AMS 117 UNIT 4 EXAM QUESTIONS AND
ANSWERS
Question 1
What is break-away wire?
Correct Answer
.015" or .020" copper wire
Question 2
What is MS20002C?
Correct Answer
High strength flat washer
Question 3
How many twists per inch should you use when safety wiring?
Correct Answer
6 to 8 twists per inch
Question 4
What is the diameter of AN17?
Correct Answer
1 1/16"
Question 5
What is MS21250?
Correct Answer
12 point bolt
Page 1 of 39
,Question 6
What is the diameter of AN4?
Correct Answer
1/4"
Question 7
What do the numbers 6 & 17 represent in the code
AN176-17?
Correct Answer
6 = 3/8" in diameter
17 = 1 7/8" in length
Question 8
What is the head marking of an MS20426 rivet?
Correct Answer
A dimple (meaning 2117 aluminum
Question 9
What are plain flat washers used for?
Correct Answer
one washer is used under the nut of a bolt and nut installation (IF you have to use 2,
1 is normally placed under the head of the bolt and 1 under the nut)
Question 10
What does it mean if MS20426 rivet has a double dash?
Correct Answer
made of 2024 aluminum "DD rivet" or "icebox rivet"
Page 2 of 39
,Question 11
How many threads must be protruding through AN363/MS21045?
Correct Answer
At least 1 full thread protruding through nut, but not more than 2 or 3
Question 12
What is AN936 made of/used for?
Correct Answer
-Made of cadmium plated alloy steel
-Use with AN960 washer to protect material surface (not to be used on primary
structures)
-Used with small head screws or in areas of limited side-to-side clearance
Question 13
How far do you have to turn a Camloc fastener in order to lock/unlock it?
Correct Answer
typically 1/4 to 1/2 turn
Question 14
How are nuts sized?
Correct Answer
According to the diameter and thread pitch of the bolts or studs with which they
will be used
Question 15
What are quick release fasteners used for?
Correct Answer
Permit quick and easy removal of access panels, fairings and cowlings
(most are not structural fasteners)
Page 3 of 39
, Question 16
What should lock washers be used with?
Correct Answer
Use with plain washers to prevent gouging soft aluminum or magnesium base
metal
Question 17
What is the rule for determining the diameter of AN bolts?
Correct Answer
The first 1 or 2 digits of the AN # indicate the diameter of the bolt in 1/16"
increments
Question 18
What is AN aircraft industry standards?
Correct Answer
AN = Air Force/Navy
a type of military spec
Question 19
What is AN364/MS21083?
Correct Answer
Self-locking nut
Question 20
What is the diameter of AN20?
Correct Answer
1 1/4"
Page 4 of 39
ANSWERS
Question 1
What is break-away wire?
Correct Answer
.015" or .020" copper wire
Question 2
What is MS20002C?
Correct Answer
High strength flat washer
Question 3
How many twists per inch should you use when safety wiring?
Correct Answer
6 to 8 twists per inch
Question 4
What is the diameter of AN17?
Correct Answer
1 1/16"
Question 5
What is MS21250?
Correct Answer
12 point bolt
Page 1 of 39
,Question 6
What is the diameter of AN4?
Correct Answer
1/4"
Question 7
What do the numbers 6 & 17 represent in the code
AN176-17?
Correct Answer
6 = 3/8" in diameter
17 = 1 7/8" in length
Question 8
What is the head marking of an MS20426 rivet?
Correct Answer
A dimple (meaning 2117 aluminum
Question 9
What are plain flat washers used for?
Correct Answer
one washer is used under the nut of a bolt and nut installation (IF you have to use 2,
1 is normally placed under the head of the bolt and 1 under the nut)
Question 10
What does it mean if MS20426 rivet has a double dash?
Correct Answer
made of 2024 aluminum "DD rivet" or "icebox rivet"
Page 2 of 39
,Question 11
How many threads must be protruding through AN363/MS21045?
Correct Answer
At least 1 full thread protruding through nut, but not more than 2 or 3
Question 12
What is AN936 made of/used for?
Correct Answer
-Made of cadmium plated alloy steel
-Use with AN960 washer to protect material surface (not to be used on primary
structures)
-Used with small head screws or in areas of limited side-to-side clearance
Question 13
How far do you have to turn a Camloc fastener in order to lock/unlock it?
Correct Answer
typically 1/4 to 1/2 turn
Question 14
How are nuts sized?
Correct Answer
According to the diameter and thread pitch of the bolts or studs with which they
will be used
Question 15
What are quick release fasteners used for?
Correct Answer
Permit quick and easy removal of access panels, fairings and cowlings
(most are not structural fasteners)
Page 3 of 39
, Question 16
What should lock washers be used with?
Correct Answer
Use with plain washers to prevent gouging soft aluminum or magnesium base
metal
Question 17
What is the rule for determining the diameter of AN bolts?
Correct Answer
The first 1 or 2 digits of the AN # indicate the diameter of the bolt in 1/16"
increments
Question 18
What is AN aircraft industry standards?
Correct Answer
AN = Air Force/Navy
a type of military spec
Question 19
What is AN364/MS21083?
Correct Answer
Self-locking nut
Question 20
What is the diameter of AN20?
Correct Answer
1 1/4"
Page 4 of 39
