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At least 415 records · Page 23

Flight service evaluation of advanced composite ailerons on the L-1011 transport aircraft

A flight service evaluation of composite inboard ailerons on the L-1011 is discussed. This is the second annual report of the maintenance evaluation program, and covers the period from July 1983 when the first yearly inspections were completed, through July 1984. Four shipsets of graphite/epoxy composite ailerons were installed on L-1011 aircraft for this maintenance evaluation program. These include two Delta aircraft and two TWA aircraft. A fifth shipset of composite ailerons were installed in 1980 on Lockheed's flight test L-1011. A visual inspection was also conducted on these components. No visible damage was observed on any of the composite ailerons, and no maintenance action has occurred on any of the composite parts except for repainting of areas with paint loss. Flight hours on the airline components at the time of inspection ranged from 6318 to 6989 hours, after approximately 2 years of service.

Stone, R. H.↗

Flight-service program for advanced composite rudders on transport aircraft

Flight service experience and in-service inspection results are reported for DC-10 graphite composite rudders during the third year of airline service. Test results and status are also reported for ground-based and airborne graphite-epoxy specimens with three different epoxy resin systems to obtain moisture absorption data. Twenty graphite composite rudders were produced, nine of which were installed on commercial aircraft during the past three years. The rudders collectively accumulated 75,863 flight hours. The high time rudder accumulated 12,740 flight hours in slightly over 36 months. The graphite composite rudders were inspected visually at approximately 1000 flight hour intervals and ultrasonically at approximately 3000 flight hour intervals in accordance with in-service inspection plans. All rudders were judged acceptable for continued service as a result of these inspections. Composite moisture absorption data on small specimens, both ground-based and carried aboard three flight-service aircraft, are given. The specimens include Thornel 300 fibers in Narmco 5208 and 5209 resin systems, and Type AS fibers in the Hercules 3501-6 resin system.

Source record↗

A preliminary evaluation of a failure detection filter for detecting and identifying control element failures in a transport aircraft

The application of the failure detection filter to the detection and identification of aircraft control element failures was evaluated in a linear digital simulation of the longitudinal dynamics of a B-737 Aircraft. Simulation results show that with a simple correlator and threshold detector used to process the filter residuals, the failure detection performance is seriously degraded by the effects of turbulence.

Bundick, W. T.↗

Measurements of the response of transport aircraft ceiling panels to fuel pool fires

Tests were performed to characterize the responses of various aircraft ceiling panel configurations to a simulated post-crash fire. Attention was given to one currently used and four new ceiling configurations exposed to a fuel pool fire in a circulated air enclosure. The tests were controlled to accurately represent conditions in a real fire. The panels were constructed of fiberglass-epoxy, graphite-phenolic resin, fiberglass-phenolic resin, Kevlar-epoxy, and Kevlar-phenolic resin materials. The phenolic resin-backed sheets performed the best under the circumstances, except when combined with Kevlar, which became porous when charred.

Bankston, C. P.↗

A preliminary evaluation of the generalized likelihood ratio for detecting and identifying control element failures in a transport aircraft

The application of the Generalized Likelihood Ratio technique to the detection and identification of aircraft control element failures has been evaluated in a linear digital simulation of the longitudinal dynamics of a B-737 aircraft. Simulation results show that the technique has potential but that the effects of wind turbulence and Kalman filter model errors are problems which must be overcome.

Bundick, W. T.↗

Flight service evaluation of advanced composite ailerons on the L-1011 transport aircraft

Flight service evaluation of composite inboard ailerons on the L-1011 under Contract NAS 1-15069 for a period of five years is discussed. The period from July 1984, when the second yearly inspections were completed, through June 1985 is covered. Four shipsets of graphite/epoxy composite inboard ailerons were installed on L-1011 aircraft for this maintenance evaluation program. These include two Delta aircraft and two TWA aircraft. A fifth shipset of composite ailerons were installed in 1980 on Lockheed's flight test L-1011. This aircraft is now inactive and inspections were therefore not performed this year. No visible damage was observed on any of the composite ailerons, and no maintenance action has occurred on any of the composite parts except for repainting of areas with paint loss. Flight hours on the airline components at the time of inspection ranged from 8787 to 10,804 hours, after approximately 3 years of service.

Stone, R. H.↗

Design considerations for application of laminar flow control systems to transport aircraft

The current status of the laminar-flow control LFC technology is summarized. Factors that have previously inhibited the application of LFC are first reviewed. Involved are the effects of atmospheric ice crystals, surface irregularities, acoustical environment, and off-design operating conditions. Aircraft design trends that are different from turbulent aircraft are discussed as are various design requirements unique to the LFC systems. Current design approaches for the principal LFC systems are reviewed. These include the system for protection of the leading-edge region from surface contamination and icing and the system for removal of a portion of the boundary-layer air. The latter includes consideration of both multiple spanwise suction slots and distributed perforations and required differences between the wing-box and leading-edge box regions.

Braslow, A. L.↗

Aerodynamics of seeing on large transport aircraft

Data were obtained in the full scale flight environment of the Kuiper Airborne Observatory (KAO) on the nature of turbulent shear layer over the open cavity. These data were used to verify proposed aerodynamic scaling relationships to describe the behavior of the turbulent layers and to estimate the optical performance of systems of various wavelengths operating within the KAO environment. These data and wind tunnel data are used to scale the expected optical effects for a potential stratospheric observatory for infrared astronomy (SOFIA) in which a telescope approximately 3.5 times larger than that on the KAO is envisioned. It appears that the use of combinations of active and passive aeromechanical flow control techniques can improve the optical behavior of systems in the SOFIA environment. Experiments to verify these potential improvements can be performed on the KAO with sufficient modifications to the cavity and aero-mechanical technique installations.

Rose, W. C.↗

Advanced concepts transport aircraft of 1995

The components of the Advanced Concepts Flight Simulation Facilities used to evaluate proposed human-machine interfaces are described. The facilities consist of: (1) an advanced concept flight station, which is a wide-body, composite airframe propelled by two turbo-fan engines; (2) an integrated air traffic control simulation; and (3) experimenter/observer stations. The flight controls and displays, and their operation are studied. The air traffic control provided in the simulation is examined. The control of the flight conditions and data collection by the experimenter are discussed.

Chappell, S. L.↗

Flight service evaluation of advanced composite ailerons on the L-1011 transport aircraft

This report covers flight evaluation of composite inboard ailerons on the L-1011 under Contract NAS 1-15069 for a period of five years. This is the fourth annual report of the maintenance evaluation program, and covers the period from May 1985 when the third yearly inspections were completed, through July 1986. Four shipsets of graphite/epoxy composite inboard ailerons were installed on L-1011 aircraft for this maintenance evaluation program. These include two Delta aircraft and two TWA aircraft. A fifth shipset of composite ailerons was installed in 1980 on Lockheed's flight test L-1011. One instance of minor damage was observed on one of the composite ailerons and was repaired. No other maintenance actions have occurred on any of the composite parts except for repainting of areas with paint loss. Flight hours on the airline components at the time of inspection ranged from 12,051]en1] to 14,046 hours, after approximately 4 years of service.

Stone, R. H.↗

Flight service evaluation of advanced composite ailerons on the L-1011 transport aircraft

This report covers flight service evaluation of composite inboard ailerons on the L-1011 under contract NAS1-15069 for a period of five years. This is the fifth and final annual report of the maintenance evaluation program, and covers the period from July 1986 when the fourth yearly inspections were completed, through May 1987. Four shipsets of graphite/epoxy composite inboard ailerons were installed on L-1011 aircraft for this maintenance evaluation program. These include two Delta and two TWA aircraft. A fifth shipset of composite ailerons was installed in 1980 on Lockheed's flight test L-1011. The previous four annual inspections had been visual exterior inspections only. For this final inspection, the lower covers were removed for access and both interior and exterior surfaces, spars and ribs, and fastener holes were inspected. No damage or defects were observed on any of the composite ailerons, and no maintenance actions had occurred except for repainting of areas with paint loss. Flight hours on the airline components at the time of inspection ranged from 14,597 to 17,180 hours, after approximately 5 years of service.

Stone, R. H.↗

Natural laminar flow nacelle for transport aircraft

The potential of laminar flow nacelles for reducing installed engine/nacelle drag was studied. The purpose was twofold: to experimentally verify a method for designing laminar flow nacelles and to determine the effect of installation on the extent of laminar flow on the nacelle and on the nacelle pressure distributions. The results of the isolated nacelle tests illustrated that laminar flow could be maintained over the desired length. Installing the nacelles on wing/pylon did not alter the extent of laminar flow occurring on the nacelles. The results illustrated that a significant drag reduction was achieved with this laminar flow design. Further drag reduction could be obtained with proper nacelle location and pylon contouring.

Lamb, Milton↗

Aerodynamics of Seeing on Large Transport Aircraft

Efforts were undertaken to obtain a set of data that examined the level of turbulence and the scale sizes in the shear layer existing over the fence quieted cavity on the NASA-Ames Kuiper Airborne Observatory (KAO). These data were to be taken during the present study and compared with data taken from previous wind tunnel experiments, for which both aerodynamic and direct optical measurements were made. The data obtained during the present study were presented and discussed in light of their impact on the quality of optical images, that is, seeing through the shear layer. In addition, scaling relationships were presented that allow optical data obtained in one aerodynamic environment to be estimated for another one at perhaps different Mach numbers, scale sizes, or aircraft configurations.

Rose, William C.↗

Flight simulation of a wide-body transport aircraft to evaluate MLS-RNAV procedures

In a collaborative effort between the Federal Aviation Administration (FAA) NASA and the U.S. Air Force, a piloted simulation was conducted to look at the issues involved with flying a large, wide-body aircraft in the airport terminal area using Microwave Landing System Area Navigation (MLS)-RNAV procedures. A variety of approach paths, departure paths, and holding patterns were evaluated during the course of the study for operational use, flight technical errors, and safety. In addition, several methods for driving the horizontal situation indicator and flight director instruments were investigated along with needle sensitivity. The ultimate goal of the simulation was to develop and verify candidate paths and procedures prior to flight tests conducted in 1986/87. Subject pilots for the simulation study were provided by the FAA, NASA, the U.S. Air Force, and the airline industry.

Branstetter, James R.↗

Human factors studies of control configurations for advanced transport aircraft

This research investigated the threshold levels of display luminance contrast which were required to interpret static, achromatic, integrated displays of primary flight information. A four-factor within-subjects design was used to investigate the influences of type of flight variable information, the level of ambient illumination, the type of control input, and the size of the display symbology on the setting of these interpretability thresholds. A three-alternative forced choice paradigm was used in conjunction with the method of adjustments to obtain a measure of the upper limen of display luminance contrast needed to interpret a complex display of primary flight information. The pattern of results and the absolute magnitudes of the luminance contrast settings were found to be in good agreement with previously reported data from psychophysical investigations of display luminance contrast requirements.

Snyder, Harry L.↗

Damage tolerant composite wing panels for transport aircraft

Commercial aircraft advanced composite wing surface panels were tested for durability and damage tolerance. The wing of a fuel-efficient, 200-passenger airplane for 1990 delivery was sized using grahite-epoxy materials. The damage tolerance program was structured to allow a systematic progression from material evaluations to the optimized large panel verification tests. The program included coupon testing to evaluate toughened material systems, static and fatigue tests of compression coupons with varying amounts of impact damage, element tests of three-stiffener panels to evaluate upper wing panel design concepts, and the wing structure damage environment was studied. A series of technology demonstration tests of large compression panels is performed. A repair investigation is included in the final large panel test.

Smith, Peter J.↗