If you go low, know your Run !
If you plan to do some ground hugging speedflying or riding, there is one thing that is most important:
KNOW YOUR RUN.
The TRUE luxury in speedriding / flying over a ski descent is that you can do an easy pre-run in safe distance from the terrain to discover all details and possible nasty traps and deadends of your new run.
The starting point is to inspect your run as if you would be planning a freeride ski or snwoboard run - inspect the terrain as best as possible (ACCURATE topo and/or satellite maps, digital maps / terrain cuts, google earth, etc.), if possible check all landing options personally on the way up (from the tram or even better walking / skinning (= ski touring) up) and preferrably do a testrun with a safe distance to ground (+ 100m) in order to make sure you got the glide reserves you need for an agressive groundhugging proximity run.
With a speedwing and its relatively little glide it is very easy to end up in a situation where you are "caught" by the terrain with no other option but a stalled crash - with some luck you might get away with it in winter on skis (if there is a thick and soft snowcover), but in summer the outcome will be most likely nasty to very nasty.
So what are some of the import factors to consider ?
> Avoid beeing caught in terrain thats flatening out so your glideangle may be less then the terrain's incliniation, PULL OUT from your proximity run early enough to have enough reserve height for the glideout with at least 25% reserve glide (terrain vs. your wings average glide angle MINUS headwind or sinking air (cadiabatic wind) effects)
When footlaunching / landing plan extra reserves to allow for a proper landing flare - at least a 90 deree turn BEFORE the landing flare should be possible to pick up speed for a soft landing on foot.
> Try to AVOID terrain that does NOT allow you to escape in free (= safe) airspace from a proximity flight (e.g. a deep valley, a gorge, a creek etc.)
> If you want to fly a double proximity line (e.g. deep gorge) make sure you approach with overspeed before you dive in and make POSITIVELY sure that it STEEPENS more than your current glideangle in order to be able to exit safely.
> Consider that headwinds might increase as you get lower (e.g. valley winds) or might be accelerated through a valley or due to other terrain features in a lower part of your run = always calculate with the possibility of a drastically reduced glideangle due to a headwind
> If you are on a personal "on sight" (no prerun) first descent in terrain that is flatter then 30 to 35 degrees in average (comfortably flyable with fun wingover turns with a wing with at least an 1:3 glide angle) at least TRY ,-) to play it safe and keep 50m distance from the terrain surface in the more shallow parts for your first run until you get a good picture of the real thing
digital satellite maps (google earth) dont tell every terrain elevation in detail and in a worst case ( e.g. high trees combined with a flat part in the terrain) might be totally inaccurate.
Also consider the possibility of sinking air or a headwind which both will drastically reduce your real world glide and plan for some reserve in Glide (25% is a good starting point)
- ATTENTION if you fly over terrain with trees then the TREETOPS are your reference surface. NOT the ground - so ANY map or digital elevation data WILL BE INCORRECT up to +/- 30 - 50m (depending on vegetation height of corse)
> Avoid the deadmans curve of speedflying, which means that you can easily end up in a situation where you have so little glide left that you need to flare in order to hold the distance to the terrain, as a result you will loose more speed and you will looose more glide until the point your wing starts to go partly parachutal and will sink out even more until you will crash with at least 25 to 50 kph forward and considerable downward speed WITHOUT any chance for an impact softening flare ...ouch.
> Dont trust maps or pictures (google earth etc.) of your landing zone - ALWAYS inspect your landing zone in person, it might look like a smooth field of grass on a picture or from 50m away, it might even be used by local paragliding pilots as their landing field of choice, BUT it could still hold very nasty surprizes for a fast approaching speedflyer pilot like big hidden rocks, big holes, fallen trees, treestumps or branches hidden in the seemingly smooth grassy field
> Watch out for Lee generating obstacles / terrain features near your landing area and avoid those lee zones as best as you can.
These have been just a few of the important factors to consider, your choosen run might have hidden danger spots like hardly visible high trees, cables from logging operations or other nasty stuff waiting to snag you - so always (if possible) hike up or at least do a pre-run with a safe distance to the ground to familiarize yourself with any new run.
Have Fun !
Paul