BRIEFING: SHIPBORNE ROLLING VERTICAL LANDING [SRVL]c.2008 Richard Scott"...
Landing aidsWith SRVL now likely to he used as a primary recovery technique on board CVF, there is an additional requirement to augment the baseline landing aids suite with a landing aid appropriate to the SRVL approach manoeuvre. To this end QinetiQ has been contracted to research, conceptualise and prototype a new VLA concept, known as the
Bedford Array, which takes inputs from inertial references to stabilise against deck motions (pitch and heave). The software-controlled lighting pattern provides an aim-point for the recovering pilot.
Justin Paines, development test pilot for QinetiQ, said: “Study work and simulator flying have shown that the F-35B has a critical vulnerability to deck motion for the SRVL manoeuvre. So while there is confidence that SRVLs can he performed safely in benign conditions with good visibility,
it was apparent that the real task drivers for the manoeuvre were higher sea states and night/poor weather conditions.”
Simulator flying undertaken on both sides of the Atlantic, including work at BAE Systems’ Warton Motion Dome Simulator in December 2007, had brought the problem into sharp relief. “Quite simply, these simulations showed that pilots would crash in high sea state conditions without a suitable stabilised visual reference,” said Paines. “The need for some sort of VLA optimised for SRVL was therefore apparent.”
Although an unstabilised approach aid was looked at early on, the ‘top end’ (recovery in Sea State 6) requirement saw it ruled out on grounds of pilot workload and risk. So a stabilised VLA quickly emerged as a sine qua non.
[SEA STATE 6: “4 to 6 metres wave height - Very rough & Surface Wind speed from Table can be from 27-33 knots”
Sea State Table:
http://www.syqwestinc.com/support/Sea%2 ... 0Table.htm &
http://en.wikipedia.org/wiki/Sea_state ]
Existing systems were evaluated, including the US Navy’s Improved Fresnel Lens Optical Landing System (IFOLS). “However, the verdict on IFOLS was that it was reasonably expensive, not night-vision goggle compatible and, as a mechanical system, presented an additional maintenance burden to the carrier,” says Paines. “So the concept of the Bedford Array was conceived, developed and fully tested in around a year in direct response to MoD requirements.”
The science behind the Bedford Array – so called because it was brainstormed at QinetiQ’s Bedford lab – is deceptively simple. A linear array of software-controlled lights is installed along the centreline of the axial flight deck, using a simple mathematical algorithm to switch on the appropriate lights according to the ship motion references input to the system. These provide a
stabilised glideslope indication for the pilot’s helmet display SRVV symbology.
“The system ensures that the pilot flying the ‘rolling landings’ makes an accurate approach to the deck, even in rough sea conditions,” said Paines. “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.”
A trial of the Bedford Array concept was undertaken aboard the aircraft carrier HMS Illustrious in November 2008, with QinetiQ using the VAAC Harrier test bed to fly approaches to a demonstration Bedford Array mounted on the ship, in order to evaluate its ability to accurately indicate an SRVL glideslope aim-point. For the purposes of the trial, the lighting array was installed in the port catwalk adjacent to Illustrious’ flight deck.
The VAAC Harrier did not actually perform SRVL recoveries to the ship, owing to the limited dimensions of the flight deck. Instead, it flew representative SRVL approach profiles to the catwalk array (down to a safety height of about 40 ft above deck) and then performed a low go-around.
QinetiQ’s VAAC Harrier flew a total of 39 sorties in the southwest approaches between 12 and 19 November 2008 to prove the Bedford Array concept. In all, 67 vertical landings and around 230 SRVL approaches were flown.
A second lighting array was rigged on the carrier flight deck itself. This was used for a parallel evaluation of the visual acuity of the lighting system, in different ambient conditions, on deck.
“This series of trials was designed to refine the operational concept, mitigate failure cases and optimise the Bedford Array visual landing aids arrangement,” said Lieutenant Commander Chris Götke, VAAC project pilot and one of the six assessor pilots participating in the trial. “The solution was first tested in QinetiQ labs and has now been proved by successful trials, and will be implemented on the new carriers.”..."
Source: http://www.zinio.com/reader.jsp?issue=3 ... v=sub&p=28 [no worketh now] so go here:
viewtopic.php?f=22&t=20304&p=265112&hilit=Paines#p265112 [& not quite the same article:
http://militarynuts.com/index.php?showtopic=1507&st=120 ]
29 Dec 2018, 16:29
