Peter R. wrote:
On 7/2/2007 3:31:14 PM, Orval Fairbairn wrote:

Sometimes, unscrupulous owners will wire the Hobbs to the master switch,
so you get charges whenever the MS is ON.


Isn't that true for the Hobbs installed by the aircraft manufacturer in newer
aircraft? I was taught that all the newer model C172s' Hobbs are wired to the
master, which results in about a 20% greater difference between their
readings and the tach.

Bonanza's don't even have recording tachs anymore. All they have is the
hobbs. My plane is similar, but it's on the gear so I don't pay for taxi.