Civil Tiltrotor for the Commuter

II. A Civil Tiltrotor Applications study was conducted

III. The potential use of the Civil Tiltrotor can provide the short-haul commuter improved service in terms of flexibility and speed

IV. Recommendations for the short-haul (commuter) Civil Tiltrotor

V. Other markets studied

VI. Brief Summary

I. There is a need for an improved national transportation system for the short-haul commuter

National Transportation System Need: Improved Mobility

Studies project large increases in the demand for air travel by the year 2000:

• 74% increase in passenger enplanements in the United States
• 32% increase in the number of jet transports in the United States

Among today's most congested airports are the 10 busiest airports in the United States, which together handle a third of all passenger enplanements. Capacity shortfall airports are prime candidates for onsite vertiports.

Yet only three runways will be added to these busiest airports before the turn of the century, and only one new airport is expected to be built (at Denver). The problems are the pervasive consumption of land, environmental impact, opposition to aircraft noise, and cost.

More airplanes will be competing for increasingly scarce runway slots. Passengers will experience delays more often and for longer periods of time. Delays are already a serious problem, especially in the crowded northeast corridor of the United States. Delays at the airport are compounded by worsening delays on roads leading to the airport.

A major contributor to airport congestion is that many people are flying short distances on relatively small aircraft. The commercial tiltrotor aircraft can help reduce airport congestion and traffic delay problems by ---

• Using on-airport vertiports to siphon off short-haul connecting travelers, thereby freeing runways slots for larger aircraft.
• Using off-airport vertiports for urban area to urban area and city center to city center service, diverting travelers away from crowded hub airports and their access roads.
• Allowing passengers to experience portal-to-portal time savings, thereby improving their mobility and efficiency.
• Extending a congested airport's useful life without major investment in air-side facilities.
• Enhancing capacity with tiltrotor aircraft, expected to be environmentally friendly, compared to other means of enhancing capacity.
• Maintaining air service to smaller communities, preserving access and mobility benefits to those communities.

II. A Civil Tiltrotor Applications study was conducted

(For further information refer to Civil Tiltrotor Missions and Applications: A Research Study, Summary Final Report -NASA CR 177452, study by Boeing Commercial Airplane Co.)

Civil Tiltrotor Applications Study

In 1983, an FAA-sponsored National Rotorcraft Program sought to identify improvements to the national interurban transportation networks and determined that conventional helicopters did not have the potential to satisfy requirements because of a lack of capacity, high operational costs, and high noise levels. Tiltrotors offered better potential to improve interurban air transport service.

In 1985, FAA Administrator D.D. Engen proposed a joint civil tiltrotor study with NASA and DOD that would capitalize on development of the military V-22 tiltrotor and document the potential of the commercial tiltrotor transport market.

Technical Summary

• Six configurations analyzed (8-75 passengers)--designs based on V-22 technology
• V-22 derivatives with pressurized fuselages can accommodate 50 passengers and meet design range objective (600 nmi)
• Passenger and community acceptance is anticipated (low noise, vibration, and emissions)
• Tiltrotors can operate in current airspace; however, improvements are needed to exploit tiltrotor capabilities for competitive service
• Early development of certification is high priority

Vehicle Design Guidelines

• V-22 derivative or technology base:
  • twin engines
  • composite airframe
  • tilting wingtip mounted rotors
  • fly-by-wire
  • advanced cockpit displays
• 600nmi design range, vertical takeoff with one engine inoperative (OEI hover)
• 800 nmi design range with rolling takeoff from 750 ft filed (STOL)
• Commuter mission profile with FAR reserve fuel requirements
• All federal aviation regulations met for safety, including Category A operations
• Ramp self-sufficiency: airstairs, APU, powerback
• Helicopter NPRM for 30 sec emergency power rating assumed
• Pressurized fuselage
• Normal passenger accommodations and amenities:
  • Seating at 30 inch pitch
  • Lavatories and galley
  • Full cabin heating and air conditioning
  • Pressurization desired

III. The potential use of the Civil Tiltrotor can provide the short-haul commuter improved service in terms of flexibility and speed

Urban Area to Urban Area. Examples of urban area to urban area markets are the Northeast Corridor, the Dallas-Ft. Worth-Houston Corridor, and the Los Angeles basin to San Francisco Bay. Such markets contain strong flows of business travel movement between regions of the urban-area, and these markets have attracted conventional fixed-wing shuttle service. Ground access to major airports in this type of market is already very difficult, particularly during morning and afternoon peak periods, and is projected by the FAA to worsen and affect greater portions of the day. The airports in these corridors are congested and, in the case of LaGuardia, Kennedy, and Washington National, slot controlled. Because of the importance of these hub airports, inclement weather can reduce capacity by as much as 50%, sending a ripple of delay through the air system of the entire nation.

A tiltrotor system interconnecting the Boston-New York-Philadelphia- Washington D.C. urban areas would require approximately 12 vertiports strategically located within high travel population centers. These vertiports would intercept travelers within a corridor close to their origin or destination. Operating in place of the existing shuttle system, the tiltrotor network could divert up to 15% of today's total passenger traffic away from airports and relieve 10% of the fixed-wing operations. Tiltrotor service in this market would provide an airborne form of intercity mass transit.

The "Spine" Network Service. The "spine" network would connect two or more city centers or high-density travel concentrations where an urban area-to-urban area tiltrotor market has not yet merged. This point-to-point market is characterized by high-frequency service and short ground access times. As a result, it would tend to function independently of major airports. Minneapolis-St. Paul-Chicago-Detroit-Pittsburgh-Washington, Vancouver, B.C.-Seattle-Portland, and San Francisco-Sacramento are examples of potential spine markets.

High Density Hub Feeder

A tiltrotor operating in the hub feeder market would connect small cities currently served by the smaller turboprop airplanes with congested or slot-constrained hub airports. In this market, the tiltrotor could provide the operator a competitive edge by avoiding or reducing the pressure on existing slots, gates, and precision approach airspace. Further, extra hub airport capacity would be provided by the onsite vertiport. As much as 15% of a congested airport's operation could be diverted to a tiltrotor hub feed system.

In the Northeast Corridor, a combined urban area to urban area and hub feeder system, if available today, could make as many as 1,000 runway slots available each day. Such a combined network would:

• Relieve the high-density airport's airside congestion by reducing fixed-wing operations
• Bypass airport ground congestion by flying point to point from local vertiports.
• Defer major capital investments in airport-related ground infrastructure (e.g., new tunnels, bridges, and access roads.)
• Using existing airport assets more fully before building new ones.
• Improve service to the traveler by cutting portal-to-portal trip times by roughly an hour each way.

Potential commercial tiltrotor service offers these advantages:

• Over helicopters:
  • Higher cruise speed
  • Lower noise
  • Lower vibration
  • Superior economics
• Over fixed-wing transports:
  • Convenient downtown service
  • Operational flexibility
  • Competitive economics

The civil tiltrotor's greater convenience and time savings can result in greater revenues per passenger.

IV. Recommendations for the short-haul (commuter) Civil Tiltrotor

To develop a viable market not only the aircraft -- but an entire and cohesive tiltrotor transportation system --- is required. A national plan for action needs to be developed, one which considers all aspects of a transportation system.

To the passenger on a portal-to-portal trip, the system needs to be perceived as accessible, safe, affordable, and convenient. Costs must be economically justifiable in terms of the value of time saved and the ease of making the entire trip.

In terms of competition, the tiltrotor does not have the luxury of beginning at "square one". It will come into service in a sophisticated, highly efficient, and deregulated environment, the modern air transportation system. It must compete on its merits in this setting.

Tiltrotor aircraft promise both a solution and a challenge. The U.S. leads this technology, but efforts outside the U.S. are also underway. Early U.S. development of a civil tiltrotor could create the benefits of a new industry and a new transportation system, but it carries risks: technical, operational, regulatory, and financial.

The following elements of a national plan for action on the civil tiltrotor are recommended:

(1) Continue studies to optimize tiltrotor configurations through use of advanced technology and low-cost designs.

(2) Develop an integrated civil tiltrotor transportation system plan, including appropriate infrastructure, operating environment regulations, and a technology demonstration plan.

(3) Continue the cooperation existing between government, industry, and customers in follow-on civil tiltrotor development program. Infrastructure Planning and Development:

• Vertiports conveniently located in metropolitan areas.
• New terminal instrument procedures to take advantage of precision navigation equipment.
• Integration into the National Aerospace System
• Certification criteria for powered lift; Continued development of airworthiness criteria

V. Other markets studied

High-Density Market. Airlines logged an average of 2000 hour of delays per day in 1986, up 25 percent from 1985. FAA predicts that the number of seriously congested airports will increase from 16 in 1986 to 58 by the year 2000.

Civil tiltrotors could capture one-third to two-thirds of this market. Key to tiltrotor's success is its VTOL ability, perceived as a necessity at one or both ends of each trip. The VTOL capability would allow passengers to begin and end their business trips near home, and to arrive at their metropolitan business destinations.

Market penetration of the civil tiltrotor is dependent on the form of service made available to the commuter i.e. portal-to-portal, through-plane service, or connect-hub service. Another factor will be the number and location of vertiports.

Low-Density Market. The low-density market is difficult to analyze because of the diversity of the market and the lack of specific market data. It is a large market, geographically, consisting of such regions as southeast Asia, Oceania, Alaska, northern Canada, and the Caribbean. The lack of ground infrastructure is one commonality in this market. Opportunities could include tourists, light, high-volume industrial products, and foodstuffs.

There is also a potential market in low-density areas for resource development applications.

Resource Development Market. One of the best potential markets for the civil tiltrotor is in support of the resource development market (i.e., resupply of offshore oil and gas platforms). This is currently one of the biggest and most successful markets for larger helicopters, and the civil tiltrotor has substantial economic advantages due to higher cruise speeds and lower operating costs. Other resource development markets exist: logging, mining support, resource exploration.

Public Service Market. In the public service market, the customer is the general public, and the costs are borne by the community. Primary missions includes police and fire department support, medical transport, drug enforcement, Coast Guard search and rescue, and border patrol.

For the public at large, the tiltrotor offers improved service in terms of flexibility and speed while at the same time reducing the sound levels and possibly the number of aircraft needed to do the same work.

VI. Brief Summary

In summary, the civil tiltrotor concept is financially viable, provided:

• Its unique advantages are exploited by a fully developed infrastructure (vertiports, surface transport interface, air traffic control).
• Tiltrotors large enough to allow economies of scale -- in operation and in cost to build -- are developed.
• Efforts are continued to provide a vehicle responsive to civil requirements.
• Joint government/ industry efforts to develop a civil tiltrotor transportation system are continued.

The commercial tiltrotor concept supports national transportation policy themes:

• Maintain and expand the nation's transportation system.
• Foster a sound financial base of transportation.
• Ensure the transportation system supports public safety and national security.
• Protect the environment and the quality of life.
• Advancing U.S. transportation and expertise.

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