Statistical analyses of transmission vibration patterns from an AH-1 Cobra helicopter were previously reported. Fourteen steady-state maneuvers were analyzed using multi-factor analysis of covariance. Based on triaxial recordings, it was found that only two maneuvers displayed reliably stationary time-series: low and high power forward climb. Principal… (More)
During the past several years, an AH-1 Cobra aircraft at the NASA Ames Research Center has been instru-mented with tri-axial accelerometers and a data acquisition system to support the experimental study of in-flight transmission vibration patterns. This paper describes the on-board HealthWatch system and presents some important initial statistical analyses… (More)
This paper presents a survey of engine health monitoring systems for commercial aircraft. The state of practice is explored first, with the purpose of identifying the shortcomings of current systems. The state of the research to address these shortcomings is them surveyed to explore the alternatives. Research and monitoring applications for various other… (More)
Complex aerospace systems are often designed in collaborative engineering environments where requirements and design decisions are rapidly made and withdrawn by various subsystems as the process evolves. As a result, the system-level management should continuously re-allocate resources (e.g. capital and labor) among various subsystems such that the main… (More)
Typical vibration monitoring systems for helicopter gear-boxes rely on single-axis accelerometer data. This paper investigates whether triaxial accelerometers can provide crucial flight regime information for helicopter gearbox monitoring systems. The frequency content of the three different directions is compared and analyzed using time-synchronously… (More)
Communicating failure mode information during design and manufacturing is a crucial task for failure prevention. Most processes use Failure Modes and Effects types of analyses, as well as prior knowledge and experience, to determine the potential modes of failures a product might encounter during its lifetime. When new products are being considered and… (More)
Product environmental impact reduction efforts largely focus on incremental changes during detailed design. Application of automated concept generation using a design repository and integral life cycle assessment approach is explored to evaluate and reduce environmental impacts in the conceptual phase of product design.
Research on the nature of the vibration data collected from helicopter transmissions during flight experiments has led to several crucial observations believed to be responsible for the high rates of false alarms and missed detections in aircraft vibration monitoring systems. This work focuses on one such finding, namely, the need to consider additional… (More)