Search Results

The 757 and 767 airplanes provide maximum commonality in equipment, flight deck configuration and handling characteristics. Pilots with three-crew ratings will be qualified to fly either airplane with a three-crew requirement, and those with two-crew ratings will have the same flexibility. In addition to crew qualification, over 80% of the LRUs in the Flight Management System are interchangeable between similar crew configurations of the 757 and 767, i.e., they have the identical part number. Seventy-five percent of the LRUs are common to both the two-and three-crew configurations. Components that have engine-related software (the Thrust Management and Flight Management Computers) will be interchangeable between 757 and 767 aircraft powered by engines from the same manufacturer.

Commercial airlines use a variety of hydraulic fluid mixtures, some of which had been reported to cause increased valve erosion. An extensive test program was conducted to determine why certain mixtures of aircraft phosphate ester hydraulic fluids cause erosiveness in valves while others have negligible effect. Use of nonerosive mixtures is important to the aircraft industry to reduce the high cost of maintenance caused by erosion. Accelerated tests were conducted to identify erosive and nonerosive mixtures of presently available fluids. Chemical tests were conducted with a matrix of test fluids to establish methods that will predict the effects measured in erosion tests. Erosiveness of fluid mixtures can now be predicted by means of two laboratory measured electrochemical properties; wall current and threshold corrosion current density.