Middle Eastern carrier Emirates underpinned its enthusiasm for the Boeing 777-300ER's economics with an order for up to 70, a colossal deal which came amid several orders at the Dubai air show - with Gulf rival Qatar Airways sparking fireworks.

Emirates' agreement handed Boeing its largest commercial aircraft order, by value, with 50 firm aircraft worth $18 billion, while the carrier is separately leasing another nine 777 freighters from Dubai-based lessor DAE Capital for its SkyCargo division.

DAE, which recently switched several Boeing 747-8F orders to the 777F, will take the aircraft from its Boeing backlog and deliver them in 2012-2015.

Emirates' combined acquisition reinforces its position as the largest 777 operator. It has 94 of the type, with 41 more on order before the Dubai agreement.

It means the 777 has secured a record number of orders for a single year - 182 net at the time of the Emirates' deal.

Boeing chief Jim Albaugh said the airframer was seeing no "pricing pressure" on the 777 despite emerging competition from the A350 family, for which Emirates has orders for 70.

He said Boeing intends to take advantage of a "lot of uncertainty" regarding the A350-1000, as it seeks to fix a timeline for an improved version of its 777 twinjet.

Albaugh said carriers will wonder whether the recently-disclosed delay to the baseline A350-900 will "cascade back" to the A350-1000.

Airbus has already pushed entry into service for the A350-1000 back to 2017 as it concentrates on the A350-900, and Boeing is looking to "answer questions" about the likely arrival time of the rival aircraft.

"If the -1000 were to come out in 2018 then we'd have a 777X come out not too long after that," Albaugh said, pitching the timeframe at "the end of this decade".

Emirates said the 777X programme "has not launched yet" but added: "When it does and is tested and piloted, we could consider entering discussions about the programme with Boeing."

With 94 777s in operation and another 41 777-300ERs on order, Emirates has accounted for 9.7% of the programme's total deliveries since 1995. That share will grow to 10.2% in March 2012, when the airline takes delivery of the 1,000th 777, the airline's 102nd of the type. When factoring in the 50 new orders, Emirates is responsible for 24% of the 777's backlog, which stands at 375 aircraft.

More from Flightglobal at the Dubai Air Show

Source: Flight International