Selection of Rivets, Hardware, and Fasteners for a Sheet Metal Repair

Question 1

What criteria can be used to decide the repairability of a sheet metal structure?

Answer 1

1. type of damage
2. type of original material
3. location of the damage
4. type of repair required
5. tools and equipment availability

Question 2

Inspection of Riveted Joints
a - what should you inspect?
b - what do you look for?

Answer 2

a. inspection consists of examining both the
shop and manufactured heads and the
surrounding skin and structural parts for
deformities
b. chipped/cracked paint around heads may
indicate shifted or loose rivets
c. joggles in removed rivet shanks indicate partial shear failure

Question 3

The presence of black residue around the rivets is an indication of what?

Answer 3

Fretting

Question 4

Rivet head cracking are acceptable under what 4 conditions?

Answer 4

1. the depth of the crack is less than 1/8 of the shank diameter
2. the width of the crack is less than 1/16 of the shank diameter
3. the length of the crack is confined to an area on the head within a circle having
   a maximum diameter of 1 1/4 times the shank diameter
4. cracks should not intersect, which creates the potential for the loss of a portion
   of a head

Question 5

What is corrosion?

Answer 5

the gradual deterioration of metal due to a chemical or electrochemical reaction with its environment

Question 6

What 3 things can trigger corrision?

Answer 6

1. the atmosphere
2. moisture
3. other agents

Question 7

What are the 5 steps to prepare a damaged area for repair?

Answer 7

1. remove all distorted skin and structure and aircraft lines
2. remove damaged material so that the edges of the completed repair match
   existing structure and aircraft lines
3. round all square corners
4. smooth out any abrasions and/or dents
5. remove and incorporate into the new repair any previous repairs joining the area
   of the new repair

Question 8

What do you look for when selecting the material to be used for a repair?

Answer 8

1. repair material must duplicate the strength of the original structure
2. if using a weaker alloy than the original structure, a heavier gauge must be used to
   give equivalent cross sectional strength

Question 9

Describe Repair Parts Layout

Answer 9

all new sections fabricated for repairing or replacing damaged parts in a given aircraft should be carefully laid out to the dimensions listed in the aircraft manual before fitting parts into the structure

Question 10

What should be considered when selecting Rivets for repairs?

Answer 10

Normally rivet size and material should be the same as the original rivets in the part being repaired
1. Rivet hole enlarged/deformed - use the next larger size rivet after reworking hole
2. Blind Rivets Needed - always consult aircraft manual for recommended type, size,
spacing, & number of rivets needed

Question 11

How do you determine rivet spacing and edge distance when completing a repair?

Answer 11

1. the rivet pattern must conform to instructions in the aircraft manual
2. the existing rivet pattern is used whenever possible