RPAS Basic cheat sheet

RPAS below 150 kg (or 25 kg depending on jurisdiction) generally fall under national rules; heavier or certified operations require type approval and licensing.

Visual line of sight (VLOS) is the default limit: the remote pilot must see the aircraft unaided, not merely via camera or FPV feed.

Maximum altitude above ground is typically 120 m (400 ft) unless a specific authorisation is granted.

Minimum horizontal separation from uninvolved people and property is commonly 30 m during operations; 50 m from congested areas and crowds.

No flight within 5 km (or as published) of aerodromes without ATC coordination; controlled airspace requires prior clearance.

Night operations, BVLOS flights and flights over people require separate authorisation in most frameworks.

Registration and remote pilot competency certificates are mandatory above a defined mass threshold (often 250 g in EASA states).

Right-of-way: RPAS must give way to all manned aircraft; a remote pilot must never manoeuvre to force a manned aircraft to avoid.

Accident and serious incident reporting is mandatory to the national authority within a defined window (e.g. 72 hours).

Standard lapse rate in the troposphere is 2 degrees C per 1,000 ft (6.5 degrees C per km).

Dew point spread of 2 degrees C or less indicates high risk of fog or carburettor-type icing conditions.

QNH is the pressure reduced to mean sea level; QFE is pressure at the aerodrome reference point.

Wind is named by the direction it blows from; a 270/20 wind blows from the west at 20 kt.

Wind gradient: surface friction reduces wind speed near the ground, so wind increases with height.

Cumulonimbus clouds bring severe turbulence, icing, hail and microbursts; avoid by at least 20 km (10 nm).

Temperature inversion traps haze and reduces visibility; it also causes wind shear at the inversion boundary.

Density altitude rises with high temperature, high elevation and low pressure, reducing lift and motor performance.

METAR is an observed routine report; TAF is a forecast; both use UTC and are valid for a defined period.