Trials prove novel QinetiQ solution for F-35B ‘rolling landings' on Royal Navy's future aircraft carriers in high sea state conditions

QinetiQ has successfully completed a series of trials using its T4 Vectored-thrust Aircraft Advanced Control (VAAC) Harrier aircraft on HMS Illustrious. These proved QinetiQ's innovative new Bedford Array visual landing aid system - which stabilises the aircraft's approach path in the presence of deck motion - as the solution for Shipborne Rolling Vertical Landings (SRVL) on the Royal Navy's future carriers, particularly in rough sea state conditions.

The UK Ministry of Defence has been funding ongoing research to refine and de-risk the use of SRVL approaches for its new jump jet - the F-35B Lightning II Short Takeoff and Vertical Landing (STOVL) Joint Strike Fighter (JSF), the UK MOD's preferred choice to meet its Joint Combat Aircraft requirement. The MOD plans to operate up to 36 JSFs from each of its two new future aircraft carriers:- HMS Queen Elizabeth, currently expected to enter service in 2014 and HMS Prince of Wales in 2016.

An SRVL landing involves a STOVL aircraft executing a ‘rolling landing' onto the carrier flight deck, using air speed to provide wingborne lift to complement engine thrust. No arrestor gear is deployed as the aircraft uses its own brakes to stop. Compared to a standard vertical landing, an SRVL recovery offers real advantages for the F-35B as heavier payloads can be brought back and safely landed onboard ship. It also has the potential to reduce propulsion system stress and therefore extend engine life.

Early studies showed that the F-35B has a critical vulnerability to deck motion for the SRVL manoeuvre and that this type of landing is not viable in all desired conditions. As a result, the MOD placed a contract with QinetiQ in 2007 to analyse the root cause of the problem and design a solution.

QinetiQ's new Bedford Array visual landing aid system was conceived, developed and fully tested in around a year in direct response to MOD requirements. The system ensures that the pilot flying the ‘rolling landings' makes an accurate approach to the deck, even in rough sea conditions. It takes inputs from external passive references and when combined with information in the pilot's Helmet Mounted Display, allows for a low workload, stabilised pilot approach in even the worst conditions.

"The UK has an incredible heritage of innovation in naval aviation and pioneered many of the things now taken for granted in the conventional carrier world,� explained QinetiQ test pilot Justin Paines, who flew the X-35B Joint Strike Fighter Concept Demonstration Aircraft. "With the Bedford Array, we've done it again and developed an approach aid that has application beyond F-35B to other forms of embarked aircraft recoveries. We have already received interest from other countries involved in naval aviation."

QinetiQ's VAAC Harrier flew a total of 39 sorties in the southwest approaches between 12-19 November to prove the Bedford Array landing system - in all 67 vertical landings and around 230 SRVL approaches were flown.

"This series of trials was designed to refine the operational concept, mitigate failure cases and optimise QinetiQ's innovative Bedford Array visual landing aids arrangement," explained Lt Cdr Chris Götke, one of the test pilots who also marked his 400th vertical landing during the trials. "The MOD turned to QinetiQ to solve this significant problem of landing laden aircraft in rough seas. This ingenious solution was first tested in QinetiQ labs and has now been proved by these hugely successful trials and will be implemented on the new carriers."

In mid-2007, a series of VAAC trials were conducted onboard the French aircraft carrier Charles de Gaulle to establish the fundamental safety, operability and operational benefit of the SRVL technique. The recent trials on HMS Illustrious could prove to be the last research tasking for QinetiQ's VAAC testbed as the aircraft is now 39 years old, and is expected to be retired from service in early 2009.

For this series of trials the Bedford Array was installed in the port catwalk adjacent to HMS Illustrious' flight deck, but due to the limited dimensions of the deck, SRVL recoveries were not preformed - instead a low go-around was flown. A second lighting array was also installed on the carrier flight deck and used for a parallel evaluation of the visibility of the lighting system in differing ambient conditions.