Tom Clements’ article in the July issue titled, “Practice Demonstration of VMCA” was a missed opportunity to clarify that just because a manufacturer has an Aircraft Flight Manual (AFM) “approved procedure” doesn’t mean it is always a good idea to follow same.
The procedure as presented in the article and AFM is in conflict with both the AFM’s information on the purpose of VSSE and various communiqués issued over the years about the hazards of single engine operations and training related to single engine stall-spin accidents in multi-engine airplanes. As stated by the AFM regarding VSSE: “Intentional failing of one engine below this speed is not recommended.” Note that this statement does not excuse purposefully rendered (or simulated) inoperative for training. Whether due to loss of rudder effectiveness OR wing stall, SE operations below VSSE has the potential for drastic rolling/wing drop components from which recovery could be impossible.
There is NEVER a pilot training nor real-life requirement (beyond certification flight testing) to duplicate nor “check” what any multi-engine aircraft’s actual AFM indicated VMCA (Red Radial Line) might be.
Instead, the sole purpose of VMC pilot training and demonstration should be to reinforce the pilot’s need to maintain directional control (HDG) in split power conditions, at all costs, primarily with use of rudder AND if/when adequate control cannot be maintained or is in doubt (for any reason known or unknown), reduction of power on all engines (toward idle) must be the first response to loss of HDG control (i.e., decrease or eliminate asymmetric thrust causing directional control problem) while then increasing airspeed (for added rudder effectiveness) with maximum application of all available rudder and flight control inputs required.
Pilot training of VMC is ONLY about control, not about performance to be obtained (max climb or min descent) during SE operations. VMC inflight training is NEVER about the Red Radial Line, it is only about maintaining directional control and the potential for loss of control in asymmetric power situations, especially with loss of airspeed. The loss of any airspeed results in reduced rudder effectiveness AND nearing loss of control potential when near and below VSSE, due to loss of margins for adequate rudder control and/or stall-spin prevention.
VMC training is about avoiding any SE operations with asymmetric thrust below VSSE and/or if control cannot be maintained at ANY SPEED, in order to avoid SE loss of control and SE stall-spin situations all together, reduce asymmetric thrust and AOA to increase control effectiveness until above VSSE. In reality, NO intentional or unintentional single engine operations should be conducted below VSSE.
If more pilots were taught the emphasis of reducing power when below VYSE and accelerating toward VSSE when directional control is in doubt (well before published VMC), there could be far fewer SE rollover accidents (i.e., right side up even off airport is better than an upside-down crash anywhere). Review King Air loss of directional control accidents (ADS & ICT, etc.) and know that an early reduction in asymmetric thrust (no matter the reasons encountered) could have completely changed the outcomes.
Please rethink “Loss of Directional Control” inflight single engine training and all SE operations …
Sincerely,
Kevin P. Hynes