The University of Texas at Austin
Studies in Ethics, Safety, and Liability for Engineers
Kurt Hoover , Wallace T. Fowler, and Ronald O. Stearman
The V-tail Bonanza
The Model 35 Beech Bonanza, better known as the V-tail, is a unique aircraft. It is easily recognizable at a glance. When the model first came out 1947, it was called ³a miracle of aeronautical design" by Walter Beech. For many years it was the most popular single engined aircraft in the world. Not only was the V-tail distinctive, but its performance and luxury made it the Cadillac of general aviation. Many pilots dreamed of one day owning a V-tail, but somewhere along the line, the dream becoming something of a nightmare.
The V-tail has a very high rate of in-flight failures. Compared with the Model 33, which is the same aircraft with a conventional straight-tail, the V-tail has a fatal in-flight failure rate 24 times as high as the Straight tail Bonanza. In spite of this glaring statistic, Beech claimed that there was no problem with the V-tail, and for many years the public seemed to agree with Beech. However, the deaths from in-flight failures continued to mount. The V-tail Bonanza is a classic tale of a dangerous item, which because of its popularity continued to kill.
V-tail Bonanza versus Straight-tail Bonanza:
Most general aviation airplanes look very similar. They are designed first with function in mind; style comes second. There are few external features on a general aviation airplane that can be modified without affecting the performance of the aircraft. About the only outwardly obviously visible feature that differs from one general aviation aircraft to another is the tail. There are straight tails, swept tails, T-tails, cruciform tails, and V-tails. The swept tails, for example, are there only for looks on most general aviation airplanes since they donıt add anything to a plane that spends most of its time at Mach 0.2 (0.2 times the speed of sound). In the never ending battle to distinguish their aircraft from the others on the market, tail configuration is one of the designer's major weapons.
In the case of the Beech Model 35 Bonanza, the tail was a very major selling point. The V-tail was not a new idea, but not many planes have used it. At the time of the introduction of the Model 35, no other general aviation airplane possessed a V-tail. The Model 35 was immediately recognizable and thereby lent the proud owner an instant boost in status. The Model 35 was a very nice airplane; the interior was plush for airplanes of its time and the performance of the airplane equalled its looks. The V-tail Bonanza quickly became the airplane that people aspired to own, like a '57 Chevy or a '67 Mustang.
Theoretically, the V-tail does with only two surfaces what a conventional tail requires three surfaces to do. Reducing the number of surfaces reduces the drag and weight. Because only two surfaces must be manufactured, the manufacturing costs are also lower. Their are also several other favorable characteristics of a V-tail. The possibility of tail buffeting from the wing and canopy wakes is reduced.
However, the V-tail, is not without its drawbacks. While it requires only two surfaces instead of three; these two surfaces must be bigger or the plane suffers stability problems, specifically spiral divergence and Dutch roll. Effective control of both yaw and pitch requires a complicated control mixer. Additional mass balance is required to restrict antisymmetric tail flutter, because the elevators cannot be interconnected. Finally, the V-tail creates greater loads on the tail and fuselage during pitching and yawing maneuvers than does the conventional tail.
The History of the V-tail Bonanza
Early Indications of a Problem:
Early on in its 36 year production there were indications that something was not quite right with the V-tail Bonanza. The plane seemed to have a high incidence of in-flight break-up, despite the fact that the overall safety record of the V-tail Bonanza was very good. Beech initially attributed this to pilot error, and it did seem that a majority of the break-ups were associated with bad weather conditions. It was claimed that turbulence associated with the weather conditions placed too much stress on the tail resulting in its failure which subsequently resulted in the crash.
In 1951, in order to ensure greater stability and to provide for growth of the aircraft, Beech enlarged the tail twenty percent. To avoid a major structural redesign of the tail and to avoid new tooling costs, Beech did not move the location of the front tail spar. When Beech modified the tail, much of the increased size was placed ahead of the front tail spar. This left the spar sixteen inches behind the leading edge of the tail. In the opinion of many aeronautical engineers, this forced the skin of the tail to carry too great a load and left the safety margin too small. Under many circumstances, this safety margin was inadequate and the tail failed.1
While Beech placed the blame for most of the accidents on weather conditions and turbulence, these factors could not account for many of the accidents, in which the pilot had been aware of rough weather conditions and attempted to go around them. Beech claimed that pilot error was responsible for these accidents. The pilots were said to have fallen victim to a condition known as spiral divergence. Flying without good visual reference, say in a cloud bank, the pilot would unknowingly get the airplane into a downward spiral. Without realizing this, he would exceed the aircraft's structural redline speed. Then for some reason, perhaps realizing the problem, the pilot would attempt to pull the nose of the plane up. Because of the excessive speed, the force on the tail would be too great; the tail would fail.
Yet even this explanation did not account for many failures which seemed to occur in normal flying conditions. One aircraft in particular suffered a structural failure of the tail in completely clear weather. Fortunately the failure was not total, and the pilot was able to land the aircraft safely. When knowledge of this incident became public, it created a storm of controversy. Apparently, the airplane had passed through the jet wash of a commercial aircraft. However, this by itself should not have produced such failure. Pilot error was insinuated by some. Beech offered to repair the aircraft, if the pilot would turn the plane over to the company. Unwilling to allow Beech to have the aircraft until it had been inspected by a federal agency, the pilot initially refused. Beech became very insistent, and the pilot was forced to hide the tail.5
Studies and Airframe Strengthening:
The very first V-tail models had a tendency to fail in the wings. Within the first two years of manufacture, it became apparent to Beech that the wing structure was inadequate. Beech increased the strength of the wings, but instead of ending in-flight failures, this action simply changed the source. Now instead of the wings failing, the tail failed. In 1952 the FAA (Federal Aviation Administration) opened a study on the V-tail Bonanza. For the next twelve years the agency accumulated statistics on the airplane, particularly on in-flight break-ups, and examined possible problems with the design. Although the study found a high incidence of in-flight failure, no action was taken and in 1964, the study was closed.1
During this time period, Beech made numerous small changes to the V-tail Bonanza. Most all of the structural modifications involved the tail. Beech apparently was aware that the structural margin on the tail was inadequate, because the purpose of the modifications was to increase the strength of the tail. However, the modifications did not end the in-flight break-ups; the tails continued to fail.
When the attempts to strengthen the tail by minor structural modifications did not work, Beech and three independent aircraft parts suppliers searched for other methods of strengthening the tail. The result was a stub spar which reduced the load on the front spar once skin buckling began. After conducting tests on its stub spar design, Beech concluded that it did not result in an appreciable increase in tail strength. However, subsequent investigation by the FAA concluded that Beech did not carry their tests to the point of tail failure and therefore, did not really have any information on which to base the decision that the stub spar kit was ineffective.4
In the early 1970s it was discovered that the tab control cables to the tail on many V-tail Bonanza were in very poor condition. The cables on many planes were worn, frayed, and sometimes coated with paint. Generally, this was the result of improper maintenance and not poor design. However, in many cases the improper maintenance resulted in slack tab cables. This in turn produced an unbalanced reversible tab that drove the rudder to flutter. In addition to all the other alleged problems, the V-tail was extremely sensitive to the problems of tail flutter. The FAA issued a directive ordering all V-tail owners to inspect the tab cables of their planes.
Throughout the 1970s, people continued to die as the result of in-flight failures of the V-tail Bonanza. The families of some of these victims sued Beech Aircraft claiming that the V-tail Bonanza was an unsafe aircraft. To support their contentions, the plaintiffs hired experts to conduct independent studies of the V-tail Bonanza. Several of the studies noted irregularities with the V-tail design, but it was difficult to prove direct cause and effect for most of the accidents. Beech won most of the lawsuits.
In 1978, the FAA commissioned STI (Systems Technology Inc.) to study problems of in-flight break-up for all aircraft. STI concluded that the V-tail Bonanza had the best overall safety record of any general aviation aircraft, but had the worst record when it came to mid-air break-up. The V-tail Bonanza was twenty-four times more likely to suffer from in-flight structural failure than the Straight-tail Bonanza. The only difference between theses two models was the configuration of the tail. Beech disputed this claim and said that the V-tail was only eight times more likely than the straight-tail to suffer from in-flight failure.4
Even accepting Beech's figures, it still seemed impossible to draw any conclusion other than the one put forward by many in the aviation industry. The V-tail Bonanza was inherently more dangerous than the Straight-tail Bonanza. However, a very different conclusion was drawn by the report. Instead of citing the V-tail Bonanza as an unusually unsafe airplane, the Straight Tail Bonanza was cited as an unusually safe airplane. About the same time as the FAA study, the NTSB (National Transportation Safety Board) conducted its own study. The FAA study had examined in-flight break-up for a wide variety of aircraft. The NTSB study examined the accident history of light, single engine fixed-wing aircraft. The conclusion of this study agreed with the FAA study.4
Beech's Attitude and Actions toward the Problem:
As previously mentioned, Beech did attempt to alleviate the problem of the V-tail Bonanza. Beech produced eighteen different versions of the the V-tail Bonanza. In addition to ongoing changes in the new planes, Beech attempted to correct the most obvious problems with the very early models. Beech offered to retrofit, free of charge, the very early models with a strengthened wing, but this proved to be almost as expensive to Beech as producing a new airplane, and the company stopped actively encouraging owners to receive the retrofit. As Beech upgraded each succeeding model, these changes were not made to the planes already in the field. Today there are still some planes flying without the strengthened wing and many more without the modifications to the tail.
From Beechıs point of view, there was no major problem with the V-tail Bonanza. The vast majority of the V-tails flying did not suffer from in-flight break-up Out of the over 10,000 aircraft made, less than 250 were involved in fatal in-flight accidents. Beech claimed that for the total number of hours flow in V-tails, the accident rate was not at all surprizing or alarming. It was neither prudent nor possible to design an airplane that would never develop problems. Besides, according to Beech, the main cause of the in-flight break-ups was still pilot error.
Through all of the mounting evidence, Beech continued to maintain that the V-tail Bonanza was safe, and for a long time there continued to be many V-tail admirers who agreed with the company. However, the publicity surrounding the V-tail was becoming increasingly more negative. In attempt to counter the increasing perception that the aircraft was unsafe, Beech launch a publicity barrage. Beech executives traveled to meetings of Bonanza clubs and other general aviation clubs. Armed with figures and charts, they tried to persuade people that the V-tail was a great plane which was being unfairly criticized. Despite the growing number of lawsuits against the company, Beech continued to manufacture the V-tail Bonanza; probably because people continued to buy it. Beech's ultimate counter to the charges that their aircraft was unsafe was that it was a high performance aircraft. By their very nature, high performance aircraft entail an element of risk. The implication was that flying a high performance aircraft required a certain amount of skill and training above that required for an ordinary airplane. If the pilot did not have the skill or want to take the risk, he should not fly a Bonanza. For a while, this attitude and approach by Beech seemed to satisfy most of the public and the strong sales of the V-tail Bonanza continued. Even this did not last. In 1982 Beech stopped manufacturing the V-tail Bonanza, but continued to manufacture the Straight-tail Bonanza.
A Conclusive Investigation?
The clubs devoted to Bonanza aircraft generally supported the company's position. However, in 1984 a personal friend of Donald L. Monday, president of the American Bonanza Society, was killed in a V-tail break-up. The American Bonanza Society was an organization that until this point had actively supported Beech's position. The death of Monday's friend, however, changed the relationship. Monday asked the chief of the FAA to determine conclusively whether deficiencies were inherent in the design of the V-tail Bonanza. The chief of the FAA, himself a former V-tail Bonanza pilot, referred the problem to a panel of experts from the DOT Transportation Research Center in Boston.
To no one's surprize the panel did discover several problems with the V-tail Bonanza. The V-tail Bonanza did satisfy the structural requirements for certification, but the requirements did not adequately address the unique characteristics of the V-tail. The handling and stability characteristics may have contributed to pilots exceeding the allowable flight envelope. The in-flight break-up rates of most single engine airplanes with retractable landing gear were significantly higher than for other categories of general aviation aircraft. The Model 33, the Straight-tail Bonanza, possessed an unusually good safety record. The in-flight failure rates of the later V-tails were better than the in-flight failure rates of the earlier V-tails.4
While the panel, did document some of the problems with the V-tail Bonanza, it did not determine conclusively whether V-tail was inherently too dangerous. The panel recommended that the certification process for V-tail aircraft be reexamined, but made no other recommendation. The report satisfied no one. Beech did not receive the clean bill of health it had hoped for, and the people concerned about the safety of the airplane did not receive strong a definitive condemnation of the airplane.
During the investigation, the FAA issued an emergency Airworthiness Directive restricting the speed of the aircraft. Subsequent to the panel report, Beech developed a modification kit for the V-tail Bonanza which supported the leading edge of the V-tail stabilizer. The speed restriction is cancelled when the aircraft has undergone the Beech modification. The negative publicity of the V-tail Bonanza has greatly decreased the resale value of the plane. People continue to fly the V-tail Bonanza, and occasionally the airplane suffers an in-flight break-up. The controversy seems to have moved to the back burner to simmer.
Safety and Ethics Issues
There are many questions involving safety and/or ethics which are raised when we examine the history of the Beech V-tail Bonanza. The ethics questions are complex. If high standards of ethical conduct are to be maintained, then each person must differentiate between right and wrong, and must follow the course which is determined to be the right or ethical course. Frequently, the determination of right or wrong is not simple, and good arguments can be made on both sides of the question. Some of the issues raised by examining the history of the V-tail Bonanza are listed below.
- In light of the comparison of in-flight break-ups for the Straight tail and V-tail Bonanzas, how could Beech claim that there was no problem with the V-tail?
- Did the chairman of the board of Beech, who was a partner in the law firm representing Beech, have a conflict of interest?
- Some of the engineers in Beech must have been aware that the aircraft was flawed. What should they have done with this knowledge.?
- Did the FAA fail to do its duty in the several lengthy, but very inconclusive investigations of the V-tail Bonanza?
- To what lengths must a company go to protect the users of its product? There will always be some risk involved in flying, particularly in flying high performance general aviation aircraft. Did Beech do enough to protect the people buying its planes?
- ³Beech 35 Airframe Failure Report." Richard B. Weeghman. The Aviation Consumer. December 1, 1985.
- "Instrumented Flight Test of the Beechcraft V-tail Bonanza." Coffey, Long, Moralez, McCullough, and Stecklein. Department of Aerospace Engineering and Engineering Mechanics, The University of Texas at Austin. May 1985
- "Reduction and Analysis of Flight Test Data for the Beechcraft V-tail Bonanza." Baade, Hazelhurst, and Lyons. Department of Aerospace Engineering and Engineering Mechanics, The University of Texas at Austin.
- ³The V-Tail Bonanza--Breaking of a Legend." Brent Silver. The Aviation Consumer. February 1980.
- ³The V-Tail Bonanza." 60 MINUTES. Central Broadcasting Company, New York, NY. March 1983.
Beech V-Tail Bonanza Assignments
The history of the Beech V-tail Bonanza is a very interesting one. From very early on in the program there were appearances of problems yet the V-tail Bonanza was manufactured for 38 years and 10,405 of them were produced. For many years, the V-tail was the hottest plane on the market. During much of this time decisions had to be made in the face of many conflicting demands. Sometimes it appears that the wrong demands were satisfied. However, hindsight is always better than foresight.
For most of the years that the V-tail Bonanza was in production, there were indications that the design of the tail was not a good one, but people kept buying the plane. Studies by both government agencies and independent experts found problems, but had no success in conclusively identifying cause and effect. Beech made numerous modifications to the airplane designs. The changes did reduce the rate of in-flight break-ups, but did not stop them. Beech rejected the use of a stub spar kit to retrofit the V-tail.
Beech never acknowledged that there was a problem with the airplane, and seemed to prefer to deal with the situation in court. This had some success for a while, but ultimately the public did became concerned with the problems. Ultimately, Beech stopped manufacturing the V-tail but continued to manufacture the Straight tail Bonanza. The resale value of the V-tail dropped, but over 6000 V-tails are still registered in the United States.
Read the General Information provided on the history of the Beech V-tail Bonanza. Consider each of the following questions carefully in light of that information and write a complete and grammatically correct paragraph answering each.
- Why did people continue to buy the V-tail even after information about the break-up began to surface?
- Why did Beech continue to maintain that the cause of the accidents was pilot error, despite the fact that the company had information suggesting otherwise?
- Was the V-tail Bonanza too unsafe to fly? Should it have been taken of the market? If so, by whom, the government or the manufacturer?
- Was a breach of ethics committed by the Chairman of the Board of Beech Aircraft, by continuing to retain his position when his law firm was benefiting from the lawsuits against Beech?
- Should either the FAA or the NTSB have recommend that the V-tail Bonanza be modified? How dangerous is too dangerous for a performance airplane? If either organization had recommended decertification, what is the likelihood that this action would have been implemented?
- Instead of consistently denying any problems, how might Beech have addressed the V-tail issue?
- The stub spar kit for the V-tail had only limited success. Why were more people not willing to spend the money for the improved safety?
- It is said that statistics can be made to prove anything. What did the statistics comparing the Straight tail and V-tail Bonanzas prove?
Choose one of the following statements, research the topic, and write a two page paper in which you explore the impact of the topic on the history of the V-tail Bonanza.
- The structural changes to the tail of the V-tail , did decrease the incidences of in-flight failure, somewhat, but did not stop them; the in-flight break-up rate of the Bonanza continued to be much higher than the average. Either Beech did not correctly understand the problem and therefore could not fix it, or the company did not want to take the steps required to fix it.
- The V-tail Bonanza consistently met the regulations required for certification, but yet continued to suffer from a high rate of in-flight break-ups. Both the FAA and the NTSB suggested that further examination of the certification process as it was applied to airplanes with v-tails be examined, but little was done to revise the regulations. Review the process by which airplanes are certified.
- Beech never admitted that a problem existed with the V-tail Bonanza. No federal study ever conclusively pointed a finger at Beech. If the company had admitted a problem, the admission would have undoubtedly been used against it court. How can a company admit and deal with a problem without opening itself to a flood of lawsuits?
- Beech successfully sold the V-tail Bonanza for 38 years. During most of this time, the majority of the public either was unaware of the possible problems, or did not believe them to be true. Despite the attempts of independent investigators, public perception about the V-tail was extremely slow to change.
Divide the class into small groups, no more than three to a group. Each group is to choose one of the four roles outlined below and develop statements outlining the position represented by those in your role and their part in the history of the V-tail Bonanza. Develop two statements: (1) what you think was the position of those in your role, and (2) the position that those in your role should have taken.
- Beech Management: Your first concern is the profitability of the company. You must balance the need for complete disclosure with the importance of product image. You may not even be convinced that there is a problem with your product.
- FAA: Your job is to insure the safety of the flying public. The agency has certification procedures which each airplane must pass. The V-tail Bonanza passed these, but still appears to have problems. Changing the certification procedures is difficult. You need Beech's help to some degree to do just about anything.
- Beech Engineer: The structural margins on the tail are small, but this reduces the weight and thus gives better performance. The V-tail is more a marketing tool than anything else. Do you think the V-tail is a bad design idea? If so, how can you convince your management since the distinctive V-tail model sells well?
- Consumer: You are looking for a new airplane. How do you evaluate the various models? What features are important? How important are cost, safety, esthetics, or performance? How do you judge the validity of the manufacturer's claims? Where can you get comparative information on the various potential airplanes?
Working in three person groups, examine the problem of protecting the public from harmful products? To what degree should the government attempt to do this? How can the need for protection from danger be balanced against the freedom to spend oneıs own money in a manner of oneıs own choice? What agencies in the government should be involved? How should industry be involved? What role should industry take in regulating itself? Can the free market be counted on to drive unsafe products out of production? How can the public be made knowledgeable about the dangers of products and safer alternatives?
Working in three person groups, consider the problems of a lower level structural engineer on the V-tail Bonanza program. You are aware that the structural margins on the tail are not large, and that the tails of a large number of aircraft have failed in the past. Your boss has told you that a total redesign of the tail is prohibitively expensive, but you are of the opinion that this is the only real solution to the problem. Consider your options. You can ignore the problem. You can leave the company which might help you personally, but will not solve the problem. Do you have other options? What are they and how might you exercise them? In doing so, try to consider the point of view of those above you in the corporate structure.