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 and support.
The V-22 Osprey had 12 hull loss accidents that resulted in a total of 42 fatalities. During testing from 1991 to 2006 there were four crashes resulting in 30 fatalities. Since becoming operational in 2007, the V-22 has had seven crashes including two combat-zone crashes, and several other accidents and incidents that resulted in twelve fatalities.
Video Accidents and incidents involving the V-22 Osprey
Crashes and hull-loss accidents
June 1991
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. 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.
July 1992
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. A titanium firewall now protects the composite propshaft.
April 2000
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 19 on board.
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. 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.
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.
December 2000
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.
March 2006
A MV-22B 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 to 7 feet (1.8 to 2.1 m) into the air (initial estimates suggested 20 to 30 feet) and then fell to the ground causing damage its starboard wing; the damage was valued at approximately US$7 million. 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 time needed for switching between the redundant FADECs to eliminate the possibility of a similar mishap occurring in the future. The aircraft was found to be damaged beyond repair and in July 2009 stricken from Navy list.
April 2010
On 8 April 2010, a USAF CV-22 crashed in southern Afghanistan. Three US service members and one civilian were killed and 16 injured in the crash. Initially it was unclear if the accident was caused by enemy fire. 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. 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.
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. 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. The actual causes of the crash may never be known because US military aircraft destroyed the wreckage and black box recorder. 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.
April 2012
On 11 April 2012, an MV-22 from the VMM-261 on USS Iwo Jima 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. U.S. investigators found no mechanical flaw with the aircraft, and human error was determined to be the cause.
June 2012
On 13 June 2012, a USAF CV-22 crashed at Eglin Air Force Base in Florida during training. All five aboard were injured; two were released from the hospital shortly after. The aircraft ended upside down and received major damage. The cause of the crash was determined to be pilot error, with the CV-22 flying through the proprotor wash of another aircraft. The USAF has restarted formation flight training in response.
May 2015
One of three Osprey aircraft participating in a training exercise at Bellows Air Force Station (Waimanalo, Oahu, Hawaii) suffered from dust intake to the right engine, sustained a hard landing with fuselage damage and caught fire. The accident lead to the death of two U.S. Marines, and injuries to 20 others. The accident caused Marines to recommend improved air filters, and require reduced hover time in dust from 60 to 30 seconds, although most pilots rarely spend more than 10 seconds in dusty conditions.
December 2016
On 13 December 2016, at 10 pm, an MV-22 crashed while landing onto a reef in shallow water 0.6 miles (0.97 km) off the Okinawa coastline of Camp Schwab where the aircraft broke apart. All five crew members aboard with Marine Aircraft Group 36, 1st Marine Aircraft Wing were rescued. Two crew members were injured and all were transported for treatment. Ospreys in Japan were grounded the following day. An investigation into the mishap was launched. Preliminary reports indicate that during in-flight refueling with a HC-130, the refueling hose was struck by the Osprey's rotor blades. On 18 December, after a review of MV-22 safety procedures, the III Marine Expeditionary Force (IIIMEF) announced that it will resume flight operations concluding that they are confident that the mishap was due "solely to the aircraft's rotor blades coming into contact with the refueling line."
August 2017
On 5 August 2017, a U.S. Marine Corps MV-22 Osprey assigned to Marine Medium Tiltrotor Squadron 265 with the 31st Marine Expeditionary Unit after taking off from the amphibious assault ship USS Bonhomme Richard struck the USS Green Bay and then crashed in Shoalwater Bay on the east coast of Australia. 23 personnel were rescued, with three confirmed dead.
September 2017
On 28 September 2017, a V-22 Osprey operating in Syria as part of Operation Inherent Resolve was damaged beyond repair in a hard landing. Two people on board the aircraft were injured. The non salvageable Osprey was later destroyed by troops.
Maps Accidents and incidents involving the V-22 Osprey
Other accidents and notable incidents
July 2006
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. 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.
December 2006
It was reported that a serious nacelle fire occurred on a Marine MV-22 at New River in December 2006.
March 2007
A V-22 experienced a hydraulic leak that led to an engine-compartment fire before takeoff on 29 March 2007.
November 2007
An MV-22 Osprey of VMMT-204 caught on 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.
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.
2009
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.
October 2014
In early October 2014, an MV-22 Osprey lost power shortly after takeoff from the USS Makin Island in the Middle East. The pilots regained control and landed safely, but one U.S. Marine drowned because of life preserver dysfunction when bailing out of the aircraft.
December 2016
On 13 December 2016 when a MV-22 crash-landed, a second MV-22 reportedly did a belly landing at MCAS Futenma.
January 2017
On 29 January 2017, an MV-22 experienced a hard landing during the Yakla raid in Al Bayda, Yemen against Al-Qaeda in the Arabian Peninsula militants, causing two injuries to U.S. troops. The aircraft could not fly afterward and was destroyed by U.S. airstrikes.
References
- Norton, Bill. Bell Boeing V-22 Osprey, Tiltrotor Tactical Transport. Midland Publishing, 2004. ISBN 1-85780-165-2.
- Whittle, Richard. The Dream Machine: The Untold History of the Notorious V-22 Osprey. New York: Simon & Schuster, 2010. ISBN 1-4165-6295-8.
External links
- A video footage of the 1991 Osprey crash with commentary
Source of article : Wikipedia
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