Inadvertent IMC


   178 Seconds to Live and Peripheral Vision  
A Stable System of Accidents
The safety trends in General Aviation may be described as a stable system of accidents over the last ten years, reference the AOPA/Nall Report.

Stable vs Unstable
Dr. W. Edwards Deming states in his book, Out of The Crisis, when describing a stable system, "It means that there is stable system of production of defective items. Any substantial improvement must come from action on the system, the responsibility of management. Wishing and pleading and begging the workers to do better was totally futile." We must change the way we are training pilots in General Aviation if we are to lower the overall accident rate or to eradicate specific accidents.

When I retired from airline flying three years ago, it was my intent to focus on training private instrument pilots with high performance aircraft. With an Elite flight simulator I'd hoped to establish a system of training, checks, and continual training to reduce the incidence of light aircraft accidents flying in IMC in North Carolina.

IMC Safe Flight


Early in this work I was approached by the State of North Caroline Aviation Department to develop an escape maneuver for private pilots without instrument rating who inadvertently fly into IMC. With the use of both The Instrument Flight Manual and the book A Pilot Guide to Safe Flying, I now have developed what I have used for three years: a standup briefing and flight training in my simulator where we fly for about 15 minutes of simulator orientation without peripheral vision, then I have the pilot fly the escape maneuver in IMC condition. All pilots have been able to perform the 180 degree turn at level flight, descend 500 feet, climb 500 feet and descend and turn again to a lower altitude. All pilots fly for more than six minutes, which is double the 178 seconds, all without peripheral vision and in a total time of 25 to 35 minutes of flight training.

To accomplish this, I have the pilot role wings level with the turn coordinator, find level fight by stopping the altimeter by placing the center dot of the attitude indicator on the horizon, and then check the vertical speed indicator and trim. The throttle is then moved to place the rpm needle in the middle of the green arc on a fixed pitch prop, or approximately 21" of manifold pressure and rpm's in the mid-green range on consent speed props, then make note of your heading.

In this escape maneuver the intent is to turn 180 degrees to fly back to visual condition. The aim is to do it in one minute at a bank angle not more than 20 degrees. With most light aircraft when the power is set to a mid range, you should have an airspeed very close to maneuvering speed. Then the turn coordinator or turn and slip indicator will give the untrained instrument pilot the best chance to control the bank of the aircraft at any speed he or she finds themselves.

It is the inability of the pilot to control bank that is the number one problem at this point. Attitude indictors have been installed in light aircraft since the late '40s and the problem of spacial disorientation persists today with modern attitude indicators and glass panels. This is why I'm asking the pilot to use the turn coordinator to control wings level flight and control bank.
Flight Safety Foundation

In a supporting document from the Flight Safety Foundation titled "Inflight Spacial Disorientation" by Melchor J. Antuñano, MD and Stanley R. Mohler, MD, in brief, they highlight the two critical visual phenomena of the human eye: the focal vision and the peripheral vision which provide spatial visual reference to the pilot. When entering an IMC condition, the first vision lost is peripheral. Even though the focal vision is present, it must be trained to interpret the instruments without the peripheral. The FAA states in its regulation of the instrument rating, a minimum of 40 hours is required to train the focal vision (the hood) to control flight without peripheral cues. Also they demand currency of six approaches every six months to maintain focal vision currency. So that leaves the private pilot at a disadvantage when inadvertently entering into IMC events. At most he/she has received no more than three hours of focal vision flying during initial training, and with a two year flight review it is unreasonable to think that a Private Pilot will be able to conduct an instrument sophisticated scan and control the aircraft.
  
Flying VFR and Enter IMC

So in my procedure, I'm asking the pilot to stabilize his airspeed by putting the throttle in the middle of the green, finding wings level flight first with the turn coordinator and attitude indicator for pitch to the horizon, and if needed stabilizing a turn with the turn coordinator. If pitch is held constant and the bank is held constant this procedure simplifies the need of a complicated scan pattern and allows the pilot to make modest control movements to steer he aircraft to safe flight.

There is one last point I would like to make: the discussion of the recovery procedure for unusual attitude recovery in the Instrument Flying Handbook warns that "during instrument flight, except in training, they are often unexpected, and the reaction of an inexperienced or inadequately trained pilot to an unexpected abnormal flight attitude is usually instinctive rather than intelligent and deliberate. This individual reacts with abrupt muscular effort, which is purposeless and even hazardous in turbulent conditions. " (page 5-26 and 5-27) 

It also states that if there is not a recommend procedures stated in the POH/AFM, the recovery should be initiated by reference to the ASI, altimeter, VSI and turn coordinator.


Elite Simulation Solutions SimCast-
Stephen Gatlin interviews Bill Wilkerson, retired US Airways Captain. Stephen and Bill discuss the program “178 Seconds to Live” and how pilots can benefit from proper training should they find themselves in inadvertent IFR conditions or have various system failures while in IFR conditions.  COMING SOON




Bill Wilkerson
IMC Safe Flight
Billclt@me.com
336 254 3714
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