Preflight planning and making the so-called "go/no-go" decision are held as holy in flying. And they should be. There are a lot of conditions where the very act of deciding to fly can put the airplane, the passengers, and the pilot in great peril. Launching VFR into questionable weather at night or IFR into the teeth of a squall line are examples of risky business. Often, though, a decision to go may be okay at the time, with the critical decision made later, after starting the engine or during the flight, when the event does not unfold as planned. In fact, it is when all the well-made plans go awry that a pilot's ability to really pilot is tested most strenuously. Skillful piloting may relay to moving the wheel and wiggling the pedals, or it may be related more to thought processes.
The preflight planning business involves several elements. The relationship between the pilot and-the airplane and the weather has to be considered. Then each of those elements has to be considered separately. We usually put the emphasis on weather because it is most often the strongest of the factors. The airplane, though, has to be considered carefully because machines have a habit of being different, or difficult. When they start giving dues, we had best pay attention.
I got a good lesson on this one morning. The airplane was preflighted in the T-hangar. Nothing amiss. Oil on nine, no water in the fuel, nothing bent, dogged, twisted, or out of place.
The airplane needed fuel, so I started it up and taxied toward the gas pump. After starting, I noticed that the oil pressure didn't seem to come up like it should. It isn't far to the pump, and my attention to parking took my mind off oil pressure for a moment. After shutting down, someone walked over and said they thought a strainer drain was stuck open. I noticed a lot of oil on the main landing gear and felt it was something other than an open drain. There was a streak of oil from the hangar to the gas pump and a big puddle of oil under the airplane. It had 2.5 quarts less than it had before being started and run for less than 2 minutes.
A check valve had failed and was routing all the oil that pumps through the turbocharger to the breather and then to the great outdoors. Nothing on the preflight could have caught this. The due was in the oil pressure. Surely, had I been going direct to takeoff instead of to the gas pump, I would not have taken off with low or no oil pressure.
The message is to be suspicious of anything that is not absolutely normal on the airplane. If it does not behave as planned, check it out. The same would go for the pilot. An example might come when one's day doesn't go as planned. If you have had a full and a hard day, it is into the evening, and something comes up that suggests you go flying, there is a strong suggestion there that all is not right. The day's activities hadn't been paced to coincide with a, Planned evening departure. There is nothing wrong with those evening flights, as long as the weather is acceptable and the pilot is alert. If you hadn't planned on flying, though, there might be a definite disadvantage.
The strongest change-in-plan challenges come after takeoff. The atmosphere in which we make plans and decisions on the ground lacks the urgency associated with planning and decision making at groundspeeds from 100 to 1,150 knots, depending on whether you fly a Skyhawk or a Concorde. As on the ground, most of the in-flight challenge relates to weather, but the airplane can also demand attention.
When the plan goes bad in flight, we have to think in several disciplines, Time is important because there is always a time by which we have to be on the ground. Distance has to be considered because we may not have the time available to go a desired distance. Options are part of the drill. What can we do other than continue to the destination? Assigning a level of urgency is important; there is a big difference between smoke in the cockpit and an isolated burp from the engine. Finally, weather has to be related to a new enroute as well as arrival plan.
Flying a light twin, I noticed an hour or so into a flight that the left fuel gauge showed substantially less fuel than the right. Engine operation was normal. My first official act was to tap on the left fuel gauge. Surely it was wrong, but there was no change after a tap or two. I had watched the fueling of the airplane and knew the load was equal on each side. I could see the caps. Both were tight with no siphoning. I turned off the autopilot, and the airplane was right-wing heavy.
Time for world-class suspicion. I turned and looked at the trailing edge of the left wing. There was a visible vapor trail behind the engine. It could only be 10OLL fuel. That led me to cool the engine down, secure it, and land at the closest suitable airport. I had been given a strong due, and after the usual moment of procrastination and blaming it on the gauge, I got with the program, heeded the clue, assigned a high level of urgency to fuel spewing out of the engine compartment, and terminated the flight as soon as possible.
Where abnormal operation of the airplane and/or engine is usually clear-cut and a mandate to do something, weather can be more insidious. It lives and breathes and changes by the minute, challenging us not to fly into thunderstorms or ice, or visually into inclement conditions, and to always land with a safe reserve of fuel at an airport with acceptable weather.
Weather information is far less reliable than the airplane, and in a lifetime of flying, we change more plans after takeoff because of weather than anything else.
What is the weakest link? Fuel. Using up all the fuel has been and continues to be a big problem in general aviation. The wind part of weather is a big factor here. Pilots who run out of gas cost the rest of us a lot of money by driving up insurance costs. Why do they run out? The prime cause is not facing reality enroute. Everyone takes off thinking he can complete the flight with the amount of fuel on board, but when the flight doesn't go as anticipated everyone apparently doesn't do a good job of changing plans. It is something that shouldn't happen but that does happen on a frighteningly regular basis to airline, military, and general aviation pilots.
There are regulatory and preflight contributions to fuel problems. The Federal Aviation Administration requirements on fuel reserve (basically 30 minutes at normal cruise for VFR day and 45 minutes for IFR and VFR night) are absolute minimums. Equally bad are some of the reserve figures in older pilot's operating handbooks. Reserve was shown as 48 pounds on a 1979 Cessna P210N, for example. That is about half what it should be. Unless the airplane has a perfectly accurate fuel gauging system and the pilot ensures that the tanks are filled to the brim with the wings level (the ball in the turn coordinator will tell the tale), best plan on at least a 1 -hour reserve at normal cruise fuel flow. The other preflight contribution comes from the wind aloft forecasts, which at times are little more than a joke. (Wind aloft information should get better with new equipment.) Any plan using wind aloft forecasts is tentative at best. To stay away from fuel problems, wise pilots consider only half a forecast tailwind component, double a headwind, and still save an hour's fuel reserve.
The test of piloting skill on fuel usage comes later, with the actual groundspeed known, the gauges getting low, and the pilot stretching to see a destination that is still over the horizon. Handling this is quite simple. If it appears that you will not land with every minute of the reserve still in the tanks, stop for fuel. I have been kidded about this, but you can ask anyone who has flown with me if I honestly don't change the plan based on a shortage of as much as a minute's fuel. I just don't have any desire to sit there and wonder if I am going to make it, and the only way I know to avoid this is to draw a line and never cross it.
Another condition where problems occur relates to unanticipated weather conditions. This is different than unforecast weather because the National Weather Service in its area forecast includes everything that might possibly happen in the covered period. This leads some pilots to discount the forecasts and, if the weather at the departure point is acceptable and the actual reports look okay, to head out. Working with a plan like this often proves successful, but a pilot who chooses to do it this way had best be ready to cut and run. Whether it is a VFR or IFR flight, staying out of trouble when things don't go according to plan is mainly a matter of making a timely decision to change the plan and land somewhere with acceptable weather.
For pilots flying VFR, the nemesis is a continuation of visual flight into a weather condition that precludes visual flight. An abnormally high number of weather-related VFR accidents occur at night. This is logical: If the original plan didn't limit cross-country flight to virtually clear weather, it's hard to tell when you are continuing VFR into adverse weather conditions in the dark. The options are fewer at night, too. At least they seem so. Where there are a lot of lighted airports, most are isolated, with nobody other than the airport cat around after the sun goes down.
The big items when flying IFR are ice, thunderstorms, and weather below minimums. Any doubt about the first two constitutes a mandate to change the plan. On the last one, the plans are best changed when you first find out the weather is below minimums. At an airport with weather reporting if it is below minimums and regardless of the forecast, best use the last airport with minimums before reaching there as the alternate, regardless of what was- filed. To hold, waiting for the weather to improve, using up the fuel reserve, is one of life's least rewarding pastimes. If there is no weather reporting and the airport isn't in sight at the minimum descent altitude or decision height, the best course of action is to fly to someplace where reported weather is above minimums. The accident reports are full of tales of pilots who shot multiple approaches, trying to make possible the impossible.
When the plan unravels after a flight begins, managing events to avoid an emergency is the true challenge. Whenever an airliner makes an unscheduled landing, it usually gets a headline or a blurb on the television news. The implication is that the lives of the passengers were in danger. In most cases, the crew was just taking decisive action to handle a situation that might have developed into a real emergency. Everything was not according to plan, so they opted to land and sort things out. Abnormal operation of the airplane and weather are the two factors most likely to drive us to a new plan. Success is in being flexible enough to accept the necessity of a new plan before the situation becomes an emergency.
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