While more than 200 Bell/Boeing V-22 Ospreys are already in service with the US Air Force and US Marines (USMC), and the first international order has been placed, the operations with this tilt-rotor aircraft are more and more restricted. Especially when it comes to landing in dusty conditions and in desert environments.
According to military sources US authorities have now officially ordered Osprey pilots not to hover any longer than 30 seconds close to the ground when landing on a dusty or sandy patch of land, down from the earlier directive of 60 seconds. Although V-22 landings are normally done in much less then that, with the aid of on board sensors and instruments, the new order is cause for concern for the tilt-rotor units operating not only in the desert lands of Asia, Africa and the Middle East, but all over the world.
Reason for the new directive is the May crash of a USMC MV-22B on Marine Corps Training Area Bellows – a former Air Force Station turned into training location – on the island of Oahu of Hawaii. According to preliminary findings one of the two Osprey engines stalled after 45 seconds of hovering, presumably due to dust that came into the engine systems during a so-called Reduced Visibility Landing – meaning in this case landing in a dust cloud the rotors just kicked up themselves.
Although RVLs not only covers these so-called “brown outs” it is not proven yet that Ospreys have similar problems with “white outs” – when the down wash of helicopter or Osprey rotors creates snow clouds in winter conditions with the same less or no visibility upon landing.
The accident at Bellows, in which 2 of the 22 marines on board died, puts the focus again on the crappy filters of the V-22 engines. Changed after to the original design was cause for engine fires, the current filters apparently allow to much dust entering the power plants. Bell and Boeing are said to work on yet another solution, but that one has not been implemented yet.
Other military assets like the old CH-46 Sea Knight helicopters the V-22s are replacing – as well as the US Army’s CH-47 Chinooks of similar size – seem to have not much trouble at all with RVLs during normal operations in training and war situations.
While most V-22 pilots manage to put their planes down in under 20 seconds, the new directive orders them to stay above the dust clouds they kick up and continue to hover there if needed until the dust has settled down and it is safe to try to land again. In war zones such increased altitude and exposure of the Osprey will increase the risk of being hit by enemy fire. Food for though for the ones deciding over V-22 tactics in the field.
© 2015 Airheadsfly.com editor Marcel Burger
Featured image: USMC MV-22B during exercise Talisman Saber 2013 (Image © USMC / Lance Cpl. Matthew Bragg)