A2 CofC - Drone Certificate of Competency Meteorological Considerations Questions and Answers

Question 1

On a hot and humid summer day in the UK, a remote pilot notices their UAS requires more throttle to hover and has a reduced flight time compared to a cool, dry day. What is the primary meteorological cause for this decrease in performance?

Accepted Answer

The lower air density provides less lift for the propellers.

Answer

Hot, humid air is less dense than cool, dry air. This condition is often referred to as a high-density altitude. Propellers generate lift by moving through the air, and in less dense air, they must spin faster or at a greater pitch to produce the same amount of lift, consuming more power and reducing flight time and overall performance.

Question 2

A remote pilot is planning to operate a 1.5kg UAS near a group of tall office buildings on a day with a steady 15-knot wind. Which of the following meteorological phenomena presents the most significant and unpredictable danger to the flight?

Accepted Answer

Mechanical turbulence from wind interacting with the buildings.

Answer

Mechanical turbulence is created when wind flows over and around obstacles, such as buildings. This creates powerful, unpredictable eddies, downdraughts, and updraughts in the immediate vicinity of the structures, which can easily overwhelm a small UAS and lead to a loss of control. The other options are large-scale weather phenomena and are less relevant to this specific, localised scenario.

Question 3

You are reviewing a Terminal Aerodrome Forecast (TAF) for a nearby airport to plan a flight for later today. The forecast includes the code 'TEMPO 1417 3000 SHRA'. What should you interpret from this information?

Accepted Answer

Temporarily, between 14:00 and 17:00 UTC, there will be periods of rain showers and visibility reduced to 3000 metres.

Answer

In a TAF, 'TEMPO' indicates temporary fluctuations in weather conditions expected for less than an hour at a time. '1417' specifies the time window (from 14:00 to 17:00 UTC). '3000' is the visibility in metres, and 'SHRA' stands for rain showers. Therefore, the code predicts temporary periods of rain showers with visibility dropping to 3000 metres during that three-hour window.

Question 4

Under UK drone regulations, maintaining Visual Line of Sight (VLOS) is mandatory for all Open Category operations. Which of the following weather conditions would most directly make a flight non-compliant with this rule?

Accepted Answer

Fog that reduces flight visibility to less than the planned operating distance.

Answer

Visual Line of Sight (VLOS) requires the remote pilot to be able to see the drone and its orientation without aid at all times to avoid collisions. If fog reduces visibility to a point where the pilot can no longer see the aircraft, they cannot maintain VLOS, making the flight illegal. Strong winds and cold temperatures affect performance, and a cloud base at 800ft is not an issue for flights conducted below 400ft, but a lack of visibility directly breaches the VLOS rule.

Question 5

On a humid day with the ambient air temperature at +1°C, a remote pilot notices a sudden, unexplained loss of performance and increased vibration from their UAS. What is the most likely meteorological cause?

Accepted Answer

Propeller icing.

Answer

Even when the ambient temperature is slightly above freezing, air accelerating over the leading edge of a propeller blade can cause a significant temperature drop (the Venturi effect). In humid conditions, this can cause moisture to freeze onto the blades, forming ice. This ice disrupts the aerofoil's shape, leading to a loss of lift, imbalance, and severe vibration.

A2 CofC Drone Practice Test

A2 CofC Drone Practice Test

A2 CofC - Drone Certificate of Competency Meteorological Considerations Questions and Answers