Prevent Structural Damage

Beware of the yellow arc during the descent phase of flight.

Tip Overspeed

Tip Overspeed

In March 2011 a pilot flying a Beechcraft B35 Bonanza near Whidbey Island, Washington, heard strange noises that he described as thumps coming from his airplane as he maneuvered to avoid a restricted area. The pilot reported that his airspeed was 165 knots, which is in the yellow arc of the airspeed indicator. Once on the ground, the pilot found several wrinkles and tears in the fuselage skin in the aft portion of the airframe.

Damage can occur to airplane structures any time you apply abrupt control inputs beyond maneuvering speed. The abrupt movements apply loads that can stress the materials beyond their structural integrity limits. It is always recommended to fly below the published maneuvering speed while flying in the mountains since there is a potential for abrupt maneuvers and unexpected turbulence. Damage is even more likely to happen if you get into the yellow arc on the airspeed indicator.

While using abrupt maneuvers to avoid traffic, an unexpected obstacle or an airspace boundary is one way to overstress the airframe, it can be damaged even without any control inputs. The loads put on the airplane's structures during turbulence can be just as damaging at certain speeds.

Always keep a close and critical eye on the instruments to make sure the airplane is doing what you expect it to do and that you don't put the airplane in a compromised position. If you are flying an airplane equipped with an autopilot and are using the vertical speed mode, it is really easy to overspeed the airplane if you don't pay attention. While flying in the yellow arc in smooth conditions is fine, you should never allow the speed to creep into the yellow when there is turbulence.

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