Originally Posted by
wrench1
Up until the incident in Sept 2024 it was my understanding the FAA and VH indicated the VH blade severe vertical was very similar to the induced Bell blade vertical. However, after the Sept incident and given the low number of VH or Bell vertical bounce events, the FAA decided to expand their investigation and issued an Airworthiness Concern Sheet against the 206L series fleet for more input. It will be interesting what response they get since this is not a common issue.
Im sure it's the VHA blades
They don't interact with the Nodal System at the same frequencies as Bell OEM blades.
Even on the ground they cause issues at idle.
Latest info from VHA is to sweep blades aft two points after initial alignment to avoid the flight regime of Vertical bounce.
Then contradictory information in another SB stating this causes tail wag at Idle on the ground and to use chord weight?
Lateral IPS rough at idle. Add 9% and settles down.
I've stated in other posts on this forum that VHA MR Blades on 206L don't track well and I suspect harmonic feed back into Nodal Beam being a primary issue.
Tab on the old blades have no effect compared to OEM blade Tab adjustment.
The later blades don't have Tabs and use wedges.
Never adjusted Tab or Wedge on VHA blades as minimal effect.
Even above 55KT PCL is the best adjustment . Their own documentation state this also upto 105KT.
To summarise I can't see a consistency of how VHA MR Blades on 206L interact with adjustments.
They are a bugger to T&B and don't respond to normal adjustments compared to OEM blades.
My opinion only.