What was found
PILOT REPORTED GYRO WAS OUT. (IFR) A/C DIVERTED TO RFD. BOTH INSTRUMENT VACUUM PUMPS FAILED, LT AND RT. NO FAULT COULD BE FOUND THAT WOULD CAUSE BOTH PUMPS TO FAIL SIMULTANEOUSLY. TOTAL TIME OF PUMPS UNKNOWN. RECOMMEND LOG BOOK ENTRIES BE MADE WHEN VACUUM ADJUSTMENTS ARE MADE. LOGS SHOULD BE EXAMINED DURING INSPECTIONS TO DETERMINE IF REGULATORS HAVE BEEN ADJUSTED TO COMPENSATE FOR FAILING PUMPS.