Skies are safer, but the human factor still persists
David Learmount/OPERATIONS & SAFETY EDITOR
A trend line drawn through the big-jet hull loss accident figures from 1991 to 2000 would show a reduction in the loss rate from about 1.5 per million flights to 1 per million flights. That is a 33.3% drop in the hull-loss accident rate in a decade, which is impressive - but is it likely to continue?
Probably, but the rate of improvement is unlikely to accelerate. Work continues with human factors, which are contributory in a high percentage of all accident causal chains at 69%, according to the Flight Safety Foundation (FSF) at its November international aviation safety seminar. This figure is not changing.
The industry is continually looking to improved technology for salvation, but the introduction of promising new equipment such as enhanced ground proximity warning systems (EGPWS), now fitted as standard on all new Airbus Industrie and Boeing aircraft, takes years to show through in fewer accidents. Re-equipment, either by retrofit or in new aircraft, is a gradual process over the world fleet as a whole. In the long term, however, the EGPWS shows huge promise in reducing crashes in the most consistently accident-prone phases of flight: approach and landing.
Boeing will soon offer a vertical situational display in the bottom sector of cockpit navigation displays. This is a sideways "cut" of the vertical profile of the flight trajectory, showing its relationship to a procedural climb or descent path and to terrain, and could raise flight crew situational awareness on approach.
One force for safety improvement previously anticipated by Flight International was substantiated: the FSF has established that airlines in alliances or even code-sharing arrangements produce 51% of the air transport industry's available seat kilometres, but suffer only 34% of the accidents. Since 1999, when the US Federal Aviation Administration required that US carriers should check out the safety standards of foreign partners, the motivation to team up only with the best was given a regulatory boost on top of the marketing imperative that already existed, emphasising the levelling-up effect that partnership has.
The increasing competition resulting from global market liberalisation also means more choice for the customer, forcing airlines to guard their safety reputations, so these two apparently contradictory forces - alliances on the one hand and increasing competition on the other - both tend to improve safety.
The seemingly inexorable trend in a growing number of countries towards separating the provision of air traffic services from government has continued with parliamentary approval for the part privatisation of the UK National Air Traffic Services. The coming year will see the preferred bidder for the public/private partnership chosen and the government will voluntarily withdraw to a regulatory role, while retaining a 49% shareholding.
It will be interesting to see how long the state takes to sell all its shares if everything goes well. There is no historical evidence to suggest that this move should be bad for air traffic control safety - the privatisation of airlines and airports has tended, if anything, to show an improvement in safety levels as companies get on with running the operation, and government agencies become truly independent safety overseers.
Meanwhile, last year showed that the mighty can still fall: the Aerospatiale/British Aerospace Concorde not only crashed tragically, but the fleet was declared "not airworthy" until its vulnerability to critical damage following tyre-burst could be mitigated. Now, six months into the accident investigation, the Anglo-French Concorde Working Group has announced that it knows enough about the causes to advise the manufacturers on developing potential solutions in four specific areas, all of which may need improvement for the aircraft to win back its certificates of airworthiness (C of A).
There is little doubt that technical improvements could see Concorde recover its C of A. The cost of the technology and of the test programme have not yet been estimated, however, so it is difficult to predict whether British Airways and Air France will be able to make a business case for re-certification, irrespective of how strong their motivation is to see their flagship aircraft operational again.
Flight testing of a BA Concorde with modifications is forecast to start in February. If this goes ahead, it should be known by late March whether the plan will work, and how quickly it can be implemented.
Evidence emerging from the Canadian investigation into the 1998 Swissair Boeing MD-11 accident off Nova Scotia has heightened the industry's awareness of aircraft vulnerability to airborne fuselage fires and the relative lack of fire detection and suppression systems in cabin and cockpit areas.
Combined with the conclusions following the 1996 Trans World Airlines 747-100 crash off Long Island, New York, this year should see a consolidation of all the tightened regulations about wiring insulation standards, fuselage insulation materials and fuel tank safety measures consolidated into a total philosophy.
This should yield improved certification standards for fire protection in new-build aircraft. Moreover, it is both the most compelling and the most attainable safety improvement objective that the regulatory authorities could hope to produce.
Source: Flight International
