Locking Devices Flashcards
Why is safteying important?
It ensures bolts, screws, nuts, pins and other fasteners do not shake loose during flight
In lockwire material identification, what does the letter code C represent?
CRES (Corrosion resistant steel)
What percentage of alloying elements are in CRES?
19% Chromium
9% Nickel
In lockwire material identification, what does the letter code F represent?
Carbon Steel (zinc plated)
What percentage of alloying materials are contained in zinc plated carbon steel
0.18-0.23% Carbon
In lockwire material identification, what does the letter code N represent?
Nickel Chromium Iron alloy
What percentage alloying elements does Nickel Chromium Iron alloy contain?
15.5% Chromium
8% Iron
In lockwire material identification, what does the letter code NC represent?
Nickel Chromium Alloy (Monel)
What percentage of alloying elements does Nickel Chromium alloy (Monel) contain?
30% Chromium
Only where can single-wire locking be used?
On small screws in a closely spaced closed geometrical pattern, on parts in electrical systems and in places difficult to reach
What method of wire locking is most common?
Double-twist
How is the number of twists per inch in locking wire determined?
Depends on the gauge of the locking wire and is given in the AMM Chapter 20
How do spring washers work
- A single or double-coil spring washer fitter beneath nut.
- Spring compresses when nut is tightened.
- This sets up friction and preventing the nut from undoing.
What type of nut are tab washers suitable for?
Plain nut
How does a tab washer work?
- One tab is bent against the flats of the nut
- The other tan is bent over an edge of the component or into a machined hole in the component
Can a tab washer be reused?
No
How does a shakeproof washer work?
- Has slanting serrations on it’s internal or external circumference
- Angle allows nut to be tightened but serrations bite into it and prevent it coming undone
Can a shakeproof washer be reused?
Yes, as long as it remains springy
When are locking plates used?
In replacement of tab washers when bolt must be repeatedly removed
How many times can split pins be used?
Once
When can Centre punching/Burring be Used?
Only when detailed in the aircraft document set
What do pip pins allow?
Rapid installation and removal of parts without tooling
What is the difference between Ring pull decent pins and Double acting steel pins?
Double acting pins can be removed by pushing or pulling the ring handle, ring pull detent pins are simply pulled out
What are the 4 principle parts of a Camloc fastener?
- Receptacle
- Grommet
- Retaining ring
- Stud assembly
What 4 parts does a stud assembly consist of?
- Stud
- Cross pin
- Spring
- Spring cup
Where are lightweight Camlocs usually used?
Internal, lightly loaded access panels
What are the two types of Dzus fasteners and where are they used?
Light duty:
-Used in box covers, access hole covers and lightweight fairing
Heavy duty:
-Used in cowlings and heavy fairings
What is the main difference between the two types of Dzus fastener?
The heavy duty Dzus fastener has a grommet
What are the 2 types of Airloc fastener available?
- Fixed type
2. Floating type
Where are stainless steel cotter pins (split pins) used ?
In locations where non-magnetic material is required
What type of nut should be used with a cotter pin?
Castellated that have been drilled for the pin
