Policy Analysis: Is this really necessary?

By way of review, in a conventional twin with wing-mounted engines, a loss of thrust on one side yaws the airplane toward the faltering powerplant. That creates an airspeed differential, with the wing to the outside of the turn moving faster than that on the inside. The resulting difference in lift is amplified by the additional airflow produced by the good engine causing the airplane to roll over toward the failed engine—particularly if that prop is left windmilling rather than being feathered. Preventing the so-called VMC roll requires adequate rudder authority to counter the yaw, which means sufficient airspeed. This is one reason (preserving altitude is another) that most engine-out training focuses on maintaining airspeed at or above that which gives the best rate of climb (or slowest descent) on one engine, labeled V_YSE.

The conspicuous exception is the so-called V_MC demonstration required on the multiengine checkride. With the critical engine (the one whose failure most adversely affects aircraft performance) at idle and the other at maximum thrust, the pilot gradually raises the nose, bleeding off airspeed at about one knot per second, until full rudder deflection can no longer maintain directional control (or initial indications of a stall, whichever comes first). Recovery involves simultaneously reducing thrust and angle of attack until V_YSE is regained, then restoring power. Done skillfully, it’s a slow and controlled maneuver, tiptoeing to the edge of controllability without tipping over.

Done skillfully, the V_MC demonstration is a controlled maneuver, tiptoeing to the edge of controllability without tipping over.But attaining that skill requires practice, during which mistakes must be expected. Instructors’ options for managing the consequent risk of entering unusual attitudes in nonaerobatic airplanes include requiring generous altitude buffers and guarding the controls with the intensity characteristic of helicopter CFIs teaching autorotations. (Upset recovery training also helps.) It’s fair to ask, however, whether the stated objective of determining “that the applicant exhibits satisfactory knowledge, risk management, and skills associated with a V_MC demonstration” justifies repeatedly putting airplanes and aviators into a situation intrinsically more hazardous than most training exercises.

It’s fair to ask whether the stated objective of the test warrants putting airplanes and aviators into a hazardous situation.Over the years, the FAA has repeatedly refined its test standards in an effort to balance long-term safety benefits with training risks. Spin demonstrations were dropped in favor of spin awareness and avoidance; slow flight was redefined to reduce unintended stalls; and a minimum 400-foot altitude was instituted for simulating engine failures during climbout in twins. Would “awareness and avoidance” of the dangers of V_MC likewise be preferable to actual demonstrations? The record of multiengine training accidents—in which unrecovered spins figure far more prominently than in personal or business accidents—suggests it could be worth considering. 

David Jack Kenny is a freelance aviation writer and statistician.