LIFE EXTENSION AND AIRWORTHINESS We are all being asked to work longer before retirement – even military aircraft!

摘要

The effective management of risk coupled with maintaining a platforms operational capability beyond that which was initially envisaged by the initial design intent, in the face of a changing financial, organisational, technological and regulatory environment is a difficult and challenging activity. There have been a number of military and civil procurement and modification programmes which have faltered as a result of these issues and factors, e.g. the Chinook MK3 which did not receive airworthiness certificates due to issues with the avionics software (which have now been addressed by MK4). This paper discusses some of the key factors, the associated risks and their relationship to each other which need to be considered for aircraft life extension programmes. This paper also discusses the implications associated with retrospective application of rules and standards. The key factors and their associated risks in relation to aircraft life extension are common across all platforms and domains and pose specific challenges when changing an aircraft baseline. Risk is generally a well understood discipline and in its broadest terms is assessed through evaluating the probability and consequence of an event. Effective management of these factors and the risks is essential to ensure that a platform can return to service. These areas which pose risk and which have a direct influence on the platform, for the purposes of this paper have been classified as being Influencing Factors (IF's). Although at first these would appear to be obvious, Atkins experience 1 MoD UK procurement policy; Concept Assessment Development Manufacturing In-Service Disposal across a number of programmes and domains has indicated that they are often addressed separately and the inter relationships between the risks associated with each is not fully understood or managed. This can result in significant detrimental risk to the programme. Processes including the MOD Architecture Framework (MODAF) (Ref.7) provides a means to analyse the risks associated with capabilities, systems and business processes in accordance with the CADMID 1 lifecycle. However, this is more easily applied to new build programmes and is often not easily applicable to a life extension programme and the risks associated across all the disciplines.