Cleared for Take-Off

By By Andrew Drwiega, Military Editor | May 1, 2010
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An airfield in Wiltshire in the southern English countryside is home to one of the most significant groups of military helicopter specialists in the UK. They are the driving force behind the upgrading of British military helicopters as well as the rapid fielding of Urgent Operational Requirement (UORs) for rotary use in Afghanistan.

Boscombe Down, a pre-World War II Royal Air Force (RAF) station still owned by the UK Ministry of Defence (MoD) although now managed by a civilian company, Qinetiq, is the home of the Aircraft Test and Evaluation Center (ATEC). Although military assets and squadrons still report to RAF Air Command it is Qinetiq, a company founded out of the break-up of the Defence Evaluation and Research Agency (DERA) in 2001, that manages work through a 25-year Long Term Partnering Agreement (LTPA) with the MoD.

“Cooperation and teamwork are the main factors that are driving the UK’s military aviation test and evaluation centre in Wiltshire,” says Commander Mark “Mario” Carretta, the commanding officer of the Rotary Wing Test & Evaluation Squadron (RWTES) who first came to Boscombe Down 10 years ago. Carretta’s experience as a pilot stretches back to 1986 when he joined 846 Naval Air Squadron flying Commando Helicopter Force Sea Kings. He is an experienced operations pilot and counts the Gulf War, Northern Ireland, Bosnia and Herzigovina, the Lebanon and Afghanistan among his campaigns. He has commanded RWTES since May 2008.


In the last few years, work has been hectic and RWTES has been involved in some modification to virtually all of the UK’s front line helicopter types. The geographical location of Afghanistan has provided significant operational problems for a wide range of helicopters potentially available to the International Security Assistance Force (ISAF), not just those of the UK. However, until recently it was the UK’s fleet of helicopters supporting the heavily tasked CH-47 Chinooks that were finding severe restrictions limiting their operational capability, largely due to altitude and temperature (hot and high).

It was recognized that improvements could be made to both the Royal Navy’s Sea King HC4 aircraft and, more recently, to the Army Air Corps (AAC) Lynx Mk9 that would increase capabilities in the austere environment that is Afghanistan.

Commander Caretta says that the RWTES’ work on testing and proving the Carson main rotor blades, five-bladed tail rotors and Display Night Vision Goggles for Royal Navy Sea King HC4 was one of the landmark cases of cross-cooperation which ended up in giving the aircraft an extra 2,000 lbs. of lift and adding another 35 knots to its average airspeed, while reducing vibration.

Testing was carried out using QinetiQ’s fleet of Mk5 Sea Kings to initially check blade performance as part of the certification process. “We needed to know how much of Carson’s own work we could read across to our own aircraft,” said Caretta. “The project involved AgustaWestland as the UK design authority for the Sea King, Qinetiq as the design authority for the Carson blade, Carson Helicopters, the Sea King Integrated Project Team (ITP) and us.” Further testing was conducted abroad in the mountains near Gunnison, Colo., which had the hot-and-high environment that the team needed in order to prove the extra capability.” Continuing testing in the U.S. might initially seem to be a costly exercise, but as Caretta points out, “we could have waited a long time to conduct all the tests in the conditions that we needed in the UK. If you have different team players all together just sitting around waiting for the right conditions to conduct testing, in the UK that can be a very slow and costly process.”

One of the revision Chinook Mk3 aircraft takes off for a test flight (note the ‘fat tanks’ on the side of the aircraft). UK MoD

Unifying the Team

The reliance on the overworked Chinook force combined with the virtual scandal of eight special forces Mk3 Chinook’s sitting in a hangar, bedevilled with certification issues for their avionics software, eventually resulted in a decision by the Ministry of Defence in 2007 to revert these digitally specified aircraft to ones with analog cockpits. The RWTES team worked with Boeing, Qinetiq and GE Aviation to turn the aircraft around in rapid time. Aircraft were being delivered to the RAF’s Chinook home base at Odiham in December, just five months after the flight of the first revision aircraft in June 2009.

“The Chinook Mk3 revision was not just a straightforward conversion to a Chinook Mk2, as the eight new aircraft all feature ‘fat tanks’ on their waist which effect handling performance,” explains Carretta. Incidentally, when alternative external fuel tanks were brought in for the WAH-64D Apache (the version built under license by AgustaWestland in Yeovil, UK), RWTES carried out the certification process.

Converting the Chinook Mk3s represented the first big program where all concerned participants came together to conduct joint testing. “It was no longer ‘them [the contractor] and us’. The MoD, Boeing, Qinetiq and RWTES got together to agree one test plan between all the parties,” Carretta explained. The test program was a continual agreement and revision process across all the parties with the result that data was gathered once and used many times without organizations working in parallel. Under the auspices of the Airborne Warfare Centre (AWC) [which collates the military side of testing], all teams (civil and military) are now in one location, which significantly cuts down time in cross-referencing and briefing, according to Carretta. This partnership works very well in terms of testing and evaluating each project.

But the work of the RWTES is not always simply following a set schedule of tests. “We don’t go looking for problems when we test aircraft. But button pushing is increasing, which can add to a pilot’s workload and actually defeat the object it sets out to simplify,” says Carretta. Other factors such as too many lights or warning sounds can be equally distracting and the testing team includes in its evaluation how necessary each distraction is and whether there is a better way of communicating the information to the crew.

The central role of evaluation and certification involves extensive work to gather data. Different weights carried within the helicopter serve to alter the center of gravity. Loads on rotor heads and tail rotors need to be measured and evaluated. “The result is nearly always a trade-off between capability and availability,” says Carretta. “The more you push the capability side, the more there is a life penalty in the endurance of the aircraft and its component parts. The trade off needs to balance the extra capability that is required against the lifecycle costs over time.”

There are up to 16 test pilots at Boscombe Down. There is also an exchange pilot from the U.S. Naval Air Station at Patuxent River in Maryland, home of the U.S. Naval Test Pilot School where aircraft such as the V-22 Osprey were tested. The team also has connections with U. S. Army test pilots in Huntsville, Ala.

Front Line First

“The focus is now very much on the front line—we are not here just to hit milestones,” Carretta points out. “There has been a drive to incorporate a constant flow of UORs over the last few years, with each one having to be cleared for use on its intended platform.”

“In virtually all cases we report to the sponsoring Project Teams (PTs) with recommendations for release to service. The PTs take our recommendations and build the safety case. From there they go through to the authority responsible for release to service—currently independent authorities within the Army (Commander, Army Air Corps), Royal Navy and Royal Air Force (CAS).” Although there have been suggestions that one single release to service authority might provide savings in these times of financial prudence, there is currently no official directive to make this happen.

There is no shortage of work on the horizon, although Carretta laments the passing of more independent work that used to be placed with the team in less austere times: “We used to do a lot of research but budget has gone for that.”

Nevertheless over the next two years, the RWTES will be involved in numerous projects. Once the RAF’s AW101 Merlin is turned over to the Royal Navy’s Commando Helicopter Force, the squadron will be employed in transforming the aircraft for embarked operations, including a folding rotor head and tail. RWTES is currently involved in the Merlin Mk1 Capability Sustainment Plus program, which includes the integration of new avionics, communications and navigation equipment and a new open architecture mission system. The Army Air Corps’ major projects include the ongoing development of the WAH-64D Apache attack helicopter and the introduction of the new Wildcat AW149 platform.

Work for the RAF includes the ongoing Project Julius and the Puma Life Extension Program (LEP). Project Julius is the standardization of the RAF’s fleet of CH-47 Chinooks that includes the integration of digital avionics, the engine upgrade to the Honeywell T55-714 as well as the incorporation of Forward Looking Infra red (FLIR) systems. The RAF’s £220 million (approximately $294 million) Puma Mk2 LEP will see 28 Puma aircraft upgraded to include new Turbomeca Makila 1A1 engines, a glass cockpit and a new defensive aides suite.

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