Roy Smith writes:

I think there's no doubt that if you take two equally skilled pilots
and put them in otherwise equal airplane and flight conditions but
give one an AP (with appropriate training) and make the other
hand-fly 100% of the time, the one with the AP will have a lower
workload, which translates directly into higher reserve of ability
to handle the unexpected which in turn translates into a safer
flight.

On the other hand, for all I know, the guy with the AP in his plane
will, over the long run, tend to get complacent and dependant on the AP,
letting his hand-flying skills erode. This leads to a decrease in
safety.

Which is the stronger factor? I have no clue, and I suspect the
insurance companies don't either.

But they do have better statistics about accidents than we can get
publicly. They know a lot about their individual policy holders, both
the ones who get in accidents and the ones who don't.

To help everyone in this discussion avoid jumping to absolutes (I'm
not accusing you of that, by the way), here's a different way to
approach the problem. Let's say you have a basic plane like mine -- a
125 kt, 160 hp, fixed-gear Warrior II with dual NAVCOM, DME, and ADF
-- that you fly a few hours each month in actual IMC and the rest in
VMC or marginal VMC (filed IFR, in that case).

You decide that you can afford to install *one* new permanent system
costing from USD 4K to USD 10K this year, and possibly one in each
following year (but not for certain). Arrange the following list in
the order that *you* think would make your IFR flying safest, putting
the highest priority item at the top. If you want, you can assume
that you already have some kind of backup vacuum system. These are
currently in alphabetical order:

Electric AI (backup)
Engine monitor (i.e. EDM 700)
HSI (slaved)
IFR GPS (non-moving-map, at this price)
Stormscope (or Strikefinder)
TPAS
Wing leveller (or other general single-axis AP)

For some people, there will come a point in the list where it makes
more safety sense each year to spend the money on additional
maintenance, inspections, and proactive replacement of typical failure
items like the alternator or vacuum pump (or even the navcom radios);
others will likely run down the full list and want to add more at the
end.

I'll post my own list shortly, but I will mention in advance that
neither the IFR GPS nor the wing leveller will be at the bottom.


All the best,


David