The Air Force plans to reinstate substantial formation flight training for CV-22 Osprey pilots that it eliminated four years ago, AOL Defense has learned. Reinstatement of the training four years after the service ended it is an implicit admission, V-22 aviators said, that better training might have prevented the June 13 crash of a CV-22B in Florida.

From now on, Air Force pilots going through initial Osprey flight training with Marine Medium Tiltrotor Training Squadron 204 (VMMT-204) at Marine Corps Air Station New River, N.C., will take a classroom course in formation flight, fly two formation flights of two hours each in a V-22 simulator, and fly one actual two-hour formation flight in the tiltrotor troop transport.

The decision to increase formation flight training for Air Force pilots at VMMT-204 is “an acknowledgement that our V-22 formation training was lacking,” said an AFSOC member who spoke without authorization. “Obviously, in hindsight, the decision removing it is questionable at best.”

Marine Corps pilots have received such formation flight training for years and regularly fly in two- and three-ship sections. The Air Force, though, whose CV-22Bs are flown solely by Air Force Special Operations Command (AFSOC) pilots, directed VMMT-204 four years ago to exempt AFSOC students from most formation flight instruction and remove it from the syllabus for Air Force students, Air Force and Marine Corps sources said. Air Force pilots instead were given more training in using the CV-22B’s inertial navigation system and terrain following/terrain avoidance radar, the sources said. The Air Force also streamlined its training at VMMT-204 to get pilots into the field more quickly, the sources said, holding each student’s total flight hours at the training squadron to about 28 to 29 hours compared to 33 or more for Marine student pilots.

The June accident near Eglin Air Force Base injured all five crew aboard, destroyed their $78.5 million aircraft and cost their squadron commander his job. The CV-22B crashed after its pilot flew through the rotor wake of an Osprey he was following in formation. The mishap Osprey went into a sudden, uncommanded roll to the left, and while the pilot and copilot were able to regain control, their aircraft hit some tall pine trees and slammed to the ground upright.

“To ensure this doesn’t happen again, we have instituted additional training procedures highlighting this hazard,” AFSOC spokeswoman Capt. Kristen Duncan said in an email. She said she was unable to provide details. A spokesman for the Air Education and Training Command declined this week to describe the changes in CV-22 training, citing undescribed “sensitivities.” Aside from what may be a reluctance on AFSOC’s part to admit having made a mistake by curtailing formation flight training, Osprey-related “sensitivities” include concerns the Japanese government has expressed in the face of protests by activists opposed to the Marine Corps’s deployment of 12 MV-22Bs on Okinawa. Japanese critics of the Marine presence on Okinawa have questioned the Osprey’s safety and the adequacy of pilot training in the wake of the June CV-22B crash and an MV-22B crash in Morocco last April also attributed to pilot error.

An Accident Investigation Board (AIB) suggested the pilots in the June AFSOC crash failed to recognize they were flying in the other Osprey’s wake partly because “CV-22 wake modeling is inadequate for a trailing aircraft to make accurate estimations of safe separation from the preceding aircraft.” V-22 pilots and other experts agree that more testing is warranted, and the Naval Air Systems Command (NAVAIR) V-22 program office will conduct more starting this spring. NAVAIR officials said those tests have long been planned, however, and Osprey pilots said the danger area behind a V-22 is sufficiently well known to avoid – provided a pilot gets enough formation flight experience to be able to judge the distances and angles involved accurately.

Lack of awareness of how dangerous the Osprey’s rotor wake can be in helicopter mode is illustrated by a popular photo,taken from the rear ramp of one CV-22B, that shows three other Ospreys as the four AFSOC aircraft took off in dangerously close formation, one behind the other, from a Kirtland Air Force Base, N.M., taxiway on May 1, 2007. The photo was made prior to a 2008 incident in which a senior Marine Corps Osprey pilot nearly lost his aircraft in an uncommanded roll off that occurred during a formation flight near New River.

Since that near-disaster in 2008, the Marine Corps has placed “great emphasis on the hazardous areas to avoid while flying formation,” one veteran V-22 pilot noted.

The hazard stems from the peculiar configuration of the helicopter-airplane hybrid Osprey. Built in a 50-50 partnership by Bell Helicopter Textron Inc. and Boeing Co., the Osprey tilts two 38-foot-diameter “proprotors” on its wingtips upward to take off and land like a helicopter and swivels them forward to fly with the speed and range of a fixed-wing turboprop airplane. The Osprey’s proprotors are undersized for the aircraft’s bulk – a design compromise dictated by the need to fly V-22s from amphibious assault ships for Marine Corps missions – and consequently have to generate a relatively large amount of thrust for each square foot of area the V-22’s rotor disks describe. As a result, when the Osprey flies like a helicopter, its proprotors leave behind a wake of turbulent air so powerful and persistent some V-22 pilots call it “Superman’s Cape.”

You don’t tug on Superman’s cape
You don’t spit into the wind
You don’t pull the mask off that old Lone Ranger
And you don’t mess around with Jim
By Jim Croce, from the song, “You Don’t Mess Around With Jim”

All Osprey pilots are taught that flying through Superman’s Cape can knock the lift out from under one of their rotors, causing an uncommanded roll. They are also instructed to avoid that danger by keeping at least 250 feet of separation between their cockpit and the cockpit of a V-22 ahead of them, staying out of the lead aircraft’s 5 to 7 o’clock position, flying at least 25 feet higher than the lead Osprey, increasing that vertical “step up” to at least 50 feet when crossing the lead aircraft’s path and never crossing the lead’s path in a descending turn.

Those restrictions appear in both the Marine Corps and Air Force flight manuals, along with illustrations of the Osprey’s rotor wake, and the AIB report on the CV-22B crash said the pilot “did not maintain the required 25 feet of vertical separation” from the lead aircraft. The AIB report also said, however, that the pilot was flying two to three times farther back from the lead than the 250 feet stipulated in the CV-22B flight manual. “Specification of a minimum of 250 feet cockpit-to-cockpit separation between aircraft in formation and charts depicting aircraft wake effects extending only to 375 feet can potentially give a false sense of security to aircrews flying at significantly greater distances in trail,” the AIB said.

Arthur “Rex” Rivolo, who in the 1990s monitored the Osprey’s development program for a federally funded think tank, issued a statement – and posted it on Breaking Defense under the screen name “Icon” – declaring that the AIB report on the June crash was a “total distortion of the facts and a blatant attempt to blame the pilots for a very serious design flaw in the V-22 aircraft.” Rivolo, a former fighter pilot who argues that the Osprey’s side-by-side rotor configuration creates insurmountable aerodynamic hazards, recalled that after a Marine Corps Osprey crashed due to an uncommanded roll at Marana, Ariz., in April 2000, killing 19 Marines, he filed an official request that NAVAIR “evaluate proprotor wake interactions in the V-22” but the tests were never completed.

Don Byrne, Bell-Boeing V-22 flight test director at NAVAIR, said in an interview that some of Rivolo’s 23 pages of test requests were performed as part of a series done to satisfy the recommendations of a special panel that examined the Osprey in 2001. The Defense Department convened the panel because of the Marana crash and another caused by a hydraulic leak and a flight control anomaly that killed four more Marines at New River on Dec. 11, 2000.

“We did do testing that defined the current envelope, that said the 250 foot cockpit to cockpit separation and 25 foot step up is safe for the fleet to use,” Byrne said. The bulk of the tests Rivolo requested weren’t done, however, because he wanted test pilots to “get fully involved in the vortex of another aircraft and experience a complete roll off – an out of control roll off – of the aircraft. That’s just not a smart thing to do and no other aircraft goes out and tests to those extremes, either.” Byrne added that the additional testing to be done isn’t of that nature.

“We already know where the ‘avoid’ regions are, as documented in the NATOPS,” Byrne said, referring by its acronym to the Marine Corps flight manual for the V-22, the Naval Air Training and Operating Procedures Standardization manual. The point of the new testing, he said, is to “see if there’s any way to reduce the limitations that are currently in the NATOPS. We’ve been requested ‘can you fly any closer than that?’ So we’re going to do it, but we’re only going to do it to the point where we start to feel the vortex interaction.”

A different NAVAIR expert involved in the issue, speaking on condition of anonymity, described the additional rotor wake testing as part of the routine work by a program office to expand knowledge about any military aircraft to improve safety and performance rather than a search for some way to alter the Osprey to prevent rotor wake roll offs.

“The answer is in training, not in a change to the aircraft,” this official said.

Experienced V-22 pilots agreed. All aircraft leave turbulence in their wake, several noted, and air traffic control towers routinely caution pilots of other aircraft to keep their distance from planes ahead of them.

“As a test pilot, I always want to do more tests,” said Bill Leonard, a former Bell V-22 test pilot who now teaches an aerodynamics course to incoming Osprey pilots at VMMT-204. “I think it’s warranted it be considered and looked at in a technical manner and then come up with an envelope, much as we have a wind envelope for operating aboard the boat. If there is such an envelope out there, the fleet needs to know about it.”

At the same time, Leonard said, mapping the Osprey’s rotor wake in greater detail may be of little help to a pilot flying a combat mission at night, when it can be hard to judge distances between aircraft and precise altitudes despite markings on other V-22s visible through night vision goggles. “In the heat of battle, people get behind the power curve and they get in trouble by losing situational awareness,” Leonard said. “If they know where the (rotor wake) boundaries are – if we tell them it is 247 feet on an azimuth of 9.7 degrees off of the aft nacelle, if we tell them exactly where it is — it won’t do any good. They have no way in the airplane to know where that is. They can’t read that in the cockpit. All they know is, it’s a lot of wind and don’t get in the wrong place.”

An AFSOC aviator agreed, saying: “The problem you have with spacing is, the further you get away from that aircraft, the harder it is to find those landmarks and references that will tell you ‘I am not in the five to seven o’clock,’ or, ‘I’m 25 feet up.'”

An operational Osprey pilot who wished to remain unidentified said V-22 crews can measure their distance to another aircraft to within one tenth of a nautical mile, or about 600 feet, using their TACAN (Tactical Airborne Navigation) receiver-transmitter but have no device on board that can measure their separation from a lead aircraft precisely. Even so, this pilot agreed with Leonard’s view that while more data about the Osprey’s rotor wake would be welcome, it would not necessarily prove vital to operational pilots.

“The data we have is very clear about the wake turbulence out to 350 feet aft of the aircraft,” this pilot said. “I’d be happy to have additional data. My opinion, as a professional V-22 pilot and taxpayer is, spend the money on something else. I have enough testing data to fly this aircraft safely. These (AFSOC) pilots were neither adequately trained nor adequately proficient with formation flying.”

The AFSOC member quoted above agreed, noting that in addition to reinstating formation flight training for its pilots at VMMT-204, since the June crash, the Air Force has required all CV-22 pilots – including those returning from deployments to Afghanistan — to go through new classroom instruction about Superman’s Cape, fly for an hour or two with an instructor to be shown “bad places to be” when flying formation, then take the controls during a formation flight with an instructor as copilot as well.

“What we’ve instituted in training after the crash is a pretty big flag to say, ‘If they’d had the training that we’re getting now, the June crash doesn’t happen,'” this source said. “It’s a pretty explosive acknowledgement that the training wasn’t adequate before.”