Sir - "Lessons from the cockpit" (Flight International, 11-17 January, P24) shows that, although the automation of aircraft is sold as an improvement in safety, it is unfortunately not all gain.
The main shortcoming is that the "modernisers" assume that the pilot receives relevant information from the instrument panel only and ignores other sources. The movements of the control column, throttle levers and trim wheel alert the pilot to what is about to happen - instruments only indicate changes once they have taken place, perhaps several seconds later. Those few seconds could make the difference between an incident and accident.
Most problems occur when something unusual happens during height acquire or if go-around is inadvertently activated. Recent serious accidents and incidents are by no means isolated cases of the limitations of the aircraft systems and their inability to learn from experience. Pilots learn and reprogram their own "software" after each flight, becoming, on the whole, very much more sophisticated in coping with problems with the aircraft systems - which experience minimal updating and certification.
Please don't isolate the pilots from the aircraft.
IAN HANNAY
Fleet, Hampshire, UK
...Under the heading "Nagoya and certification" in "Lessons from the cockpit", there is a statement that the European Joint Aviation Authorities (JAA) argued that it should not be possible to disconnect the autopilot by normal use of the control column during an automatic landing.
As the original Airbus A300 and its A300-600 and A310 pre-dated the JAA procedures and a common JAA design code, it is not strictly correct to refer to a JAA certification. They were certificated by a joint, French and German civil aviation authorities' process, followed by validation by the UK Civil Aviation Authority.
Secondly, under the heading "Software changes", it is stated that the UK CAA ordered suppression of the pitch-trim-operation warning sound on the A300-600 and A310.
This is not correct. No changes were required by the CAA from the basic standard offered by the manufacturer. On the original A300, the CAA identified a problem during an automatic landing flare of excessively noisy operation of the trim in motion warning. Airbus addressed this by deleting the trim in motion warning when the autopilot was in a command mode.
The CAA is very much aware of concerns over the man-machine-interface issues raised by modern automatic flight-control systems. We are represented on the US Federal Aviation Administration Commission looking into these issues, together with colleagues from other JAA authorities.
The JAA is establishing a human-factors group to address these issues, together with the wider aspects of human factors in certification, operations, maintenance, medical and licensing areas.
K M PERRIN
Head of flight department
Safety Regulation Group
Civil Aviation Authority
Gatwick, West Sussex, UK
...It is worrying that Airbus chief engineer Bernard Ziegler dismisses criticism from pilot groups and ardently defends Airbus thinking on design matters. Worse still, perhaps, Aerospatiale's Jean-Pierre Daniel wishes to incorporate yet more technology to remove yet more control functions.
I believe that this approach is the crux of some of the problems experienced by Airbus operators - the technology has arrived ahead of our ability to decide how best to use it. Airbus seems to want to incorporate advanced technology before establishing the need for it, but, because it is possible, this does not mean that it is necessary.
Designers and must listen and respond to the comments of users, from whom there can be no better judgement of an aircraft.
To err is human and even Airbus designers are human, I think.
WILLIAM SCOTT
Long Sutton, Hampshire, UK
Source: Flight International
