Turbulence and R44
Flying a lot in the south-east france (the mistral area), I have been a lot in very windy and gusty weather. Many times it happened that wind suddenly and unpredicted by Met goes to over 50 knts at low altitude (25 knots would be a calm day). I always managed to fly through it, but a few times I got kicked around so badly that I swore not to get caught in that again. In the case of a 'flying' 65 knots storm between Cannes and Marseille, I wisely back tracked even though ATC advised to continue., still landed with 45 knts.
What I learned
- avoid turbulence. Especially in mountainous areas you should be able to read where the vortices are, how big they will be etc. If you feel you can not do this, stay away. I do not know the particulars quoted by choppersafari, but 2 miles away can be far too little in some cases. Yesterday, departing from Le Castellet, gusting 35 knots I prefered to climb to FL55 (even though I was at MTOW) to be clear of St Baume mountain (3600ft), because to wind was coming from an unusual direction, so that I was not shure where the severe turbulence would be even though I think I know the area well.
- mountain flying techniques are very help full, look for laminar flow areas. These are sometimes also close to the ground, but for that you need to know the technique and the area well
- big vortices near mountain ridges need special attention. Sudden down drafts, especially if preceded by heavy updrafts, create low-G conditions. I always do a moderate flair into does : reducing speed from 105 to 80 and making shure the tail is low enough.
- if you are caught in an updraft and conditions permit, let it take you up. There will be a downdraft later in which you do not want to enter nose down at high speed.
- you also get sudden horizontal changes : for instance tail wind on top of a vortex projects you later in a windless area : this can create overspeed situations (going from 105 to 135 IAS in a few seconds) dangerous again if not anticipated
- if you are caught do not oversteer, reduce speed. This is particularly difficult, especially if you are badly kicked around and it appears the machine is not coming back by it self. Remember that the yawing creates side slip, in side slip you are supposed to steer the cyclic into the wind and not away from the wind which happens if you let your sence of equilibrium take over, exposing you to mast bumping. So it is perhaps better not to steer as indicated in the manual.
- avoid very low weights (for instance just pilot, with minimum fuel)
Delta3
Last edited by delta3; 3rd Apr 2005 at 10:50.