In the past, the RAF's approach to corrosion was reactive: corrosion occurred, was identified and then rectified. Such a strategy is no longer acceptable, as corrosion rectification is costly both in terms of material and aircraft availability. More importantly, as escalating replacement costs force us to retain aircraft in service for ever-longer periods, the threat posed to structural integrity by corrosion and repeated corrosion repairs can no longer be tolerated. Consequently, the RAF has had no option but to develop a policy of corrosion prevention. Although good husbandry can contribute greatly to corrosion prevention, it is difficult to implement effectively at a time of reducing manpower and increasing operational commitments. Aerospace Maintenance, Development and Support, part of Headquarters Royal Air Force Logistics Command, has therefore been actively involved with the evaluation and trialling of a range of important corrosion prevention techniques that are compatible with the RAF's current stance. Aircraft washing and rinsing practices have been reviewed to confirm their effectiveness, and trials have shown that dehumidified air permeates readily through a full size airframe, reducing relative humidity and arresting the rate of corrosion. From our work we have concluded that effective washing should be supported, where possible, by freshwater rinsing, and, if a cost effective system can be developed, structural dehumidification should also be practised. Notwithstanding a policy of corrosion prevention, we know that we operate aircraft that have already accumulated corrosion damage which has to be located and recorded. Non-destructive testing is employed widely, and the use of information derived from the process to populate structural databases is being explored. Additionally, we are involved with refining the methodologies associated with structural inspections to ensure the ongoing integrity of our ageing aircraft fleets.
