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Wind Gradient - Nasty!

04/02/2007

Permalink 20:30:00, by admin, 359 words   English (ZA)
Categories: student, twin astir, take offs & landings, thermaling & soaring

Today was my first full day of winch duty. I was pre-warned that this would be a very boring and lonely duty as one sat alone at the opposite end of the airfield with your only visitor being the guy who would come retrieve the cable after each launch.

I packed in a good book, some sandwiches, water and my trusty Canon and was ready for the day. The winch launching went well and I received two compliments. After eight launches it was about 2pm and I was called for my flight of the day.

Winch Duty

As things turned out the weather had improved greatly by then; the previous longest flight was 15 minutes and I was up for 46 minutes, only to return on command from the instructor F(5) as others still wanted to fly.

The instructor complimented me on my good launch which was very nice, especially considering the 50º fresh cross wind. The thermals were very broken, but strong enough in places to get us to 2000 ft. The landing was however another story.

My previous experiences with 26L have not been good, especially when the wind is blowing. Normally the instructor tells me to come in high with a VERY short final approach. That way we dive onto the runway at speed.

This time it was a long final, I kept the speed at 120 km/h to make provision for the wind gradient that I knew was coming. Only problem was, I didn’t expect it to be quite so severe. As we hit the gradient it felt as if the plane suddenly dropped a few metres and the nose pitched down. I got a big fright and immediately closed the brakes, the plane ballooned and with the help of the instructor I flared and landed.

Later he explained that what I had felt was not the plane dropping, but a sudden deceleration from 120 km/h to 100 km/h. So I should just kept on going and not adjusted the brakes as 100 km/h was still fine. Makes sense now, but at the time it felt very uncomfortable. So that’s another lesson learned. Total cost for the day: 117,80ZAR.