The first international Joint Strike Fighter, an F-35B for the UK, was rolled out on November 22, one week before a parliamentary report shed more light on the UK’s decision to switch from the STOVL F-35B version to the conventional carrier landing F-35C version. The UK bought three F-35Bs for operational test and evaluation, before last year’s cost-driven change of plan.

A senior Ministry of Defence officer told members of parliament that the F-35C offers more inter-operability with allies and more payload/range and that the switch would make it easier “to integrate sovereign weapons into the larger bomb bay.”

He also said that the UK would no longer be exposed to the risk of developing a shipboard rolling vertical landing (SRVL) technique to safely “bring back” a weapons-laden F-35B to the carrier, and without the damage to the carrier deck coatings that might be caused by the powerful STOVL engine downwash. Lockheed Martin has denied the potential for deck damage, and none has been reported after recent sea trials of an F-35B by the US Marine Corps (USMC).

The UK will complete two new aircraft carriers in 2016 and 2019, before converting one for the F-35C and mothballing or selling the other. The parliamentarians repeated concerns about the cost and technical risk of the American electromagnetic aircraft launch system (EMALS) that the UK wants to fit, in preference to steam-driven “cats and traps.”

However, tests of the first EMALS system at Lakehurst airfield, N.J., are proceeding to plan. On November 18, the third F-35C test aircraft was launched by the system, which is due to be installed on the USS Gerald R. Ford in 2015, and on all large U.S. aircraft carriers thereafter. The UK is likely to acquire the second EMALS shipset.

The UK will not decide how many F-35Cs to buy until late 2012. But the new report makes clear that few will be acquired before 2020.