Depends on the shop and specific prop whether any repair is possible or available. However, usually when the corrosion has left pitting then your options become very limited or nil. Best option is to call a shop and get their input.
There has been various fixed pitch hub cracking over the years with associated ADs, but don't recall any in-flight hub failures off-hand.
It would never have left the factory like that.
Yes, as noted, this prop needs to go to a prop shop that has the manuals, knows the limits, and has access to the manufacturer if there are any questions or grey zones. Very little can be done to a propellor in the field by an A&P ± IA.
That’s a new to me technical term. Please explain.
.Loosely it's a form of electrochemical crevice corrosion that sets in when fluid is trapped in a feature (think groove or thread) and never or rarely exchanged. Usually it's worse with large scaling factors, which is a scalar that relates to the depth vs. width of the feature trapping the fluid. Here the bolt would have been "smooth" and the bore was likely fairly smooth, thus in principle leading to a low scaling factor and higher (less acidic) pH in the fluid. That said, the pics do show a "grooved" pattern even on the non-corroded portions. Regardless, the manifestation of the corrosion it the OP's pics does look like it at least partly due to this phenomenon.
Agree. Not enough suspect get removed regularly is the issue. Canada seems to have nipped the issue in the bud by making sure it comes off at least every five years. The cost of overhauling a fixed pitch in the US is about 1/5 the cost of a new prop!
Sounds like a made up term....well done. It's not found in AC 43.13....nor was it taught at my prestigious university....and giggle was no help
The mechanism and scaling factors are known and discussed in the literature. The "stagnant pool" is something that a few academics I know used, but as you note, it's a not a term of art. Does describe the situation well.Sounds like a made up term....well done. It's not found in AC 43.13....nor was it taught at my prestigious university....and giggle was no help
Forms of Aircraft Corrosion
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I guess you're background is in aquatics....swimming pool corrosion is very common.
The prop shop doesn't have to do it. A mechanic with a decent pair of eyeballs and the dimensions for that prop can do it. Some prop shops will give you the dimension chart from the manual, too.
Going back to OP, a decent set of eyes could see that it was corrosion. Based on the amount seen in the pics, the dimensional analysis could still of been perfect - i.e. a pin gage in the mount hole(s) would still be good. However, since there is corrosion, it would take IMHO the repair station to either know that degree of corrosion is acceptable, know that it is not, or have access to the manufacturer if it's a grey zone. Apparently it was not and the prop was condemned since the corrosion caused a defect from which a crack could potentially start.
I definitely agree!I just bought this plane a few months ago and had a pre-buy/annual done to it.Prop may or may not have come off during annual
It would "not" be common to remove a prop....just because....even for an annual.