Tag Archives: CV-22

“Air Force’s CV-22 Osprey tilt-rotor aircraft accident report is a total distortion of the facts” top aviation expert says.

The Air Force Special Operations Command has released the results of the investigation into the Jun. 13, 2012 accident of a CV-22B. The tilt-rotor aircraft, which was assigned to the 1st Special Operations Wing, was flying in a two ship formation when it crashed at approximately 6.45 pm local time during a training mission to the north of Navarre, Florida on the Eglin Range.

All five of the 8th Special Operations Squadron aircrew were seriously injured but none suffered life threatening injuries.

The AFSOC, commander convened an Accident Investigation Board to investigate the crash and the circumstances surrounding it and designated Col. Hans Ruedi Kaspar, 23rd Air Force vice commander as the board president.

The Accident Investigation Board President released his findings and said that there was clear and convincing evidence that the cause of the crash was the crew’s failure to keep the aircraft clear of the lead aircraft’s wake. The result of this was an “uncommanded” roll to the left along with a rapid loss of altitude which resulted with an impact with the terrain.

The aircraft was destroyed upon impact with the loss valued at approximately 78 million USD.

Although Pentagon press secretary George Little speaking to reports recently said: “The Osprey is a highly-capable aircraft with an excellent operational safety record, which includes more than five years of worldwide deployments and 140,000 flight hours,” the safety record of the tilt rotor aircraft, in spite of the DoD, Air Force and Marine Corps claims, has been much debated in the recent past.

Even the loss of a U.S. Marine Corps tilt rotor aircraft that crashed in Morocco during African Lion joint exercise, with two marines killed and two other severely injured in the crash, and few other safety occurrences (that got a special attention on media attention even though they were quite normal) contributed to fuel concerns in those who believe the aircraft is unsafe.

Among them there is A. Rex Rivolo, who is Chief Technology Officer of an aerospace corporation in Virginia, has seventeen years experience in DoD Test and Evaluation community as senior advisor to the Office of Secretary of Defense and served as the principal analyst for the MV-22 and CV-22 at the Institute for Defense Analyses (IDA), a nonprofit organization paid to do independent research for the Pentagon.

Rex has some strong credentials: he was a pilot for six years at the US Air Force and 22 years at the Air National Guard. He has some 7,500 flight hours in both tactical fighter planes and helicopters, including 531 combat missions with the F-4E Phantom in Vietnam. He has earned 5 Distinguished Flying Crosses, 28 Air Medals.

“The findings of the Accident Investigation Board (AIB) for the CV-22B, tail number 06-0032, crash on 13 June 2012 are 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” he told The Aviationist.

The serious safety concerns over the V-22 response to interactions with proprotor wakes of another V-22 were raised as early as 1996 when pilots began reporting incidences of uncommanded roll during flights of multiple aircraft.

“I personally observed several instances of this while flying on the V-22 in the late 1990s as an observer supporting the Pentagon’s Director, Operational Test & Evaluation (DOT&E) during the V-22 operational test period. In their desire to meet cost and schedule milestones, these concerns were given little attention by Bell-Boeing and the USMC management team and they consequently mounted a strong campaign to discredit these concerns with DOT&E. This effort, supported by some of the world’s best aeronautical engineers and pilots convinced DOT&E that the problem was indeed minor and the concerns were overblown.”

“Following the 2000 crash at Marana in which uncommanded roll due to wake intrusion was a possible contributing cause, I recruited Professor Gordon Leishman, one of the world’s top rotorcraft scientists, to investigate the phenomenon using numerical simulation” Rivolo told The Aviationist.

The result of these calculations clearly indicated that V-22 rotor wake intrusion could be a serious hazard to V-22 because of the side-by-side design: “Based on these concerns, I succeeded in resurrecting the issue with DOT&E and the Director demanded that a test and evaluation program be designed and executed to quantify the seriousness of the phenomenon.”

“This test and evaluation program, known as Test Request 65 (TR-65), was designed by DOT&E, Bell-Boeing and the USMC. The TR-65 document, dated 9 June 2000, described over 23 pages of test sequences to be performed to evaluate proprotor wake interactions in the V-22. Eighteen months later, TR-65 was scrapped based on the then current flight experience in which no uncommanded rolls were experienced in the aircraft during formation flight. Based on a strong Bell-Boeing and USMC push to dismiss a “non-issue”, DOT&E acquiesced and TR-65 was never completed.”

As a consequence, the pluri-decorated former combat pilot says, the CV-22 Flight Manual, known as the “Dash-1”, contains only minor guidance in Section V (Operating Limitations) on formation flight position to avoid wake intrusion.

Rivolo believes that if TR-65 had been executed to completion, the uncontrollable rolls experienced by V-22 when intruding into another V-22 wake would have clearly been demonstrated along with the dangers of the phenomenon.

The entire text from Section V of the Dash-1 regarding formation flight limitations Rivolo sent us reads as follows:

1. VTOL/CONV mode formation flying requires a
minimum cockpit-to-cockpit 250 ft separation and 25 ft
step up; step up is to be maintained all the way to landing.
The requirement for step up is designed to prevent
asymmetric wake interactions caused when one rotor
on the trail aircraft encounters the wake of the lead aircraft.

2. During APLN mode formation flight, maintain a
minimum cockpit-to-cockpit separation of 250 ft along
the bearing line. With less than 50 ft step up/down,
avoid lead aircrafts’ 5-7 O’clock.

“There are “Cautions” or “Warnings” throughout the Dash-1 concerning serious flight safety issues in various phases of flight but none on wake intrusion – a phenomenon that can result in an uncontrollable roll and consequent crash. This would certainly seem to warrant a “Caution” or a “Warning” within the Flight Manual.”

Rivolo says that as a consequence of the nonexistent TR-65 test results, the Dash-1 seriously underplays the significance of wake intrusion in V-22.

“It is noted that the Formation Flight Limitations in the Flight Manual only address a “minimum” separation; once outside that separation pilots can “legally” fly anywhere they wish in proximity to other formation aircraft. Unfortunately, the aircraft wakes remain active well outside this minimum separation and pilots can fly into them with catastrophic results. That the pilot was well outside of the minimum spacing limitations for formation flying is verified by the AIB in their Report which states:

“Although the MC did not maintain the required 25 feet of vertical separation from the MLA, the MA was two- to three-times the 250 feet and 375 feet distances referenced above and still encountered the MLA’s wake”

Rivolo believes the accident was clearly not caused by “pilot error” but it was the direct result of a basic design flaw in V-22 – the side-by-side rotor configuration and its susceptibility to rotor wakes.

“This accident will happen again and again,” he says.

Richard Clements contributed to this post.



Osprey tilt rotor aircraft crash has raised new safety concerns. But it might have been caused by human factor.

Recently, U.S. Department of Defense officials have had to organise a director level meeting with the Japanese Ministry of Defence and department of Foreign Affairs, to provide an update with regards to the MV-22 and CV-22 Osprey aircraft issues.

Pentagon press secretary George Little spoke to reporters and described the meeting as “An effort to address concerns about the aircraft by the governor of Okinawa” as the Department of Defence plans to base the MV-22, the Marine Corp version of the aircraft, to the Asia Pacific region.

Little also said “The Department of Defence takes the inquiries made by the Japanese government seriously and provided relevant information to the extent currently possible.”

“The Osprey is a highly-capable aircraft with an excellent operational safety record, which includes more than five years of worldwide deployments and 140,000 flight hours” Little said.

This came in light of another incident that involved a CV-22 Osprey that crashed on Eglin range in Florida on Jun. 13 2012 that has fueled once again concerns about the safety of the tilt rotor that, in spite of the Air Force and Marine Corps claims, has been much debated in the recent past.

However, the last episode could have had in the human factor its “root cause”. Indeed, AOL Defense’s Richard Whittle reported that the pilot in command of the Osprey that has recently crashed in Florida, was also the co-pilot of an AFSOC tilt rotor aircraft that crashed in Afghanistan on Apr. 8, 2010.

It’s not been disclosed whether the pilot Maj. Brian Luce or co-pilot Capt. Brett Cassidy were at the controls of the Osprey when it went down last June during a training exercise. All onboard suffered undisclosed injuries but were released from hospital a couple of days later.

The CV-22 was flying in helicopter mode along with another Osprey. Among the possible causes of the crash there is the possibility that it went into the rotor wash of the other tilt rotor aircraft: a powerful turbulence that can cause an unrecoverable “roll off”. Osprey crew members are warned to keep a safe distance to prevent this dangerous situation.

“The results of the Accident Investigation Board will guide our decisions, if there’s some misbehaviour on the part of the crew or if they performed in a way that was unsatisfactory, it’s too early to say whether they will or won’t face any disciplinary action” said 1st Special Operations Wing’s commander Col. James Slife in an interview with AOL Defense.

With an investigation still in progress, it’s too early to determine what will happen to Luce and Cassidy with regards to a disciplinary hearing or whether they will face penalties for the crash. However, in the meanwhile, Slice has relieved Lt. Col. Matthew Glover of command at the 8th Special Operations Squadrons since “philosophically” all the military services hold commanders responsible for what happens in the units, he said to AOL Defense.

The accident that Luce had been in previously in Afghanistan took place during a night raid against insurgents, where the Osprey had a “Hard Landing” and had caught its nose in a ditch when the nose wheel collapsed and flipped the Osprey onto its back killing 4 of the 19 occupants.

The crash investigators in that occasion found several contributing factors to the crash but none that could be singled out as the “root cause”. Among them: all from the crew being distracted as they pressed to make their landing zone, a 17 kts tailwind and a possible loss of engine power (although this was overruled by the commander of AFSOC, citing engineering studies that detected no evidence of power loss).

Noteworthy, about two months ago, a U.S. Marine Corps tilt rotor aircraft crashed in Morocco during African Lion joint exercise with two marines killed and two other severely injured in the crash.

Richard Clements for TheAviationist.com