Israel is continuing to evaluate a possible acquisition of the Bell Boeing V-22 Osprey, with fresh details having emerged about the experience gained by two of its helicopter pilots in flying the tiltrotor type.
The Israeli air force magazine has released parts of a report written by senior helicopter pilots, identified only as Lt Col Avi and Lt Col Nimrod, who flew the US Marine Corps' MV-22 in the USA during 2011 and 2012.
During their assessment, the pair flew the type in conditions ranging from daylight to pitch darkness, and during dust landings and operations in other extreme conditions. They were accompanied by Israeli technical experts, who also completed a thorough evaluation of the V-22 system.
Israeli air force magazine
Avi, a Sikorsky CH-53 helicopter pilot at the Israeli air force's flight test centre, pointed out several factors with the tiltrotor concept that might challenge some pilots.
"The plane is naturally energetic. The accelerations are literally breathtaking and the mid-stage in which the plane transitions from a vertical standpoint to a horizontal one is problematic as well," he says.
"The pilot uses a control stick and a system that is similar to a throttle. In one standpoint, the control stick serves to determine altitude while the 'throttle' serves to determine speed. In the other standpoint, each of them serves the opposite role. In the mid-stage you feel like you're losing control of the plane. I imagined that the fly-by-wire system would function more smoothly, but discovered that in some cases we needed to intervene."
However, Avi says that in all other areas, the system surpassed his expectations. "One of the biggest problems that helicopter pilots have when flying a plane with fixed wings is stalling", he explains. "On regular planes it's very easy to lose control, while on the V-22 you need to try very hard to stall."
In their report, the pilots also tried to address the tiltrotor's ability to meet Israel's operational needs.
Israeli air force magazine
"We examined how the plane would alter operational activities we've carried out and will carry out in the future deep in enemy lines," Nimrod says. "While some of the operations would have changed completely with its help, there are some that would not have been altered at all. For example, in the situation in which we needed to bring back forces from Lebanon, I suspect that the plane had no real advantages." However, he notes: "It's safe to assume that when evacuating injured people inside Israel, the plane would be a less efficient choice, but when rescuing from far away land, using the plane would make a significant difference.
"We realised that the plane will absolutely change the name of the game. It will be able to carry out operations that we never imagined that one of our planes could execute. If we purchase the plane, our ranges of activity will dramatically change and we'll be able to reach points we've never even dreamed of," he concludes.
The air force's final report following the evaluations was in favour of purchasing a number of V-22s for use during missions defined as special operations, and not as direct replacements for its existing helicopters. As previously reported by Flightglobal, the general staff of the Israel defence forces is also considering a possible lease agreement for between six and eight V-22s.
Deliveries of the V-22 have so far been made only to the USMC and US Air Force, with the Bell Boeing partnership still seeking its first export customer for the type. Some 159 of the aircraft are currently operational, as recorded by Flightglobal's Ascend Online Fleets database.