← All explained questions · Supplemental · II — Preflight Procedures
A pilot finds the right wing tank fuel cap missing during preflight. The CORRECT response is to
Choices
depart anyway — modern aircraft don't need fuel caps.
Fuel caps are required equipment.
✓ do not fly the aircraft.correct
The missing cap allows fuel siphoning in flight (Bernoulli effect over the wing) and contamination on the ground; replace the cap before any flight, or ground the aircraft and report to maintenance. A missing fuel cap is a no-go item. In flight, low pressure over the wing siphons fuel out the open port — pilots have lost most of their fuel in cruise from a single missing cap, with no warning until the gauge dropped or the engine quit. On the ground, contamination ingress is also a problem. Replace before flight, no exceptions.
tape over the opening with duct tape.
Tape will fail in flight with disastrous results.
fly only the right tank empty first.
Burning the right tank doesn't restore the cap or prevent contamination.
Why
The missing cap allows fuel siphoning in flight (Bernoulli effect over the wing) and contamination on the ground; replace the cap before any flight, or ground the aircraft and report to maintenance. A missing fuel cap is a no-go item. In flight, low pressure over the wing siphons fuel out the open port — pilots have lost most of their fuel in cruise from a single missing cap, with no warning until the gauge dropped or the engine quit. On the ground, contamination ingress is also a problem. Replace before flight, no exceptions.
FAA source: FAA-H-8083-3C, AFH Ch. 2, visual inspection; aircraft POH/AFM fuel system limitationsbrowse the reference library →
Original study question written for this course — representative of FAA knowledge-test topics, not an actual current FAA exam question.