November 2002 Volume 45 / Number 11
Ask ASF's database
Bruce Landsberg, ASF's executive director, still flies regularly—despite reviewing ASF's database.
Would you like to learn more about safe flying? Learning from history is a great way to avoid repeating it. The case-study method used in business schools and civil engineering colleges around the country has been proven many times over. Study the wreckage of a building or the action leading up to a catastrophic business decision and then determine the factors that led to the problem. In aviation we have thousands of case studies, but there's a new place you can go to learn more about being safe.
How safe is the make and model aircraft that you're flying? What's the record of that hot new homebuilt that's been heavily advertised? What are the safety records of airports in different states? Do any airports stand out? Inquiring minds want to know.
Back in 1989 my predecessor at the AOPA Air Safety Foundation, Adm. Don Engen, felt the need for more science in ASF's approach to general aviation safety. With a grant from the Emil Buehler Foundation, ASF's safety database was born. We are indebted to both the National Transportation Safety Board and the FAA for providing the raw data—the accident information. The database has been upgraded over the years with considerable emphasis on error checking. Occasionally, a Bell 47 (a helicopter) might come to us coded as a single-engine fixed-gear airplane, or VFR weather at the accident site might be coded as IMC. With about 1,600 accidents per year, it's easy to make an occasional slip-up. We decided early on to limit the scope of ASF's database to fixed-wing airplanes that weigh less than 12,500 pounds. This covers the vast majority of general aviation aircraft. It also represents the population where most accidents occur. In 1991, the first Joseph T. Nall Report was produced from the information in the database. It was named in memory of Joe Nall, an NTSB member and GA enthusiast who died on an ill-fated charter flight in Caracas, Venezuela. By today's ASF standards, it was a modest effort but it was our first attempt to take a detailed look at GA's accident picture. Since then the Nall Report has expanded into an illustrated, four-color review of the prior year's GA accidents. It is distributed to leading aviation universities for use in their safety classes as well as to the pilot community. Quite a number of government agencies also use the report to assess GA's safety picture.
ASF reviews the data to determine where to put the emphasis for seminars, online courses, and safety advisors. With limited time and funds not everything can be a priority, so we have to pick the battles carefully. The "softness" of data requires care in interpretation. Another challenge is getting past the accident du jour—a media-driven mentality—that is not always easy to overcome. The latest disaster will always occupy the most column inches and network minutes, frequently with the most distorted perspective. That's where the numbers can be a balancing force.
Case in point: After a Cessna 335 accident in which the governor of Missouri, Mel Carnahan, was killed, the perception was that instrument failures or vacuum pump failures were widespread. That was brought up in many articles and on TV tabloids. The database showed the facts—on average only two to three accidents per year over the past 10 years have been attributed to equipment failure. Ninety percent of the problem results from VFR pilots pushing their weather limits (see "Safety Pilot: The 90-Percent Solution," February Pilot).
ASF's database is now available online. It's open to anyone and it's very easy to look up a particular accident. If you know the date—even the approximate date—the aircraft tail number, or the state, within a few seconds the database will come back with a list that matches the search criteria. You can enter ranges in some fields to broaden the search. If the accident is very recent, it will show up in preliminary status with a basic description that something bad happened. This includes where and when, with usually only a few details, which may be inaccurate. In about six months a factual report will replace the preliminary report. It will be technically correct but will contain no probable cause of the accident. A final report will appear anywhere from eight to 18 months after the accident or after the factual report and generally will include the probable cause.
The search function allows a variety of queries. You could look at the 10-year history of a particular aircraft make and model. Let's take a fictional example: How many Prop-Bender 271s crashed and for what reason? If you're contemplating the purchase of such an ill-named machine it's probably wise to see where pilots are having difficulty. Perhaps landing accidents are prevalent because the aircraft is heavily used in training. If there is some indication of gear collapses, then maybe it's good to learn a bit more about the construction. In contrast, the Weather-Wacker WW-63 may be a fine cross-country machine except when its pilots tangle with weather.
In every ASF analysis of particular aircraft, we've found that how the aircraft is used is far more likely to be a source of difficulty than any design issue. However, aircraft are compromises, like all the other machines in our lives, and trade-offs do occasionally show up. Sometimes that leads to an airworthiness directive or to special training emphasis. In other instances it's just the nature of the beast and pilots need to adapt if they're going to fly that make and model.
Browsing the database is always instructional, sometimes entertaining, and frequently sobering. The natural inclination is to assume that none of us would ever be so stupid as to engage in the folly perpetrated by some of our fellow aviators. There are some clear cases of aeronautical Darwinism. But there are other cases that give one pause.
For example, take this worst-case scenario: a single-engine aircraft is being flown at night in poor weather by a rated and competent pilot when, without warning, the engine breaks a crankshaft and stops—right now. The pilot just has time to get off a distress call, switch the transponder to 7700, and advise his passengers that they will be landing a bit short of the destination. The aircraft lands in a river, but luckily it drops onto a sandbar just below the surface. The pilot goes from having the worst of luck to the best of luck, all in one night. There are no serious injuries and everyone is rescued several hours later. Makes you think carefully about night IFR.
Want to check on an old friend, an aircraft that you flew years ago? I went looking for one of my favorites, a 1968 black-and-white Cessna 150, 89J (we called it 89 Joker). The Joker had a heart of gold and probably an extra 10 horsepower tucked under the cowl. She flew straight and seldom broke down. I said goodbye to her in the late 1970s and always wondered how she fared. Sadly, the database showed that Joker came to her demise in 1991 doing what she did best, teaching a new student the secrets of flight. On downwind leg the student reached for the carb heat, pulled another control instead, and the engine stopped. Joker wound up in a gravel pit short of the runway, damaged beyond repair. The student, uninjured, learned a valuable lesson: Do not confuse mixture and carb heat, lest the engine lose motivation.
Scanning the database brings thousands of stories to life. Some are simple with short narratives; others are complex. Some have happy endings and others are tragic. In any event, you will begin to understand the risks and avoid those areas where history predicts an unfortunate outcome. Happy hunting.