Cross wind landing techniques
Posted: Wed Nov 02, 2011 12:00 pm
I have been reading a bit about causes of aviation accidents and also about gyro specific accidents lately. Obviously human error is on top of the list and I include wire strikes and CFIT under this, even though in some instances this might not be the case. The three other major factors are blade flap, loss of rotor RPM in flight (a scary prospect that I would like to discuss and get some advice on later) and wind, mostly on landing. I see in a lot of accident reports things like “a sudden downdraft”, “a sudden gust of wind”, “loss of directional control”, etc, etc. Are we as gyro pilots so spoiled by these magic wind resistant machines of ours that we sometimes neglect to assess the full possible effect of the wind, especially on take-off and landing? Do we really anticipate the downdraft of the wind coming over the hanger, or the lack of lift as we decent behind the trees, or the “sudden gust” as we come out behind the hanger into the open?
Something that I have learned from an experienced flying buddy of mine is his constant awareness of the wind direction and affect, knowing when to expect lift and downdrafts as well as preferred landing direction in case of an emergency. Another interesting principle that he applies, not sure if all chopper pilots do this, is flying 500ft AGL against the wind and 700ft AGL downwind. Do we as gyro pilots consider this wind effect when flying at tree top or at 300ft and what difference the wind direction will make to an emergency situation, our glide ratio, our landing roll, loss of altitude to turn into the wind to land or does wind direction only mean a lekka tail wind or @#%& head wind for us on cross country trips.
Actually the amount of wind related gyro incidents should not be surprising. We fly in high wind when a lot of fellow aviators might choose to keep their aircrafts in the hangers and we land at low or zero speed when we might be at the greatest risk, to all the above mentioned factors, without or with limited rudder authority.
How do we avoid these incidents? Obviously we need to be aware and anticipate the above mentioned wind affects but also with good cross wind landing technique. But what is the best cross wind landing technique?
I hear guys saying that doesn’t matter how big the cross wind component you land as per normal, obviously with your rotor into the wind to track centre line and with rudder input to keep you straight. This way you know how much control & rudder input is needed to maintain centre line. You will lose most off or all rudder authority just before touchdown and stand the risk of being turned sideways, but this will not matter as your speed is at zero.
Others promote the crab approach to maintain centre line and to pull the gyro straight with rudder input just before touchdown. The risk here is getting the timing and amount of input right as you almost only have one chance. Rudder input too early and you will drift from centre line and need to correct with stick input. Too late, too much or too little input and you might touchdown sideways. Again they say this should not matter as your speed should be at zero.
But what if you don’t get it 100% right and your speed is not zero?
Others promote coming in faster and with more power than normal and touch down faster and not to attempt a zero speed touchdown. This way you always have rudder authority, even after touchdown and will be assured of a straight landing. I suppose this fits with Jim Davis’s theory that in some circumstances you can attempt a greaser of a landing and in others it is better to “plunk” her down on the runway as quick as possible. The only risk here with forward speed and with an angled nose wheel (to adjust the rudder) at touchdown, is keeping your nose wheel of the ground for as long as possible or to straighten it as quick as possible.
Others say come in with more power than normal and it is safe to do a zero speed touchdown.
The other day I also heard someone saying you must come in higher than normal and dive onto centerline as it is easier to dive onto centerline than try and maintain it during normal approach in cross winds. I must admit, I haven’t tried this one yet.
Hopefully the experienced pilots and instructors can help me out here. What technique do you guys prefer and teach your students?
Just for interest, does everyone have a favorite cross wind direction preference and do you choose your landing direction accordingly. Some might prefer the wind coming from the left to push the stick left against the wind and apply right rudder as per usual take-off procedure (my preference) and others might prefer pulling the stick right into the wind and applying left rudder. Do you consider this on a full cross wind landing if any runway direction will suffice?
Something that I have learned from an experienced flying buddy of mine is his constant awareness of the wind direction and affect, knowing when to expect lift and downdrafts as well as preferred landing direction in case of an emergency. Another interesting principle that he applies, not sure if all chopper pilots do this, is flying 500ft AGL against the wind and 700ft AGL downwind. Do we as gyro pilots consider this wind effect when flying at tree top or at 300ft and what difference the wind direction will make to an emergency situation, our glide ratio, our landing roll, loss of altitude to turn into the wind to land or does wind direction only mean a lekka tail wind or @#%& head wind for us on cross country trips.
Actually the amount of wind related gyro incidents should not be surprising. We fly in high wind when a lot of fellow aviators might choose to keep their aircrafts in the hangers and we land at low or zero speed when we might be at the greatest risk, to all the above mentioned factors, without or with limited rudder authority.
How do we avoid these incidents? Obviously we need to be aware and anticipate the above mentioned wind affects but also with good cross wind landing technique. But what is the best cross wind landing technique?
I hear guys saying that doesn’t matter how big the cross wind component you land as per normal, obviously with your rotor into the wind to track centre line and with rudder input to keep you straight. This way you know how much control & rudder input is needed to maintain centre line. You will lose most off or all rudder authority just before touchdown and stand the risk of being turned sideways, but this will not matter as your speed is at zero.
Others promote the crab approach to maintain centre line and to pull the gyro straight with rudder input just before touchdown. The risk here is getting the timing and amount of input right as you almost only have one chance. Rudder input too early and you will drift from centre line and need to correct with stick input. Too late, too much or too little input and you might touchdown sideways. Again they say this should not matter as your speed should be at zero.
But what if you don’t get it 100% right and your speed is not zero?
Others promote coming in faster and with more power than normal and touch down faster and not to attempt a zero speed touchdown. This way you always have rudder authority, even after touchdown and will be assured of a straight landing. I suppose this fits with Jim Davis’s theory that in some circumstances you can attempt a greaser of a landing and in others it is better to “plunk” her down on the runway as quick as possible. The only risk here with forward speed and with an angled nose wheel (to adjust the rudder) at touchdown, is keeping your nose wheel of the ground for as long as possible or to straighten it as quick as possible.
Others say come in with more power than normal and it is safe to do a zero speed touchdown.
The other day I also heard someone saying you must come in higher than normal and dive onto centerline as it is easier to dive onto centerline than try and maintain it during normal approach in cross winds. I must admit, I haven’t tried this one yet.
Hopefully the experienced pilots and instructors can help me out here. What technique do you guys prefer and teach your students?
Just for interest, does everyone have a favorite cross wind direction preference and do you choose your landing direction accordingly. Some might prefer the wind coming from the left to push the stick left against the wind and apply right rudder as per usual take-off procedure (my preference) and others might prefer pulling the stick right into the wind and applying left rudder. Do you consider this on a full cross wind landing if any runway direction will suffice?
