The decision making process needs to consider so many variables:
1 Aircraft type and loading - e.g. Baron versus Apache versus Chieftain/C402 etc. A 285 hp Baron with four on board is not too bad a performer, and in the right hands could probably execute a single engine missed approach from the ILS minima. But see 3. below for the caveat. A 150 hp Apache is committed to a landing at the time the engine fails, no matter what skill level you have. Certain laws of physics can not be denied. 150 h.p. in a draggy airframe such as an Apache can only propel it forwards and downwards - albeit fairly slowly. A Chieftain or C402 with every seat occupied probably lies somewhere between these two.
2 Temperature. Under extreme summer conditions turbocharged twins will suffer overheating if the remaining engine is flogged at the low speeds required to avoid obstacles when climbing. Normally aspirated engines won't be developing rated horsepower on a hot day. Plus of course density altitude affects all aircraft.
3 Pilot familiarity with the type and overall proficiency. A five hour endorsement won't prepare most pilots adequately for such a critical event as a OEI missed approach from the minima in a fully loaded twin. And now that formal endorsements are not required on each type, pilot familiarity and overall proficiency will be even more pertinent to such decision making. How the Examiner will adequately assess this on a flight test will be interesting to watch - safely from the ground, thank you.
Re the reference to the VH CLY accident. If that was the Heron, it was not caused by an engine-inoperative lack of performance. An engine out in a Heron is almost a non event. In fact we could and did take off on three engines sometimes, though not with passengers. The cause of that prang was as in 3 above. If you dump the flaps from the landing setting back to the takeoff setting on a Heron, in a split second they go from about 60 degrees to about 20 degrees - with predictable consequences.
Last edited by Mach E Avelli; 5th Dec 2014 at 00:36.