AVIATION SAFETY

Aviation Safety

Aviation Safety

IntroductionAccidents such as failure to get airborne, collision with obstacles after take-off and over-run on landing, occur frequently to light aeroplanes - (over 20 cases per year). Many have happened at short strips, often when operating out of wind or where there was a slope. Poor surfaces such as long or wet grass, mud or snow, were often contributory factors. These were performance accidents and many, if not all, of these accidents could have been avoided if the pilots had been fully aware of the performance limitations of their aeroplanes. (Pavia 2007) Better a disappointed passenger than a grieving widow! Do not rely on the 'It will be alright' syndromeThe pilot in command has a legal obligation to check that the aeroplane will have adequate performance for the proposed flight. If you are using a 3000 metre runway a cursory check of performance will do, but where is the dividing line - 700, 1000 or 1500 metres? This will be decided by a large number of variables and only by reference to performance data, including climb performance, can the safety, or otherwise, of the particular flight be properly determined. (Brownstein 2006)

Finding The InformationThe data needed to predict the performance in the expected conditions may be in any one of the following:

The Flight Manual, or for a few older aeroplanes, the Performance Schedule.

The Pilot's Operating Handbook or the Owner's Manual. This is applicable to most light aeroplanes and sometimes contains Change Sheets and/or Supplements giving additional performance data which may either supplement or override data in the main document, e.g. a 'fleet downgrade'.

For some imported aeroplanes, an English language Flight Manual approved by the airworthiness authority in the country of origin, with a supplement containing the performance data approved by your aviation authority. (Pavia 2007)

Use Of Performance DataMany light aeroplanes are in performance group E, and certificated with UNFACTORED data, being the performance achieved by the manufacturer using a new aeroplane and engine(s) in ideal conditions flown by a highly experienced pilot. It is unlikely that your aviation authority has verified the Performance Data on all foreign aeroplanes; in some cases a single spot check may be made.

To ensure a high level of safety on UK Public Transport flights, there is a legal requirement to apply specified safety factors to un-factored data (the result is called Net Performance Data). It is strongly recommended that those same factors be used for private flights in order to take account of:

Your lack of practice

Incorrect speeds/techniques

Aeroplane and engine wear and tear

Less than favourable conditions (Brownstein 2006)

Performance data in manuals for aeroplanes certificated for the purposes of Public Transport may include the Public Transport factors, (i.e. Net Performance) but manuals and handbooks for the smaller aeroplanes often do not. For foreign manufactured aeroplanes the Net Performance may be included as a Supplement. Manuals usually make it clear if factors are included but if in any doubt you should consult your aviation authority.

Performance PlanningA list of variables affecting performance together with Factors for non-Public Transport ...