Flight and Weather Briefing
The pilot of a single-engine aircraft received a weather briefing for a VFR flight. The briefing indicated IFR weather conditions along the intended route of flight. Despite this, the pilot stated he conducted the flight under VFR because he "did not trust his instruments."
Emergency Declaration
Approximately one hour after departure from Laramie, Wyoming, the pilot requested the Laramie weather in an attempt to return. The pilot then radioed that he had lost his gyros and declared an emergency. The Flight Service Station (FSS) received a special VFR clearance due to weather below VFR minimums, but was unable to issue it because radio communications had been lost.
Post-Accident Investigation
Post-accident investigation revealed that the vacuum pump had been installed without the shear shaft coupling. The airframe and engine logbooks did not identify previous work performed or the person(s) who may have worked on the pump.