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Air-Blasting with angular plastic blast media promises to be an effective and more environmentally secure method of removing paint and contaminants from aircraft for inspection and repainting purposes than conventional chemical treatments. Laboratory testing can be useful for determining optimum media sizes, and comparing different media for speed of paint removal and media breakdown. This paper explains the details of one test program, including a means for determining relative residual stresses imposed by plastic blasting. A discussion is also included on the effect of contaminants in the media on residual stress development.

It has been demonstrated in practice that inadequate training and/or process requirements have produced conflicting results. The purpose of this paper is to outline an acceptable training program in use by commercial airlines and the military. It may not be the only program in use, but it should be representative of what is required to enable plastic media blast (PMB) to become a viable process for commercial aviation processing as well as military or other industry applications. In addition attempts are made to document in bibliographical sequence test data supporting plastic media blast process applications. The objective again is to produce data supporting the viability of plastic media blast processing. As well as data already existing, we have included data currently being collected that may or may not support plastic media blast processing.

LASC-GEORGIA operates a large aircraft assembly plant located in Marietta, Georgia. This facility is owned by the U. S. Government and is known as Air Force Plant No. 6. As a part of the assembly operation, various metallic structures have metal finishes applied to them. Some of these parts are plated. A large portion of the parts are aluminum and may receive anodize or conversion coating finishes. Both the plating and aluminum finishing operations generate waste water that must be treated to meet National Pollution Discharge Elimination System (NPDES) discharge limits.

Project successfully produces data supporting generic nature of diffused aluminide coatings for gas turbine hot section components. The Department of Defense will prepare military specifications for use in competitive procurement of such coatings. The second objective of the project, to develop a low cost, generic coating procedure indicates cost savings of 50 to 80% and is basis for DoD process specification. Paper includes arguments and supporting data. A unique aspect of the project is that it was funded by commercial interests in lieu of the taxpayers.

Electrochemical metallizing (ECM) has been widely used in aircraft maintenance and OEM applications, but is far from reaching it's potential. Although ECM has been around for more than twenty years, it still represents a small part of metal finishing as a whole, thus making information describing the process not readily available. Most of the problems experienced with the process, aside from solution contamination, stem from improper tooling design, and will be the focus of this paper. Tooling and other areas covered will be as follows: 1 Anode design: choosing proper anode design for the job. 2 Flow-thru anodes: for more efficient distribution of electrolytes. 3 Precision build-ups: plating to size. 4 Solution and anode cooling: to prevent over-heating of solutions at the anode/work-piece interface and the effects on the deposit. 5 Masking techniques: how to make the tape work for you by reducing high and low current density problems. 6 Heavy build-up: depositing .050″ or more.

Magnesium alloys axe widely specified for aero-engine lubrication system casings because of their inherent lightweight. Advances in engine design and performance have increased lubricant temperatures to the point that magnesium corrosion can occur due to reaction with the hot oil. Work, carried out under Ministry of Defence contract has shown that Dow 17 anodic pretreatment of magnesium provided superior protection against hot lubricant attack compared to HAE anodic and chromate conversion coatings. Sealing the Dow 17 film with suitable epoxy or phenolic resins provided protection up to 200°C. Protection up to 225°C was obtained using a polyimide resin as the sealer.

A freeze crystallization process is being demonstrated for treating a wide variety of wastes generated in the plating and other industrial shops at the Norfolk, VA Naval Aviation Depot (NAD). As envisioned the freeze process will treat various rinses, plating baths, and cleaning solutions for recycle at the NAD, greatly reducing and even eliminating discharges to the industrial waste treatment plant. The manner in which the freeze process will be incorporated to do this includes: remove water with sufficient purity for recycle as rinse water and in bath makeup; concentrate the chemicals in rinse waters for recycle to plating baths; concentrate pickling wastes to recycle the concentrated acid while precipitating the dissolved metals for removal as innocuous sludge; concentrate paint strippers and solvents in rinses and other contaminated waters, separating useful organics from residual aqueous concentrates.

Many factors affect the susceptibility of steel to hydrogen-induced delayed brittle failure. The most important factor is the strength level of the specific steel alloy. Other factors are the applied load and hydrogen control. The susceptibility of high-strength steels to this type of failure can be determined with a sustained load test using notched round-bar tensile specimens or Douglas Aircraft Company stress rings. This paper describes the Douglas method of embrittle­ment testing(ASTM F519, Type 2a) for plating processes and contains information on how the stress rings were used to rate the relative embrittling tendencies of various plating processes. Stress rings and four different-sized loading bars were used to determine the susceptibility of electrolytic tank plating processes (cadmium, chromium and sulfamate nickel) and electrolytic brush plating processes (cadmium and sulfamate nickel) to hydrogen embrittlement under sustained load.

HOTOL is intended to provide a low cost means of delivering payloads to low earth orbit. The vehicle is thus designed for unmanned and largely-autonomous operations with very limited contact with a ground station. This paper outlines the Command and Control Systems studies undertaken to date and proposed for future phases.

A survey of the general problem of aerothermal reentry is made, showing the complexity of the problem for HERMES as well as for future ASTS. The present status of the TPS solution choosen for HERMES is given. Under consideration are ceramic composites or carbon carbon for hot structures, insulation using for hot zones either ceramic composite shingles plus internal multiscreen insulation or ceramic tiles, and for lower temperature zones flexible external insulation. The difference between HERMES and other potential Space Transportation Systems are studied. A comparaison is made between HERMES solutions and other possible TPS systems.

The future of commercial space activity is inherently dependent on the availability of an economic launch system. In order to be able to embark on the full development of such a system it will be necessary to bring a wide range of technologies to maturity in all the major disciplines. These technologies are largely common to all proposed configurations of Advanced Space Transportation Systems. Estimates of hypersonic aerodynamic parameters are currently uncertain due to the inadequacy of aerodynamic theories and wind tunnel techniques in the presence of molecular dissociation of the air, viscous effects, separation and surface catalysis. This paper will address the areas of aerodynamic heating and force/moments/control powers. The current methodology as applied for HOTOL is described, including comparisons between prediction and wind tunnel measurements. A programme of technology development covering theoretical methods, wind tunnel experiments and free flight models is described.

The development of simulation codes for hypersonic flow computations is the pacing ilea in the definition of a reentry vehicule such as the European HERMES, in order to complement the experimental facilities which cannot cover the complete flight envelope. An important step is the validation of the codes with wind tunnel data and flight test results. Some validations are presented, in this paper indicating that the models of the physical and chemical phenomena are satisfactory.

Despite recent advancements in the physics and chemistry of high temperature air flows, large uncertainties remain to be reduced. Numerical procedures are necessary for advancement of understanding and modeling of their effects. Unfortunately, they have complex effects on the complex shapes of orbiter like U.S. Shuttle Orbiter and Hermes, and on the flight-test results, where they are mixed together with other complex phenomena, related to viscous flows. For clarification of the engineering implication of modeling uncertainties, some results of comparisons are given for different physical and chemical modeling on the simple shape of an AOTV. They emphasize the effect on the pitching moment and on the heat transfer, and give correlated variations in the bow shock wave, conclusions are given on the research to be pushed, and its inclusion in the Hermes aerothermal research program, presently in progress amongst the European scientific community.

The Active Thermal Control Subsystem of a newly designed spaceplane suggests the adoption of special fluid loop architecture and control, specific high technology equipment, dedicated ground test facilities and new concepts in schedule management. The design drivers for the Active Thermal Control system imply the need for a high degree of flexibility, in order to accomodate the large range of heat loads with a continuously changing operational and environment conditions. Fluid loop systems represent a viable concept in overcoming these problems. They offer the possibility of collection, transport and dissipation of significant amounts of thermal power enabling adequate means of close temperature control.

This paper provides a summary of the data and findings from a ten-month evaluation of the Traffic Alert and Collision Avoidance System (TCAS) II Industry Prototype installed on a Piedmont Airlines' Boeing 727 aircraft. The data presented represents quantitative and qualitative information on the performance of TCAS II in the National airspace System (KAS) and identifies the impacts of TCAS on Air Traffic Control and the flight crew. The information provided concentrates on the characteristics of the TCAS encounters and the operational use of the system.

A perceived, developing pilot shortage and experience level erosion is investigated. Case studies of three major airlines' pilot recruitment efforts are presented. The effect of major airline recruitment on two regional commuter carriers' experience levels is examined. The results and trends are summarized.

Although the United States is still a world leader in aviation, with the aeronautics industry holding a unique position in its contribution to trade, national security, and as a symbol of technological might, this position is severely threatened. The technical margins that have long provided U.S. preeminence have narrowed, in recent years, as foreign competition has increased. This paper reviews recent advances in technology resulting from NASA's aeronautics research that has helped the U.S. maintain its leadership. In order to respond to the increasing competition, NASA plans to increase its aeronautical R&T efforts, next year, in composites, propulsion, and aviation safety/automation. These increased efforts, building on the ongoing programs, provide an important next step in technology development for strengthening U.S. aeronautics competitiveness into the 21st Century.

For winged, horizontal take off and landing vehicule, the propulsion system appears as one of the key technologies. Based on the progresses in advanced technologies like cryogenic propulsion, high temperature materials, this paper will present progress on current concept studies of airbreathing/rocket combined engines with some consideratons on questions raised by the vehicule / engine system integration (air inlet / engine performances / aircraft trajectory and thrust requirements).

The commercial pressures have never been so great. As liberalisation spreads, operators are created and doomed, or merge to survive, rather reminiscent of the immediate post World War II era. Although regulatory authorities are assured of survival, they too are being subjected to unprecedented pressures from the whole of the aviation industry as well as increasing public pressure for improved safety standards. This paper seeks to identify some of the key developments and problems in airworthiness matters as UK moves towards much closer ties with Europe, including the control of maintenance standards and making the best use of technical resources.

The paper traces the development of the approach to airworthiness taken by Canadian government authorities from its origin through to current practices. It describes the Aerospace industry, the carriers and general aviation in statistical terms, indicates the impact of economic regulatory reform and suggests the way ahead for Canadian and other authorities lies in the attitude and methodologies practiced by the European authorities in their development of JARs. I SHOULD PERHAPS start this presentation with a short word about authorities. At the conclusion of a speech on safety regulation by Mr. Ronald Ashford of the UK Civil Aviation Authority, reported in Flight International of April 19, 1986, the following quotation from St. Paul to the Romans appeared: “You wish to have no fear of the authorities? Then continue to do right and you will have their approval, for they are God's agents working for your good”.