RPAS Basic flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

VLOS

Visual line of sight: the remote pilot maintains direct unaided visual contact with the aircraft at all times, allowing control and separation from other traffic without instruments.

Maximum operating altitude

The standard ceiling for small RPAS operations is 120 metres (400 feet) above ground level unless a specific authorisation or exemption permits a higher flight.

Right of way, RPAS

An unmanned aircraft must always give way to manned aircraft and must never be manoeuvred so as to force a manned aircraft to take avoiding action.

RPAS registration threshold

In many frameworks, unmanned aircraft above 250 grams must be registered and the operator's registration number displayed on the airframe.

Semicircular rule

Magnetic tracks from 000 to 179 degrees use odd thousands of feet; tracks from 180 to 359 degrees use even thousands, giving vertical separation between opposing traffic.

Squawk 7700

A transponder code selected to indicate a general emergency. It alerts air traffic control that the aircraft requires priority assistance and immediate attention.

QNH

The altimeter setting that makes the instrument read elevation above mean sea level when on the ground at that location. Used below the transition altitude.

Position report format

A standard radio report containing four elements in order: aircraft identification, position, time, and altitude or flight level.

Mayday call

The spoken distress signal, transmitted three times, used when an aircraft is threatened by serious or imminent danger and requires immediate assistance.

Dihedral effect

An upward angle of the wings from root to tip. It increases lateral (roll) stability because a sideslip raises the lower wing's angle of attack.

Angle of attack

The angle between the wing chord line and the relative airflow. Exceeding the critical angle causes a stall regardless of airspeed or weight.

Wing loading

Aircraft weight divided by wing area. Higher values increase stall speed, reduce manoeuvrability and typically give a faster, less buoyant ride.

Quadcopter yaw control

Yaw is produced by increasing the speed of one diagonal rotor pair while decreasing the other, creating a net torque about the vertical axis without changing total thrust.

Static pitch stability

Achieved when the centre of gravity lies ahead of the neutral point, so a disturbance produces a restoring moment that returns the aircraft to its trim attitude.

LiPo storage voltage

Approximately 3.8 volts per cell. Storing lithium polymer cells at this level slows chemical degradation and reduces the risk of swelling or fire.

LiPo C rating

The maximum continuous discharge current expressed as a multiple of capacity. A 5,000 mAh pack rated 20C can deliver 100 amps continuously.

Motor Kv

The no-load speed constant: revolutions per minute produced per volt applied. Higher Kv gives higher rpm and lower torque for a given propeller load.

Electrical power formula

Power in watts equals voltage multiplied by current (P = V x I). Total energy available equals capacity in amp-hours multiplied by nominal voltage.

ESC function

The electronic speed controller converts battery DC into three-phase AC and varies motor speed by pulse-width modulation in response to throttle commands.

Fail-safe

A programmed response on loss of command or video link, such as hover, land, or return to home, intended to prevent uncontrolled flight.

Hypoxia onset

Above roughly 3,000 to 4,000 metres cabin altitude, reduced oxygen saturation impairs judgement, night vision and coordination before the pilot notices symptoms.

Hyperventilation

Excessive breathing rate lowers blood carbon dioxide, causing dizziness, tingling and cramps. Treatment is controlled slow breathing and reassurance, not additional oxygen.

Spatial disorientation

A mismatch between the pilot's vestibular sensations and the aircraft's actual attitude. Pilots must trust flight instruments rather than physical feelings.

Circadian low

Periods of natural drowsiness around 03:00 to 06:00 and 15:00 to 17:00 local time, when fatigue-related errors and vigilance lapses are most likely.

Carbon monoxide hazard

An odourless gas from combustion heaters or engines that binds haemoglobin, causing headache, confusion and loss of consciousness. Suspect it whenever unexplained symptoms appear.

Closed-loop communication

The sender transmits a message and the receiver repeats it back for confirmation. This readback technique prevents misunderstandings in high-workload flight phases.

Standard lapse rate

Temperature decreases by about 2 degrees Celsius per 1,000 feet, or 6.5 degrees Celsius per kilometre, in the lower atmosphere under standard conditions.

Dew point spread

The difference between temperature and dew point. A spread of 2 degrees Celsius or less indicates air close to saturation and a high probability of fog.

QFE

The pressure setting that makes the altimeter read zero, or height above the aerodrome reference point, when the aircraft is on the ground there.

Density altitude

Pressure altitude corrected for non-standard temperature. High temperature, high elevation and low pressure raise it, reducing lift, propeller thrust and engine or motor performance.

Cumulonimbus avoidance

These clouds contain severe turbulence, icing, hail and microbursts. Avoid them by a wide margin, typically at least 20 kilometres or 10 nautical miles.

METAR versus TAF

A METAR is a routine observed weather report issued at set intervals. A TAF is a forecast of expected conditions covering a specified future validity period.