Guide to Aircraft Maintenance Lingo

When approaching a maintenance project for your owner-flown aircraft it is essential that you are up-to-date with the lingo used to describe the replacements and repairs. While these aircraft maintenance terms accomplish similar goals, they each have a distinct meaning and fit different needs.

When an aircraft component becomes inoperative there are four options; it can be replaced with a new component, a rebuilt one, an overhauled one, or the bad component can be repaired. It is vital to know precisely what each option means and how to choose which is best for your situation.

  • New: A new component has never before been used. The manufacturer designs new components to comply with most recent fits and limits.
  • Rebuilt: A rebuilt component is used and has been rebuilt to fit new fits and limits. A distinguishing element about a rebuilt component is that the original manufacturer works it on.
  • Overhaul: An overhauled component is a used part that has been repaired according to the manufacturer’s approved technical data. This means that an overhauled part conforms to original service limits, but not necessarily any new fits or limits. If you are looking for a repaired part in compliance with new limits be sure to specify that you need a new limits overhaul. A new-limits overhaul is essentially the same thing as a rebuild, but it does not have to be performed by the original manufacturer.
  • Repaired: A repaired component is distinct from the other categories because it does not involve a replacement. It takes an inoperative component and restores it to working condition. There are no obligations to follow fits, limits, or any other procedures in the manufacturer’s overhaul manual. A repair is concerned with restoring functionality through any means available with no requirements to measure anything.

Now that you have a basic understanding of the various replacement and repair options, how can you decide which option is best for your situation?

There are many factors in play when making this decision, a big one being cost.

Almost always, a repair is going to be your most cost efficient option. An overhaul is more expensive because it adheres to many meticulous regulations that require additional time labor. Certain components, such as a propeller or seal, can be fixed with half the cost if they are repaired rather than overhauled. With other components, you might see even more variation in the costs. For example, a malfunctioning gyro flight instrument can cost ten times as much to be overhauled than repaired. It will definitely be worth your time and money to evaluate if a simple repair will satisfy your need before committing to a full overhaul.

Another contributing factor is the need for compliance with new fits and limits.

If the component needs to be changed or upgraded to new regulations, then a simple repair will not be sufficient. In that case, you need to decide between a new limits overhaul, a rebuilt component by the original manufacturer, or if it’s time for a brand new component.