Originally Posted by
wrench1
As to the Van Horn blades collective bounce issue, even Bell had similar issues with this phenomenon with factory blades and as I recall even an accident or 2 as well. There can be various reasons behind collective bounce, and I believe if this was a more common occurrence with VH blades than Bell blades, then there probably would have been more regulatory action taken.
I believe that the description of "Collective Bounce" is a misnomor at best.
In the instances I was personally involved with, the pilots literally thought that their time was up and the aircraft was going to throw itself apart.
I'm not going to embellish the facts with how they described it to me "post incident" but suffice to say I was at first sceptical then that gave way to concern.
Both instances occurred before VHA provided any formal feedback.
Subsequently and after I don't know how after how many reports were made to VHA, advice was issued over time in three statements.
In order of issue:
1. Offset Cyclic to right,/do not lower collective.
2. Raise Collective and offset Cyclic.
3. Sweep both blades aft two points to reduce likelihood of onset.
Item 3 obviously being a maintenence action.
Yes, the situation when it occurs is controllable providing the pilot has been made aware of the phenomenon and is briefed on how to handle it.
Don't get me wrong VHA deliver a good product, just the information needs to made more readily available for operators and pilots.
Currently the distribution of that information is via Van Horn only and therefore relys on an organisations own internal procedures to pass that information onto the crews at the sharp end.
That may be the "weak point" right there?