AM Installation Techniques 2 — Questions and Answers
Question 1: When installing AN fittings on aluminum tubing, what is the correct procedure for flaring the tube end?
- Use a double-flare tool to create a 37-degree flare (Correct answer)
- Use a single-flare tool to create a 45-degree flare
- Use a double-flare tool to create a 45-degree flare
- Use a single-flare tool to create a 37-degree flare
Correct answer: Use a double-flare tool to create a 37-degree flare
AN fittings on aluminum tubing require a double-flare at 37 degrees to prevent cracking and provide a leak-free seal.
Question 2: What is the primary purpose of applying thread-locking compound (such as Loctite) on aircraft fasteners?
- To prevent corrosion between dissimilar metals
- To prevent fasteners from loosening due to vibration (Correct answer)
- To lubricate threads during installation
- To seal threads against fuel and oil leaks
Correct answer: To prevent fasteners from loosening due to vibration
Thread-locking compounds prevent fasteners from backing out due to aircraft vibration and dynamic loads.
Question 3: During hydraulic line installation, a technician notices the tube is slightly short. What is the correct action?
- Stretch the tube carefully to make it fit
- Replace the tube with one of correct length (Correct answer)
- Add a coupling in the middle of the run
- Use a flexible hose section to bridge the gap
Correct answer: Replace the tube with one of correct length
Tubes must be replaced with correctly dimensioned pieces; stretching compromises tube integrity and is not an approved repair.
Question 4: What is the minimum bend radius typically specified for aircraft rigid tubing to prevent stress concentration?
- Twice the tube outside diameter
- Three times the tube outside diameter (Correct answer)
- Equal to the tube outside diameter
- Five times the tube outside diameter
Correct answer: Three times the tube outside diameter
A minimum bend radius of three times the tube OD is required to avoid work-hardening and stress cracking.
Question 5: When installing a bonding jumper to an airframe structure, what surface preparation is required?
- Paint the contact surfaces before attaching
- Remove all paint and anodizing from the contact area (Correct answer)
- Apply corrosion-inhibiting compound before bonding
- Clean with solvent only, leaving primer intact
Correct answer: Remove all paint and anodizing from the contact area
Bare metal-to-metal contact is required for effective electrical bonding; paint and anodizing must be removed from the mating surfaces.
Question 6: Which of the following identifies an incorrectly installed AN bolt in a tension application?
- The bolt head is on the upper side of a horizontal joint
- The nut side has a cotter pin through the castle nut
- The bolt shank threads extend through the nut more than three threads (Correct answer)
- The grip length equals the total thickness of the joint materials
Correct answer: The bolt shank threads extend through the nut more than three threads
Excessive thread extension beyond the nut (more than three threads) indicates the wrong grip length bolt was used.
Question 7: When routing aircraft wire bundles, what is the minimum clearance from control cables and moveable surfaces?
- 1/2 inch (Correct answer)
- 1/4 inch
- 1 inch
- 3/4 inch
Correct answer: 1/2 inch
Wire bundles must be routed with a minimum 1/2-inch clearance from control cables and movable surfaces to prevent chafing and interference.
AM Installation Techniques 2
When installing AN fittings on aluminum tubing, what is the correct procedure for flaring the tube end?