Steam-navigation versus GPS failure rates
I'm interested in the relative failure rate of old steam (gyro driven instruments and DME, ADF and VOR) versus GPS. Who has had failures of what, and and what rate per flight hour?
I'll start things off. I have flown about 250 hours in various spam cans and suffered two total gyro instrument failures. One non-erecting AI discovered at the pre-flight check stage (prior to departure for an flight in IMC) and one HI that failed in flight precessing at a sufficient rate to make it useless. One pump had sufficiently poor vacuum that it was entered as a defect at the conclusion of the flight.
I have had one failure each of DME and ADF and an unservicable GS though the localiser continued to work.
Combined time on Spam Cans and LAA types of about 450 hours with both panel-mounted GPS and hand-held devices has so far scored a zero failure rate.
How have other people fared?