« Quote of the Day: To Be or To Do? | Main | How to Advance U.S. Nuclear Security in Five Simple Steps »

Apr 12, 2010

TrackBack

TrackBack URL for this entry:
http://www.typepad.com/services/trackback/6a00d8341c68bf53ef01347fd34f1c970c

Listed below are links to weblogs that reference Why the Recent Osprey Crash Is Turning Heads: An Explainer:

Comments

Terry

from the great G2mil.com blog. There are links there. http://www.g2mil.com/crumbles.htm

Apr 11, 2010 - CV-22 Crash Data

A recent "Aviation Week" article "The Need for Speed" quoted Col. Clay Hutmacher from the 160th Special Ops Aviation Regiment:

“Above 4,000 ft., there’s a significant [hovering] limitation on the V-22,” he said. Tiltrotor engineers concede that while the V-22 hovers well in many situations, the special twist and size of its “proprotors” leave it unable to carry as much useful load pound-for-pound as most helicopters hovering in similar conditions.

“I’m not disparaging the V-22,” Hutmacher said. Hovering ability, however, is critical to the 160th, because “at the end of the day, our mission is going to terminate in a hover.”

One CV-22 didn't terminate in a hover, and crashed 7 miles west of Qulat city, Afghanistan, which is listed at 5085 feet altitude, about the same as Denver CO. What does the pilots manual say? Some pilots and aviation experts have quietly expressed alarm that the manual includes old performance objectives in their charts rather than results from testing. If pilots use charts that exaggerate range and altitude performance, they may come up short and crash.

For example, some V-22 salesmen claim that V-22s can hover at 10,000 feet, although official stats have long showed a 7000 feet (HOGE) hover capability. NAVAIR and Boeing recently downgraded that to 5400 feet as V-22s were sent to Afghanistan. The actual figure varies depending on temperature and gross weight (payload and fuel.) Col. Hutmacher said HOGE is less than 4000 feet, yet if the mishap CV-22 pilots assumed it was safe to hover up to 5400 feet, that may have caused their fatal crash!

In comparison, the common Blackhawk helicopter has one-third the engine power and is a third smaller than the V-22, yet its big rotors allow it to lift the same payload vertically. This is because the V-22 has smaller, twisted "proprotors." While the V-22 is limited to landing at 5400 feet, (or perhaps 4000 feet) an Army Blackhawk crashed last year during a routine training operation in Colorado while attempting to land at 14,200 feet!

Apr 10, 2010 - CV-22 Crash
Here is my uninformed knee-jerk analysis of Thursday's CV-22 crash. The pilot was very experienced. Since a pilot and flight engineer died while others survived, I suspect it hit nose first. I will guess at two causes.

1. The CV-22 was performing out of its very restricted flight envelope, trying to hover at mid-altitude with payload to perform a mission helicopters often do. It failed during a landing approach, rolled to one side and impacted nose first. Pilot error of course, but by a senior pilot called a "CV-22 evaluator" by the USAF.

2. The other possibility is an engine failure. The V-22 can fly with one engine out in the airplane mode only! If in the helo mode, it must convert to the airplane mode but needs several seconds and 2000 feet of altitude. If that is not an option, it makes a very hard crash landing since it can't autorotate.

Recall the USAF has still not released the summary of a Class A CV-22 mishap at Kirkland on Mar 2, 2009. Why? And would the timely release of that mishap report provided information to the crew of this CV-22 as how to avoid problems? And recall the recent USAF CSAR report that noted the V-22 cannot safely hover at over 4000 feet.

Apr 4, 2010 - The V-22 Disaster

The V-22 scandal just gets worse. An Army helicopter brigade has been assigned to support Marines in Afghanistan since their new ultra-expensive MV-22s can't do the job: The V-22 Disaster.

The comments to this entry are closed.