Friday, November 27, 2009
Monday, November 9, 2009
The wind
Thanks to TS/H Ida, it has been a bit windy of late for this part of the world. I have seen quite a few pilots struggle with landings in strong winds, gusty winds, and cross-winds. I have also heard quite a few mis-conceptions about technique. This seems an opportune time to review high wind and gusty wind landing recommendations.
It is important to remember that the airplane does not know it is in windy conditions. It only knows what the airspeed going past the wings and control surfaces is. It has no idea that when it is 20 feet over the runway at 60 knots that the ground is only moving by at 35 knots due to a headwind - but your eyes and brain sure do!
Many pilots believe it is necessary to carry excessive speed into their landings due to higher than normal wind conditions. Combined with a cross-wind this can lead to control problems as noted in the Airplane Flying Handbook in part:
"• airspeed on touchdown.
• Failure to apply appropriate flight control inputs
during rollout.
• Failure to maintain direction control on rollout.
• Excessive braking."
During gusty conditions, a SLIGHT, increase in airspeed may be helpful for maintaining control. From the AFH: "One procedure is to use the normal approach speed
plus one-half of the wind gust factors. If the normal
speed is 70 knots, and the wind gusts increase 15 knots,
airspeed of 77 knots is appropriate. In any case, the airspeed
and the amount of flaps should be as the airplane
manufacturer recommends."
Keep in mind the airplane will not land until the airspeed is at or near stall speed. Also remember to hold the nose wheel slightly off the runway until you no longer can hold it off. This increases directional control, prevents wheel-barrowing and loss of directional control, and enhances aerodynamic braking.
For further reading, here is a link to the appropriate section of the AFH: http://www.faa.gov/library/manuals/aircraft/airplane_handbook/media/faa-h-8083-3a-4of7.pdf
TakeFlight!
Paul
It is important to remember that the airplane does not know it is in windy conditions. It only knows what the airspeed going past the wings and control surfaces is. It has no idea that when it is 20 feet over the runway at 60 knots that the ground is only moving by at 35 knots due to a headwind - but your eyes and brain sure do!
Many pilots believe it is necessary to carry excessive speed into their landings due to higher than normal wind conditions. Combined with a cross-wind this can lead to control problems as noted in the Airplane Flying Handbook in part:
"• airspeed on touchdown.
• Failure to apply appropriate flight control inputs
during rollout.
• Failure to maintain direction control on rollout.
• Excessive braking."
During gusty conditions, a SLIGHT, increase in airspeed may be helpful for maintaining control. From the AFH: "One procedure is to use the normal approach speed
plus one-half of the wind gust factors. If the normal
speed is 70 knots, and the wind gusts increase 15 knots,
airspeed of 77 knots is appropriate. In any case, the airspeed
and the amount of flaps should be as the airplane
manufacturer recommends."
Keep in mind the airplane will not land until the airspeed is at or near stall speed. Also remember to hold the nose wheel slightly off the runway until you no longer can hold it off. This increases directional control, prevents wheel-barrowing and loss of directional control, and enhances aerodynamic braking.
For further reading, here is a link to the appropriate section of the AFH: http://www.faa.gov/library/manuals/aircraft/airplane_handbook/media/faa-h-8083-3a-4of7.pdf
TakeFlight!
Paul
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