Thursday, March 8, 2007

Remember the projectile enrichment tutorial Mr Koh gave us, the one where we were asked to read up on relative velocity? You would have noticed the part in the textbook regarding winds blowing aircraft off-course, and the pilot having to turn into the wind to correct for the drift. So here are 2 videos, to show just how much trouble these nasty winds can cause.

Video 1: Boeing's Crosswind Landing Flight Tests (B777-200, B747SP, B777-300) The jets here are being tested to see how they respond to landing with severe crosswinds (the winds are 60 knots, gusting to 70), so no passengers.



Video 2: A JAL flight landing in the now closed Hong Kong Kai Tak airport, with a crosswind gusting across the runway, with passengers.



The approach to Kai Tak is a very strange one, because of the mountains around the airport, the pilots have to manually turn the plane to line up with runway 13. Normally, the pilots can simply tune the radios to receive the appropriate signals and the plane will line up with the runway right in front of them. The radios provide vertical navigation too to guide the planes down safely. But for Kai Tak, there is no runway in sight. Instead, there is a red and white checkerboard where the runway is supposed to be. The captain hand flies the plane in, turning using the approach lights mounted on the ground as a reference. This is called the IGS or checkerboard approach, so no Autopilot can do this. This is why you see the flight in the video turn suddenly, it is not a case of pilot forgetting to read his instruments. By the way, winds around mountains are generally strong very turbulent and unfortunately, not really predictable.. and they have caused a few problems to flight crews.

Enjoy the videos!

Yong Lin

-posted by 07S6K at 8:46 PM