The V-22 was developed to meet the provisions of the April 1995 Joint Multi-Mission Vertical Lift Aircraft (JMVX) Operational Requirements Document (ORD) for an advanced vertical lift aircraft. The JMVX ORD calls for an aircraft that would provide the Marine Corps and Air Force the ability to conduct assault support and long-range, high-speed missions requiring vertical takeoff and landing capabilities.
Developmental Test and Evaluation (DT&E) was conducted and managed by the Rotary Wing Test Directorate, Naval Air Warfare Center Aircraft Division (NAWCAD), Patuxent River, Maryland, using an Integrated Test Team comprised of Bell-Boeing and Government personnel. Operational Test and Evaluation (OT&E) is being conducted by Marine Helicopter Squadron One (HMX-1) Multi-Service Operational Test Team (MOTT) and monitored by the Commander, Operational Test and Evaluation Force (COMOPTEVFOR), Norfolk, Virginia. The MOTT consists of selected aircrew and engineering personnel from the Marine Corps and Air Force who have received V-22 factory training. V-22 Operational Evaluation (OPEVAL) was performed at Marine Corps Air Facility (MCAF) Quantico, Virginia, and multiple sites throughout the United States, and the CV-22 Unique Initial Operational Test and Evaluation (IOT&E) was performed at Kirtland Air Force Base (AFB), Albuquerque, New Mexico.
Since entry into FSD in 1986, the V-22 T&E program concentrated principally on engineering and integration testing by the contractors. Three periods of formal development test by Naval Air Warfare Center-Aircraft Division (NAWCAD) Patuxent River, plus OTA participation in integrated test team (ITT) activities at Patuxent River, provided some insight into the success of the development effort.
During EMD, prior to the formal period of Operational Evaluation (OPEVAL), a Multi-Service Operational Test Team (MOTT) conducted four periods of operational testing. The first three of these periods, OT-IIA, OT-IIB, and OT- IIC involved flight operations, using operational test pilots, of the two prototype aircraft developed under the FSD program. While these aircraft had acknowledged shortcomings with respect to weight and payload, this testing provided early opportunity to explore the use of a tilt-rotor aircraft to perform operationally oriented missions. During these three test periods, operational test pilots flew a total of 61.3 hours in FSD-prototype V-22.
After transition to EMD in 1992, an integrated contractor/government test team conducted all tests until OT-IIA in 1994.The first operational test period (OT-IIA) was performed by COMOPTEVFOR, with assistance from AFOTEC, from May 16 to July 8, 1994, and accomplished 15 hours of actual flight test operations, within an extremely restricted flight envelope. The Navy, with Air Force support, published a joint evaluation report addressing most mission areas the V-22 is to perform.
OT-IIB was conducted from September 9, to October 18, 1995, and comprised 10 flight hours in 18 OT&E flights, plus ground evaluations. A joint Air Force/Navy OT-IIB report was published. Partly in response to DOT&E concern expressed over the severity of V-22 downwash in a hover observed during OT-IIA, the Navy conducted a limited downwash assessment concurrently with OT-IIB, from July to October 1995.
In accordance with the approved TEMP, OT-IIC was conducted in six phases at NAS Patuxent River and Bell-Boeing facilities in Pennsylvania and Texas, from October 1996, through May 1997.
Significant flight limitations were placed on the FSD V-22 in OT&E including:
- not cleared to hover over unprepared landing zones until OT-IIC
- no operational internal or external loads or passengers
- moderate gross weights only
- not cleared to hover over water.
In addition, FSD aircraft equipment was not representative of any mission configuration. Together, these aircraft clearance and configuration limits produced an extremely artificial test environment for OT-IIC.
The OT-IIB report expressed serious concerns regarding the potential downwash effects, and recommended further investigation. While a limited assessment of downwash and workaround procedures was included in OT-IIC, complete resolution of the downwash issue would not be possible until the completion of OPEVAL, just prior to milestone III in 1999.
The Navy conducted an aggressive LFT&E program on representative V-22 components and assemblies, in compliance with a DOT&E-approved alternative LFT&E plan. The V-22 program was granted a waiver from full-up, system-level LFT&E in April, 1997. The vulnerability testing that the program is performing is appropriate and would result in the improvement of aircraft survivability.
With DOT&E encouragement, the Navy greatly expanded the scope of OT-IIC to get better insight into the effectiveness and suitability of the EMD design. The results, while not yet conclusive regarding the potential operational effectiveness and suitability of operational aircraft, were encouraging. The six phases of the OT-IIC Assessment included: (1) shipboard assessment, (2) maintenance demonstrations, (3) tactical aircraft employment via FSD aircraft and manned flight simulator, (4) operational training plans, (5) program documentation review, and (6) software analysis.
In assessing the operational effectiveness and suitability COIs, COMOPTEVFOR and AFOTEC found that in most cases, only moderate risk exists that the COIs would not be satisfactorily resolved when development is complete. Enhancing features observed during OT-IIC included aircraft payload, range and speed characteristics better than the stated operational requirements. In addition, reliability, availability and maintainability of the EMD aircraft appeared to be significantly improved over those of the FSD aircraft.
Several areas of concern first discovered in OT-IIA or OT-IIB remained unresolved because of limitations to the EMD flight test operations. These concerns included severe proprotor downwash effects during personnel insertion and extraction via hoist or rope. In addition, concerns exist in the areas of communications, navigation, and crew field of view. New concerns arising from OT-IIC regarding the EMD schedule are being addressed by the program manager. Also, the reliability and maintainability of a few subsystems require management attention.
The test reports issued following OT-IIB and OT-IIC concluded that the MV-22 had the potential to be operationally effective, but highlighted several areas of concern to the operational effectiveness and operational suitability of both the MV-22 and the CV-22. Those concerns included the effects of the high-velocity proprotor downwash beneath a hovering Osprey, low system reliability, and problems with the defensive electronics countermeasures system.
OT-IID, conducted from 1 September - 31 October 1998, was the first operational test period to use MV-22 aircraft developed under the EMD program. OT-IID was conducted using EMD aircraft numbers 9 and 10, the final two aircraft delivered under the EMD program. OT-IID consisted of 142.6 flight hours conducting operationally realistic missions in four locations: NAS Patuxent River, MD; New River MCAS, NC; Camp Dawson AAF, WV; and Eglin AFB, FL. Aircraft operations included confined area operations; mountainous area landings; formation flight; use of night vision devices; low altitude terrain tactics; and alternate insertion/extraction procedures performed with Marines and Special Operations Command personnel. Due to the developmental status of the test aircraft, some flight maneuver restrictions and other mission limitations were imposed, but these limitations did not prevent assessment of the potential operational effectiveness and suitability of the V-22. Of particular note for this stage of OT, Marine Corps and USAF personnel performed all operational-level maintenance on aircraft number 10 throughout OT-IID, providing valuable insights into the operational suitability of the V-22.
Results from OT-IID indicated that the V-22 should provide the required range and payload capabilities needed to meet Marine Corps and Special Operations Forces (SOF) requirements. The V-22 appeared to offer significant maneuverability and handling advantages as compared to rotary wing aircraft; e.g., rapid deceleration upon arrival at a landing zone and rapid acceleration during departure. OT-IID testing suggested that, with fully developed tactics, these capabilities should provide substantive maneuver and survivability advantages. In addition, OT-IID results indicated that with modified operational procedures, required tasks could be performed despite the downwash experienced in the rotary mode, which had been an issue of concern in previous OT&E. Most downwash issues, with the exception of shipboard and rescue operations, were assessed favorably in OT-IID. For example, operational pilots demonstrated the ability to conduct mountainous area landings at unprepared sites, as well as being able to deploy a rubber boat and SOF team despite the downwash-induced sea spray generated by V-22 operations only a few feet above the water.
Due to a number of test-peculiar conditions and limitations, the report of OT-IID jointly issued by the Navy and Air Force operational test agencies did not include any quantitative reliability, maintainability, or availability assessments. Nonetheless, an independent assessment of the OT-IID data conducted by DOT&E found that key suitability parameters measured during OT-IID fell far below required performance levels. This assessment concluded that Mean Flight Hours between Aborts (MFHBA) and Maintenance Man-Hours per Flight Hour (MMH/FH) are significant risk areas that should be watched closely in OPEVAL.
The operational test and evaluation required by 10 U.S.C. 2399, called OPEVAL, tested a number of operationally representative missions with four aircraft from the first low-rate production lot at a variety of locations, including hot, dry, and humid conditions. Also during OPEVAL, three periods of testing were conducted from LHA, LHD, and LSD ships at sea. In total, OPEVAL accumulated in excess of 800 flight hours. The test team included 15 pilots and approximately 90 service maintenance personnel.
The MV-22 entered Operational Evaluation in November 1999 with fewer deficiencies than any aircraft in the history of naval aviation. It did so while facing unprecedented reliability standards, exposing more blemishes early on but ultimately resulting in a safer, more reliable aircraft. During exhaustive evaluation at Marine and Naval facilities throughout the country, the MV-22 logged 805 flight hours in 522 sorties. The Multi-Service Operational Test Team evaluated the aircraft's suitability for use by Marine Corps' operating forces through a series of representative missions from amphibious ships, airfields, remote sites, confined areas, ranges and other test facilities.
During OPEVAL, MV-22s conducted testing at sea. Early in OPEVAL, the Multi-Service Operational Test Team (MOTT) deployed for ten days aboard USS SAIPAN (LHA 2). Two months later, a second deployment of nine days was conducted aboard USS ESSEX (LHD 2). A third five-day period of at sea testing was conducted in June aboard USS TORTUGA (LSD 46). During the deployment aboard USS SAIPAN, the two MV-22s assigned at that time to the MOTT experienced a number of reliability and maintenance problems. As a result, very few of the planned MV-22 missions from the carrier were accomplished. The later at sea periods were more successful, and the MV-22 missions that were conducted largely demonstrated the ability to carry out key ship-to-shore mission segments.
During shipboard tests aboard USS SAIPAN (LHA 2), V-22 test pilots experienced a roll anomaly while descending from hover. This anomaly consisted of uncommanded roll oscillation of approximately a 90-degree amplitude. Postflight analysis revealed that the roll was consistent with factors that might include an aberration in the aircraft's flight control systems logic, or air-load asymmetries caused by vehicle/ship interactional aerodynamics. Tests investigated flow patterns in the vicinity of each rotor disk. Flow-field pattern variations with height demonstrated clearly that a large ground vortex forms upwind of the inboard rotor at very low wheel heights above deck. The presence of this ground vortex is consistent with prior full-scale tests and with video from the actual incident. When the rotor system was moved laterally, the vortex tended to vary in size and location, depending on model proximity to the deck edge. The effects of ship superstructure on flow asymmetries showed that the port-side superstructure tends to trap the upwind ground vortex, whereas superstructure removal produced smaller upwind vortices and flow asymmetries. The tests also investigated the effect of deck proximity on the vehicle roll moment. When the rotor system was moved laterally from a position outboard of the deck edge inwards to a position over the desired landing spot (figure 3), the roll moment was found to vary significantly, further substantiating the flow-visualization findings. The roll moment was found to also vary with traverse height, providing further insight into the complicated shipboard rotorcraft interactional environment.
OPEVAL testing also confirmed the capability of the MV-22 to self-deploy. The MV-22 demonstrated the capability to fly 2,100 rim with one aerial refueling during a self-deployment flight from California to Maryland in 8 hours 10 minutes, exceeding the JORD threshold by almost 4 hours. The deployment was conducted with two developmental test 400-gallon tanks rather than two production representative 800-gallon tanks, thus precluding the aircraft from flying the deployment profile designed for overwater flight (e.g., CONUS - Hawaii) due to insufficient capacity to meet overwater regulatory fuel reserve requirements. Two 800-gallon tanks should allow for an even longer flight profile.
The operational testing conducted on the Osprey provided an adequate basis to evaluate the operational effectiveness and operational suitability of the MV-22. However, additional testing was needed to verify correction of deficiencies, the effectiveness and suitability of waived items, and to investigate the vortex ring state. Live Fire Testing demonstrated the ability of the MV-22 and CV-22 to survive impacts by the required threat and, in some cases, beyond the required threat projectiles and continue to function. The MV-22 and CV-22 incorporated a number of vulnerability reduction features, which were proven effective in live fire tests. However, the MV-22, as tested, was not operationally suitable, primarily because of reliability, maintainability, availability, human factors and interoperability issues. This conclusion was based on the failure rate of components during testing, exacerbated by a non-fleet representative logistics structure and an immature automated maintenance publication system.
Operational testing of the MV-22 did not confirm that the MV-22 as configured and tested during OPEVAL is operationally suitable. The MV-22 demonstrated marginal mission reliability, excessive maintenance manpower and logistic support requirements and inadequate availability, interoperability, human factors documentation, and diagnostics capabilities. In the latter half of OPEVAL, the trends on some key measures of suitability were positive, suggesting that the aircraft has the potential to eventually meet its suitability requirements. Nonetheless, taken as a whole or considering only its improved suitability data from the second half of OPEVAL, the MV-22 failed to meet several important JORD established thresholds. Moreover, the demonstrated results for MV-22 mission reliability, maintainability, and availability were less favorable than the same measures from the fielded CH-46 fleet. The OPEVAL results also failed to confirm the reliability and diagnostic improvements postulated before the test.
Marine Corps and Navy leaders were briefed 11 October 2000 on the Operational Evaluation Report, issued by the Navy's Operational Test and Evaluation Command. The MV-22 Osprey was judged operationally effective and operationally suitable for land-based operations, validating eight months of comprehensive evaluation and moving the tiltrotor aircraft a major step closer to full-rate production. The report stopped short of declaring the aircraft suitable for ship-based operations, pending additional evaluation of the Blade Fold Wing Stow system. Since completion of Operational Evaluation, the system designed to fold and stow the prop rotors and wings was modified and successfully demonstrated at the V-22 final-assembly facility in Amarillo, Texas.
Successful sea trials would pave the way to full-rate production and multi-year procurement. While the issue of shipboard compatibility awaited resolution, the report confirmed that the MV-22 met or exceeded all other key performance parameters. In key capabilities, the MV-22 proved its superiority to the CH-46E and CH-53D, the aging medium-lift aircraft the Osprey would replace. In the most telling comparison - to the CH-46E - the MV-22 boasts twice the speed, five times the range and triple the payload capacity. The report concluded that these and other enhancements unique to the MV-22 would revolutionize assault-support operations.
On 21 December 2001 Pete Aldridge, defense undersecretary for acquisition, technology and logistics announced that the troubled V-22 Osprey aircraft would go through a two-year flight test program. The new flight test program, starting in April 2002, is a comprehensive, two-year look at the aircraft. The tests would further explore the occurrence called vortex ring state, deemed responsible for the first crash of a V- 22 in Arizona that killed 19 Marines. The tests also must explore shipboard compatibility. For example, he noted the need to look at what happens when one rotor is over the flight deck and the other is over the side of the ship, conditions which could include take-off, landing or craft on deck. The test would also explore low-speed hover conditions, such as landing when the props blow up dust, debris, snow and other things. The testing would also include combat maneuverability and formation flying, including refueling conditions.
DoD has slowed down production of the V-22 to the minimum sustaining level. This would allow changes to be made to production aircraft. Aircraft already built would be retrofitted.
Based on developmental tests since returning to flight in 2002, DOT&E has increased confidence that the V-22 characteristics involving VRS are well understood and knowledge of VRS consequences is widespread in the V-22 community. Several factors contribute to this confidence:
. Extensive HROD testing confirmed the V-22 VRS envelope; the flight conditions necessary to enter VRS were
verified and closely matched predictions by aerodynamic modeling and simulations.
. Published operating limitations appear adequate for normal conditions. DOT&E and the program would investigate the question of whether that margin may be reduced under unusual wind or maneuvering conditions.
. Published operating limitations are equivalent to all other rotorcraft and testing has proven that V-22 has more margin between the limitation and the VRS boundary.
. In maneuvering testing inside the VRS region, pilot control inputs delayed VRS onset and did not precipitate it.
. The flight simulators and flight syllabus emphasize avoiding the phenomenon.
. Flight manual cautions, warnings, and advisories were amended.
. An HROD warning system is present for both pilots and appears functional.
. Readability of the pilots' vertical speed indicator has improved.
. Nacelle tilt is a powerful VRS recovery tool, demonstrated and understood.
These items tend to reduce the likelihood of another mishap caused by VRS. For any rotorcraft, including the V-22 tiltrotor, the ability to save the aircraft- or at least ensure the survival of its occupants- in the event of a single or dual engine failure must be determined. In either the airplane or helicopter mode, the recommended procedure in the event of an engine failure is to convert to airplane mode, proceed immediately to a suitable landing spot, convert back to helicopter mode and land as soon as possible. The ability of the V-22 to perform single-engine landings is better than the helicopters it replaces. In the event of either sudden dual-engine failures, or a single failure of one engine coupled with a failure of the interconnecting drive train, while the aircraft is in either airplane or in the helicopter mode, the recommended method to recover is to tilt the nacelles down and attain the best glide speed available, then flare to a survivable landing.
In 2003, the program demonstrated by flight-test the recommended speed and altitude approaches to the landing field that allow the pilot to perform a survivable landing if the second engine fails during approach. This testing validated the fidelity of the V-22 simulators. Although testing of this procedure all the way to landing is not practicable, limited testing has confirmed that, while the aircraft can perform an auto-rotative descent, it cannot consistently auto-rotate to a safe landing. The approach to safety adopted long ago by the program is to minimize the possibility of such disastrous occurrences through system design. DOT&E would pursue, in conjunction with the program office and VMX-22, possible means to minimize the Fleet Marine Force mishap rate.
The effectiveness of the V-22's vulnerability reduction features was demonstrated during LFT&E. A continuous process of design refinements has been an integral part of the overall system engineering effort since the start of live fire testing, and several design changes have been made based on the test results, such as revising the sponson fuel tank structure. This process continues with particular emphasis on addressing the concerns outlined in the November 2000 LFT&E report.
The following are survivability assessments of the design changes and efforts to address the results of the original LFT&E program:
. Fire protection can be effectively provided to the mid-wing nacelles, main landing gear dry bays, and underfloor
. The design changes to the hydraulic system made since November 2000 have a negligible impact on the aircraft's vulnerability.
. The aircraft battle damage repair program continued to experience delays due to insufficient funding and is now nearing a contract award. It is programmed to be funded through FY06.
. The impact of adding internal mission auxiliary fuel tanks, countermeasure dispensers, and improvements to the engine nacelles require further study.
The V-22 Integrated Test Team (ITT) conducted Shipboard Suitability Phase IVc for 10 days aboard USS Wasp (LHD 1) beginning Nov. 12, 2004. The primary objective of this phase was to complete interaction testing between a V-22 parked on the flight deck and another V-22 hovering in front of it. Additional test objectives included flight envelope expansion for all port side landing spots aboard the LHD, developing a night short takeoff envelope, and evaluating the latest flight control software version.
While the ITT was busy working on Wasp's flight deck, a group of maintainers from Tilt-Rotor Operational Test Squadron (VMX) 22, the V-22 operational test and evaluation squadron based at Marine Corps Air Station New River, were in the hangar bay conducting maintenance demonstration testing. Tests included removing both engines, jacking the aircraft and cycling the landing gear, and removing prop-rotor hubs and blade assemblies. The VMX-22 team's findings are to serve them well during the squadron's upcoming operational evaluation. This was the fourth and final underway period for the ITT since the program's return to flight in May of 2002.
The amphibious assault ship USS Kearsarge (LHD 3) conducted landing operations with the MV-22 Osprey. The landing operations, which took place Dec. 7-13, 2004, was an effort to qualify 23 Marine Corps pilots from Marine Tilt Rotor Test and Evaluation Squadron (VMX) 22 on day deck landings, as well as to provide a "foundation" of experience for future operations. To complete their qualifications in accordance with the Marine Corps Training and Readiness Manual for air crew, the pilots performed a minimum of five landings on the ship's port side of the flight deck; two spots on the forward end of the flight deck (spots two and four); and two on the aft section (spots seven and nine). In addition to their qualification, the pilots performed a minimum of two short takeoffs. Of all the landing spots on the flight deck, spot seven is considered the most challenging of the four spots because of its location near the ship's island, which narrows the landing space for the aircraft. However, with the skill of the pilots and the ship's flight deck crew, the operation encountered no problems.
MV-22 OPEVAL (OT-IIG) was conducted by Marine Tiltrotor Operational Test and Evaluation Squadron Twenty-Two (VMX-22) at MCAS New River from March to June 2005 and found to be operationally effective, operationally suitable and recommended for Fleet introduction. The OT-IIG report was completed and released by Commander Operational Test and Evaluation Force (COMOPTEVFOR) in August 2005. The report found the Block A MV-22 to be operationally effective and suitable. VMX-22 utilized eight MV-22s to conduct the OPEVAL at multiple locations including MCAS New River, North Carolina; Nellis AFB, Nevada; Marine Corps Mountain Warfare Training Center, Bridgeport, California; western U.S. test ranges; and embarked aboard the USS BATAAN (LHD 5) in the western Atlantic. Missions were executed during operationally relevant scenarios consistent with a small-scale contingency and were flown under a variety of environments, operational tempos, and threat levels. All key performance parameters met or exceeded threshold requirements. As a result of the successful OPEVAL, the Defense Acquisition Board approved Milestone III in September 2005, authorizing Full Rate Production of the Osprey.
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