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The observed revenue service deterioration characteristics of the CF6-6D engine are analyzed to determine the detailed causes of the SFC and EGT increases. Cruise trend data from DC-10-10 revenue service operations and maintenance test cell results are utilized to define deterioration status. Effects of design changes and installation losses are included. Deterioration rates are seen to be reasonable compared to previous airline experience. Test results are presented for systematic performance field restoration of a deteriorated engine. Preliminary revenue service results are presented for the CF6-50 engine, the CF6 growth engine, which is installed on the DC-10-30, A300B and 747-200.

An automatically controlled transit system is being installed at Bradley International Airport. The system has two purposes: demonstration of automatic transit for urban applications, and transportation from a remote parking lot to the airport terminal. The 0.7 mile guideway includes both at-grade and elevated sections. A 550 ft bypass at the intermediate station simulates an off-line passenger terminal. Provisions for extension of the guideway to serve future facilities have been included. The two 25 ft long vehicles are each powered by two 60 hp electric motors. An on-board computer controls the operation of the vehicle. The vehicles are air-conditioned and have two-way communication capabilities. Design of the guideway began in November 1973. Construction of the guideway was begun in July 1974 and was essentially complete in December 1974. The construction was completed in April 1975 when the system was energized and testing begun.

The Tampa and Seattle-Tacoma Intra-terminal transit systems have been in service long enough to judge the validity of their concepts and the success of their designs. These two systems have been accepted by the Authorities that own and operate them. They have excellent safety and performance records. The public accepts their driverless cars routinely. The two systems are described and compared. They are similar in many respects but differ in their basic application to the airports, one being a shuttle and the other a loop system. As a result of their specific application, the automatic control systems differ. Operating and performance summaries are given. Both systems provide the same level of service and both have an availability over 99%.

Since 1972 NASA has pursued a program aimed at advancing the technology and establishing a data base appropriate for the possible future development of supersonic cruise aircraft. This paper briefly reviews the objectives and status of the propulsion portion of the program. Building upon a continuing series of propulsion system studies, research activities are under way in noise and pollution reduction, inlet stability, and materials.

The environmental and economic goals projected for advanced supersonic transports will require revolutionary improvements in propulsion systems. Variable cycle engine concepts that incorporate unique components and advanced technologies show promise in meeting these goals. Pratt & Whitney Aircraft is conducting conceptual design studies of variable cycle engine concepts under NASA sponsorship. This paper reviews some of the design considerations for these engine concepts. Emphasis is placed on jet noise abatement, reduction of emissions, performance improvements, installation considerations, hot-section characteristics and control system requirements. Two representative variable cycle engine concepts that incorporate these basic design considerations are described.

Many airlines find themselves at present in a transition period with regard to Engine Health Monitoring. The manual concepts used up to now are being replaced by computerized versions and almost parallel to this comes the introduction of the “On Condition Modular Maintenance.” The new High Bypass Engines (engines of the 3rd generation) along with the 2nd generation engines, were designed for “Modular Maintenance.” As a result, the efforts toward achieving an automatic engine performance control were also intensified. These new ideas of engine monitoring were repeatedly considered in determining the Modular Maintenance Concept. Both in the past and at present, airlines have to some extent applied very different engine trend monitoring methods, in theory and in practice. This shows that even good methods are not universally suitable.

In recent years several government and industry groups (DOT, CAB, NASA, M.I.T., AAC, etc.) have attampted to define policy and recommendations for the nation's short-haul low/medium density air transport needs. This paper is an attempt to determine what plans have been recommended, what impact these plans have had on the industry, and what remains to be done. The writer found a diversity of opinions within the industry on the key elements which would form the foundation of a short-haul air transport policy. The writer has taken the liberty of presenting his own conclusions, which he hopes will stimulate the industry into positive policy action.

Utilizing the background acquired in the development of the C-130, C-141, and C-5 aircraft, the Lockheed-Georgia Company has maintained a continuing effort in the conceptual and preliminary design of advanced transport configurations with the overall objectives of improving the efficiency and flexibility of aircraft as cargo carriers. Of a variety of innovative design concepts incorporating technology advances in all applicable areas, the Spanloader concept is one of the most promising for future heavy logistics aircraft. This paper presents a description of the Spanloader design concept, performance characteristics, and mission flexibility. Alternate designs are presented including the use of hydrogen fuel and nuclear propulsion.

Jet engine rotors are the most highly stressed large volumes of material in the engine. They possess millions of inch pounds of kinetic energy at normal speeds. Considerable care in design and analysis must be taken to ensure that the parts do not fail over the full life cycle of the engine. In this paper, major design criteria are identified and discussed, with special emphasis on the long-life aspects of disk design methodology. The role of fracture mechanics is discussed as it applies to intrinsic material defects as well as the residual life of the part after crack initiation. Future trends, including the impact of powder metallurgy on design, and retirement of disks for cause are discussed.

Automatic landing has been developed to the point where all the wide-bodied jets have it as basic equipment. The techniques presently employed are generally founded upon the technology of the last two decades - especially with respect to analog computation and gyroscope references. Several new techniques are now available which can substantially improve the autoland systems for the next generation of transport aircraft. These include airborne digital computers, the use of integrated air-data and strapdown airplane motion reference systems, expanded use of automatic system test, and the development and employment of the Microwave Landing System (MLS). These new technology developments promise to provide expanded operational benefits, reduced maintenance, and increased availability over that of contemporary autoland systems.

A brief listing of major elements of the ground, airborne and other elements of the All Weather Landing System is presented. The chronology of growth in the use of this system by a major trunk airline in the last decade is reviewed. Problems considered by the author to be basic to further deployment and development of the system are discussed and tentative solutions to these problems are suggested, namely: 1. Continuous recording and public dissemination of Runway Visual Range data for all Category II and III periods at existing and proposed runways of these Categories is suggested to provide the most cost-effective basis for decisions regarding further deployment of ILS systems and MLS systems. 2. It is recommended that an industry group be convened to review and, probably, revise certification requirements for aircraft intended to operate below Category II minima in order to break the stalemate presently inhering in those activities.

The author has been continuously involved with the development and implementation of Category I and II approach operating procedures for American Airlines. This paper describes the Industry's success to-date and proposes a more economical means of attaining CAT IIIa capability.

The principal design features of the NASA QCSEE UnderThe-Wing and Over-The-Wing powered lift propulsion systems are given. In the UTW engine, these include noise reduction features, a variable pitch low pressure ratio fan, a fan drive reduction gear, an advanced core and low pressure turbine with a low pollution combustor, a digital control, and advanced composite construction for the inlet, fan frame, fan exhaust duct, and variable area fan exhaust nozzle. The OTW engine is similar but has higher fan pressure and a fixed pitch fan. Both engines are scheduled to be fabricated and tested starting in 1976.

Design of the YC-14 over-the-wing nacelle, utilizing the CF6-50D engines, presented unique engine installation conditions which have been accommodated with very minor impact to the baseline commercial engine design. Major installation features which affect the engine are reviewed including engine mounting, engine/aircraft deflections and nacelle sealing, effect of the confluent-flow exhaust nozzle on engine cycle matching, and inlet/thrust reverser/engine compatibility. Design solutions and planned testing to evaluate the installation are discussed.

In a recently completed program, static and wind tunnel measurements have been made of the basic noise, noise reduction, and performance characteristics of externally blown flap (EBF) propulsive-lift systems. The static tests were performed on an outdoor model rig. Noise evaluations were made for parameters such as basic system geometry, flap slot dimension variation, elimination of flap slots, sweep angle variation, passive flap trailing edge modifications, active (blowing) trailing edge modifications, and for an ejector/decayer exhaust system. The wind tunnel evaluation determined forward speed effects on EBF systems noise characteristics. The results from the experimental programs are discussed as to their application to full scale short haul aircraft.

A highly noise suppressed TF 34 engine was used to investigate the noise of several powered lift configurations involving upper-surface-blown (USB) flaps. The configuration variables were nozzle type (i.e. slot and circular with deflector), flap chord length, and flap angle. The results of velocity surveys at both the nozzle exit and the flap trailing edge are also presented and used for correlation of the noise data. Configurations using a long flap design were 4 dB quieter than a short flap typical of current trends in USB flap design. The lower noise for the long flap is attributed primarily to the greater velocity decay of the jet at the flap trailing edge. The full-scale data revealed substantially more quadrupole (V8) noise in the region near the deflected jet than observed in previous sub-scale tests.

A complete STOL (Short Take-off and Landing) system is currently providing public transportation service between the urban centres of two large Canadian cities. Passenger and public reaction, plus operating experience in a competitive environment is providing some interesting data, useful in developing future STOL systems as an important component in the improvement of transportation in general. The Demonstration is showing that STOL systems are capable of quickly providing fast, convenient, short-haul service, while at the same time respecting the composite concerns of society, encompassing air-pollution, noise, land-use, energy-consumption and economics.

The solution to the short haul cost/benefit dilemma is Federal Government funding of system development costs. One means of introducing VTOL to short haul transportation would be development of the S-65C multi-mission helicopter with customers sharing development costs.

This document describes the results of cost effectiveness, marginal benefit, marginal cost, and total cost analyses with respect to several noise abatement options being considered by the United States government, including retrofit of aircraft which do not meet the noise level limits of Federal Aviation Regulation Part 36.

This paper is an attempt to establish the rationale for monitored, or reduced, thrust operations in Air Canada and their effect on safety, reliability, aircraft performance and economics. It explains why an approach to operating at less than maximum takeoff thrust has been developed. It demonstrates the effects of monitored thrust on power plants, operating temperatures, and training procedures. Lastly, the paper explains how monitored thrust will produce an improvement in the environment and how it achieves an incremental saving in fuel.