Accidents and incidents involving the V-22 Osprey

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USAF CV-22 Osprey flies a test mission

The Bell Boeing V-22 Osprey is an American military tiltrotor aircraft with an accident history that has generated some controversy over its perceived safety. The aircraft was developed by Bell Helicopter and Boeing Helicopters; the companies partner in its manufacture.

The V-22 Osprey had 7 hull-loss accidents with a total of 36 fatalities. During testing from 1991 to 2000 there were four crashes resulting in 30 fatalities.[1] Since becoming operational in 2007, the V-22 has had three crashes resulting in six fatalities including one combat-zone crash,[2] and several minor incidents.

Crashes[edit]

June 1991[edit]

A miswired flight control system led to two minor injuries when the left nacelle struck the ground while the aircraft was hovering 15 feet (4.6 m) in the air, causing it to bounce and catch fire on 11 June 1991.[1] The pilot, Grady Wilson, suspected that he may have accidentally set the throttle lever the opposite direction to that intended, exacerbating the crash if not causing it.[3]

July 1992[edit]

On 20 July 1992, pre-production V-22 #4's right engine failed and caused the aircraft to drop into the Potomac River by Marine Corps Base Quantico with an audience of congressmen and other government officials. Flammable liquids collected in the right nacelle and led to an engine fire and subsequent failure. All seven on board were killed and the V-22 fleet was grounded for 11 months following the accident.[1][4][5] A titanium firewall now protects the composite propshaft.[6]

April 2000[edit]

A V-22 loaded with Marines, to simulate a rescue, attempted to land at Marana Northwest Regional Airport in Arizona on 8 April 2000. It descended faster than normal (over 2,000 ft/min or 10 m/s) from an unusually high altitude with a forward speed of under 45 miles per hour (72 km/h) when it suddenly stalled its right rotor at 245 feet (75 m), rolled over, crashed, and exploded, killing all nineteen on board.[7][8]

The cause was determined to be vortex ring state (VRS), a fundamental limitation on vertical descent which is common to helicopters. At the time of the mishap, the V-22's flight operations rules restricted the Osprey to a descent rate of 800 feet per minute (4.1 m/s) at airspeeds below 40 knots (74 km/h) (restrictions typical of helicopters); the crew of the V-22 in question exceeded this operating restriction with a rate more than 100% greater.[9] Another factor that may have triggered VRS was their operating in close proximity, which is believed to be a risk factor for VRS in helicopters. Subsequent testing has shown that the V-22, and the tiltrotor in general, is less susceptible to VRS, the conditions are easily recognized by the pilots; recovery from VRS requires a more natural action by the pilot than recovery in helicopters, the altitude loss is significantly less than for helicopters, and, with sufficient altitude (2,000 ft or 610 m or more), VRS recovery is relatively easy.[1]

As a result of testing, the V-22 will have a descent envelope as large as or larger than most helicopters, further enhancing its ability to enter and depart hostile landing zones quickly and safely. The project team also dealt with the problem by adding a simultaneous warning light and voice that says "Sink Rate" when the V-22 approaches half of the VRS-vulnerable descent rate.[1]

December 2000[edit]

On 11 December 2000, a V-22 had a flight control error and crashed near Jacksonville, North Carolina, killing all four aboard. A vibration-induced chafing from an adjacent wiring bundle caused a leak in the hydraulic line which fed the primary side of the swashplate actuators to the right side rotor blade controls. The leak caused a Primary Flight Control System (PFCS) alert. A previously undiscovered error in the aircraft's control software caused it to decelerate in response to each of the pilot's eight attempts to reset the software as a result of the PFCS alert. The uncontrollable aircraft fell 1,600 feet (490 m) and crashed in a forest. The wiring harnesses and hydraulic line routing in the nacelles were subsequently modified. This caused the Marine Corps to ground its fleet of eight V-22s, the second grounding in 2000.[1][10][11]

April 2010[edit]

On 8 April 2010, a USAF CV-22 crashed in southern Afghanistan.[2] Three US service members and one civilian were killed and 16 injured in the crash.[12] Initially it was unclear if the accident was caused by enemy fire.[13][14] The loaded CV-22B was at its hovering capability limit, landing at night near Qalat (altitude approx. 5,000 feet) in brownout conditions, in turbulence due to the location in a gully.[12][15] The USAF investigation ruled out brownout conditions, enemy fire, and vortex ring state as causes. The investigation found several factors that significantly contributed to the crash; these include low visibility, a poorly executed approach, loss of situational awareness, and a high descent rate.[16]

Brig. Gen. Donald Harvel, board president of the first investigation into the crash, fingered the "unidentified contrails" during the last 17 seconds of flight as indications of engine troubles.[17] Harvel has become a critic of the aircraft since his retirement and states that his retirement was placed on hold for two years in order to silence him from speaking publicly about his concerns about the aircraft's safety.[18] The actual causes of the crash may never be known because US military aircraft destroyed the wreckage and black box recorder.[19] Former USAF chief V-22 systems engineer Eric Braganca stated that the V-22's engines normally emit puffs of smoke and the data recorders showed that the engines were operating normally at that time.[20]

April 2012[edit]

On 11 April 2012, an MV-22 from the VMM-261 on USS Iwo Jima (LHD-7) crashed near Tan Tan and Agadir, Morocco, during a joint training exercise, named "African Lion". Two Marines were killed and two others were seriously injured, and the aircraft was lost.[21][22][23] U.S. investigators found no mechanical flaw with the aircraft,[24] and human error was determined to be the cause.[25]

June 2012[edit]

On 13 June 2012, a USAF CV-22 crashed at Eglin Air Force Base in Florida during training. All five aboard were injured;[26] two were released from the hospital shortly after.[27] The aircraft ended upside down and received major damage.[28] The cause of the crash is being investigated.[27][28][29] The USAF has restarted formation flight training in response.[30]

Other accidents and notable incidents[edit]

March 2006[edit]

A V-22 experienced an uncommanded engine acceleration while ground turning at Marine Corps Air Station New River, NC. Since the aircraft regulates power turbine speed with blade pitch, the reaction caused the aircraft to go airborne with the Torque Control Lever (TCL, or throttle) at idle. The aircraft rose 6 feet (1.8 m) into the air[31] (although initial reports suggested 30 feet), and then fell to the ground with enough force to damage one of its wings; the total amount of damage was approximately US$7 million.[32] It was later found that a miswired cannon plug to one of the engine's two Full Authority Digital Engine Controls (FADEC) was the cause. The FADEC software was also modified to decrease the amount of time needed for the switch between the redundant FADECs to eliminate the possibility of a similar mishap occurring in the future.[33]

July 2006[edit]

A V-22 experienced compressor stalls in its right engine in the middle of its first transatlantic flight to the United Kingdom for the Royal International Air Tattoo and Farnborough Airshow on 11 July 2006.[34] It had to be diverted to Iceland for maintenance. A week later it was announced that other V-22s had been having compressor surges and stalls, and the Navy launched an investigation into it.[35]

March 2007[edit]

A V-22 experienced a hydraulic leak that led to an engine-compartment fire before takeoff on 29 March 2007.[36] It was also reported at that time that a more serious nacelle fire occurred on a Marine MV-22 at New River in December 2006.[36][37]

November 2007[edit]

An MV-22 Osprey of VMMT-204 caught fire during a training mission and was forced to make an emergency landing at Camp Lejeune on 6 November 2007. The fire, which started in one of the engine nacelles, caused significant aircraft damage, but no injuries.[38]

After an investigation, it was determined that a design flaw with the engine air particle separator (EAPS) caused it to jam in flight, causing a shock wave in the hydraulics system and subsequent leaks. Hydraulic fluid leaked into the IR suppressors and was the cause of the nacelle fires. As a result, all Block-A V-22 aircraft were placed under flight restrictions until modification kits could be installed. No fielded Marine MV-22s were affected, as those Block-B aircraft already incorporated the modification.[39]

2009[edit]

An Air Force CV-22 suffered a Class A mishap with more than a $1 million in damage during FY 2009. No details were released.[40]

October 2014[edit]

In early October 2014, a MV-22 Osprey lost power shortly after takeoff from the USS Makin Island in the Middle East, but the pilots were able to regain control and land safely. One U.S. Marine was killed when bailing out of the aircraft.[41]

References[edit]

  1. ^ a b c d e f "Saving the Pentagon's Killer Chopper-Plane". Wired, July 2005. 
  2. ^ a b "CV-22 Osprey Crashes in Afghanistan". ISAF_NATO. 9 April 2010. 
  3. ^ Whittle 2010, pp. 200-202.
  4. ^ "V-22 Osprey crash kills 7 Aircraft second of 5 prototypes to go down." Fort Worth Star-Telegram, 21 July 1992.
  5. ^ Norton 2004, pp. 46–47.
  6. ^ Whittle 2010, pp. 246
  7. ^ Gross, Kevin, Lieutenant Colonel U.S. Marine Corps; Tom Macdonald, MV-22 test pilot; Ray Dagenhart, MV-22 lead government engineer (September 2004). "Dispelling the Myth of the MV-22". Proceedings (The Naval Institute) (September 2004). Retrieved 2009-04-09. 
  8. ^ Cox, Bob. "V-22 Pilots Not To Blame For Crash, Widows Say", Fort Worth Star-Telegram, 4 June 2011.
  9. ^ Norton 2004, pp. 62–63.
  10. ^ Dao, James. "After North Carolina Crash, Marines Ground Osprey Program." New York Times, 13 December 2000.
  11. ^ "Marine V-22 Ospreys cleared to soar again." Spokesman-Review, 6 September 2000.
  12. ^ a b "The high cost of building a new flying machine". Charlotte Observer. 2 May 2010. 
  13. ^ "ISAF: 4 killed in U.S. aircraft crash in Afghanistan". CNN. 9 April 2010. 
  14. ^ Hodge, Nathan (9 April 2010). "Controversial Spec-Ops Tiltrotor Crashes in Afghanistan". Wired. 
  15. ^ McIntyre, Jamie. "CV-22 Lost Due to Pilot Error". dodbuzz.com, 18 May 2010.
  16. ^ "CV-22B Accident Investigation Board", "CV-22 Accident Investigation Board Results Released". U.S. Air Force, 16 December 2010.
  17. ^ Rolfsen, Bruce. "Generals clash on cause of April Osprey crash." Airforce Times, 22 January 2011.
  18. ^ Axe, David. "General: ‘My Career Was Done’ When I Criticized Flawed Warplane". Wired, 4 October 2012
  19. ^ Thompson, Mark. "So Why Did That V-22 Crash?".[dead link] Time. 18 December 2010.
  20. ^ Axe, David. "Air Force Engineer Takes on General Over Controversial Warplane Crash." Wired Magazine, 15 October 2012.
  21. ^ Majumdar, Dave. "Two killed in USMC MV-22 accident in Morocco." Flight International, 11 April 2012. Retrieved: 13 April 2012.
  22. ^ "Two U.S. Marines killed in Morocco helicopter crash". BNO News, 12 April 2012. Retrieved: 16 April 2012.
  23. ^ "ASN Wikibase Occurrence # 144945" Aviation Safety Network, 15 April 2012. Retrieved: 16 April 2012.
  24. ^ "MV-22 Osprey that crashed in Morocco was mechanically perfect" Yomiuri Shimbun, 9 June 2012. Retrieved: 15 June 2012.
  25. ^ Whittle, Richard. "Marines Peg 'Bad Flying' As Cause of April V-22 Crash in Morocco". AOL Defense, 9 July 2012. Retrieved: 10 July 2012.
  26. ^ "5 airmen injured when Air Force Osprey crashes during training mission in Florida Panhandle". Washington Post. Associated Press. 14 June 2012. Retrieved 16 June 2012. 
  27. ^ a b "Two airmen injured in Osprey crash released from hospital". Northwest Florida Daily News, 15 June 2012. Retrieved: 16 June 2012.
  28. ^ a b "5 airmen hurt in Osprey crash near Navarre". Pensacola News Journal, 14 June 2012. Retrieved: 16 June 2012.
  29. ^ "Air Force Osprey crashes at Florida base, injures five". CNN, 14 June 2012. Retrieved: 16 June 2012.
  30. ^ "Crash Drives Air Force to Restart CV-22 Pilot Formation Training: EXCLUSIVE."
  31. ^ "V22 Osprey's 3.2 second accident Flight" accessed Oct 14, 2013
  32. ^ "Osprey Down: Marines Shift Story on Controversial Warplane’s Safety Record". Condé Nast, 13 October 2011.
  33. ^ White, Lance Cpl. Samuel D. (2006). "VMM-263 ready to write next chapter in Osprey program". Marine Corps News. United States Marine Corps. Archived from the original on 2006-06-26. Retrieved 2006-04-10. 
  34. ^ "V-22 Osprey Makes Precautionary Landing En Route To UK". Air-Attack.com. Retrieved 2007-08-06. 
  35. ^ Castelli, Christopher J. (n.d.). "Navy Probes Multiple V-22 Surges, Stalls". NewsStand. InsideDefense.com. Retrieved 2007-04-08. 
  36. ^ a b "Hydraulic Problems Vex V-22". Defensetalk.com. 2007-04-05. Archived from the original on 2007-09-27. Retrieved 2007-06-08. 
  37. ^ Bob Cox (31 March 2007). "Fire reported after leak of hydraulic fluid". Star-Telegram.com. Retrieved 2007-04-08. [dead link]
  38. ^ "Osprey helicopter makes emergency landing". Havelock News, 7 November 2007.
  39. ^ "V-22 mishap probe prompts US fleet restrictions". FlightGlobal, 4 December 2007.
  40. ^ http://www.afsc.af.mil/shared/media/document/AFD-080114-111.pdf
  41. ^ [1]

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