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Propellers have not changed much over time – feathering can be a matter of life or death.
low pitch (not feathered) setting. The crash occurred 0.6 miles west of the approach end of the runway.
Very few multi-engine aircraft can maintain altitude with an engine inop- erative, gear down and flaps fully ex- tended. Feathering the propeller on the inoperative engine is also paramount to aircraft performance on a propeller- driven aircraft. In the mental fog that accompanied the mechanical malfunc- tion, the pilot failed to account for the drag that the aircraft was encountering as a result of its configuration. Con- trols in the aircraft allowed a quick remedy for gear, flaps and propeller settings – and would have substantially increased performance, allowing the remaining 310-horsepower engine to complete the emergency landing.
As airspeed decayed below Vmc, a pronounced roll into the failed engine would have inevitably developed. The ailerons do not have the control author- ity to manage this at slow airspeeds, requiring an increasing amount of rudder to counter the roll. The rud- der shouts at the pilot to lower the nose, reconfigure and climb away – or lower the nose and crash right-side-up if no better option is available. Yet all too often, the pilot, oblivious to the information being conveyed by the rudder, keeps increasing the elevator until the roll becomes a Vmc spin. Too many pilots have succumbed to Vmc rolls throughout the history of multi- engine flight. The results are nearly always fatal.
The rudder can be confounding and is likely the most overlooked device on an airframe. Its importance is integral to pilot proficiency, but it is also in danger of being overstated. In one of those little contradictions common to life, the proper approach is to know your rudder well – just try not to use it too much.
(g-forces) as opposed to pitch or bank angles. Pilots perceived the imme- diate need to intervene at pitch and bank angles substantially less than the “unusual attitude” definition of 25-degrees nose up, 10-degrees nose down, or 45-degrees of bank.
While preventative awareness of pitch and bank is commendable, ag- gressive reactions are generally un- necessary. A benign atmospheric force (or wake turbulence) often disturbs a flight only momentarily. Passenger aircraft are almost uniformly designed to be stable so that a disturbance will automatically result in a restorative force. Sudden g-forces can create the dreaded startle response, which routinely produces inappropriate reactions to otherwise mild upsets. One-sixth of pilots admitted to inap- propriately over-controlling or mak- ing inputs in the wrong direction in response to sudden stimuli. Pitch ex- cursions based on improper pilot input were rare (likely due to the kinesthetic of g-force feedback). Inappropriate roll commands were more likely. The rud- der was the greatest offender.
Troublingly, many of the erroneous rudder inputs were calculated to have exceeded certification criteria. While none of them exceeded the ultimate structural load limits, they nonethe- less transgressed the margin of safety built into the certification process. The reality of this was reinforced by a companion simulator study that revealed the tendency for pilots to over-control the rudder (exposing the
8 • TWIN & TURBINE / February 2021
vertical stabilizer to large g-forces) with the ham-fisted application of rudder inputs. Each type of aircraft is unique, and it is incumbent on pilots (and training programs) to de- velop type-specific techniques ap- propriate for the particular airframe. In general, modern swept-wing air- craft (those with active yaw damp- ers) do not require much rudder input outside of asymmetric thrust or cross- wind conditions.
“Between 1994 and 2003 there were [multiple aircraft] accidents across the globe which resulted in more than 2,100 fatalities – all the result of air- craft upsets.” – FAA “Perspectives of Directional Control Events”
From the NTSB Database
Overusing the rudder can have dev- astating consequences, yet it is also dangerous to ignore it. The rudder conveys important information to a pilot, and proficiency in interpreting that information can be indispensable to successfully resolving an in-flight disturbance. An overemphasis on rud- der use is uncalled for, but the failure to develop proficiency on it can be reckless.
The crash of a Cessna 414A in pictur- esque Kahului, Hawaii, had (as most accidents do) many factors. The Part 91 aircraft was carrying three occupants, all of whom died. The left engine failed for undetermined reasons while the aircraft was preparing for landing. The recovered aircraft was configured with the flaps fully extended and the gear down. Both propellers were found in a
Stan Dunn is an airline captain and check airman. He has 7,000 hours in turbine powered aircraft, with type ratings in the BE-1900, EMB-120, EMB- 145, ERJ-170, and ERJ-190. Stan has been a professional pilot for 14 years, and has been flying for two decades. You can contact Stan at Stan@fly- ingformoney.com.