Jim Macklin wrote:
Get a better and more qualified instructor. 100 hours is
very little time in a particular model, but this guy is
either ignorant or you didn't understand him.

Actually, you're displaying the ignorance here.

The syncrophaser is used to get both props turning at the
same speed and with the blades in phase to reduce noise.

Correct, that is the primary purpose. However, its range of command is
limited - generally 25-50 RPM. Many also have an indicator (the needle
the instructor is talking about) which tells you which way to make the
adjustment to bring the props within the range of command of the
synchrophaser. Since the prop governors used in piston airplanes are
proportional-only controllers (no integral component) the RPM on the
failed engine WILL drop - and it will drop by enough to take it out of
the range of command, though not enough to be obvious (or even
noticeable) on the average GA tach. In that case, the needle will
become an effective indicator not only than an engine has failed, but
which one.

In
any multiengine aircraft, you identify a failed engine in
positive steps. The problem with the in-line airplanes is
that only reduced take-off performance (reduced climb)
alerts the pilot to an engine failure.

Only if he ingores the information provided by the synchrophaser.

Michael