Heeeeelp!
 

hi everyone. I have one of theose strange questions. on a robinson R22, is the auxilary fuel gauge a primary instrument that requires an entry in the 'acceptable deferred defect' form if it is under reading? my argument was that its an optional extra and the aux tank will always drain first that it may not be, any thought on this? happy flying

"Optional" instruments are optional in that they are not required to be fitted for certification. Once fitted, however, a pilot has to be able to trust them - so yes, if it is not working it is a requirement that it is reported, and further operation requires dispensation (usually through an MEL).