Mearse,
First, I note that you are new to PPRuNe posting, if not the site ... welcome and, as you appear to have an appropriate background, your input will be awaited in topics to come ... with any luck, we might all learn from your considerable experience ... and isn't that the main value of PPRuNe to us all ? Hopefully you are not constrained too much in your ability to enter into some of the discussions ....
Agreed .. Vmcg is a very conservative approach to a critical handling consideration and is intended to put a generally reasonable fence around that problem.
Interestingly, there are those certification flight test people about who would far prefer to see your alternative scenario adopted in the interests of better matching aircraft to role and providing more appropriate data and guidance to the operator/pilot. It is, of course, the pilot who is in the interesting position of being able to detect that he/she has a major problem evolving rapidly ... and the operator who has to wear the legal and financial cost of the ensuing investigation.
The sort of approach which Mutt and I adopt can be extended to many of the more hazardous activities with which pilots might be faced ..
(a) increasing takeoff speeds within the available range for a particular runway to provide better Vmca protection during a very low weight takeoff. (This can be be quite significant for swept wing jets)
(b) techniques for OEI training in turboprops
(c) OEI missed approach minimum heights
are just three f'instances immediately springing to mind.
The real point of discussions such as this is a philosophical one ... whether, with a little bit more knowledge of what goes into determining certification matters generally, (and Vmcg, specifically, in this case), Pilot Bloggs' employer ought to be providing sensible operational guidance for specific circumstances in which the already conservative limits might not be sufficiently so and for which there may be simple protecting remedies. This is not just for Pilot Bloggs' protection but is the stuff of sound corporate governance.
It has been my observation over many years that there is a surfeit of highly imaginative ignorance and folklore in this industry.
As one who has been involved with the educational side of the industry off and on over my entire career, it is painfully obvious that one of the critical problems is that ignorance begets ignorance and, in process, that which began as ignorance eventually becomes folklore and, unfortunately, often enshrined as gospel.
When I hear some of the technical nonsense which is endemic in areas of the aviation marketplace, for example, I can only despair as to the confusion caused in the minds of younger pilots coming up through the ranks.
One example I can bring to mind from the dim past involved a local proficiency check session on my then aircraft Type. The check pilot asked me a question along the lines of "under such and such conditions and with two engines out, what sort of climb performance might I expect ?" .. to which I answered "not much" (or words to that effect, your Honour) .. whereupon the said check pilot, in his usual paternalistic fashion, proceeded to talk me through the relevant charts, thereby arriving at a more accurate answer of several feet per minute climb rate. He, quite obviously, had not the slightest idea of how the data was derived and what significance it represented.
The folklore associated with the subjects suggested above could fill novels ....
Back to Vmcg, the very great majority of pilots has absolutely no comprehension of how the typical aircraft behaves in this corner of the envelope.
Some years back, Australia unilaterally implemented an ICAO suggestion that such things ought to be addressed for operations from narrower than "standard" runways. Some of the subsequent test programs (simulator and runway) showed very clearly that this is a problem well worthy of sombre reflection and consideration.
I have videos from some of the test programs which show aircraft quite dancing about on the runway during the intial gyrations following a contrived critical failure.
All Mutt and I are on about .. is that knowledge can be applied usefully ... and might just be the thing which saves the aircraft on a particular occasion .....
Just a thought ...
Last edited by john_tullamarine; 14th July 2002 at 01:56.