FAA Private Pilot Helicopter (PRH)Human FactorsMedium
A pilot flying a piston helicopter with the cabin heater on notices a mild headache and unusual drowsiness during a long flight. There is a faint exhaust-like odor in the cabin. What should the pilot do?
- ATurn off the heater, open fresh air vents, and use supplemental oxygen if available
- BIgnore the symptoms since headaches are common during long flights
- CIncrease cabin heat to relieve the headache
- DDescend to a lower altitude to increase air density
Show answer & explanationAnswer & explanation
Correct answer: A. Turn off the heater, open fresh air vents, and use supplemental oxygen if available
A faint exhaust odor with headache and drowsiness are classic signs of carbon monoxide entering the cabin, often through a cracked exhaust heater manifold. The pilot should immediately shut off the heater, ventilate the cabin with fresh air, use 100% oxygen if available, and land as soon as practical.
Why the other options are wrong
- B. Ignoring symptoms of possible CO poisoning could be fatal.
- C. Increasing heat would worsen CO exposure if the heater is the source.
- D. Descending alone does not address the source of contaminated air in the cabin.
Carbon Monoxide (CO) Poisoning
Colorless, odorless gas that can leak into the cabin through cracked exhaust heat exchangers, binding to hemoglobin and causing hypoxia-like symptoms.
- Symptoms: headache, drowsiness, dizziness, impaired judgment
- CO has 200+ times greater affinity for hemoglobin than oxygen
- Response: heater off, fresh air, oxygen if available, land ASAP
Memory trick: 'Silent gas, cracked heater' — smell nothing, feel everything.