English: A Royal Air Force 230 Squadron Puma HC1 helicopter based at RAF Benson, Oxfordshire is pictured flying past The Shard skyscraper during a training flight over London. The sortie included low and medium level transit flights, landing at un-prepared sites and navigation exercises involving a refuelling stop at RAF Marham, an over flight of RAF Wyton and flying through the London heli-lanes. The Puma HC1 first entered service in 1971, and the RAF currently has a fleet of 34 aircraft available to the front-line Support Helicopter Force. The aircraft are operated by Nos 33 and 230 Squadrons, both based at RAF Benson. The combined Puma Force is separated into 5 operational flights and an operational conversion flight, which offers flexibility in its role with both desert warfare and arctic warfare specialist equipment available for fitting to the aircraft.The Pumas are used as battlefield helicopters within the Joint Helicopter Command and provide tactical troop and load movement by day or by night. The aircraft can carry up to 16 fully-equipped troops, or up to two tonnes of freight carried either internally or as an under-slung load. The other major role is that of casualty or medical evacuation support, for which up to six stretchers can be fitted.