Safety Notices

The small quick link (copy of a maillon-rapide) securing the lines to the risers on a Paramania glider failed during the test flight of a new wing.

The wing was produced at the Gin factory, so a number of different brands could be affected. (Gin gliders appear to use the real deal)

Do check that your are stamped or engraved with the EN number.

http://paramotorcentral.org/viewtopic.php?f=7&t=31947&p=36703

This winter I saw another glider stall in big ears and analysed an accident where that was the likely cause. That makes 3 I've seen and several more I've heard about. All on modern, sensible gliders in good condition. In the last two the pilots were badly hurt.

The problem is that in big ears you have about normal forward speed and plenty more downward speed (a much reduced glide angle). As paragiders maintain normal attitude in big ears, the result is a significant increase of angle of attack. The result of that is it doesn't take much for the glider to stall; a bit of turblence, a shear layer, brake, some rain, line skrinkage or cell stretch could all do the trick.

Current advice is that big ears should be immedialty and smoothly followed by application of full speed bar to get the angle of attack somewhere sensible again.

I suggest that big ears + bar should only ever be used when actually necessary and I can only think of two possible scenarios:

1. If you're in a cloud, or have made a mistake and are about to enter, and are following a compass bearing to escape in the right direction (without a compass you might just go round and round or hit something).

2. Possibly when bottom landing in wind much more than trim speed to avoid landing going backwards, thus gaining speed with extra collapse resistance. But entering a slower and/or turbulent boundry layer near the ground is one of the causes of big-ear stalling. I'd favour just enough speed bar and rear riser control if it's bumpy.

Clearly, both of these scenarios are to be avoided in the first place.

I think any other situation is better handled with speed bar, spiral dive or just patience. B-line is solely for if you're in a cloud and have forgotten the compass.

From Dave's fine website, http://notaminfo.com/ukmap & our NOTAMS page:

H1193/11: Air display will take place
Q) EGTT/QWALW/IV/M/W/000/025/5051N00033E002
AIR DISPLAY/AEROBATICS WI 2NM 5051N 00033E (MARINA PAVILLION, STLEONARDS ON SEA) 11-04-0131/AS 2.
LOWER: Surface, UPPER: 2,500 Feet AMSL
FROM: 23 Apr 2011 14:00 GMT (15:00 BST) TO: 23 Apr 2011 17:00 GMT (18:00 BST)

The turbulent days of spring will be with us imminently; we have already had a few good thermalling days and February has barely started.

The rougher air may encourage less well informed pilots to change their chest/waist strap setting. Before doing so, you must be aware of the effects of the riser separation:

Too wide and although you will have good feedback and weightshift authority, this may become wearing. You will also experience increased spiral stability (the tendency to stay spiralling - not a good thing) and within a range of deflations you will get tilted more aggresively. This tilting can result in line twists.

Too narrow and you will not get enough feedback to tell you when to land, you are also more likely to suffer deflations and more likely to suffer line twists.
Every glider has a designed chest/waist strap setting which will optimise perofrmance and safety. Use it! If in doubt of the setting for your wing, RTFM.

The pilot's moment of inertia will also affect the likelihood of line twists. If you fly very upright, with your feet down, 'the old man position' you will exhibit pretty much your lowest possible moment of inertia and would be unlikely to get line twists. If you fly very supine &/or with your feet out as if in a stirrup or pod, then you exhibit a high moment of inertia. This is not all bad, but it can complicate the handling of big deflations. It is far simpler, whenever you feel a deflation is likely, to lower your feet and maybe also sit up. This has the added benefit of making most harnesses less rigidly cross braced and so more likely to ride out the rough air.

If it's rough and you are near the ground, say 100', you should go into the PLF position. You may not think it looks cool, but walking away from a 60% deflation and subsequent crash looks a whole lot cooler than the alternative. In which regard, the next time you are on the hill waiting for conditions, why not have a PLF practice session. It'll definitely be a good laugh, because most pilots are hopeless at them!

If you find you have a big deflation when fully supine, initially roll with it and bring your legs down slowly. What you don't want to do is find yourself rotating and then quickly lower you're legs as that will cause the rotation to accelerate.

In my experience, line twists are usually caused not on any initial deflation, but occur when the initial deflation recovers fast and the canopy violently rotates in the opposite direction. This is when you want your moment of inertia to be as low as possible.

Don't forget your sunscreen, I managed to get sunburnt on Tuesday!

TTFN
Steve Purdie