Density Altitude and Drone Performance: What Part 107 Pilots Must Know

What to carry into your next study session

• Density altitude is the altitude in the standard atmosphere that matches the current air density. High elevation, hot temperatures, lower pressure, and humidity can raise density altitude; the resulting thinner air reduces aircraft performance. This is part of the Part 107 knowledge area on the effects of weather on small UAS performance.
• Less-dense air can reduce propeller efficiency and available thrust. That can leave less margin for climb, acceleration, payload, range, speed, maneuverability, and stability—especially at a high-altitude airport or other high-elevation launch site on a hot day. A higher power demand can also make actual battery endurance shorter than a conservative preflight estimate.
• Before launch, compare the airport or launch-site elevation with current temperature, pressure, wind, and weather; account for payload and the manufacturer’s operating limits; and keep a conservative battery and performance margin. If the aircraft cannot safely meet the planned climb, control, and landing margins, revise or delay the mission.