Yeah but....
To: RobboRider
I made a point about what can happen and used a personal experience to illustrate the point. Granted it happened in 1952 but you seemed to have missed the point.
What I suggested was that WD-40 is not a preservative. Its' sole purpose is to displace water. WD-40 was developed to protect the stainless steel skin of the Atlas Missile and it was not called WD-40 at that time. WD-40 like liquid Wrench and other similar products is capable of weeping into very tiny crevasses on metal surfaces and in the process it displaces water where Liquid wrench penetrates rusted surfaces. All of these products contain petroleum distillates that can react with the bonding material.
My second point is that you can not use a product in the maintenance and servicing of an aircraft if that product is not approved for that function. The aircraft manufacturer will run tests or they will have the product manufacturer submit the product to an approved laboratory for testing for the intended function. If the product is not in the approved materials list in the maintenance handbook then it can't be used. Also, if WD-40 is approved you must only use it for the approved purpose.
Also, if you use WD-40 on the blades as a preservative the film of WD-40 will attract sand and other entrained particles and upset the delicate aerodynamics of the blades.
I have worked as a Reliability, Maintainability and Systems Safety Consultant since 1968 and problems like this are constantly being raised.