EH101 flight operations
Keywords Aircraft, Reliability, Maintenance, Testing, GKN Westland,Helicopters
The two Anglo-Italian EH101 aircraft involved in the intensive flight operations programme (IFOP) in Aberdeen are clocking up the hours. Between them PP8 and PP9, the civil pre-production aircraft, have completed more than 3,500 hours of the 6,000 flying hour programme.
The IFOP began in 1996 and is designed to prove the reliability and maintainability of the EH101 and the time between overhauls of major components. Flown by commercial pilots provided under contract by Bristow Helicopters, each aircraft will typically fly two three hour sorties per day, six days a week, the sorties being simulated civil and military mission profiles. At peak flying rates the aircraft have logged as many as ten flying hours in a day.
A major milestone was reached in April when PP9's main gearbox and accessory and tail gearboxes were taken out for their 1,500 hour inspection. The results,said Flight Trials Manager Harold Cunningham, were excellent. "Everything was in first class working order. The gearboxes were reassembled and put back into the aircraft without the need for any replacement parts".
With PP8's flying hours already well over 1,900, the 2,000 hour gearbox inspection will be undertaken in the next few weeks.
Another key milestone reached recently was the successful meeting of the mean time between attributable failures (MTBAF) requirement. Under GKN Westland's contract with the UK Ministry of Defence, the EH101 had to complete 500 hours flying in which there was less than one attributable failure of any sort in every four hours. According to GKN this target was comfortably achieved and the aircraft completed the last 70 hours of the programme with no recorded faults of any description.
The IFOP programme is planned to conclude in summer 2000, by which time the pre-production fleet will have logged a total of more than 10,000 flying hours.
GKN Westland also reports that with a total of 45 new airframes on order, the Super Lynx production line at Westland's Yeovil, UK, plant is at its busiest for many years. The programme, we are told, took another step forward recently with the first flight of the second of seven new Super Lynx being built for the German Navy. Thirteen new Super Lynx are also in production for a Far East customer and GKN Westland is upgrading to Super Lynx the 17 existing German Navy Mk88 Sea Lynx and eight Lynx in service with the Danish Navy.
The upgrade programmes for the German and Danish aircraft are the first life extension orders to include the supply of new airframe structures into which the existing aircraft's engines, flying controls, hydraulic systems, avionics and electrical systems are transferred. This innovative approach offers operators a cost effective, short lead-time approach to extending the aircraft in service for many years to come. Typically, a more traditional upgrade, where the airframe is stripped down and refurbished, takes the aircraft out of service for some 12 months. Using the re-airframing option the aircraft is back in service after only four months. The latest standard Super Lynx airframe also incorporates an uprated fuselage which has the potential to take the all-up weight of the aircraft to well over 12,000lb (5,500kg).
