Tranny Lube failure
Correct me if I am wrong but I believe that your wondering is should a gearbox puke out all it,s lubrication ....do the blades keep turning?
Yes they do...until the gears and bearings within the box reach a temperature point that begins to bake the residual lubrication. Without any lubrication , the metal to metal contact and extreme forces that a 15 ton helicopter put upon them, begin to fail as well as build incredibly high frictional forces.
At this point, further application of power can overcome this rapidly increasing friction and keep the blades turning but at some point either the power runs out or the incredible heat build up causes a catastrophic failure and either a blades will begin to slow and eventually sieze or the mast / transmission will fail. At this point your a greasy manhole cover and gravity wins another one
As the gearbox fails, the increasing friction also precludes successful autorotion.
With some operators, an impending gearbox failure (high teps and or low pressure) calls for a Land As Soon As Possible and in other cases....a Land or Ditch IMMEDIATLY I
I am curious as to the S92,s RFM Emergency Checklist and/or Cougar,s ECL calls for with respect to Gear Box malfunctions.
Last edited by rumline; 13th Mar 2009 at 17:13.
Reason: the usual grade IV spelling & grammer