By Mike Bliss
What do Florida, Texas, and Arizona have in common? They are the top three states for flight training, accounting for roughly 40% of all flight training in the US. While their year-round good flying weather is a major draw, abundant sunshine can bring some very hot days – especially to the cockpit of an airplane. Because heat exhaustion and heat stroke can escalate rapidly, both instructor and student must stay alert for the warning signs of heat stress.
To recognize and prevent heat stress, pilots must understand how heat affects the body. Heat stress occurs when the body absorbs or generates more heat than it can dissipate. One of the first signs of heat stress is heavy sweating, which can lead to dehydration. As dehydration progresses, it can trigger other symptoms such as cool, moist skin, lightheadedness, headache, nausea, and fatigue. If left unaddressed, heat stress can escalate to heat stroke – a serious medical emergency marked by confusion, fainting, or erratic behavior.
Even if the more serious symptoms of heat stroke do not develop, milder heat stress can still impair a pilot’s attention, reaction time, and overall performance. If the instructor notices an abnormal struggle to maintain airspeed, altitude, or heading – missed radio calls, misread instruments, or skipped checklist items, it should be recognized as heat stress induced and corrective action taken. Transfer controls immediately, direct maximum airflow to the student, and consider climbing to a higher altitude for cooler air, especially if you have been performing low-level ground reference maneuvers. The affected pilot should sip water, and if safety dictates, terminate the flight.
The danger of heat stress begins before entering the cockpit. Direct sunlight and heat radiating from the tarmac during the preflight inspection frequently leave the pilot overheated, even before they climb into the cabin. Conditions only worsen after entering the cockpit because of the buildup of heat due to the greenhouse effect and stagnant air. Because heat stress is cumulative, it can become dangerous before anyone realizes there is a problem. That is why it is important to monitor symptoms from the time you walk outside.
Heat stress can be mitigated or prevented by adopting these best practices:
- Review or discuss the warning signs of heat stress prior to flight.
- Arrive for the lesson well hydrated. Drink plenty of water and electrolyte solutions before and even during the flight.
- Avoid caffeine and energy drinks, which can accelerate dehydration.
- Avoid excessive exercise and sweating prior to the flight, e.g., coming directly from the gym.
- Wear lightweight, light-colored, breathable clothing.
- Whenever possible, conduct the preflight inspection in the hangar or in shade.
- Minimize time in the cockpit before engine start.
- Create as much ventilation as possible by leaving windows, air vents, and doors open during ground operations.
- If you feel the onset of heat stress, take action – possibly landing to spend time in an air-conditioned space.
- During the hottest summer months, consider shifting flights to nighttime.
Anticipating environmental conditions is an important part of a pilot’s responsibility. Whether managing winter cold or summer heat, staying prepared and knowing the danger signs of operating in those conditions will ensure each flight remains safe and productive.