• If no on-the-road failure of a component is acceptable, then the ECLS should be set at the earliest known failure point.
• If a component is not critical, or its failure can be easily dealt with when the vehicle is on the road, then using the MTBF point as the replacement point may be acceptable.

ECLS, or Expected Component Life System (sometimes referred to as Expected Component Life Cycle System), is a method involving the study of vehicle maintenance trends and replacing parts and components before they fail.

The first step to effectively using ECLS to determine PM checklists is having accurate maintenance data. By digging through the maintenance records and mining data out of the records, the maintenance manager can determine the Mean Time Between Failures (MTBF) for all parts and components on the vehicle. The MTBF is nothing more than the average miles or hours that a component fails.

Once the MTBF has been determined, the next step is to determine the ECLS replacement schedule for the component. If the ECLS is set at the MTBF, roughly half of the vehicles will suffer a failure of the component or part before it is replaced. If the ECLS is set at the earliest known failure point, then many times the part or component will be removed from the vehicle well before replacement is necessary.

The basic question becomes, what is an acceptable on-the-road failure rate? If no on-the-road failure of the component in question is acceptable, then the ECLS should be set at the earliest known failure point. However, if the item is not a critical component, or an item whose failure can be easily dealt with when the vehicle is on the road, then using the MTBF point as the replacement point may be acceptable.

Doing the legwork to determine when components fail and establishing realistic cut-off points is what helps determine when components should be replaced. This is one key to avoiding on-the-road breakdowns.