** Out-of-balance tires can shake an airplane
on takeoff, causing some pilots to fear
pre-stall buffets.**
Have you ever advanced the power, gathered momentum on the runway and pulled back on the yoke or stick at the appropriate airspeed – only to be greeted by a shaking in the controls as you lift off that makes your mind start thinking about pre-stall buffets, your uncomfortably high angle of attack and proximity to the trees?
Since Part 23 airplanes aren’t typically equipped with angle-of-attack indicators, all we have to judge our margin above stall is the airspeed indicator and control feel. But, honestly, when was the last time you had your airspeed indicator calibrated? And are you really certain about your current weight, or whether you cleared all the frost off the wing?
If your airspeed is increasing and you’re climbing nicely out of ground effect, chances are the vibration you feel through the yoke isn’t a stall buffet at all -- rather, it’s probably caused by your slightly out-of-balance tires shaking the airframe as they leave terra firma and keep right on spinning. The remedy, of course, is to briefly step on the brakes to stop them. This is the recommended procedure immediately after takeoff in some retractable gear airplanes.
Still, it’s always a good idea to know your takeoff weight, density altitude and whether your airspeed indicator is reading accurately. That way you won’t be second guessing yourself during a critical phase of flight. And for extra peace of mind, an AOA indicator is an excellent investment.
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