Learning Experiences: 08/06


Running Out Of Rudder

When I was a Flight Instructor, one of the pieces of trivia we dispensed to students was that Maximum Demonstrated Crosswind isnt necessarily the absolute maximum crosswind you can land in. It merely represents the crosswind the test pilot landed in safely during certification of the aircraft. (Hence the word demonstrated.) Its not necessarily an upper limit. But theres an important detail I recently learned.

In my baby pilot days, I was terrified of crosswind landings because no one had taught me how to use rudder properly. (Its impractical, but everyone should learn to land in taildraggers first.) But one day it clicked. Now as an old pilot, I enjoy landing in strong crosswinds. Its fun, and a diversion from normal landings. (Thats after 7000 hours of landings.)

When I was instructing, I would occasionally take a 152 up for touch-and-goes when the winds were too challenging for students. We often get a strong, steady 30-knot wind from the north here. With this wind, tower has us land to the east on our east/west runway. (Maybe they know something we dont?)

After an exciting takeoff-I was bolder back then-I learned a 152 cannot be landed in a 30-knot crosswind. You run out of rudder. I had to keep going around until the wind subsided to 25. Then I was able to land.

Now that Im flying a Glasair, Ive found that I can land in that 30-knot crosswind. So, when the ASOS at St. Johns reported the winds out of 210, gusting to about 30, instead of landing into the wind on Runway 21, I chose a crosswind landing on 14. (The fuel guy wanted to go home, and 14 was a closer entry.)

No problem, I thought. This will be fun. No one ever told me that theres a difference between the maximum crosswind capability for a left crosswind verses a right crosswind in a single-engine airplane.

Im not sure why this is-I doubt its P factor, since the engine isnt making much power in the landing. I doubt its slipstream effect, since the wind blows prop wash away. Perhaps its the way the rudder hinges on the Glasair. Air may stall at the hinge line (on the right) when the rudder is deflected fully left.

At one point or another, this phenomenon can be hotly debated in various locations on the Internet. Whatever the reason, I ran out of left rudder and couldnt land the plane. When a sideslip didnt work, I tried more power and kicking the plane around, but there still wasnt enough rudder. I even touched down crooked on the wide runway, but it was impossible to keep from weathervaning at speed. In a twin, I could have used asymmetric thrust.Instead, I made the fuel guy wait while I went around and landed on 21.

So I learned something new. Now I have two numbers listed for our airplanes maximum crosswind limit: 30 knots for a left crosswind; 25 for one from the right. You might want to consider this if ever you push the crosswind envelope of your plane.


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