IA Fuel Systems & Hydraulic Systems Inspection 1 — Questions and Answers
Question 1: According to AC 43.13-1B, what category of fuel leak is defined as moisture or fuel that appears as a wet spot but does not form drops?
- Running leak
- Heavy seep
- Seep (Correct answer)
- Stain
Correct answer: Seep
AC 43.13-1B defines a 'seep' as fuel leakage that appears as a wet spot but does not form dripping drops, representing the lowest-severity leak category.
Question 2: Which regulation specifically lists fuel filters and strainers as items that must be inspected during an annual inspection?
- 14 CFR Part 91.411
- 14 CFR Part 43, Appendix D (Correct answer)
- 14 CFR Part 23.971
- 14 CFR Part 65.95
Correct answer: 14 CFR Part 43, Appendix D
14 CFR Part 43, Appendix D provides the scope and detail of items to be included in an annual or 100-hour inspection, which includes fuel system components such as filters and strainers.
Question 3: What is the primary aeronautical purpose of fuel tank venting in aircraft fuel systems?
- To prevent dangerous pressure or vacuum buildup as fuel is consumed and temperatures change (Correct answer)
- To prevent fuel from siphoning when the engine is stopped
- To maintain inlet pressure at the engine-driven fuel pump
- To allow water to drain from the bottom of the fuel tanks
Correct answer: To prevent dangerous pressure or vacuum buildup as fuel is consumed and temperatures change
Fuel tank venting prevents dangerous pressure buildup or a vacuum from forming as fuel is consumed and as temperature changes cause fuel volume to expand or contract.
Question 4: During an annual inspection, an IA finds a fuel selector valve that is stiff and requires significant force to move between positions. What is the correct action?
- Lubricate the valve with engine oil and return the aircraft to service
- Document the condition in the records and advise the owner to monitor it
- Repair or replace the valve before returning the aircraft to service (Correct answer)
- Apply Teflon tape to the valve stem to ease operation
Correct answer: Repair or replace the valve before returning the aircraft to service
A fuel selector valve that requires excessive force to operate is a safety hazard that could cause pilot error during an in-flight emergency; it must be repaired or replaced before the aircraft is returned to airworthy service.
Question 5: Which type of contamination poses the greatest immediate risk of engine stoppage in a piston aircraft fuel system?
- Particulate matter from tank corrosion
- Water contamination (Correct answer)
- Microbial growth (dark slime)
- Fuel system sealant residue
Correct answer: Water contamination
Water contamination is the greatest immediate hazard because even small amounts reaching the carburetor or fuel injectors can cause sudden engine stoppage, making it a direct flight safety threat.
Question 6: When inspecting flexible fuel hoses during an annual inspection, which condition requires immediate replacement?
- Surface crazing visible only under magnification with no through-cracks
- Slight discoloration from normal heat exposure
- Hose installed for more than 5 years regardless of visual condition
- Visible cracks, hardening, or deterioration of the outer cover (Correct answer)
Correct answer: Visible cracks, hardening, or deterioration of the outer cover
Flexible fuel hoses with visible cracks, hardening, or deterioration of the outer cover indicate material breakdown that compromises structural integrity and could lead to fuel leakage or rupture.
Question 7: An IA discovers dark slime (microbial contamination) in an aircraft's integral fuel tanks during an annual inspection. What is the required action before return to service?
- Drain the tanks, refuel with fresh aviation fuel, and return to service
- Add an FAA-approved biocide additive to the fuel and complete the inspection
- Clean and treat the tanks per the manufacturer's instructions and applicable ADs (Correct answer)
- Document the finding and advise the owner to have the tanks treated at next annual
Correct answer: Clean and treat the tanks per the manufacturer's instructions and applicable ADs
Microbial contamination must be addressed by cleaning the tanks and treating them per the aircraft manufacturer's maintenance procedures and any applicable Airworthiness Directives before the aircraft can be returned to airworthy service.
IA Fuel Systems & Hydraulic Systems Inspection 1
According to AC 43.13-1B, what category of fuel leak is defined as moisture or fuel that appears as a wet spot but does not form drops?