sophistication of
the processes and equipment used in the overhaul process from shop to shop. The answers
that a prop shop provides to these questions should give you a better understanding of
their capabilities and qualifications. Does the shop maintain the required sample program
approvals to perform critical required overhaul tasks?
Sample Program
Approval Listing
Are the non-destructive tests
performed by certified Level II
inspectors?
Ask to see the certifications.
When are the blade
dimensional inspections performed?
Many shops take measurements before they grind the blade but not after grind. While it's a
good idea to take measurements before grind, a dimensional inspection must take place
after grind to ensure that the blade meets the requirements of Hartzell Manual 133.
Will your aluminum
blade be anodized or alodined?
While both are permitted, anodize provides corrosion protection that is far superior to
alodine.
What new parts will be
provided in the overhaul price?
Price quotes can vary greatly from shop-to-shop. Compare what parts are included in each
shop’s overhaul kit. Also, insist that you are getting genuine Hartzell replacement
parts.
What procedure does
the prop shop use to perform shot peen?
Ask what procedure is used. Many shops do not
use any procedure to control shot angle, intensity or duration. Shot peen is a critical
operation to improve part fatigue resistance. Done incorrectly, it can actually damage the
part and reduce fatigue strength. |