Software aids engine repair

Edited by the Engineeringtalk editorial team Jul 30, 2007

Brookhouse's help has provided British Airways with a tool to carry out repair jobs which would normally cost in excess of US $200,000 if sent back to the manufacturer.

By reverse engineering a full bond and support tool for a GE-90 inlet skin, Brookhouse, of Darwen has allowed British Airways Engineering's Fleet Support Facility to carry out a cost-effective repair at its London Heathrow workshops while providing the company with an in-house capability to repair any future, similar engine damage.

The Fleet Support Facility (FSF) is the main support workshop at Heathrow and undertakes complex approved repair of many aircraft components.

This avoids sending parts back to original manufacturers for repair, which would incur higher costs and longer repair lead times.

In fact, the structured, in-house repair facility has the potential of cost avoidance of over GBP 1 million per year.

Bird strikes represent an all too familiar hazard faced by aircraft engines and it was as a result of such a bird strike that the inlet skin of the GE-90 was damaged and sent to the FSF workshop for repair.

However, the manufacturer's specification requires that any damaged inlet skin, which is essentially a composite panel of sandwich structure construction, has to be cured at a temperature of 177C at the original autoclave curing pressure.

To achieve this, a full bond tool is necessary to maintain the panel profile and to prevent any distortion during the repair cycle.

Having already made use of Brookhouse's expertise, notably in the building of a similar bonding and support tool for a damaged D-duct of the GE-90, FSF decided to send the damaged inlet skin to Darwen .

The first step was to effect a temporary repair of the damaged area to restore the panel to its original surface geometry.

The panel was then used as the original pattern for the support saddle of the tool and was located in a specially manufactured, wooden holding fixture while it was laid up with carbon fibre.

The saddle was then cured on the component in an autoclave.

Having established the correct tool geometry, the carbon fibre support and backing structure was then attached to the saddle and the complete, rigid assembly was located in steel handling trolley.

A special requirement for the tool was its overall size, as it had to be able to be located, with the panel, in the FSF autoclave.

This was achieved with just 20mm clearance.

Final repair of the damaged panel, incorporating the use of a specially manufactured honeycomb core, was effected at the FSF and the complete assembly was successfully cured on the support and bond tool at elevated temperature and pressure, with no distortion or damage to any part of the structure.

Moreover, the FSF now possesses a tool to carry out similar repair jobs, which would normally cost in excess of US $200,000 if sent back to the manufacturer.

Brookhouse is a company which is totally focused on the aerospace sector.

It offers design and manufacturing for composites tooling, a facility for the repair of composite components and a capability for design, prototyping, manufacture, testing and finishing of complete composite components.

As a result, Brookhouse can offer its worldwide aerospace customers a global facility to take responsibility for complete parcels of composites' development and manufacture projects.