January 1, 2011
By Barry Schiff
Last April’s column touched on three unrelated topics, items that individually did not justify a full column but were thoughts nevertheless worthy of discussion (“ Proficient Pilot: 3 in 1”). Here we go again.
The first topic involves an e-mail that I received last September from AOPA Pilot reader Mike Kennedy, a financial planner who was about to take the checkride for his private pilot certificate. He asked how he could learn to perform a more effective preflight inspection of his airplane, a Cessna 172R Skyhawk. That was an interesting question. Many instructors do not have the expertise needed to teach pilots how to thoroughly inspect all of the airplanes in which they instruct. I suggested to Kennedy that he hire a local airframe and powerplant mechanic to point out the idiosyncrasies of his airplane. It seemed logical that someone trained to repair a given model knows best what to look for during a preflight inspection.
Kennedy acted on my suggestion and reported that it was time and money well spent. He says that he “learned a ton.”
Please forgive what could be mistaken for braggadocio, but I thought so much of my idea that I decided to do the same. I, too, hired a mechanic and similarly received an education, invaluable information that is useful to me and to those with whom I fly. My mechanic pointed out, for example, the importance of gripping the exhaust stack to ensure that it is not loose. “A loose stack,” he advised, “indicates an upstream crack that could enable hot exhaust gases to flow into the cowling instead of out of it. The result,” he warned, “can be an engine fire.” (He cautioned not to do this with a bare hand if the engine is hot.)I’ve been flying for 58 years and was amazed at how much there was to learn about what is often a perfunctory chore.
Item 2: Last month I got into a heated discussion with a group of instructors regarding the best way to simulate an engine failure when presenting a student with a simulated forced landing. There are, of course, only four possible ways to do this. The first is to simply retard the throttle. A problem with this is that keeping a throttle closed for a prolonged period can lead to spark-plug fouling and the possibility of carburetor ice (except in fuel-injected engines).
Another method is to turn off the fuel-selector valve. The problem with this is that turning off the supply valve empties the supply lines downstream of the valve. Restoring power can take an agonizingly and dangerously long time. (Otherwise, a good way to surprise a student with an engine failure is when you can turn off the fuel valve without him noticing.) Turning off the fuel supply to a fuel-injected engine is not a good idea because these engines can be difficult to restart following fuel starvation.
A third way to simulate failure is to turn off the magnetos, but this is hard on an engine and can result in serious backfiring. The fourth method is to retard the mixture-control lever to the idle-cutoff position. This is easiest on the engine. By retarding the mixture control with the throttle open, there remains substantial manifold pressure, induction air delivered to the cylinders that cushions engine deceleration.
You can understand why there are differences of opinion on this subject. Engine manufacturers are unanimous, however, in recommending that engine failures should be simulated on single-engine airplanes by retarding the throttle.
When “failing” an engine on a twin, it is best to retard a mixture control because this action can be hidden from a student’s view (by using a chart, for example). Retarding a throttle isn’t practical because it deprives the student of having to identify which engine failed, a necessary part of training. After the student retards the throttle on his own (part of the engine-failure checklist in a twin), the instructor can then return the mixture control to the full-rich position, which restarts the engine in idle.
Killing the engine at flight’s end is not done with the magnetos because this leaves unburned fuel in the cylinders. Someone moving the propeller of a hot engine could cause a cylinder to fire and do bodily injury.
Item 3: Last November, Alan Blair, president of the UFOs, invited me to stop by their annual meeting at the recent AOPA Aviation Summit in Long Beach. This group of UFOs has nothing to do with unidentified flying objects. These are the United Flying Octogenarians; only a pilot who has served as pilot in command on or after his eightieth birthday is eligible for membership. The UFOs consist of retired airline and military pilots, flight instructors, and even freshly minted private pilots. The international group was started in 1982 and now boasts a membership of more than 600 men and women.
It has been a very long time since I was the youngest person in a large room filled with so many pilots. I felt like a kid again. I never thought that I would look forward to joining the UFOs, but if the next eight years pass as rapidly as have the past eight years, I would like very much to become eligible for membership in this distinguished group. I would even love to have the opportunity to help form and become a charter member of the UFCs, the United Flying Centenarians.
Barry Schiff is a Fellow of Britain’s Royal Aeronautical Society. Visit the author’s website.
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