How to Read an Illustrated Parts Catalog (IPC)

What an IPC actually is

An Illustrated Parts Catalog (IPC) is the manufacturer's master parts list for an aircraft, engine, or accessory. It pairs an exploded-view line drawing (the "figure") with a table that lists every part shown in that drawing, its part number, how many are used, and which airframes it applies to. Unlike a maintenance manual, an IPC doesn't tell you how to do a job — it tells you what to order when you're doing one.

Every part number on this site was extracted from a real IPC table, which is why each part page shows a figure number, an item number, and an IPC page reference back to the original diagram.

Figure numbers and item numbers

IPCs are broken into figures — typically one figure per assembly or sub-system, such as "Figure 32-10: Main Landing Gear" or "Figure 71-00: Engine Mount." Each figure has its own exploded-view drawing with small item numbers (callout balloons) pointing to every part. The parts table for that figure lists the same item numbers down the left column, so you can go back and forth between the drawing and the table to confirm you've found the right part.

Item numbers are not unique across the whole catalog — Figure 32-10 and Figure 53-00 can both have an "Item 5." The item number only means something within its own figure, which is why you always need both the figure number and the item number to pinpoint a part in the original document.

Reading the indenture (assembly) levels

Parts tables are organized by indenture level, also called the "next higher assembly" structure. The top-level (least-indented) line is the complete assembly; everything indented underneath it is a component of that assembly. A dash, asterisk, or extra leading spaces in the nomenclature column usually signals a sub-part:

This matters because the same hardware item (a washer or nut, for example) often shows up under dozens of different assemblies throughout the catalog — it isn't unique to one figure. On this site, indented sub-parts are shown with a "↳" marker on each part and figure page.

Usable-on / effectivity codes

Not every part listed in an IPC applies to every airplane of that model. Manufacturers built the same model for years, often with running production changes — a different fuel selector valve starting at a certain serial number, for example. To handle this, IPCs assign each affected part an effectivity code (often called a "usable on code"), typically a single letter or short code like A, B, or C.

The front matter of the catalog (the "Effectivity Codes" or "Legend" section) maps each code to a serial number range or block of airplanes. So Usable on Code: B might mean "applies to serial numbers 17265001 through 17266500." Before ordering a part, check that your airplane's serial number falls inside the range for the code shown — if a part has no code (shown as "—" on this site), it generally applies across the whole model run covered by that catalog.

Quantity per assembly (UPA)

The "Qty" or "Units Per Assembly" column tells you how many of that part are used in one instance of the parent assembly — not how many are on the whole airplane. A bolt listed with quantity 4 under "Main Landing Gear Leg Assembly" means 4 per leg; if the airplane has two main legs, you'd need 8 total. Watch for notes like "AR" (as required) on consumables such as sealant, safety wire, or lockwire, where the quantity depends on the job rather than a fixed count.

Cross-checking the part number format

Manufacturer part numbers usually encode a family relationship. A base number like 0511289 with different dash-suffixes (-1, -2, -4) typically represents left/right-hand versions, different finishes, or successive design revisions of the same basic part. Standard hardware — bolts, nuts, washers, rivets — instead follows industry-wide numbering systems such as AN (Air Force-Navy), NAS (National Aerospace Standard), and MS (Military Standard). These standard parts are interchangeable across manufacturers as long as the dash number (which encodes diameter, length, or material) matches what the IPC calls for.

Putting it together

1. Find your part on this site, or in the printed IPC, by part number or by browsing a figure.
2. Note the figure and item number — this is your link back to the exploded-view drawing.
3. Check the indenture level to understand what assembly the part belongs to.
4. Confirm the effectivity/usable-on code matches your aircraft's serial number.
5. Verify the quantity per assembly against how many instances of the parent assembly your airplane has.
6. Always check the part number and effectivity against the current revision of the official IPC before ordering — catalogs are revised, and this site is a reference index, not a substitute for the controlled document.