If historical reference and natural laws of physics don't give you the answer to that question, then I'm not even gonna try myself.
And if you say, "I didn't mean repairing while deployed in the air." Then we do have it. It's called taking the bird back to the hangar. Also, ad hoc field repair was not much of an option in WWII.
And if you did mean it, I refer you to my first paragraph.
I beginning to believe in childhood euthanasia for stupidity.
[To Whom It May Concern - the afore written line of text was meant as a joke, not a personal insult, albeit a decidely pointed one.]