Peter R. wrote
An interview with the pilot suggests that poor avionics maintenance may
have been the cause.

I wonder how many of those "Loss of control in IMC" accidents,
generally attributed to pilot error, are really the result of multiple
failures. Face it, guys - we're flying old obsolete junk. I know
lots of pilots who tell stories of multiple failures on a single
flight. It happens.

However, flying into low IMC immediately after the
aircraft returned from maintenance may have been a bad decision.

In my opinion, it's an absolutely unacceptable decision. Test flights
are day-VFR events. I've had things go wrong on test flights before,
and they didn't always have an obvious connection to the maintenance
being performed. However, since I always landed the plane, I was
always able to do a detailed examination of the intact systems
afterwards - and in the end, it always turned out that the failures
were related to the maintenance, though in non-obvious ways that
generally pointed out previous marginal maintenance and/or very poor
design that clearly did not include a complete analysis of the failure
modes.

But of course he had a parachute. Would he have launched into low IMC
without a parachute immediately following maintenance?

Michael