Fitness to Fly with a Cold and a Sedating Antihistamine
Captain M is 42, a non-smoker, on day 2 of a 4-day trip. She has a mild upper respiratory infection: nasal congestion, sore throat and a feeling of 'fullness' in her ears. Last night she took a 10 mg cetirizine tablet (a sedating antihistamine) at 22:00 and slept 6 hours. Report time is 06:00 for a 2-hour flight in a pressurized twin-jet; planned cruise altitude is FL340, cabin altitude about 8,000 ft. During boarding she notices mild ear pain and fatigue, but says she feels 'okay to fly'. The first officer is junior and has not raised concerns. Company policy allows OTC medication if 'non-drowsy', but does not list cetirizine. She has no fever. She plans to use a nasal decongestant spray before departure. The flight is a passenger service with a forecast of moderate turbulence.
1. Using the IMSAFE framework and the physiological evidence in the scenario, decide whether the captain is fit to fly this sector. Justify your decision.
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IMSAFE points to several unacceptable factors. Illness: she has an upper respiratory infection with ear fullness and pain. Medication: cetirizine is an antihistamine that can cause drowsiness and slowed reaction time; the company's 'non-drowsy' policy does not list it, so it is not authorised. Fatigue: only 6 hours of sleep after a sedating tablet. Symptoms: ear pain at cabin altitude is a warning of Eustachian tube dysfunction, not a trivial complaint.
The decision should be not fit to fly. A pressurised aircraft at 8,000 ft cabin altitude still exposes her to reduced oxygen partial pressure and to pressure changes during climb and descent. With a cold, the middle ear may not equalise, risking barotrauma, severe pain or even perforation. Moderate turbulence increases the rate and magnitude of pressure changes. The antihistamine adds sedation, and her self-assessment of 'okay' is unreliable because the symptoms are subjective and she is motivated to complete the trip.
She should report unfit, seek aeromedical advice and be replaced. The junior first officer's silence is an authority-gradient warning sign: the crew should discuss fitness explicitly before dispatch.
2. Explain why a 'mild' cold and a cabin altitude of 8,000 ft can still be operationally significant, even in a pressurised aircraft.
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Pressurisation protects against severe hypoxia, but 8,000 ft is not sea level. Alveolar oxygen partial pressure falls to roughly 55–60 mmHg, equivalent to breathing about 15% oxygen at sea level. Healthy crew tolerate this, but the reserve is reduced, and fatigue, sedating medication or illness can worsen performance. Night vision and complex cognitive tasks are especially sensitive.
The cold matters because the Eustachian tube connects the middle ear to the nasopharynx. Mucosal swelling can block it, so the crew member cannot equalise pressure during ascent and descent. The result can be ear pain, temporary hearing loss, barotrauma or perforation. Ear pain during boarding already shows that equalisation is marginal. A nasal decongestant spray may reduce swelling briefly but does not guarantee Eustachian function and can cause rebound congestion. Turbulence makes the pressure changes more abrupt, increasing the risk. The problem is therefore not the 'mild' cold alone but the combination of blocked pressure equalisation, mild hypoxia, fatigue and medication.
3. What should the captain and the first officer do before departure, and what should the operator learn from the event?
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The captain should declare herself unfit before dispatch, inform the operator and arrange a replacement. She should not 'push through' with a decongestant spray. She should document the cold and cetirizine, contact the aeromedical examiner or company medical advice line, and ask when she may return. She should also avoid self-medicating before future duties without checking the approved list.
The first officer should use graded assertiveness rather than silence: for example, 'I am not comfortable with the ear pain and cetirizine; can we discuss fitness before we go?' If the captain dismisses the concern, the first officer should involve the duty manager or chief pilot. This is a communication and coordination barrier, not disloyalty.
The operator should review its OTC medication policy, publish a clear list, and provide 24-hour medical advice. It should train crews on IMSAFE, Eustachian dysfunction and the authority gradient, and audit whether junior crew feel able to challenge. A no-blame report should capture the near-miss so that the policy gap is corrected.