PGA;
Skills will be lost, that became very evident during my last sim when the cpt was flying his raw data ILS, all over the place.
Obviously this was debriefed, however the reply was: "I stick in the a/p at 100ft and disconnect at 200", well the result was there......
It was good fun flying in to foggy Paris this morning from FL90 onwards without ap/a-thr/fd's.
I used to hand-fly every approach both on the A320, A330 and A340 even though no one else would or wanted to, until disconnection was restricted by the Ops Manual to "non-traffic, non-busy" environments - essentially, every time an incident occured which involved hand-flying, the restrictions got tighter, but the training syllabus did not change from its priority on automation use. Eventually disconnection became a risk to one's career because it was so strongly discouraged and if one had an incident, the policy provided the avenue for blame.
Automation does contribute to flight safety - no doubt. When fatigue is high, one is being vectored into LaGuardia or Hong Kong, etc and things are very busy for the two or three pilots, (3rd being the Relief Pilot), then engaging is a smart thing to do; when navigation precision is required as for the SIDS especially out of Europe (thinking London, Frankfurt, Paris, mainly), engagement is wise even if one is fresh.
However, the Ops Manuals ought to guide crews regarding appropriate levels of automation engagement right down to fully-manual, no FD hand-flying and the airplane SOPs ought to permit full disengagement when appropriate so that crews are not violating company policy or SOPs. Believe it or not, some associations/unions have to fight hard to ensure these provisionsf within their company.
Personally I wouldnt' fly the Paris arrivals by hand but that's just me - many might and do it well out of familiarity if nothing else.
The key is engagement that suits both the pilot flying, the crew complement and the traffic/ATC/weather/fatigue circumstances and beyond trusting experience and training, it is pretty difficult to make specific rules.