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Air Safety Institute Safety Spotlight

The impossible turn

It's the stuff of nightmares. You launch uneventfully, engine roaring at full power during the initial climb. Everything seems fine until you reach 500 feet agl, and then-silence. The engine quits.

With back-pressure and right rudder from the climb still applied, the aircraft quickly decelerates toward an uncoordinated stall. You correct just in time, pitching down for best glide. The windscreen fills with rapidly approaching terrain. Behind you lies a mile of smooth, level pavement, beckoning like a siren's song. Your mind races. The call grows louder. Slamming the yoke hard left you succumb and begin the "impossible turn."

On October 28, 2006, a Vans RV-6 experienced a loss of engine power on climbout from Turlock Municipal Airport in Turlock, California. While the pilot was maneuvering in an attempt to return to the runway, the aircraft stalled and struck the ground. The pilot and a passenger were seriously injured.

The aircraft took off from Runway 30 at 4 p.m. for a local VFR flight. The pilot configured the airplane for the initial climb. After reaching about 500 feet agl, the engine lost power and the airspeed dropped. The pilot began a turn back toward the runway. The airplane stalled, and the pilot attempted to recover. The airplane entered a secondary stall, descended rapidly, and crashed. A post-accident examination of the engine revealed spark plug fouling and other factors that contributed to the loss of engine power. The NTSB cited broken piston rings as the cause of the mechanical failure. The crash was attributed to the pilot's failure to maintain adequate airspeed while maneuvering for a forced landing, which resulted in a stall.

The return-to-airport maneuver has been labeled the "impossible turn" with good reason: It requires substantial altitude and involves aggressive maneuvering. Taken by surprise, pilots often fail to maintain airspeed and end up having stall/spin accidents. For a gliding aircraft attempting to maintain airspeed, any banking of the wing will increase the sink rate. Meanwhile, stall speed increases with angle of bank. For a crippled airplane already flying low and slow, this combination of lost altitude and rising stall speed can quickly turn a bad situation into a tragic one.

Unless the airplane is close to pattern altitude, or the pilot has already started a turn when the engine fails, it's generally safer to land within the area visible out the windscreen. Maintaining control of the airplane all the way to the ground, even if landing off airport, greatly increases the chances of walking away from a mishap.

The accident pilot and his passenger were very fortunate to survive this crash. With the benefit of hindsight, the pilot told the NTSB that the accident "could have been prevented if he had more engine-out practice." Words of wisdom for us all. For more information, take the AOPA Air Safety Foundation's online course Essential Aerodynamics: Stalls, Spins, and Safety (www.asf.org/aerodynamics).

An aviation technical writer with the AOPA Air Safety Foundation, Carl Peterson creates interactive courses and other safety education materials for the aviation community. He has been flying since 1989.

By Carl Peterson

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