plane. This wake can prove troublesome if air- 
planes taking off and landing are not provided 
adequate separation. The rolled-up vortex 
sheet will be strongest when the preceding air- 
planes is large, high gross weight, and operat- 
ing at high lift coefhcients. At times this tur- 
bulence may be falsely attributed to propwash 
or jetwash. 
383