Quick question for anyone who will help. Is it legal to adjust the "0" on a VSI. If the needle reads 100' high or low can a pilot or A&P adjust this back to "0"? There is a small screwdriver slot just to the lower left side of this instument that will change the needles setting. Or does this instrument have to be adjusted by a instrument repair shop.Answer:
The only thing sillier than the question, is the answer: no.
It is not in the list of preventative maintenance items in FAR 43 Appendix A(c) that a pilot may do under FAR 43.3(g).
It is not on the list of things an A&P may do in FAR 145 Appendix A. In fact, FAR 65.81(a) explicitly excludes any repair or alteration of instruments from the privileges of an A&P certificate.
FAR 145 Appendix A(e)(1)(i) explicitly specifies that a Class 1 instrument repair rating must be held in order to diagnose a malfunction in a rate of climb indicator, or under A(e)(1)(ii) to maintain or alter one. So FAR 43.3(e) and FAR 145.31(e)(1) apply, and only an FAA certified instrument shop is authorized to adjust a ROC indicator to read zero. Same thing if you are contemplating adding fluid to your compass.
In such cases, it is best to pray. Most effective is the traditional form which involves "laying on of hands" on the object of prayer. Healing may also be facilitated by screwdrivers and torque wrenches. This is an issue of religious freedom, beyond the realm of the FAA.
Yes, sometimes I invite my A&P attend services, too. The only rational response to such regs is to know when to ignore them.