"How are General Aviation pilots expected to maintain IFR proficiency when the regulations for currency (FAR 61.57) only require 6 approaches every 6 months? It doesn't seem like enough." - Phil R.
“There are two ways to address this question. First, I’ll answer from my experience as an instrument instructor in airplanes generally equipped with very capable autopilots. Most pilots do a superb job of flying coupled approaches.
Pilots tend to have less success, however, when hand-flying approaches. The most critical problems arise when an abnormal procedure drives a rapid transition from coupled to hand-flown conditions, especially if the abnormality takes the pilot from an everything-operating, autopilot coupled operation to hand-flown, partial panel conditions with little warning. It’s a common error to become over-dependent on cockpit automation and lose your ability to smoothly and accurately fly under instrument flight rules.
Given that experience, I recommend pilots maintain at least the minimum IFR currency in each operating mode: fully coupled approaches, raw data hand-flying, hand-flown flight director approaches (if the airplane is so equipped) and partial panel approaches.
I strive to mix it up like this for my own currency…6 approaches coupled, 6 hand-flown, 6 flight director, 6 partial panel. That means it takes 24 actual or practice approaches every 6 months at a minimum (18 if I combine the partial panel with the hand-flown approaches). It’s also good to demand both glideslope-assisted and step-down approaches of your IFR currency.
There’s also value, I believe, in flying practice approaches away from airports where you usually fly. Part of the workload of an IFR approach is interpreting the chart and tracking your progress through the procedure. If you fly your approaches-for-currency all at the home ‘drome or your frequent destinations, familiarity prevents you from experiencing the full workload.”