Use Of And Future Of The CH-46 Assault Helicopter In The United States Marine Corps AUTHOR Major Kenneth D. Bonner, USMC CSC 1990 SUBJECT AREA Aviation EXECUTIVE SUMMARY I. Purpose: To show the history of the CH-46 assault support helicopter and highlight problems concerning the service life of the airframe and dynamic components. The replacement aircraft and issues surrounding it were examined. II. Problem: The CH-46 is rapidly approaching the service life of the airframe and its dynamic components without a solution to replacing our current medium lift helicopter. III. Data: The CH-46 has served the USMC well for over 26 years. The airframe and dynamic components service lift has been established as 10,000 hours by the Navy. One airframe has already reached the limit and the Navy has made a recommendation on revising maintenance practices to extend the service life to 13,000 hours until we can build some more CH-46s and do a service life extension program on the remaining ones to make them last until 2020. The other alternative recommendations to date have been looked at and rejected because they cost too much or required more research and development which costs more money and time than the USMC has to make a decision on the medium lift replacement aircraft. A cursory look was made into the Osprey which seems the way to go in the future. The salvation for the Osprey as an option is in the hands of the American people and Congress. IV. Conclusions: A requirement urgently exists to solve the CH-46 medium lift replacement problem and the most cost efficient, least time consuming plan is to remanufacture the CH-46 and SLEP the rest of them. This will set the USMC back regarding the over the horizon attack capability, but fiscal constraints are the culprits. V. Recommendations: Submit the remanufacture and SLEP option to DOD as the most efficient and least expensive option. This keeps money in the POM budget, and if Congress restores funding for the Osprey, it can be reprogrammed. If Congress does not restore funding for the Osprey, we have a realistic, cost effective solution in place. USE OF AND FUTURE OF THE CH-46 ASSAULT HELICOPTER IN THE UNITED STATES MARINE CORPS OUTLINE THESIS STATEMENT. The United States Marine Corps has a dilemma in deciding what to do about the medium lift replacement for the CH-46 as they approach the end of their designed service life in view of the Department of Defense decision to cancel the MV-22. I. History of the CH-46E A. First Flight B. Foreign Military Purchases C. Commercial Application II. Mission A. Troop Transport B. Transport of Supplies and Equipment C. MEDEVAC III. Aging Airframe and Dynamic Components A. CH-46 Airframe B. CH-46 Dynamic Components C. SR&M Improvements IV. Implications of Cancelling the Osprey A. Service Life Extension Program B. Remanufacture the CH-46 C. Replacement Aircraft D. Pentagon Plan for Medium Lift Replacement V. Attempts to Save the Osprey A. CMC Appears Before Congress B. Congressional Support C. Foreign Interest VI. Conclusion The first flight of the CH-46 prototype was made on April 22, 1958. The CH-46 made its first official flight in October 1961, a year from the contract signing. The first deliveries to squadrons was scheduled in early 1964 to Marine Aircraft Group 26. Designated the HRB-1 by the U. S. Marine Corps before the Defense Department revised military aircraft designations. It was procured through the Navy Bureau of Weapons and is the first helicopter BuWeps has bought from inception on a fixed-price contract. The CH-46 was the first helicopter to come under the Weapons Readiness Analysis Program (WRAP) as part of the new Navy maintenance package system. Basically, the WRAP system calls for providing various card-file maintenance instruction packages by the contractor designed for various unit levels. Each package is to contain step-by-step maintenance instructions for the particular command level involved and also will specify the manpower skills required in detail to carry out the instructions in the package. The CH-46 helicopter was bought by foreign military services also. Boeing Vertol delivered three ships to its licensee, Kawasaki Aircraft, and the major components for seven more. The Royal Canadian Air Force ordered six helicopters with oversize sponsons fuel tanks providing 900 more gallons of fuel. The specific operational requirement by the Canadian Air Force was for 190 helicopters. The Swedish forces initially ordered nine helicopters to be used as anti-submarine warfare aircraft. All of these foreign governments still operate the CH-46 helicopter today. Kawasaki Heavy Industries, Ltd. still is manufacturing its version of the aircraft, the KV-107, under license from Boeing Vertol. The last KV-107 was scheduled for delivery to the Japanese Self Defense Forces in February 1990. In the early 1960's, the CH-46 was also used by commercial operators and some CH-46s are still in use today under the designation as a BV-107. New York Airways used the helicopter as a twenty-five passenger transport for the routes around the New York area. Columbia Helicopters in Washington state has used the civilian version (BV-107) all over the United States in externally lifting logs from inaccessible sites for many years. They have also used it in Norway to externally lift tall power line transmission towers in remote uninhabited terrain. The CH-46 is designed to provide helicopter transport of supplies, equipment, and personnel for the landing force during the ship-to-shore movement and within the objective area. Extreme mobility, gained by using helicopters extensively in tactical operations, is an important part of Marine Corps doctrine today. It allows Marines to operate in areas well removed from their rear bases for extended periods of time. Using helicopters to insert and extract long-range reconnaissance teams provides a highly effective intelligence capability. The helicopter gives a commander an additional means for locating the enemy, and its speed and mobility provide the freedom to fix the enemy, mass sufficient combat power, and destroy the enemy over distances previously impossible to cross so rapidly. In helicopterborne operations, movement of troops, supplies and equipment is accomplished by helicopters. The increase in mobility and freedom of action provides a ground commander with combat options never available to him in the past. The helicopter's flexibility and versatility permit a ground commander to reduce time and space limitations normally encountered in the movement of assault forces. Because an assault force embarked in helicopters can cross terrain obstacles, bypass hostile areas, and attack and destroy or seize objectives deep in hostile areas, a commander is able to concentrate the necessary combat power at the decisive time and place and, once the desired result is attained, rapidly redeploy his forces where necessary. Marine Corps CH-46 squadrons transport personnel and cargo, provide utility combat support, and provide other air support as directed for the landing force during the ship-to-shore movement and within the objective area during subsequent operations ashore. These operations are part of the assault support function of a Marine Aircraft Wing. Marine CH-46s are employed for both tactical and administrative/logistic missions. Tactical missions consist of helicopterborne assaults to seize critical terrain, isolate pockets of enemy resistance, or conduct raids. Administrative/logistic missions include supply or resupply of troops, movement of equipment, nontactical movement of troops, messenger and liaison service, and casualty and prisoner- of-war evacuation. The use as a medevac helo is especially important in a cold environment because the CH-46 has a heater and can carry 15 litter patients and two attendants. The CH-46 was procured from 1963 through 1971 with the intent to fill a twenty-four year requirement for medium lift in support of the United States Marine Corps. The planned life has since been converted to flight hours for airworthiness certification purposes, more specifically, for the purpose of determining what fatigue life the aircraft and critical systems must meet. In 1978, the Navy established the service lift of the CH-46 as 10,000 hours. The CH-46 airframe service lift of 10,000 hours was established as a qualitative indication of life for planning only and is not a limit based on a fatigue test. Therefore, fatigue testing was not accomplished nor was any planned to substantiate structural certification past 10,000 flight hours. Evaluation of the CH-46 airframe fatigue analysis, fatigue test results and in-service experience data indicates the CH-46 airframe can be safety operated beyond 10,000 hours. This will be possible with a certain amount of testing and analysis, as well as additional maintenance inspection requirements, primarily during depot maintenance. Some civilian operators have logged over 25,000 hours on the BV-107 in commercial operations as reported in Rotor and Wind Magazine. However, these commercial operators are not operating the airframe in the corrosive environment aboard ships either. There are numerous dynamic components (rotor system, drive system and flight controls) which have a life limit equal to or less than 10,000 hours. These components will require replacement, fatigue tests, or modifications to provide a longer life. This problem has arisen once again because the CH-46 was planned to last 10,000 hours so there was no requirement to track components or items which exceeded the 10,000 hour limit. We need to reexamine current fatigue data using current mission profiles. Some components can be extended based on current testing. The CH-46 and its dynamic components require a service life assessment program (SLAP) to extend the airframe and its dynamic components to 13,000 hours. It will be more cost efficient to redesign some components and make some of them out of composites so they will last longer and reduce the weight. The Naval Aviation Depot at Cherry Point has previously reported that it will cost $500,000 and eight months to complete the service life assessment program on the CH-46. The CH-46 fleet is rapidly approaching the 10,000 hour planned service life. One airframe in the Navy has already reached the 10,000 hour mark according to officials at NAVAIR. The Marine Corps planned to have the CH-46 out of the inventory by 1999. This phase out is obviously not going to happen at that time, as we have no approved replacement identified at the current time. Some interim measures to keep the CH-46 operational past the 10,000 hour mark have been planned by the Naval Aviation Depot at Cherry Point in conjunction with officials at NAVAIR. Until other modifications resulting from a SLAP on the CH-46 can be identified, some modifications to our maintenance program have been identified. When the aircraft reach their designed service life of 10,000 hours, they will be sent to depots to induct the aircraft into a modified standard depot level inspection (SDLM) program. This will extend the aircraft past its designed service life of 10,000 hours. The inspection will follow basic SDLM guidelines with emphasis placed on increased evaluation of areas that have been historically prone to corrosion and wear along with areas previously identified as having fatigue crack potential. An aircraft successfully completing the modified inspection would be permitted to continue in service for another service period. A service period is defined as having to return to depot every 24 months of service. When the new period end date (PED) is reached, the cycle will be repeated. It is imperative that aircraft being certified beyond the current service life be reinspected at the depot. For this reason, the aircraft service period adjustment (ASPA) inspections will be eliminated for these aircraft. An ASPA is where a team from depot comes to the squadron and conducts a limited inspection of certain areas. If the material condition of the aircraft warrants, an adjustment to the induction cycle at the aircraft's PED for depot level maintenance is made. It should be noted that the H-2 and H-3 communities have utilized the SDLM inspection concept to extend their aircraft beyond the 10,000 hour mark set by NAVAIR for all helicopters in the Navy's fleet. The CH-46 has already gone through a safety, reliabil- ity, and maintenance program (SR&M). The purpose of this was to reduce the costs of ownership, keep aircraft readiness at a sufficient level so operational capability would not be seriously degraded and to enhance the safety of the air- craft. The aviation planners looked at the 3m data of the 160 items composing unscheduled maintenance. The top fifty accounted for 92% of the problem. Thirty two items become the SR&M program as some of the top 50 were already the subject of an engineering change proposal (ECP) or were in research and development to correct the problems. The first SR&M aircraft improved CH-46 was finished by the depot at Cherry Point in November 1983. The recent cancellation of the Osprey by the Secretary of Defense has the Marine Corps scrambling to solve the medium lift replacement for the CH-46. We basically put our eggs in one basket concerning the Osprey and have to react as best we can in the aftermath of this decision. One proposal is to enter into a service life extension program (SLEP) to extend the service life of existing CH-46s through the year 2020 by optimizing safety, cost effectiveness and operational suitability for the UH mission in addition to application to the CH-46 mission until phase out. Current estimates by NAVAIR indicate we will have to SLEP some airframes and procure additional aircraft to make up for attrition of the CH-46 fleet. The Osprey was due to be introduced into the fleet in 1992 as well as increasing numbers of CH-46 aircraft would go out of USMC inventory. The weapons system manager for the CH-46 believes it would take seven years before the first SLEP hardware implementation kits could be available. Also 10% of the CH-46 fleet will have reached or exceeded the 10,000 hour service life. The Marine Corps is analyzing a four phase life extension and upgrade for its fleet of CH-46 assault support helicopters as an alternative to the Pentagon's plan to replace the aircraft with a derivative of the UH-60 Black Hawk and buying more CH-53Es. In addition to a renewed CH-46 program, we are considering the Westland/Agusta EH 101, Boeing's Model 360 technology demonstration helicopter. These alternatives, plus the V-22 itself, are under study in an independent cost and operational effectiveness analysis being prepared for Congress and the Pentagon. Secretary of Defense Cheney has indicated in the Washington Post that the Osprey is killed regardless of what the study recommendations indicate. We have to consider the aircraft options as we help prepare Navy aviation acquisition budget plans for fiscal year 1992-1997 that is to be submitted to the Pentagon in April. A CH-46 program would cost less than a UH-60 derivative and the Black Hawk is too small. The CH-46 carries a Marine squad of 16-18 Marines, while the UH-60 is sized to an Army squad of eleven soldiers. A stretched version of the UH-60 to accommodate the larger squad would lead to substantial development costs and take too long. The 1950's technology CH-46 has been out of production since 1971. The SR&M upgrade did not extend the aircraft's service life, and CH-46s will start reaching their 10,000 hour service life in increasing numbers in 1993. Time is short and the 19 February 1990 issue of Aviation Week Magazine reports the Marines have a plan revolving around the CH-46. In distinct phases, some-of them occurring simultaneously, the CH-46 plan entails: A service life extension program for most of the current fleet. The emphasis would be on dynamic components, including the rotor system, transmission and hydraulics. New production of CH-46's as quickly as possible. These helicopters would be manufactured with improvements already made in fleet aircraft, but otherwise would have the configuration in which the CH-46 was last produced. This phase would be held below 100 aircraft, providing for no more than attrition of the fleet. Development and production of a CH-46E derivative, being called the CH-46X. The upgrade would include modern equipment developed for other programs, including integrated controls and the V-22 derived glass cockpit incorporated in the Boeing MH-47E and Sikorsky MH-60K special operations forces helicopter. Upgrade of all E models in the field into the X configuration. A thorough remanufacturing program would start the new X models off with new lifetimes lasting well into the 2020's. In the end, we would have a fleet of X's about the same size as its current fleet of E's--about 350 aircraft. This plan assumes that current Marine Corps force levels will survive Pentagon budget cutting. Aircraft numbers would be reduced if force levels were reduced. We would seek a reallocation of fiscal year 1991 budgets to accelerate a reopening of the CH-46E production line at Boeing. Table 1 shows how the CH-46E new production would be configured. Table 2 shows the CH-46X new production configuration. The CH-46X would have to be capable of carrying the tow-configured HMMWV (7900 lb) externally and a crew of three (750 lb) internally out to 50 NM and return with 20 minutes of 10% initial fuel, whichever is greater.4 The Pentagon plan would replace plans for the Ospreys with a mix of CH-53E and HH-60 helicopters to meet the Corps' medium and heavy lift needs. A Pentagon cost comparison done in 1989 showed that buying 176 CH-53 and 590 HH-60 helicopters would cost $6 billion more than the Ospreys, if produced jointly by Bell-Boeing. If there were competition between Bell and Boeing for the Osprey line, the V-22 savings would be about $8.5 billion on the helicopters according to DOD. The helicopters would be cheaper if the CH-53Es were used in a double sling mode--meaning they were rigged to carry two HMMWVs instead of one. Under the double sling proposal, the Corps would need only 225 CH-53Es and 478 HH-60s to meet its needs, saving about $2.2 billion over the Osprey. CMC reports he considers this dialogue of dual sling options totally ridiculous. "It has nothing to do with coming from the sea in a wide variety of scenarios . . . It has nothing to do with warfighting." To make the double sling work, vehicles must be bolted together on ship before they may be carried ashore, creating an extra logistical and administrative burden. Once ashore, the equipment must be unbolted before it can be used, which would impede the speed and flexibility of the assault. Anyone who has ever planned an amphibious operation knows we don't need a problem like this. The deck would be fouled for a long time while we bolted the vehicles together. There simply isn't enough room aboard a ship to do this effectively. The CH-53E and HH-60 mix has other problems. The CH-53E was built for logistics and endurance on the battlefield. It was never designed as an assault helicopter, but we have used it like that in some situations. It simply was not designed to land on the sloping terrain in an assault like a CH-46, and it has a tremendous radar signature. The Black Hawk carries about half the troops as the CH-46 or the Osprey. We would have to get twice as many helicopters and twice as many pilots and crew chiefs to get the same lift as a CH-46 or Osprey. There isn't a snowball's chance in hell of getting any extra Marines in the fiscal situation we are in. We would need extra support equipment to maintain the helicopter mix envisioned by the Pentagon. In a 20 February 1990 House Armed Services Committee hearing in response to repeated questions about the V-22 Osprey program cancelled by the Secretary of Defense, CMC said, "finding an aircraft to meet the Corps' medium lift needs is the most pressing issue for Marines this year. The aging CH-46 helicopter is entering its 26th year of service life. While it has served us well, we can no longer expect it to carry Marines in harm's way on the modern battlefield." Gray said, "Precision guided munitions and hand-held surface-to-air missiles place the 30-year old helicopters and the Marines they carry at risk." The Commandant has urged Congress to take a new look at the affordability issue surrounding the V-22 Osprey. Navy Secretary Lawrence Garrett has said the Navy stands by the Pentagon decision to cancel the program. The Secretary of Defense has recently testified that it's a great concept, but that it's an affordability issue. The Osprey would not be affordable if bought for Marine Corps use alone. Given the era of declining budgets, the Pentagon must consider multi-mission aircraft for the future. The V-22 has potential for missions like antisubmarine warfare, special ops and drug interdiction. We are at the upper edge of the helicopter technology envelope and if we want to make a significant leap in capability, we must pursue a different avenue. As soon as the Osprey started flying, the Marine Corps would have to fight for their delivery positions. The other services would jump on the bandwagon as soon as they started flying. A bipartison coalition of eleven lawmakers recently held a pro-Osprey press conference in front of the National Air and Space Museum to lobby for continued funding of the V-22. The Department of Defense has ignored the direction of the legislative branch by cancelling contracting for the aircraft while Congress was in recess. The lawmakers are touting the V-22 for its commercial benefits in addition to its military function. Without a guaranteed military market, the V-22s manufacturers would not continue spending money on the aircraft. It is unlikely any airline would order it until they see it in production and operation. The Congressmen are seeking to have the Federal Aviation Administration use one of the V-22 prototypes as a new technology demonstrator and evaluation aircraft. They also want the FAA to continue its present research studies into tilt-rotor technology. Senator Gramm called the V-22's tilt-rotor technology the way of the future and reported Japanese, West German and French companies are all considering production of such aircraft. He warned if the United States does not produce the V-22, we could lose thousands of jobs and sales to foreign companies in the 1990's.5 I have read articles saying the Japanese have hired several designers from Bell Helicopters to develop a similar aircraft for commercial and military markets. Recently, an article in Aviation Week stated the Japanese had let a contract in Fort Worth, Texas to construct a manufacturing facility for aircraft production. I believe a tilt-rotor will be built but will it have an American or foreign label? The medium lift replacement program has the Marine Corps scrambling to find a stop-gap replacement for the cancelled V-22 Osprey. The Navy and Marine Corps have spent over $2 billion in the research and development of the tilt-rotor, a multipurpose aircraft that can take off and land like a traditional helicopter and transition to a conventional fixed wing aircraft in forward flight. I doubt the Marine Corps will pursue another Marine only aircraft because of the cost. This eliminates the Boeing 360 from consideration. The EH-101 is not much farther along in development than the V-22 and possesses several serious drawbacks, including the fact that it is not armored, carries its fuel under the aircraft rather than in outboard sponsons and does not possess the troop carrying capacity we require. Assuming the V-22 does not get put back in the budget by Congress, upgrading our fleet of CH-46 helicopters and supplementing them with some new CH-46 airframes is possibly the cheapest alternative. There is not more time for research and development of another airframe. The CH-46 is rapidly approaching the end of its service life in ever-increasing numbers. Some CH-46 aircraft may have to be parked because the dynamic components are reaching the end of their service life and we don't have replacements on board. The drawback to remanufacture and SLEP of existing CH-46 airframes is--we will have them for 20-30 years. I believe Congress will save the Osprey because of its commercial applications. The Marine Corps is still convinced that tilt-rotor or tilt-wing technology is the way to go, because the helicopter is physically constrained to a maximum forward speed. Eventually we may have an entire family of tilt-rotor aircraft, both larger and smaller than the size of the present V-22, performing a variety of heavy lift and escort/gunship roles. A tilt-rotor variant could replace the OA-4 and OV-10 also. This development must continue even if the Marine Corps buys something else because the concept of tilt-rotor or tilt-wing is too good to abandon. Click here to view image ENDNOTES 1 William H. Gregory, "Vertol Flys CH-46A Assault Helicopter," Aviation Week and Space Technology Magazine, October 22, 1962, p. 30. 2 David A. Anderton, "Vertol 107 Aims at Low Cost Versatility," Aviation Week and Space Technology Magazine, March 6, 1961, p. 53. 3 David F. Bond, "CH-46E Replacement May be CH-46X: Marines Believe UH-60 is Too Small," Aviation Week and Space Technology Magazine, February 19, 1990, p. 18. 4 J. P. Cress, Director, Naval Air Systems Command Detachment, Program Manager Air (Field) -266, Marine Corps Air Station, Cherry Point, North Carolina, letter about USMC CH-46 restart program. 5 Elizabeth Donovan and David Steigman, "Gray: V-22 Substitute Scheme 'Ridiculous'," Navv Times, March 5, 1990, p. 4. BIBLIOGRAPHY Anderton, David A., "Vertol 107 Aims at Low Cost Versatility." Aviation Week and Space Technology Magazine, March 6, 1961, 52-57. Bond, David F., "CH-46E Replacement May Be CH-46X; Marines Believe UH-60 Is Too Small." Aviation Week and Space Technology Magazine, February 19, 1990, 18. Cress, J. P., Director, Naval Air Systems Command Detachment, Program Manager Air (Field) -226, Marine Corps Air Station, Cherry Point, North Carolina, letter about USMC CH-46 restart program. Donovan, Elizabeth and David Steigman, "Gray: V-22 Substitute Scheme 'Ridiculous,'" Navy Times, March 5, 1990, 4. Gregory, William H., "Vertol Flys CH-46A Assault Helicopter." Aviation Week and Space Technology Magazine, October 22, 1962, 30-32. Holzer, Robert, "Marine Corps Scrambles to Replace Cancelled V-22." Defense News, February 26, 1990, 3. Department of the Navy. "Assault Support Helicopter Tactical Manual (U) MWP 55-9-ASH, Volume 1 (Rev D), September 1987.
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