General aviation's hardware - the aeroplane - is rarely examined for safety shortcomings.

David Learmount/LONDON

ACCEPTANCE OF LOWER levels of safety in private general aviation (GA) than in airline operations would seem almost logical: airline professionals ought to do it better. There seems to be an industry blind spot when it comes to GA aircraft, however. They are rarely analysed with a view to major safety improvements as airline aircraft are.

Among those few countries which catalogue GA safety statistics in detail, the USA reports a fixed-wing fatal-accident rate which is moving slowly, but steadily, upward (see chart) even when the number of events goes down. In Canada, the rate seems to be almost static, but is higher than the USA's; in the UK, the 1995 rate was slightly higher than that for the previous year, but the three-year moving average has continued a downward trend to consolidate what is believed to be the world's lowest GA fatal-accident rate.

After an airline accident, every factor is examined in minute detail, including the aircraft, its systems and its cockpit. Even a mature aircraft type with a good safety record, may suddenly be assaulted by industry critics and regulatory authorities for having a control device where ergonomics are less than perfect.

Despite the relatively unhappy performance of safety rates in the two biggest GA nations, where excellent commercial-air-transport figures have shown an improving trend over the past ten years, the critical process applied to airliners is not applied with the same rigour to GA aeroplanes. This is despite the fact that GA aircraft have accidents, including fatal ones, more often; and in the knowledge that the pilots who fly them are, by definition, more likely to be error-prone through lower experience levels and, in many cases, through lack of flying continuity.


The only nation with a large GA sector which analyses its GA accidents from almost all angles is the USA, which produces number-crunching studies conducted not only by the National Transportation Safety Board (NTSB), but also (in the low-weight, fixed-wing, arena) by the Aircraft Owners and Pilots Association (AOPA). There is every reason to believe that, despite the fact that the US GA fatal-accident rate shows an increasing trend, it is probably the safest in the world, next to the UK's. The reason for the upward trend is not just an increase in accident numbers, but a decrease during the 1990s in GA activity - which is also true of Canada.

Even these analyses, however, for all their meticulous categorisation, seem somewhat resigned in their attitudes. The US AOPA's just-published Joseph Nall's report for 1995 explains why, saying: "Accident rates in general aviation have always been higher than in air-carrier operations. Because of its versatility, GA has risks that others do not share. If the versatility was minimised, we would lose much of the utility of GA." The report, much more detailed and graphical than its predecessors of previous years, emphasises that some operations, for example, agricultural aviation, law enforcement and banner towing "-are relatively high-risk".

Business aviation in the Nall report (which does not include aircraft heavier than 5,700kg, or jets) shows up as GA's safest zone, conducting 16.2% of the USA's GA flying, but accounting for only 4.6% of the accidents and 6.5% of the fatal accidents. "Personal flying" is judged by Nall to be the most dangerous sector, carrying out 38% of GA flying, but accounting for 65% of accidents and 68.4% of fatal accidents.

While pointing out that regulatory requirements are fewer for the GA sector, thus putting more responsibility for safety upon individuals, the Nall report does not criticise the tools of the trade - the aircraft. Asked about this missing factor, AOPA comments that GA safety could be improved by bringing the benefits of the "glass cockpit" to the average GA aircraft, increasing the amount of information available and thus improving pilots' "situational awareness". It can certainly be said of most private light aircraft that the cockpits and their basic equipment have not evolved much since the 1950s. The only "revolution" has been the replacement of the three-pointer altimeter.

At a more basic level, the Association says that lives could be saved and injuries avoided by making compulsory five-point pilot-seat harnesses and wider seat belts.


AOPA's other recommendation is that the GA pilot's task should be simplified. The Association is certainly not alone in targeting cockpit and aircraft simplicity: NASA is leading an industry programme called the advanced general-aviation transport experiment (AGATE), and its aims are likely to prove to be the most powerful single instrument for change in the world's GA industry. Potential for improved safety is certainly a part of the AGATE project, but only time will tell whether better GA safety is a direct product of it.

Simplicity is stated as the prime AGATE objective; safety is definitely not the actual rationale. Using a liberal interpretation of the programme's acronym, the latest NASA newsletter illustrates the priorities by proclaiming, "The first 'A' in AGATE means 'Affordability'".

Mike Durham, NASA's deputy manager for AGATE, explains the industry-based motivator for it, saying: "We asked people what it would take to get them to fly more, or to start flying. The answers are cost and time." The AGATE team is working to reduce those two factors, with simplicity seen as the key to success in both. "The results have translated into the AGATE programme," says Durham.

As a classic example of ease of operation, Durham cites the single-lever power control (SLPC), in which a full-authority digital engine-control (FADEC) unit enables a single power-lever to take charge of the propeller pitch and the RPM - a combination usually handled by two levers. The SLPC, through the FADEC, would also take over the functions of other engine-control devices such as condition levers, fuel/air mixture and ignition-timing controls.

The other main leap in cockpit simplicity proposed by AGATE, explains Durham, is "-a software-driven environment supported by a databus standard that all competitors can plug into". This would enable cockpit standardisation on a level unavailable today, suggests Durham, further reducing training time and cost, cut by devices such as the SLPC. The end result, suggests AGATE research, would be to cut training time by half.

If the purpose is to make GA flying more accessible to more people, safety must be a part of the AGATE objective. Improving pilot situational awareness is an AGATE objective, but, again, reduced training-time is cited as the primary rationale, with improved safety apparently as its secondary effect.

Early AGATE proposals for improved situational awareness look as if they come close to those of the airlines, and assume huge advances in digital information-processing technology, together with its increased affordability. NASA says that the AGATE aircraft will have:

single-lever FADEC power controls;

global-positioning-system navigation in an integrated flight-management system;

flat-panel displays, for integrated graphic navigation, weather and traffic information;

electronic primary flight display;

datalinked information transfer.

Also a part of the AGATE dream are terrain display, sophisticated ground-proximity warning and head-up graphical displays to provide the pilot with a safe trajectory to follow on approach to landing.


In the USA, according to the Nall report, there were 383 fatal accidents in 1995, out of 1,853 fixed-wing GA accidents. The NTSB lists a larger total, 2,065 accidents, up from 1994's total of 1,997. The NTSB list includes jets and aircraft heavier than 5,700kg, which Nall's does not. The NTSB also, lists separately, an additional 75 air-taxi accidents. Air taxis are categorised under GA in most countries, but not by the NTSB. AOPA does not include them in its report because of the nature of its membership, which tends to be private and corporate.

Among the Nall-reported fatal accidents, 18 (4.7%) were believed to have been caused by "mechanical or maintenance-related failures". Among those failures, some 75% were attributed to the engine/propeller, which makes power-unit failure, therefore, the cause of between 3% and 4% of the fatal accidents. Engines were not within the AGATE remit, so NASA Administrator Daniel Goldin is supporting plans for a GA-propulsion programme, to be managed by NASA Lewis, to start in 1997. "With this last technology puzzle piece in place," says NASA, "we have the basis for a well-balanced portfolio for revitalisation."


It could cynically be said that the reason why the GA industry tends not to concern itself overmuch with matters such as cockpit standardisation and ergonomics is that the figures every year prove that some form of basic pilot-misjudgment, or malpractice, is the primary cause of the average GA accident.

The Nall report for 1995 gives "manoeuvring", which, in the USA, means aerobatics, "buzzing" a point on the ground, or some form of low-height activity, as the largest single cause (36.1%) of fatal accidents in single-engined fixed-gear aircraft. The more sophisticated the aircraft is, the less likely the pilot seems to be to indulge in "manoeuvring", or to make mistakes while doing it. In single-engined retractable-gear aircraft, the proportion reduces to 16.9% and, in multi-engined machines, it drops to 2.5%, says the Nall report.

The Nall figures put "weather" second to manoeuvring as the cause in the single-engine fatal categories, but, for multi-engined types, it comes out as the top cause by far, at 47.5%. On weather-related accidents, AOPA comments: "Many of these accidents occur during instrument-flight-rules operations. Because of the higher impact speeds and the manner in which weather-related accidents occur, these accidents are more severe in multi-engined and complex single-engined aircraft. "

The actual causes of weather-related fatal accidents listed in the Nall report "...usually involved controlled flight into terrain or [collision with] other objects, or uncontrolled flight because of spatial disorientation or pilot-induced structural failure of the aircraft". What the report calls "attempted visual-flight-rules into instrument-flight-rules [conditions]" starts the chain of events which leads to disaster in 83% of weather accidents involving single-engined fixed-gear aircraft; 55% of the events in single-engined retractables; and 63% of the weather-related accidents in multi-engined GA aircraft.

The UK has always listed "continued flight into adverse weather" as its most persistent single cause of fatal GA accidents. During the period 1981-95, it accounted for 30% of all GA fatal accidents (for single- and twin-engined aircraft). The UK's nearest equivalent to "manoeuvring", as the USA defines it, is a combination of what the UK Civil Aviation Authority calls "low aerobatics, or low flying", and "loss-of-control VMC [visual meteorological conditions]". Together, they accounted for 40% of all 1981-95 UK GA fatal accidents.

The UK's long-term experience in both weather-related and manoeuvring fatal accidents is, therefore, proportionately almost identical to that of the USA.

1995 turned out to be an exception to the UK's normal experience, because continued flight into adverse weather did not feature under that heading; the one controlled-flight-into-terrain fatal accident, however, could have been categorised as such. The largest 1995 UK GA fatal-accident category was loss of control in VMC, which accounted for four out of the 12 fatal GA accidents. With such a small sample (compared with the US industry's annual experience) short-term figures are statistically of doubtful significance. In its General Aviation Safety Information Leaflet, reviewing 1995 GA accidents, the CAA comments, however: "The worrying factor in the 1995 accidents is the significant number of loss-of-control accidents, sometimes involving an audience, or peer-pressure. All pilots must guard against the 'I'll show them' syndrome."


Australian regulators, having accepted that more precise monitoring was needed of the country's diverse GA industry, set up a committee which found:

an absence of robust indicators on the safety of aviation or the performance of the Civil Aviation Safety Authority (CASA);

a shortage of information on the low-capacity regular-public-transport and GA sectors;

inadequate regulatory protection against predatory pricing and other destructive competition;

a poor relationship between the industry and the regulatory agencies, including CASA.

Following the report, increased (and unannounced) surveillance of charter operators has been implemented; also, codesharing arrangements between major carriers and local service operators are to be made more transparent "at the point of sale", and the fact that different levels of safety regulation exist at the different operator levels is to be made clear to passengers. Meanwhile, regulatory and accident-investigation arms are to prepare and publish "aviation-safety indicators".

1995 represented a poor year for Canadian GA, in terms of simple numbers. The country's Transportation Safety Board (CTSB) reports that there were 42 fatal accidents in the fixed-wing GA sector, compared with 30 in 1994. Private-aircraft fatal accidents made up 23 of the 1995 total, says the CTSB, and the remaining 19 were "Category III and IV small commercial carriers", which means local, training, fire fighting and agricultural operators. The average annual number of fatal GA accidents since 1991 (inclusive) was 42, but there has been a decline since then of about 0.5% in the annual hours flown, so the fatal-accident rate has increased marginally. Non-fatal private-aircraft accidents decreased from 172 to 161, while Level III/IV carrier non-fatals increased from 123 to 145.


With the use of existing equipment, or equipment, which has introduced little in the way of innovation, there are no signs that the world's biggest GA region - North America - has become any safer over the last five, or even ten, years. Just as airline safety seems to now have reached a near-level plateau so, it appears, has that of general aviation. Human factors are accepted by both sectors of the industry as the area in which significant improvement can be sought.

Meanwhile, looking for serious GA innovations, the AGATE team's objectives for future GA aircraft design, manufacture and operation are all related to providing flying which is significantly easier to learn and costs less, thus leading to more accessible flying.

The Nall report, however, finds that as in most years, rule breaking or misjudgment leading to fatal accidents (as exemplified in manoeuvring accidents), occur more frequently in the simpler and cheaper single-engined categories. Pilot professionalism - in attitude at least and, possibly, in skill - appears to increase in direct proportion to aircraft price and sophistication. This "evidence" may be circumstantial, so it does not necessarily follow that decreasing cost and complexity, and therefore increased ease of access for the public to the future world of GA, will lead to irresponsible flying.

As proposed,the AGATE aircraft looks as if it will be inherently safer than today's. Future pilots will be not necessarily less accident-prone.

Source: Flight International