Return to Flight – Vulcan

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11 March 2014

Revival

Marshall Aerospace and Defence Group’s role as the Engineering Authority on the return to flight of Avro Vulcan XH558 gave the UK nation back its most iconic Cold War aircraft.

After 33 years of sterling service to the RAF, Avro Vulcan XH558 was officially grounded in 1993, following her final flight to Bruntingthorpe Aerodrome, Leicestershire. She was purchased by a family firm, C Walton Ltd, with the thought that she might one day fly again. A detailed feasibility study to return XH558 to the air began in 1997, but it would not be an easy task; the team, headed by Dr Robert Pleming, faced many daunting challenges along the way.

Obstacles in her path

Considered a ‘complex’ ex-military aircraft by the Civil Aviation Authority (CAA), XH558’s restoration to airworthy condition required contractual involvement from her original constructor: in this case, BAE Systems, as the descendant of A.V. Roe. However, resource constraints prevented the company taking on the restoration project – an initial setback for the team.

Fortunately, an alternative solution was found. BAE Systems, supported by the CAA, identified Marshall Aerospace and Defence Group (Marshall ADG) as having the necessary engineering experience and capability to take on such a complex project. Marshall ADG agreed and assumed the role of Engineering Authority on XH558’s restoration to flight.

As the aircraft was grounded and could only taxi, the restoration had to be carried out at Bruntingthorpe, where one of the hangars was turned into a CAA-approved workshop. Computer links were set up to give the engineers direct access to the Marshall Aircraft Design Office and its Engineering, Production Planning, Quality Assurance and Supplier Management departments in Cambridge.

Technical challenges

Once XH558 had been purchased by the Vulcan to the Sky Trust, a registered charity, and a technical team recruited and trained, the heavy engineering work commenced – but this was not without its own unique difficulties.

A particularly challenging task was the embodiment of ‘Modification 2222’. This modification, designed to strengthen the wing rear spars and extend fatigue life, should have formed part of the service due in 1993 when XH558 was retired. The basic design had been developed by BAE Systems, but it fell to Marshall ADG to manage the manufacture of tooling and parts and carry out the modification.

Further difficulties arose from discrepancies between drawings and the actual state of the aircraft, which hindered the considerable electrical work demanded by the project. During XH558’s ‘taxiing only’ years, a number of electrical repairs had been made which did not meet the standards required for an airworthy aircraft, and thus needed to be re-engineered.

For some of the aircraft systems requiring replacement, complete overhaul was impractical or impossible. For example, the Military Flight System (MFS), comprising compasses, gyroscopes and attitude displays, proved prohibitively expensive to refit with like-forlike parts. Modern commercially-available solutions provided an alternative, but needed to be integrated onto the Vulcan platform.

50 of the aircraft systems that would not be required for XH558’s display career were removed or deactivated. This required careful planning and design so that the systems could be removed without compromising the structural integrity and safety of the aircraft and its remaining systems.

Furthermore, the CAA stipulated that XH558 meet modern certification requirements, so it was necessary to upgrade radios, add a Mode S transponder, a Global Positioning System (GPS), Distance Measuring Equipment (DME) and an Altitude Alert System (AAS).

Revival

Despite the complexity of the project, Marshall ADG rose to the technical challenges. All the work on the aircraft was supervised on site by Marshall ADG technicians under the approvals granted to Marshall by the CAA. Significant amounts of engineering design work were carried out by staff in the Marshall Aircraft Design Office, including approvals of repairs and replacement materials, safety cases for removal of systems, and the necessary changes to aircraft documentation. The combination of on-aircraft technical support and back-office design support made Marshall ADG uniquely well-suited to the Vulcan restoration project.

XH558

The return to flight of Avro Vulcan XH558 was a remarkable feat of engineering. Marshall ADG recorded around 22,000 production hours and 40,000 engineering hours. However, due to the charitable nature of the work, the actual figure is estimated to be much higher. The XH558 restoration project does not only owe its success to the overwhelming support from the public and the British aviation industry; it was the culmination of a decade of hard work and dedication by the Vulcan to the Sky Trust and the fullycommitted expert engineering team from Marshall ADG.