Asked by Angus Robertson
(Moray)
Asked on: 17 March 2015
Ministry of Defence
Joint Strike Fighter Aircraft
Commons
227873
To ask the Secretary of State for Defence, what steps have been taken to eliminate uncommanded wing drop when manoeuvring the F-35B.
Answered by: Mr Philip Dunne
Answered on: 25 March 2015
The Joint Strike Fighter programme has completed an extensive period of dedicated development flight test to both assess the impact of uncommanded wing drop (called transonic roll off) and mitigate its impact. The results of flight test have been to use a combination of control surface inputs from the leading edge flaps, trailing edge flaps and horizontal tails which have been applied differentially using software driven flight controls when the aircraft is operating at elevated angles of attack in the transonic flight condition.
It is extremely difficult to totally remove transonic roll from the transonic area of the flight regime, but these changes in the software control laws have lessened its severity and it has been assessed that they are now acceptable by the experienced flight crews that have flown with them. The programme leadership, which includes the UK Ministry of Defence, has concluded that they will allow the aircraft and pilots to execute the mission. The programme will continue to monitor and refine the flight control laws throughout the life of the aircraft as the aircraft’s capability develops and if the target set and mission changes.
Asked by Angus Robertson
(Moray)
Asked on: 17 March 2015
Ministry of Defence
Joint Strike Fighter Aircraft
Commons
227874
To ask the Secretary of State for Defence, what assessment he has made of the effects of buffeting and transonic roll-off on the ability of (a) the helmet-mounted display systems to display symbology and (b) gyroscopes in the inertial platforms to operate correctly on the Joint Strike Fighter F-35B.
Answered by: Mr Philip Dunne
Answered on: 25 March 2015
The Joint Strike Fighter programme has completed an extensive period of dedicated flight test to assess the impact of buffeting and transonic roll-off on both the helmet mounted display and gyroscopes in the inertial platforms. The conclusion of these flight tests, which have used changes in the flight control laws to mitigate both conditions throughout the flight envelope, is that the helmet mounted display and gyroscopic equipment meet the required performance specification and are fit for purpose to allow pilots to execute the mission. It is only in one area of the flight regime where buffet makes screen symbology difficult to read, and this is at the extremes of the envelope and extremely short lived as the aircraft manoeuvres, it is considered that they can be overcome by pilot training. These flight trials have included UK test pilots who have agreed with the conclusions of the US experts from government and industry.
Asked by Angus Robertson
(Moray)
Asked on: 17 March 2015
Ministry of Defence
Joint Strike Fighter Aircraft
Commons
227875
To ask the Secretary of State for Defence, how many production Joint Strike Fighter F-35B aircraft have been received by the UK armed forces; and how many of those aircraft have achieved supersonic speeds.
Answered by: Mr Philip Dunne
Answered on: 25 March 2015
The UK has received three F-35B aircraft in the low rate initial production phase. None of the production aircraft have achieved supersonic speeds to date. Although the F-35 design has been tested up to supersonic flight there is currently a flight restriction that prevents this as the aircraft are awaiting modification. There is currently no requirement for the aircraft to achieve supersonic flight in support of the UK’s current phase of introduction to service which is focused initial operational test and training activity.
Asked by Angus Robertson
(Moray)
Asked on: 17 March 2015
Ministry of Defence
Joint Strike Fighter Aircraft
Commons
227936
T