Some years ago, a Bonanza-owner friend discovered at runup that one of his two mags was misfiring badly. Personally, Im reluctant to fly with any significant problem that affects the engine(s), propeller(s), landing gear or primary flight controls. There are a lot of variables to consider, and every pilots risk tolerance is different. Its a lot like asking if its safe to fly in this weather. Now, how do you decide whether or not its safe to fly home with the problem? Thats not an easy question to answer. Okay, you have a problem and youve determined its cause. The moral: Dont fly with an anomalous symptom-even a seemingly innocuous one-unless and until youre satisfied you know exactly whats causing it.Once you know the cause, you can make an informed decision whether to fly now and fix later or vice-versa. It turned out that there was a major problem with the prop due to an assembly error when the props were overhauled three years earlier that could have resulted in loss of a blade in-flight … which quite often is a fatal scenario. Since the only red liquid I could think of was the red-dyed oil in the hub of my McCauley propellers, I decided to make a precautionary landing to investigate. Had I not followed up on the static in the radios, the harness could easily have fallen off the mag in a few more flight hours.Īnother time, while flying home to California from Oregon, I spotted a tiny trickle of reddish liquid on the top of the left engine nacelle. I pulled the left engines cowling and discovered the nuts securing the ignition harness to the right magneto were loose and backing off the studs-one was completely gone and the other three were well on their way. After some experimentation, I discovered that the noise would disappear when I turned off the right magneto on the left engine. But I knew my airplane well enough to know this wasnt normal, so I investigated further. It was so subtle that Id have completely ignored it if I had been flying any other aircraft other than mine. I recall one occasion when I noticed a little static in my comm radios that I never heard before. Are you absolutely certain about where that fine oil mist on the windshield is coming from? What that slight fuel odor in the cockpit really means? Why the engine seems to be running rougher than usual? Does that dead #5 EGT indication signifies a non-firing cylinder or just a broken wire? In cases like these, you need to investigate further before making a go/no-go decisionExperience teaches us that even seemingly minor anomalies are worth investigating before flight. Sometimes, however, the cause is not so obvious. Often the cause is obvious-flat tire, inoperative radio, burned-out landing light bulb, noisy attitude gyro-and your decision is often straightforward. When wrestling with these and other issues, your first question should be this: Do I know exactly whats wrong? Unless you are confident that you know the cause of a problem, you cant make an informed decision about how serious it is and whether or not its safe to fly with it. So, do you fix it now … or fix it later? Is fixing it now really necessary? Is fixing later really safe? It all depends. But sometimes it isnt-witness numerous NTSB accident reports in which the probable cause is pilots decision to operate the airplane with a known deficiency. Theres a strong temptation to defer the maintenance until a more convenient time, and often thats a perfectly reasonable thing to do.
Its natural to ask yourself whether its really necessary to fix the problem before further flight, or whether its okay to press on and get it resolved after you return home. Itll be a miracle if you can find a local A&P at Sheepdip on a Sunday … and if you do, youll get the uneasy feeling that Bubba knows hes got you and your American Express card by the short ones. To add insult to injury, mechanicals invariably seem occur at the most inconvenient possible time and place-like Sunday at Sheepdip County Airport when youve just gotta be back at work Monday morning. Its always uncomfortable when youre far away from your usual support system-your trusted mechanic, your hangar, your toolbox. Nothing is more frustrating than dealing with mechanical problems while on the road.