[Walter Atkinson]

Kevin:

The only reason I post the following is to point out that my recommendation is based on a lot of real-world AND research experience. Just for the record, my qualifications are:
ATP SEL&S, MEL&S, CFII, MEI, A&P, piston engine researcher (Carl Goulet Memorial Engine Test Facility).

A lot of mechanics worry that an in-flight mag check is dangerous but have no data to support their concern. I continue to ask "What stress is it they are concerned about?" So far, none of them has ever had a suggestion as to just what could be a problem. When asked for specifics, they don't have any or are usually grossly misinformed about the effects of single mag operation. (Maybe it's just a fear of the unknown.)

We have been doing in-flight mag checks on EVERY flight for many years.

One should realize that during single mag operation, the stress on the engine goes DOWN as the thetaPP is later, the pressures are lower and the CHTs run cooler. (The EGT's go up as a result.)

PLEASE, let's not offer conjecture about some unknown and unidentified boogie man as a reason not to do something very helpful.

One of the best ways to stop detonation is to simply switch to a single mag. I've demonstrated that countless times on the engine test stand.

Please offer any reason that anything bad could happen during an in-flight mag check. If there is such a ligitmate concern, I'd like to either dispell it, or if I have never examined the particular issue, I'd like to do so.

Specifically, just what is so dangerous about doing an in-flight mag check? Maybe I can set you mind at ease.