________ ___ _______ ensure that the hardware we use is safe,
correct and of identical quality and construction from aircraft to
aircraft

(a)  

(a)   is a test of quality required for a particular purpose

(a)   is the data providing dimensions, weights,
performance, locations etc

acronym for air force navy

(a)  

acronym for military standard

(a)  

acronym for national aerospace standard

(a)  

acronym for military specifications

(a)  

(a)   is an acronym which you will encounter a great deal in
aircraft maintenance industry

Military Specifications provide exact instructions for the
(a)   of aircraft hardware specifications

There are also _______ ________ which over see and ensure
meticulous quality control in the production of aircraft
hardware

(a)  

It should be noted that all global aviation governing bodies Also have their own set of (a)   which ensure that the
proper industry and applicable military specification are strictly
adhered too

are parts that are not produced or
maintained in accordance with the relevant standards or
specifications

(a)  

Purpose
• To allow parts to be fastened
together with the same
strength as unthreaded
fasteners.

(a)  

Advantage
• Allows the parts to be
assembled and disassembled
an almost infinite number of
times.

(a)  

most common thread type

(a)  

There are five classes of thread types.
• Class 1 - loose fit
• Class 2 - free fit ( most aircraft screws )
• Class 3 – medium fit ( most aircraft bolts )
• Class 4 – close fit
• Class 5 – tight fit

which is the most common in aircraft

(a)  

External Threaded Fasteners have their threads on the
outside of the fastener, such as a (a)  

Internal Threaded Fasteners have
their threads on the inside of the
fastener, such as a (a)  

Aircraft Bolt Terminology

Everything below the head of the
bolt

(a)  

The width of the shank measured
in 1/16-inch increments. It is important to
remember torque is based on the shank
(a)   not wrench size

The (a)   of the shank
measured in 1/8-inch increments

Is the unthreaded portion
of the shank

(a)  

You want to select a bolt who’s ____ _____ is identical to the
thickness of the two parts being joined

(a)  

A slightly longer ____ _____ is acceptable if necessary and you may
use washers under the bolt head and nut to compensate for the
added length, up to 1/8 inch

(a)  

A slightly shorter grip length is (a)  

The letter C between the diameter and length indicates the bolt
is?


(a)  

No letter, then the bolt is constructed of ___ ______ Nickel Steel


(a)  

The letter A at the end of the length indicates the bolt has?

(a)  

The addition of the letter H after the diameter indicates the bolt head
is drilled for?

(a)  

Standard Aircraft Bolts ___ to ____

(a)  

Drilled Head Engine Bolts ____ to ____

(a)  

Close Tolerance Bolts _____ to _____

(a)  

Internal Wrenching Bolts ______ to ______

(a)  

Clevis Bolts ____ to ____

used only in shear load applications

(a)  

Nuts that require some external locking feature
to keep it in safety

(a)  

Nuts the will remain in safety on their own


(a)  

Low Temp Self-Locking Nuts

(a)  

These are self locking nuts which can be either all metal or nylon/fiber lock
types.
• They are riveted onto the structure to permit access
panels to be removed quickly.
• They can be fixed or floating
to allow for screw/bolt alignment

(a)  

These are self locking all metal type
nuts.
• They are stamped out of sheet metal
and are not for structural use.
• Typically found in general aviation
light aircraft

(a)  

non self locking nuts must be locked onto the bolt by means of
a ______ ___, check nut or spring washer

(a)  

The threaded end of the nut is slightly oval or out of
round. As the bolt turns up through the threads is reforms
the oval portion of the nut. This provides the locking
action to hold the nut and
bolt in safety.
• These nuts are generally used in
areas of high heat, above
250 degrees F

(a)  

These nut types are like the AN365; however, they are of a lower
profile and are approved for shear loads.
• They are normally used on clevis bolts.
• They are NOT to be used in areas of high heat above 250
degrees F

(a)  

Very common, uses cotter pin to safety nut.
• Used in both shear and tension applications.
• Made from cad plated nickel
steel, unless otherwise stated.
• Designation Code- AN310C-4
– AN310- Castle Nut
– C- Material Corrosion Resistant Steel
– 4- (dash #) fit AN4 bolt.

(a)  

Like AN310 Castle Nut, however profile is much thinner.
• Used for shear applications. Typically, on clevis bolts and uses cotter pin for safety.
• Designation Code AN320D6
– AN320- Shear Castle Nut
– D- Material (2024 Aluminum Alloy)
– 6- (dash #) used on AN26 Clevis Bolt

(a)  

Have no castellation thus require a spring type lock washer or check nut to lock
them in safety.
• Are used in both shear and tension applications.
• Are available in L/H or R/H thread.
• Designator Code- AN315D 4R

(a)  

Used to lock aAN315 Plain Nut in safety.
• Install on fastener behind plain nut. Ensure it is tightened against the plain
nut.
• Designator Code AN316-4R
– AN316- (nickel steel)
– 4- Fits AN4 bolt
– R- Indicates right hand thread
– L – Indicates left hand thread

(a)  

These are specifically used on screws.
• They are typically constructed from Carbon Steel. However, also available in
corrosion resistant steel,
brass and 2024 aluminum alloy.
• AN340 is for NC series threads.
• AN345 is for NF series threads.
– These nuts are Non-Structural

(a)  

threads may be damaged,
or bolt may stretch and eventually fail

(a)  

excessive loads may be
applied to the bolt resulting in failure

(a)  

When torquing self-locking nuts, you must add the _______ _____ to the torque recommended for the hardware

(a)  

This rundown torque can be found by using a ____ ____ _____ ______ and running the nut down until it protrudes through
the locking feature of the nut and reading the value.

(a)  

provide a bearing surface area for nuts and act as shims
to obtain proper grip length for a nut and bolt combination and to
line up cotter pin holes and castellated nuts

(a)  

AN960- Made from cad plated steel, however available in alternate
materials.
• They are available in nominal thickness and a thin series which is half the
thickness.
• Designation Code AN960CL-516
– AN960 - Plain washer
– C - Material (corrosion resistant)
– L - Light series (half thickness)
– 516 - 5/16” hole


(a)  

AN935 split lock washers are used when a self-locking nut is not, or castellated
nut and cotter pin is not practical. These are not to be used in structural
applications.
• When using a split lock washer
install a plain washer between
lock washer and the material to
prevent damage

(a)  

Used in auxiliary structure such as
panels and fairings. Their entire shank is threaded, thus
no grip. They have a Class 2 fit

(a)  

can be used in place of bolts in both shear and tensile loaded
areas. They have a grip and are made from cad plated high strength steel.
• They are available in NF or NC

(a)  

Non-Structural.
• Normally found in interior applications or auxiliary structure in light
aircraft when coupled with a U type Tinnerman® nut.
• There are two types:
– Type A which has a sharp point (gimlet)
– Type B which has a blunt point and
slightly finer threads

(a)  

(a)   reuse cotter pins