Midlands suppliers are hoping for a substantial spin-off from the major engines order announced by Rolls-Royce earlier this week.

The aerospace group revealed it had won a deal worth up to $8.4 billion (£4 billion) from fast-growing Gulf airline Emirates.

Rolls will provide Trent XWB engines to power up to 120 Airbus A350s, which were ordered as part of $35 billion (£16.7 billion) worth of business unveiled by Emirates at the Dubai Air Show.

As well as the A350s order, Emirates firmed up deals on the eight A380 superjumbos for which it signed letters of intent earlier this year.

It also placed orders for an additional three of the double-decker aircraft, bringing its total firm order to 58.

The A380 order could be good news for West Midlands firms, with around 100 companies in the region supplying into the aircraft.

Among the Midland companies involved are GE Aviation in Wolverhampton, which supplies wing flaps and slats, while Dunlop in Coventry supplies wheels for the A380.

And Emirates unveiled 12 firm orders for Boeing 777s, valued at $3.2 billion (£1.5 billion). Emirates now has 57 Boeing 777s pending delivery and is on course to become the world's largest 777 operator.

The Trent XWB is the fourth version of the Trent family ordered by Emirates and will bring its Trent powered-fleet to potentially 175 aircraft. The XWB - extra wide body - is designed in Derby, but Rolls has not said where work on the latest Emirates order will take place.

The contract further develops the company's relationship with Emirates and with the Middle East.

Rolls chief executive Sir John Rose said: "Emirates has become one of the world's largest and most profitable airlines and we are delighted that Rolls-Royce will continue to be part of this success story through our involvement in the A350 XWB."

The Emirates agreement with Airbus comprises firm orders for 50 A350-900s and 20 A350-1000s, plus 50 options for the A350-900s. The first A350 - seen as a rival to Boeing's 787 Dreamliner - will be delivered to Emirates in 2014.

Sheikh Ahmed bin Saeed Al-Maktoum, Emirates' chairman and chief executive, said the airline's total order book now stood at 246 aircraft, all wide body, and worth more than $60 billion (£28.7 billion).

It currently has an all wide-body fleet of 111 aircraft, serving 97 cities in 61 countries.

Sheikh Ahmed said: "In 2003, our plan was for Emirates to have 100 aircraft by 2010. We have already surpassed that target. Growth and demand has exceeded the most optimistic projections."

The firm orders placed with Airbus have a list price value of $20.2 billion (£9.7 billion).

Meanwhile Doncasters Group, a global manufacturer of precision components and assemblies to the aerospace industry, has agreed a contract with Rolls-Royce to repair and overhaul Front Combustion Liners (FCLs), known as annular combustors, for the Rolls-Royce RB211-535C, 524 and a partial load on the 535E4 engines.

The repairs will be handled at the Airmotive division of Doncasters Aerospace Components in Shrewsbury which specialises in the repair and overhaul of gas turbine engine hot section combustion and associated components serving the aerospace and industrial gas turbine industries.

The RB211 engine models are used in a number of aircraft including the Boeing 747 - 400, Boeing 757 - 200, Boeing 757 - 300, Tupolev TU204 and Boeing 767.

Annular combustors, while more compact than cannular combustors, are often more problematic to restore due to the fact that they have to be repaired as a whole rather then in sections.

Cannular combustors are usually found in older engines and Aero Derivative Industrial Gas Turbine engines.

All modern Aero designed engines incorporate the annular combustor.

As combustors - which determine the efficiency of the engine - are seen as a 'core' product, Rolls-Royce manufacture all their annular combustors in house.