Bryant Jordan at our sister blog DoD Buzz wrote about the Headquarters Marine Corps' explanantion behind what happened last April when an MV-22 crashed during an exercise in Morocco that killed two crewmembers. Here's an excerpt from Bryant's post:
The accident occurred as the Osprey was taking off, turning to avoid a busy landing field even as it was rotating its proprotors to transition from helicopter mode to fixed wing.Longtime DT readers may remember a post back in 2006 where I predicted there would be six Class A V-22 mishaps within the first three years of fleet introduction. Among my itemized flight scenario predictions was this:
As it did that, the center of gravity moved forward – pointing the Osprey’s nose down – and a strong tailwind pushed the plane forward and downward. The co-pilot, he said, failed to adjust the nacelles during the turn to overcome the effects of the nose-down altitude.
“The aircraft is now committed and it flies into the ground,” said Marine Corps Lt. Gen. Robert E. Schmidle Jr., deputy commandant for Marine Corps Aviation. The Osprey only reached an altitude of about 50 feet above the ground before it crashed, killing two Marine aircrew members, Cpls. Robby A. Reyes and Derek A. Kerns.
Had the pilots kept the aircraft in helicopter mode until they had gained speed and altitude, the accident probably would not have happened, Schmidle said.
The test pilots (both active duty and civilian) did amazing work during the High Rate of Descent (HROD) phase of developmental test at NAS Patuxent River back in 2002 and 2003. They validated the V-22’s vortex ring state (VRS) envelope. (DT readers will remember that VRS was what caused an Osprey to crash near Marana, Arizona back in 2000, killing 19 Marines.) Improvements have been made in the vertical speed displays and aural warning systems. But the fact remains that — while there are no “unknown unknowns” about VRS and that there is a buffer between the operational rate of descent limit of 800 feet per minute and where VRS occurs — the rate at which the V-22 develops a high rate of descent is unique to the V-22. Basically, the crew has to hawk the VSI gauge constantly during a descent. A moment’s inattention can result in the vertical speed getting out of hand. (The test pilots actually had an inadvertant VRS entry during HROD testing because they got distracted for a second.) So imagine junior pilots during high op-tempo periods (deployed) at night, on goggles, and operating with not enough sleep (never happens if you follow NATOPS, right?) Yes, this is a training issue in that crews can be taught to watch the VSI readout on the display, but in spite of the comprehensive understanding Osprey crews have of the phenomenon (thanks to the Developmental Test Team at Pax River), somebody’s going to be tired and distracted (and maybe under fire) and will enter VRS close to the ground. The outcome won’t be good.And in the case of this Morocco crash the outcome wasn't good. Doubtful VRS was the issue, but vertical speed obviously was.
The comments with Bryant's post vividly show the two camps most interested parties fall into: Those who believe that pilot error will always be part of the equation as long as humans are in the loop, and those who believe the V-22 is inherently flawed because of its design, etc.
No airplane is crash-proof. If a pilot wants to fly a JSF into the ground he can. Even drones crash on occasion. But sometimes airplanes have aeromechanic tendencies that make them crash-prone. (Along with having worked in the V-22 Joint Program Office for three years as the spokesman, I have 2,800 hours as a Tomcat RIO; talk to me about inducing yaw rates at high angles of attack with that airplane.)
The V-22's operational mishap rate would suggest the airplane is NOT crash-prone. However, certainly relative to conventional rotary wing aircraft, the Osprey has -- literally -- more moving parts, and that can bite a pilot when operating near the ground. As Gen. Schmidle said, had this co-pilot done everything but program the nacelles forward at that time he probably wouldn't have hit the ground.
A couple of flight adages come to mind:
- There are no new mishaps; just new pilots causing the same old mishaps.
- You can only tie the record for low flight.