Study Guide – Meteorology101

Introduction An inflight emergency is usually an unexpected and unforeseen event that can have serious consequences for an unprepared remote pilot. During an emergency, a remote pilot is permitted to deviate from any part of 14 CFR part 107 to respond to the emergency.When a remote pilot does deviate from a rule due to an emergency, the remote will report the emergency if asked to do so by the FAA (also referred to as “the Administrator”). Inflight Emergency A remote pilot is responsible for the safe operation of the small UA at all times. A remote pilot must ensure that the aircraft is in a safe operating condition before flight, that there is not any hazard to persons or property, and that all required crew members are properly briefed on the operation and emergency procedures. Before every flight, a remote pilot will conduct a preflight inspection of the aircraft. If any irregularities’ are found in the inspection, they must be corrected before the small UA is operated. Some small UA manufacturers will provide the remote pilot with preflight inspection items. For those small UAs that do not have a manufacturer checklist, the remote should develop a checklist that will provide enough information that the aircraft will be operated in a safe condition. When a remote pilot does experience an inflight emergency, the pilot may take any action to ensure that there is not a hazard to other people or property. For example, if during a flight the small UA experiences as battery fire, the remote pilot may need to climb the small UA above 400’ AGL to maneuver to a safe landing area. In this instance, a report will need to be made only if asked to do so by the FAA. When other crew members are used during a flight, all of those crew members must be briefed on the flight and the planned emergency procedures for the flight. The briefing will be given to any visual observers (VO) that might be used and any non-certificated person who is allowed to manipulate the flight controls of the small UA. For more information about emergencies, refer to 14 CFR part 107 and AC 107-2. Determining the Performance of Small Unmanned Aircraft Introduction The manufacturer may provide operational and performance information that contains the operational performance data for the aircraft such as data pertaining to takeoff, climb, range, endurance, descent, and landing. To be able to make practical use of the aircraft’s capabilities and limitations, it is essential to understand the significance of the operational data. The use of this data in flying operations is essential for safe and efficient operation. It should be emphasized that the manufacturers’ information regarding performance data is not standardized. If manufacturer-published performance data is unavailable, it is advisable to seek out performance data that may have already been determined and published by other users of the same small UA manufacturer model and use that data as a starting point. Effect of Temperature on Density Increasing the temperature of a substance decreases its density. Conversely, decreasing the temperature increases the density. Thus, the density of air varies inversely with temperature. This statement is true only at a constant pressure. In the atmosphere, both temperature and pressure decrease with altitude and have conflicting effects upon density. However, a fairly rapid drop in pressure as altitude increases usually has a dominating effect. Hence, pilots can expect the density to decrease with altitude. Effect of Humidity (Moisture) on Density The preceding paragraphs refer to air that is perfectly dry. In reality, it is never completely dry. The small amount of water vapor suspended in the atmosphere may be almost negligible under certain conditions, but in other conditions humidity may become an important factor in the performance of an aircraft. Water vapor is lighter than air; consequently, moist air is lighter than dry air. Therefore, as the water content of the air increases, the air becomes less dense, increasing density altitude and decreasing performance. It is lightest or least dense when, in a given set of conditions, it contains the maximum amount of water vapor. Humidity, also called relative humidity, refers to the amount of water vapor contained in the atmosphere and is expressed as a percentage of the maximum amount of water vapor the air can hold. This amount varies with temperature. Warm air holds more water vapor, while cold air holds less. Perfectly dry air that contains no water vapor has a relative humidity of zero percent, while saturated air, which cannot hold any more water vapor, has a relative humidity of 100 percent. Humidity alone is usually not considered an important factor in calculating density altitude and aircraft performance, but it is a contributing factor.