AMT Sheet Metal Structural Repair 2 — Questions and Answers
Question 1: When performing a flush patch repair on aircraft skin, the patch must overlap the damaged area by at least how many rows of rivets?
- One row
- Two rows (Correct answer)
- Three rows
- Four rows
Correct answer: Two rows
A flush patch must overlap the damage by at least two rows of rivets to restore original strength.
Question 2: What is the primary purpose of a joggle in sheet metal repair?
- To increase the thickness of the repair patch
- To allow overlapping sheets to lie flush without a step (Correct answer)
- To provide additional corrosion resistance
- To reduce the weight of the repair
Correct answer: To allow overlapping sheets to lie flush without a step
A joggle is an offset formed in sheet metal to allow two overlapping pieces to remain flush on the surface.
Question 3: Which type of rivet is most commonly used in aircraft sheet metal repairs to original structure?
- MS20470 (AN470) universal head (Correct answer)
- MS20426 (AN426) countersunk head
- MS20615 (AN615) pan head
- MS20470 (AN470) brazier head
Correct answer: MS20470 (AN470) universal head
The MS20470 (AN470) universal head rivet is the most widely used rivet for general aircraft sheet metal repairs.
Question 4: What is the minimum edge distance for a rivet in a sheet metal repair?
- 1.5D (1.5 times the rivet diameter)
- 2D (2 times the rivet diameter) (Correct answer)
- 2.5D (2.5 times the rivet diameter)
- 3D (3 times the rivet diameter)
Correct answer: 2D (2 times the rivet diameter)
Minimum edge distance for rivets is 2D (twice the rivet diameter) measured from the center of the rivet to the edge of the sheet.
Question 5: When selecting replacement rivets for a sheet metal repair, you find the original rivets are 2117-T4. What is the primary advantage of this rivet material?
- It has the highest shear strength of all aluminum rivets
- It can be driven in the as-received condition without heat treatment (Correct answer)
- It is immune to corrosion in all environments
- It is harder than 2024-T4 rivets
Correct answer: It can be driven in the as-received condition without heat treatment
2117-T4 (AD) rivets are field-ready because they do not require refrigeration or re-heat treatment before driving.
Question 6: What ratio is used to determine the correct rivet diameter for a sheet metal repair based on the thickness of the thickest sheet being joined?
- 2 times the sheet thickness
- 3 times the sheet thickness (Correct answer)
- 4 times the sheet thickness
- 5 times the sheet thickness
Correct answer: 3 times the sheet thickness
Rivet diameter should be approximately 3 times the thickness of the thickest sheet being joined.
Question 7: When drilling out a rivet for removal, the drill bit should be the same diameter as:
- The rivet shank (Correct answer)
- The rivet head
- The rivet hole
- The rivet manufactured head
Correct answer: The rivet shank
When removing a rivet, the drill is sized to match the shank diameter to drill out the head without enlarging the hole.
AMT Sheet Metal Structural Repair 2
When performing a flush patch repair on aircraft skin, the patch must overlap the damaged area by at least how many rows of rivets?