component appears. For example, the nose landing
gear system appears in figure number 027-00.
Group Assembly Parts List
A group assembly parts list consists of a figure
with its associated parts list. The illustration of a
particular component is shown broken down into the
detailed parts that make up the component. Each item
in the illustration is numbered. A listing of parts in the
assembly follows each illustration of the assembly.
This parts list is in the same order as the part numbers
shown in the illustration. The parts list gives the
manufacturers part number of the part, its description,
and other information. Figure 3-3 shows a typical IPB
illustration. Figure 3-4 shows a listing of parts for the
nose landing gear in figure 3-3.
Use of the IPB When the Part
Number Is Not Known
At times, you will need to find a part number for
an item that does not have the part number inscribed
on it. Suppose you need a bracket assembly. You
should be able to identify the following facts:
What type of aircraft the component you are
repairing is from
The component the bracket was removed from
The bureau number of the aircraft from which
the component was removed
For the purposes of this particular problem,
assume that the nose landing gear strut was removed
from an aircraft with Bureau Number 158620. If you
follow the steps listed below, you can get a
1. Obtain the landing gear IPB for the aircraft.
2. Refer to the alphabetical index of the IPB (fig.
3. Locate the Nose Landing Gear Shock Strut,
figure No. 027-00 (fig. 3-2).
4. Turn to figure 027-00 and look at the IPB
illustration (fig. 3-3). Callout 2 of this illustration is for
the nose landing gear strut. At this point, you should
compare the old strut to the strut shown in the
illustration. Select the desired part. In this case, callout
2 of figure 3-3 is the desired part.
5. Refer to the parts listing for the illustration index
number 2 (fig. 3-4). This index number establishes the
relationship of the part in the illustration and the part in
the list. It is for part number 2577818-011E<F, Strut
NLG Shock, and it has a CAGE or manufacturers code
6. Check the Use-On Code column to see if this
strut is used on that particular aircraft, Bureau Number
7. Refer to the Usable-On codes list A at the foot
of the list.
8. Have material control cross-reference the part
number to its applicable NSN in the Master
Cross-Reference List (MCRL) and verify it as a good
number in the Management Data List Navy (ML-N).
IPB Information Elements
The following text is a detailed discussion of the
various features found in the group assembly parts list
in figure 3-4.
Title (callout 1 in fig. 3-4). The title is on the first
line under description. It describes what major
component system is being broken down in the parts list.
It is identical to the title in the illustration (fig. 3-3).
Index number. As stated previously, this number
(callout 2 of fig. 3-4) establishes the relationship
between parts in the illustration and the corresponding
Part number. The part number (callout 3 in fig.
3-4) is the manufacturers part number. Two other terms
also may appear in this position, NO NUMBER and
COMMERCIAL. The term no number indicates that the
item has no assigned part number, but may have a model
or type number that appears in the index. The term
commercial in this column indicates that the item should
be procured from a commercial source.
Unit per assembly column. Refer to figure 3-4.
There are three different types of codes that could
appear in this column: 2, showing a specific quantity,
shown by callout 4; AR, shown by callout 5; and REF
shown by callout 6. Lets examine callouts 4, 5, and 6 in
In callout 4, the number designates the quantity
used on a particular assembly. For example, there are
two screws with part number MS27039-1-22.
In callout 5, the abbreviations AR (as required)
indicates a specific quantity has not been established
for this part. The quantity necessary to achieve a
desired result is used.
NOTE: When the letters AR appear, no specific
quantity is recommended. Sometimes, when