NEW TECHNOLOGY

Many countries are enjoying a remarkable expansion in commercial air traffic as growing populations, increasing wealth and the loosening of sanctions make air travel more attractive and accessible. This growth is being fed by an ever increasing supply of the very latest aircraft, principally from the two big manufacturers, Airbus and Boeing – aircraft equipped with the most modern systems for navigation, communication and engine management.

The manufacturers will argue that all this slick technology will offer operators substantial savings with reduced fuel burn, better aircraft utilisation and simpler, quicker flight crew transitions onto type. They might also argue that some of the new systems make the operation safer by adding layers of defence against mid-air collisions, flight into terrain or unstable approaches. Both of these arguments are correct but ignore the fact that in some cases new technology, or more accurately the way that we humans interact with the technology, has been a factor in the evolution of undesirable conditions and even accidents.

To illustrate this point it is worth going back a few years to the previous generation of jet aircraft. If a system was not performing as expected it was normal practice for the pilot (or more likely the flight engineer) to switch it off and back on in an attempt to recover normal service. Alternatively they might have pulled and reset the relevant circuit breaker, of which there were multiple panels in the cockpit. However, that is no longer necessarily the case. In a recent accident one pilot elected to resolve an intermittent flight control system fault by resetting a circuit breaker in flight, just as he had previously seen an engineer do on the ground. Unfortunately, that particular system takes some time to recover after a reset and in the meantime the flight characteristics of the aircraft changed to the extent that the other pilot lost control and the flight ended in the sea.

In another case, one pilot made a simple numerical error when commencing the take-off performance calculations and used a take-off weight value precisely 100 tonnes less than the actual take-off weight. Partly due to the process by which data was transcribed from the paper loadsheet into a laptop electronic flight bag, and then back from the laptop to a paper flight log and finally from there into the flight management system, this error was never identified, even though there were four pilots in the cockpit at the time. There were probably many other factors at work but the multiple interactions with technology apparently ‘blinded’ the pilots to a substantial and rather obvious discrepancy. The aircraft did eventually get airborne but sustained major damage after scraping its tail along the runway and through the overrun area before lifting off.

So why is it that technology designed to improve efficiency and accuracy can sometimes have the opposite effect? Take-off performance calculations are far more precise when performed by computer software as opposed to the old fashioned tables and graphs. Electronic flight control systems undoubtedly allow for smoother, simpler flying when they are working as designed. So it is not the technology that is at fault, or indeed the concepts that support it. Although in the first case described above there was a technical fault with the flight control system, a cracked electrical solder in fact, if the pilots had managed the deficiency in accordance with the abnormal procedures they wouldn’t have fixed the fault but they probably would have completed the flight.

Part of the problem is that we humans have evolved to chase animals and pick berries and not to operate things with buttons and levers – not yet anyway. Consequently our behaviours and thought processes are based on conditions that are no longer very relevant to the environment in which we work. Unlike just a few years ago, most of a pilot’s job today revolves around monitoring and managing systems, the actual functionality of which he or she would probably struggle to understand. It is sufficient in most cases to know what the input options are and what the outputs can be expected to look like; what goes on in between is of little operational significance. This is the fundamental principle behind claims that pilot training has been simplified, (and that can be interpreted as being quicker and therefore cheaper), by modern aircraft systems.

That is true to a great extent but it brings with it some unwanted baggage. Firstly this lack of understanding of what happens between control selections and the eventual outcomes can become a liability when systems do not function correctly or if conditions are encountered that fall outside the design specification of the system. This was starkly illustrated in a high altitude stall event a few years ago when the flight dynamics were so far removed from what was deemed to be ‘normal’, that a critical stall warning system intermittently suppressed itself, in accordance with its design. The loss of the warning contributed to the confusion amongst the pilots, who could not resolve a number of apparently conflicting pieces of information. If they had fully understood the warning logic they may have had a better chance. The investigation also determined that the pilots had not received training in high altitude stalls, presumably on the basis that the systems would protect them and they would never have to manage such a situation.

Secondly, these modern systems are so reliable that deviations outside of ‘normal’ are incredibly rare. Now that should be regarded as a good thing of course but as a result, and apart from the controlled environment of a simulator, pilots might go many years without ever seeing something significantly ‘abnormal’. This can lead to an over reliance on the aircraft systems and a reduced ability to recognise any undesirable deviations before it is too late to recover. Hour after hour of safe and predictable flight may eventually be interrupted by a sudden and unexpected flight condition and the industry is beginning to acknowledge the debilitating influence of the ‘startle’ effect on pilot performance in an emergency.

This is not a Luddite’s case against modern technology in aircraft; far from it. Terrain awareness systems alone have dramatically reduced the number of inadvertent collisions with the ground and bearing in mind the high fatality rates associated with those accidents, they have undoubtedly saved hundreds of lives. No, the point is that as this new technology sweeps through our commercial aircraft fleets, it radically changes the way that pilots must interact with their aircraft systems, how they think and how they behave. Manufacturers, regulators and operators must accept that fact and ensure that the training offered to pilots – initial, recurrent and upgrade – truly addresses the actual demands of the equipment they are to fly.

Jo Gillespie

Gates Aviation Limited