Last year saw three high-profile air fatalities. General and corporate aviation should start worrying

David Learmount/LONDON

Last year tainted corporate aviation's safety image, and this year has started badly. Several high-profile public figures lost or came close to losing their lives in corporate and general aviation aircraft accidents.

In pure safety terms, it should only matter that life is lost, not whose life it is. But for the corporate aviation industry, from manufacturer onward, high-profile lives stand out. Corporate aviation is the chosen transport of many VIPs, sportsmen and women and wealthy individuals, so any accident to a business jet or high-specification light aircraft has an above-average chance of involving high-profile casualties.

All such accidents put the aircraft and their operation in the spotlight. This may have an insidious and unquantifiable effect on corporate decisions to invest in aircraft.

Senior executives worry as much about flight safety as anyone else. Many large multinational companies have long had policies about not putting more than one very senior executive on the same airliner or corporate jet when they would probably not think twice about putting them in the same car or train.

Last year was certainly not favourable either statistically or in image terms. The listed turbine aircraft accidents in 1999 compared with 1998 rose from 70 to 100, and fatal accidents from 29 to 40 (see related article).

Three "high-profile" corporate or general aviation events occurred during 1999. Greece's deputy foreign minister and six other passengers were killed when the pilots lost control of the Greek presidential Dassault Falcon 900 aircraft during descent into Bucharest, Romania on 14 September. Golf star Payne Stewart and two pilots died in an unnerving Learjet 35 accident in which the aircraft flew on autopilot for about four hours with no signs of life on board until it ran out of fuel and crashed in South Dakota (24 October).

Flying his own single-engine piston-powered Piper Saratoga, John F Kennedy Jnr and his wife died during an instrument meteorological conditions (IMC) approach to Martha's Vineyard on the US east coast. This year, racing driver David Coulthard escaped from a badly damaged Learjet 35A in which both pilots were killed on landing at Lyon, France (Flight International, 9-16 May). Only last week two leading UK-based jockeys were injured and the pilot killed when a Piper Seneca crashed on takeoff from a race course.

In Greece the emerging details of the presidential Falcon accident (see related article) have begun to cause a stir. A leaked investigator's report blames almost all the parties involved for what amounts to complacency - a trait not normally associated with presidential aircraft operations. The aircraft's operators, Olympic Airways, are threatened with prosecution for alleged negligence in maintenance and for the aircraft's inadequate emergency checklist. The pilots are accused of ignoring standard operating procedures and the civil aviation authority is charged with failing in its safety oversight duties.

Although the aircraft made a safe landing at its destination, Bucharest, with no external sign of damage, the cabin was in turmoil with six passengers dead, one dying, one seriously injured and two with minor injuries. Those who survived without serious injury, including the flight crew of three, did so because they were wearing their seat belts when, during the descent, the aircraft began to porpoise violently, throwing the passengers from the cabin floor to the roof and back again. The official accident report by the Romanian authorities is expected later this month. Meanwhile, a parallel Greek investigation has pinpointed a malfunctioning pitch feel system as the accident's primary cause.

Video shot by one of the casualties reveals that, though illuminated, the instrument-panel caution light indicating the pitch feel malfunction was ignored by the pilots. Crucially, the checklist did not contain the procedure for dealing with the problem, which includes slowing the aircraft to less than 260kt (481 km/h) indicated airspeed (IAS).

The report alleges that the cockpit voice recorder (CVR), which was unserviceable, and the pitch feel fault were long-standing defects which had not been rectified, and that the pitch feel would not have malfunctioned if a recommended modification had been carried out.

Hypoxia theory

The cause of the Payne Stewart Learjet accident is still a mystery. Military aircraft flew alongside the fated aircraft and reported misted cabin windows and no signs of activity or of external damage. Unsubstantiated industry suggestions are that - contrary to initial speculation that there had been an explosive decompression - the aircraft may never have pressurised fully and the occupants, including the crew, passed out from hypoxia during the climb, which was when the last report from the crew was recorded.

The precise reason for the crash of John F Kennedy Jnr's Saratoga may never be known because it did not carry a flight data recorder (FDR). But the US National Transportation Safety Board (NTSB) said there was no apparent technical fault in the aircraft when it was recovered from the sea.

The accident happened on a night approach over water in either IMC or marginal visual meteorological conditions (VMC), a classic combination of conditions for inducing sensory disorientation or "vertigo". Just after the aircraft had started its descent into Martha's Vineyard, local radar recorded it entering a 4,700ft/min (24m/s) rate of descent in a turn, before the signal was lost. Kennedy was a private pilot without an instrument rating, but had undergone an IMC familiarisation course to prepare him for unexpected encounters with deteriorating weather.

Stanley Roscoe of the US Crew System Ergonomics Information Analysis Centre says he believes that Kennedy's "graveyard spiral" was the result of a phenomenon known as "horizon control reversal", which has been studied and documented by aviation and ergonomics specialists for decades. In a conventional artificial horizon, it is the horizon line which moves relative to the pilot, whereas the aeroplane symbol is "fixed" - physically fixed in an electro-mechanical instrument - to the angle of the real aircraft. Therefore the pilot may perceive the aircraft as not moving in response to controls.

The situation that can lead to horizon control reversal occurs if the pilot perceives the horizon line - because it moves relative to him - as being the controllable symbol on the instrument. If one wing is low, the pilot's attempt to roll the horizon bar toward 'wings level' relative to the aircraft symbol, increases the aircraft's bank, inducing confusion and sensory disorientation because the result is the opposite of what the pilot perceives it should be.

Many accidents have, or may have, been caused by this, Roscoe says, explaining that a potential modification to how artificial horizons operate could reduce the risk of it occurring. But the industry has failed to take up the issue. Although Roscoe's theory is that it would be better if the aircraft symbol were seen to respond more dramatically - relative to the pilot - to control inputs, he does not recommend the unadulterated "outside looking in" type of artificial horizon favoured in the former Soviet Union, particularly for military aircraft, in which the horizon is fixed relative to the real aircraft and the aircraft symbol is "flown", as it might be in a computer game, relative to the horizon bar.

Hybrid instrument

His recommendation is a hybrid, in which the horizon bar 'moves' to stay true with the real horizon. The aircraft symbol also moves, in the correct roll direction, relative to the pilot, providing psychological reassurance that the aircraft itself is responding to control input. The trouble is that such a device depicts bank on the instrument as greater than it really is, so selection of a specific angle of bank would need to be a specially learned technique.

Other instruments have come in for criticism in the sense that they are, like artificial horizons, designed to aid the pilot but may end up putting him or her at risk. Around 69% of US Aircraft Owners and Pilots Association (AOPA) members and 60% of avionics shop owners believe that Global Positioning System (GPS) satellite navigation moving map displays and other advanced avionics are contributing to the loss of basic pilot navigation skills.

AOPA President Phil Boyer, speaking at the recent Aircraft Electronics Association convention in Reno, Nevada, USA, said: "The new gee-whiz avionics on the exhibit hall floor at this convention are just the tip of the iceberg. It will not be long before many pilots, even of many single-engine aircraft, will enjoy terrain mapping, ground proximity warnings, collision avoidance, lightning strike data, radar returns and near real-time weather graphics and text."

Avionics retailers are also concerned that pilots can buy a new avionics device, but there is no system for ensuring that they are trained to use it. They agreed that it is more difficult to learn to use modern avionics than traditional ones, but the shop owners and AOPA members differ on where the responsibility for training lies. Around 34% of AOPA members believed training was the pilot's responsibility compared with 11% of avionics shop owners. However, 36% of shop owners believe the shop should provide training, while 53% said that the avionics manufacturers should be responsible for it.

Two-thirds of AOPA members who recently purchased a new GPS receiver said their avionics shop offered no help in learning to use it.

The NTSB estimated figures for all US general aviation in 1999 showed continuing improvements in both non-fatal and fatal accidents. The rate for all classifiable accidents was 7.05 per 100,000 flying hours, which is the lowest ever rate and compares with a rate of 10.9 in 1982. In the last three years, however, the improvement rate has slowed: it was 7.28 in 1997. For fatal accidents, the estimated 1999 rate was 1.26 per 100,000 flying hours. In 1982, for example, the rate was 1.99.

In 1999, the UK experienced an unwelcome upturn in light aircraft fatal accident numbers, with 15 fatal accidents compared with 10 in 1998. The situation reflects something of a plateau, however, because although 10 fatal accidents was the lowest ever number, it has been as low as that three times before, the first time in 1982.

World trends

Although the UK Civil Aviation Authority is reluctant to comment on most of the 1999 accidents because they are still under investigation, it observes: "Mountains had an influence in three of them and bad weather seems to have influenced at least three more. Take-off accidents, including practising for engine failure, account for five, and landing accidents for three. Loss of control, for whatever reason, seems to be a major factor in five of the accidents, and there was one mid-air collision."

New Zealand has carried out a wide-ranging analysis of its aviation safety trends, and it records the fact that the trend is worsening steadily for fixed-wing GA aircraft below 2.7 tonnes maximum take-off weight. In the third quarter of 1999 the all-accident rate for this category was running at 15 per 100,000 flying hours, twice the US rate of 7.28.

The news is better for aircraft in the 2.7-5.7 tonne band, the accident rate for which is improving fast, having been 20 per 100,000 flying hours in 1996 and dipping to just over 2 by late 1999. The overall GA accident rate, says the New Zealand CAA, is improving steadily, having shown just over 14 accidents per 100,000h in 1989 and reaching an estimated 8 in 1999. France has not presented rates or trends, but reports that in 1999 there were 162 accidents to private fixed wing light aircraft of which 21 were fatal, killing 37 people.

Although private GA will probably always remain unpredictable, indications are that aviation authorities and flying associations can persuade the industry as well as pilots to work at becoming safer.

Meanwhile at the top, business jet end of the industry, where aircraft sales have shown record buoyancy in recent years, the participants need to worry, just as airlines do, about the perceptions of their safety standards.

Source: Flight International