Business aviation is guilty of underestimating just how vulnerable it is when it comes to safety, according to recent analysis. This is despite the fact that accident rates in the USA and Europe are generally falling

More than three fifths of the world's fleet of business aircraft is in the USA, so analysis of what happens there remains a critical global safety benchmark (see box). There is evidence the world fleet distribution may be changing slowly, the most obvious indicator being that "rest-of-world" orders for new business jets in 2006 exceeded - for the first time - the number placed by US operators.

A recent analysis of business-jet safety incidents in UK airspace has indicated that the overall sector, contrary to accepted industry opinion, does not have an underlying safety performance rivalling that of airlines, even if the upper, corporate, tier of business aviation does. This study, however, refers to incidents as indicators of risk, rather than accidents as proof of it.

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A Citation overran the runway on landing at Carlsbad-McClennan-Palomar, California, on 24 January 2006, killing all four on board

Speaking at the European Business Aviation Convention and Exhibition in May, Richard Schofield, safety division chief at UK air navigation service provider NATS, said 3.5% of the movements in the airspace it manages are business jets, but 16% of level-bust incidents, 33% of failures to follow standard instrument departures and 12% of altimeter-setting errors involve business jets. In addition, he said that 10% of the particularly dangerous error in which a pilot correctly acknowledges a level-change instruction, but fails to carry it out, involve business-jet operations.

Navigational errors

Schofield also revealed that 10% of "gross navigational errors" in the Shanwick Atlantic oceanic area are committed by business-jet crews, and said that, although this represents only a small number of incidents, it is disproportionate to the amount of business-jet activity across the North Atlantic.

As for runway-incursion incidents, Schofield revealed, the largest number in the UK occurs at London Heathrow airport. But that is a function of the airport's complexity and number of total movements, which includes a tiny proportion of business-aircraft operations, he said. The highest rate of runway incursions in the UK, however, occurs at Farnborough, which primarily handles business and corporate aircraft.

Schofield said his motivation for presenting these statistics was that incidents that are not heeded eventually become accidents. He pointed out that 25% of all business-jet incidents in UK airspace are level busts, and this rate is getting worse.

Also at EBACE, the UK Civil Aviation Authority's head of flight operations David Chapman came to similar conclusions, but using accidents rather than incidents as an indicator. Taking UK fatal accidents per million flying hours, the total business-aviation rate is eight and a half times that for large public transport aircraft and in line with the rate for pure freight operations, which Chapman said is unacceptable. He presented evidence that suggests one reason for the disparity between airline and business aircraft safety is that the airlines have been br ought fully into the CAA's long-established mandatory occurrence reporting scheme, but the reporting from the business-aviation sector is proportionately much lower, so sector weaknesses remain hidden and untreated.

High standard

But data presented by business aviation safety analyst Robert Breiling and Stuart Matthews of the Flight Safety Foundation shows that, in US corporate operations involving jets flown by two professional pilots, safety standards are as good as those of the airlines. The FAA shows the latest US airline fatal accident rate as 0.22 per million departures and, although the corporate aviation fatal accident rate is measured by flight hours instead of departures, the latest FAA figures show it achieved a rate of less than 0.1/100,000h from 2004 to 2006 inclusive.

Robert Matthews of the FAA's Office of Accident Investigation says there are many reasons the accident rate is so low. They include gradual long-term improvements in air traffic control services, weather forecasting and dissemination, engine reliability, ground proximity warning systems and traffic collision avoidance systems, and more frequent use of better flight simulators. More recent beneficial effects, says Matthews, have come from advanced avionics, the effective use of satellite navigation, better automation and fleet modernisation.

On the other hand, two respected co-speakers at this year's Flight Safety Foundation/National Business Aircraft Association corporate aviation safety seminar presented incident information that indicates changes in traditional crew training patterns are needed to improve a poor record of managing engine problems.

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This Challenger SE corporate jet rolled rapidly just after lift-off in snow showers at Moscow Vnukovo, and a wingtip hit the ground

A study by Patrick Veillette and Eric Wickfield from major fractional ownership operator Netjets has found that pilots appear to be more likely to mishandle an inflight engine failure than used to be the case - although they point out that issue of mishandled engine problems has always been underestimated.

Crew errors

As engines become more reliable, powerplant failures are rarer, yet the number of accidents and incidents related to engine failures is not decreasing, the study concludes, explaining: "There is an increase in the frequency of crew errors when dealing with engine problems," adding that this occurs because pilots frequently misinterpret the problem and take inappropriate action as a result.

This state of affairs was acknowledged after some engine-related accidents in the 1990s, prompting the US Aerospace Industries Association and its European counterpart, among others, to begin studies of turbofan-related accidents that involved inappropriate crew responses. This study was not confined to the corporate/business aviation, but its results are reflected across the sector spectrum and remain valid today.

Citing what they call anecdotal evidence - the result of pilot replies to questions - Veillette and Wickfield report that, although 66% of reported engine-related accidents and incidents involved compressor stalls, only 3% of professional pilots reported receiving any practice at recognising and dealing with this kind of engine problem during their last four recurrent training sessions.

All pilots receive recurrent simulator training in engine failure during take-off, and pilot responses to questionnaires indicate that 83% of them think this is the most frequent flight phase in which failures occur. Actually, says the study, in business jets "the vast majority" of engine failures leading to accidents or incidents occur in the cruise, so the simulator training does not reflect reality. "Train for reality, not legacy. Look at the accident and incident data and modify the curriculum to reflect reality," Veillette and Wickfield recommend.

Meanwhile, the past 12 months have not been accident-free for US business jets. There were three fatal accidents involving Cessna 560-series Citations, two of which were chartered and one of which may have been classifiable as a corporate flight, but this is not yet clear from the National Transportation Safety Board preliminary report. All three accidents involved apparently unstabilised approaches, two of which resulted in fatal overruns. One involved an attempted late go-around during which the aircraft hit the ILS localiser antenna with its landing gear and crashed. Outside the USA a Citation I - a German-registered company aircraft - suffered apparent controlled flight into terrain in Iraq.


The most puzzling accident of 2006 among business jets was the collision of an ExcelAire Embraer Legacy 600 - on its delivery flight from the manufacturer - with a Gol Boeing 737-800. The aircraft were heading in opposite directions on the same Brazilian airway at the same flight level. Both had airborne collision avoidance systems (ACAS), but neither crew received a resolution advisory.

The Legacy survived despite losing oneof its winglets and part of its horizontal stabiliser, but the 737 crashed with the loss ofall on board. Brazilian investigators are trying to determine why both aircraft were at the same level, and why the ACAS did notoperate. Criminal prosecutions against air traffic controllers and the Legacy pilots are being prepared although the technical accident investigation still appears to have a long way to go.


Source: Flight International