Modifying ageing aircraft always presents a challenge, not only with regard to gaining access to original data, but also from the variability of airframe build standards. This was the case with a client that was modifying a Boeing 727 aircraft to be the first line of defence to clear oil spills through an integrated dispersant system. Stirling were contracted to provide an aerodynamic evaluation of the spray boom and the complete design of the ventilation system, from feasibility to detailed drawings.
As there was little original data available, we conducted several aircraft surveys to recreate the necessary data. The main issue that the client faced was that the dispersant was classed as a flammable fluid, which added additional safety requirements to the design and required our specialist engineering support.
The major technical challenge was in the venting system, which we took ownership of to provide a solution that encompassed performance modelling and verification, safety assessments (FHA, SSA), the creation of full-drawing packs of the venting system, and providing support to preliminary and critical design reviews and test planning.
The new venting system has been built to Stirling’s design and the aircraft is now certified for its new lease of life.