Downloaded from https://www.everyspec.com ADS-79D-HDBK A.3. DEFINITIONS Hazard: A real or potential condition that could lead to an unplanned event or series of events (i.e., mishap) resulting in damage to the system, death, or injury. System: The organization of hardware, software, and data needed to perform a designated function within a state environment with specified results. A.4 INTRODUCTION To qualify the structural integrity of an air vehicle, the US Army specifies a Structural Demonstration program and a Flight Load Survey (FLS) program. The structural demonstration tests are used to demonstrate the safe operation of the air vehicle to the structural design envelope.
The objective of the FLS is to measure flight loads on components. Thus, the typical aircraft conditions flown represent the gross weight (GW), center of gravity (CG), external stores, airspeed, and altitude combinations representative of the design load conditions. However, Army aircraft systems are subjected to almost continuous upgrades of capabilities and expansion of missions, creating new critical loading situations which were not flown during the initial FLS.
It is essential that fleet management includes a task that will establish and track the relationship between the original design loads used by the original equipment manufacturers (OEMs) and the loads experienced during operational usage. Fatigue Life Management (FLM) and usage/load monitoring, using flight recorder data, will provide the information needed to determine and track this relationship. An FLM system should provide the capability to measure and record the actual environment (examples: usage, loads, configurations) experienced by Army aircraft systems.
Through analysis these data can be correlated with established structural integrity methodologies to establish appropriate maintenance actions. As explained in the basic ADS (ADS-79D-HDBK), the goals of the CBM system are to minimize burdensome maintenance tasks, increase aircraft availability, improve flight safety, and reduce maintenance cost. The primary mechanism of FLM is to enable updating of the usage spectrum required for maintaining airworthiness of Army aircraft systems. The secondary mechanisms include providing: a. Intervals at which specific component maintenance or replacement actions are required. b. Usage statistics for each operational command base, unit, or aircraft. c.
The rate at which the fatigue capability of a component is being used and an estimate of the remaining fatigue life. d. Usage and loads data to support a balanced approach in establishing damage repair limits. e. Data required for effective Risk Management of the Army‘s fleet of aircraft systems. (For example, the loads environment prior to and during a mishap incident provides data required to evaluate the incident and minimize the readiness impact on the fleet.) It is not the intention of a FLM system to control the manner in which Army pilots perform their missions.
However, the CBM system will make possible the tracking of the loads environment that the aircraft experiences in terms of severity, duration, and frequency of occurrence. This will make it 35