Establishing a Vibration Threshold Value, Which Ensures a Negligible False Alarm Rate for Each Gear in CH-53 Aircraft Using the Operational Data [Spiral-bound]

Mehmet Elyurek (Author)

Book Description

Publication Date: 2003

This is a NAVAL POSTGRADUATE SCHOOL MONTEREY CA report procured by the Pentagon and made available for public release. It has been reproduced in the best form available to the Pentagon. It is not spiral-bound, but rather assembled with Velobinding in a soft, white linen cover. The Storming Media report number is A465024. The abstract provided by the Pentagon follows: Rotating machinery such as gears plays an important role in control of an aircraft. The condition of this machinery is a key ingredient to both platform safety and mission success, especially in military operations. The purpose of the thesis research is to establish a vibration threshold level for each particular gear in CH-53 aircraft such that, while minimizing in-flight risk, a negligible false alarm rate is obtained. This study uses Box-Jenkins time series modeling (ARMA) with regression, Mahalanobis distance metrics, goodness-of-fit tests and the Bonferroni correction to explore the structure of the historical acquisition datasets for particular gear type and aircraft, to set vibration threshold values for "Warning" and "Alarm" situations. Although 28 datasets could not be modeled because of small sample sizes, the other 224 data sets were successfully modeled using ARMA with regression modeling technique. The Mahalanobis distance metric was then used to set a threshold value of "Warning" and "Alarm" for each gear type. These threshold values were then checked with new data and 200 outliers for "Warning" and 69 outliers for "Alarm" were detected. These outliers might be evaluated as false alarms.

Product Details

• Spiral-bound: 97 pages
• Publisher: Storming Media (2003)
• Language: English
• ISBN-10: 1423514009
• ISBN-13: 978-1423514008