Parts is Parts!

Learning how to manage aircraft parts can make you more efficient and keep you out of hot water

As a maintenance organization, you purchase parts to be installed on an aircraft in one of two distinct ways:

  1. Parts vendors — From a supplier or vendor who sells either new or used parts.
  2. Outside services vendors — From a supplier who actually repairs parts and returns them to you.

New parts do not have to come directly from the aircraft manufacturer; however, your supplier should be able to provide you with evidence (documentation) that the part has been through one of the five certification methods and made it through successfully. The documentation that you accept needs to be more than just a promise, it should include some concrete evidence from the FAA-approved manufacturer of the part.

In order to ensure that used parts are eligible for installation, we must make sure that they have “traceability.” What a word. Simply stated, the history of the parts must be traceable back to the most recent certification method. If it comes with a Part 43.9 maintenance sign-off from an agency that is properly qualified and authorized to certify the quality of the part, that is sufficient. A Part 43.9 sign-off is a proper 8130-3 or serviceable tag. Also, it just makes good business sense to establish solid long term relationships with good vendors.

Inventory management

Management of inventory is important in all types of business. When parts are purchased and not rotated out (sold), the unusable inventory becomes more of a liability than an asset. Even though it is on the books as an asset, your inventory can be tying up your liquid assets.

You may have heard the term just-in-time (JIT) inventories. This type of inventory management refers to purchasing the parts and materials so that you receive them “just-in-time” to use them right away. The whole philosophy is based around the truth that inventory that is sitting and not being moved is a bad use of the company dollars.

In the service business, JIT does not work as well — some say it does not work at all. Here, JIT inventory might mean getting the part just in time to put it on the airplane while the pilot is performing his pre-flight to leave the shop. Not good!

What we can do in the service business is learn from what we are moving, what parts are selling. We need to be able to capture the information as parts are sold, and then use that information to evaluate and plan purchases. Good data will help the parts manager order the supplies and materials that are used on a regular basis in volumes that make sense. Even then, there are always parts that come up that are not in stock and that need to be ordered — many times at the expense of higher freight and AOG charges. The goal is to plan well enough that the list of things we AOG is very small and the parts we stock are rotated through just about as fast as they are ordered. Develop a means of tracking what you sell and how often.


The receiving person, commonly called a receiving inspector, acts as a sentinel of sorts to prevent the entry of bad parts into your system. This job is very important and the person needs to be trained well in order to do a complete job in the receiving area. The receiving inspector must:

  • Check the content of a box with the packing list to verify that everything was included.
  • Check that the contents of the box were not damaged during shipping.
  • Verify that the part has with it the appropriate paperwork supporting its traceability.

If the receiving inspector finds something that is questionable, he or she needs to know what to do with the parts. It is a good idea to have an area set aside in or near the receiving area where these parts are placed in quarantine until a quality control manager can be brought in to help out.

Life-limited parts

Part 43.10, Disposition of Life-Limited Parts, speaks to this specific type of part. The regulation uses the following words to define life-limited parts. “Life-limited part means any part for which a mandatory replacement limit is specified in the type design, the Instructions for Continued Airworthiness, or the maintenance manual.” In other words, aircraft life-limited parts are those parts identified by the aircraft manufacturer or production certificate holder as having a total mandatory life limit of some increment counted in hours, cycles, landings, or by calendar.

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