The safety equation

November 1, 1998

There is seldom a simple answer to a simple question. At a recent AOPA Air Safety Foundation seminar, a pilot came up to me to ask what the real scoop is on safe flight. He wanted to know how risky it is, as many of us do. That depends on a variety of factors. A straight answer to this question involves multiple qualifiers and more dissembling than the average politician running for reelection.

It is easier working equations with constants rather than variables, but the safety equation is almost completely variable — with one exception. How safe do you want to be? You can be perfectly safe from aeronautical mishaps by not flying, only to fall victim to an errant driver, stray bullet, or meteorite. Is flying less safe? Well, yes and no. Yes, because exposure is reduced, but no, because you're not as proficient.

Starts to sound like the famous Catch-22.

Starting with the least variable part, the aircraft is generally reliable if it is properly maintained and suited for the mission. The certification process, as much as we may fuss about it, ensures some degree of performance. Very few airplanes come apart in flight unless they are being flown outside the envelope. This is good, and we've come to depend upon it. But let's get into the variables. If the airplane is not approved for flight in icing conditions and there are icing conditions en route, then the risk has gone up — is that a function of the aircraft or the weather? The pilot has, in theory, the ability to change which airplane he flies. In practice, this usually doesn't happen, because most of us have only one airplane at our disposal and, in most cases, flight into known icing is not one of its approved operations.

Weight is similar — put two moose on a one-moose airplane and the risk has gone up. Now you need to either get a two-moose machine or divest yourself of one moose. It's basic math that the aircraft is approved for flight with only so much weight on board. When that number is exceeded, the margin goes down. Place the weight improperly and things won't balance — the risk goes way up. The pilots in Alaska know a lot about this, especially the aspects of handling moose.

Maintenance of the aircraft is essential. While it's difficult, perhaps impossible, to make a statistical correlation between the age of an aircraft and its probability of involvement in an accident, it is only logical that older machines will be more prone to failure. Corrosion, wiring, flight control cables, propellers, engines, and all other parts do not escape the passage of time. When something fails, the risk goes up — sometimes a little, sometimes a lot. Old aircraft require constant mechanical vigilance to manage the risk.

So far, we've discussed the easiest part of the safety equation — the aircraft. It is the most predictable variable; maintain it well and operate within the limits and you have managed that risk. Now let's go to a less predictable but measurable aspect, the phase and type of flight. Takeoffs and landings are the highest risk phases for an accident. Unfortunately, we haven't figured out how to go aloft or return without takeoffs and landings, so there will always be exposure. Managing the risk is easy to say but not quite as easy to do. Be proficient with crosswinds. This is the number one cause of damaged aircraft. It's tough to schedule a crosswind where and when you need it for practice, but look for the opportunities.

Use runways with adequate length. The pilot operating handbook is a good start, but it's based on ideal numbers — new airplane, new engine, test pilot with exceptional skills, etc. The ASF recommends adding a minimum of 50 percent to whatever distance the manufacturer was able to coax out of the aircraft to clear a 50-foot imaginary obstacle. Our obstacles are real and so are the consequences. One reason the airlines have very few entanglements off the end of the runway is that they've overengineered their arrivals and departures. Much time is spent figuring the worst-case senario and then adding a margin. If an engine quits, what is the climb gradient under the worst temperature and weight combination? Pilots of single-engine airplanes can consider off-airport options; suppose there is a tailwind or standing water on the runway.

These are all items you may have thought about, but how do they apply to this airport at this time?

Follow the appropriate pattern procedures. As you've heard many times, the midair collision threat is the greatest around airports, so keep a sharp lookout. That time when the pilot is most distracted — takeoff and landing — is precisely when the aircraft seems to demand the most.

Configuration, power setting, navigation equipment — there's always something to divert the attention. If you keep in your mind the image of two aircraft colliding, there will be no difficulty in setting priorities.

Accidents occurring during a type of flight are also predictable from a statistical sense. Personal flying, the kind most of us do, is the greatest risk because pilots seem less likely to exercise good judgment than when they are flying on business or receiving flight instruction.

While in training, pilots are encouraged to do the right thing under the watchful eye of a CFI. The experience is controlled and usually with a good risk-management approach. Instructors don't like to be put in compromising situations. We suspect that pilots flying on business are more experienced and may have aircraft that are more capable. The emotional aspect may be less of a factor as well — getting to a business meeting may exert less emotional pressure than getting the family to or from a holiday location. There may be less financial pressure. After all, the company is frequently paying for the flight and the expenses, so if there is an extra night in the hotel, it's not coming out of the pilot's pocket.

Now let's get to the messier part of the mix, and weather is one part of that.

Predictable? Absolutely! When VFR is needed to get home, it's two days away in the forecast; and when pilots need some basic instrument weather training, the sun shines for a week. Now, try to guess when and where thunderstorms are going to turn a hazy summer afternoon into a turbulent maelstrom. Try again when the omnipresent winter icing threat is really going to freeze the tail feathers. Daytime VFR is the safest kind of flight. Night VFR is not quite as good.

When the weather goes to IMC, then the ante goes up. For VFR pilots this should not be too complex. Forecasts for marginal conditions are usually quite accurate, and it's only a short step from marginal to unflyable. It's time to look at the risk/reward equation. Are you willing to bet your life and that of your passengers on a marginal forecast and wishful thinking that the weather is not quite as bad as they say? Do you have an alternate plan, and perhaps more importantly, do you have the will to use it? These intangibles can fog the assessment of risk, if you forgive the pun.

For IFR pilots flying in IMC, all the usual questions on currency and experience come into play and, if you haven't noticed, we have slipped into the most complex part of the equation, the wild card: Us. Like the weather, pilots fit easily into general categories, and then it gets complex. There are some well-known risk factors. Pilots with a total time of less than 200 hours are at a higher level of risk than more experienced aviators because they are still learning the basics and exploring new situations. The learning curve will continue for a lifetime, but it is very steep here. Less than 100 hours in a particular make and model puts pilots in a higher risk category because they are learning about the aircraft. This risk is so noticeable that the airlines designate new captains as "high minimum." Sure, they've just come out of training and are highly proficient in the academic sense — much like the new private pilot. However, the rule says that IFR landing minimums must increase by 100 feet and a half-mile visibility above the published minimum approach until more experience is gained with the aircraft. Seasoning counts.

The one exception in the safety equation that may override the other variables is attitude. A low-time pilot with a cautious, responsible attitude will take fewer risks than the cocky mid-timer who thinks he's seen it all. Generally, the real old timers aren't too brazen because they realize that the safety equation is complex and the variables can shift rapidly. Read the accident reports, put yourself in someone else's cockpit, and most aviation survivors come to realize that dangers can be subtle.

There is one last observation that doesn't negate the value of risk management but requires some maturity to understand. There are some serious risk-takers who defy the odds and survive despite predictions to the contrary. You know the type. They fly in marginal weather, too close to the ground. They overload the aircraft, skimp on maintenance, and ignore all the other tenets of safe flight. There are possibly thousands of pilots who regularly take risks that are statistically insane and yet they depart the planet from nonaeronautical causes. It's not fair, but that's probability. Being safe does not eliminate risk — it reduces it. We fly because of the challenge, the joy, the practicality, the romance.

The reward of flight is worth the risk. You want guarantees? Call the tax man.


See also the index of "Safety Pilot" articles, organized by subject. Bruce Landsberg is executive director of the AOPA Air Safety Foundation.