F/A-18(A-D) Wing Root Fatigue Life Expended (FLE) Prediction Without the Use of Strain Gage Data
Abstract
U.S. Navy and Marine Corps F/A-18 aircraft are subject to two life-limiting metrics--actual flight hours and fatigue life expended (FLE). While flight hours can be mitigated, fatigue on the airframe cannot. The fatigue expended per flight varies based on the mission; it is recorded by seven strain gages throughout the airframe. Because strain gages are unmonitored systems, they are subject to drift and/or failure. Consequently, Naval Air Systems Command (NAVAIR) accumulates approximately a month of strain gage data for each Navy and Marine Corps F/A-18 before analyzing the data for such anomalies. This results in a latency period of roughly six weeks between the mission being flown and the squadron receiving the FLE for that mission. This research identifies regression models by which to predict the NAVAIR reported FLE using real-time metrics stored by the aircraft during flight, thereby, eliminating the latency issue and allowing squadrons to better manage their aircraft. This research shows that the NAVAIR FLE number can be accurately predicted (adjusted R squared approx. 0.95) using in-flight metrics, such as weight-off-wheels time, minimum g, maximum g, and wing root trigger events.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2010
- Accession Number
- ADA524711
Entities
People
- Jason M. Lindauer
Organizations
- Naval Postgraduate School