Operating Limits, VLOS, Populous Areas and Approvals

Operating limits are the first safety fence

Most remote pilots remember the headline rules: keep the aircraft in visual line of sight, stay under the normal height limit, keep away from people, avoid prohibited or restricted areas unless authorised, and do not interfere with emergency operations.

Those rules are not trivia. They are the first safety fence. When a job cannot fit inside them, the operation needs a different approval path, a different procedure or a no-go decision.

A 10 second loop in side view, not to scale. A remote pilot launches a drone over rising ground on a sunny day. Three limits are drawn one at a time: a VLOS sight line from the pilot's eyes to the drone, a 120 metre (400 feet) AGL ceiling that follows the ground surface rather than the launch point, and a 30 metre dome around a bystander. With 'Inside limits' selected, the drone flies the job inside all three and lands. With 'Too high' selected, the drone climbs beside a tall mast and breaks through the ceiling, which turns red, and APPROVAL OR NO-GO appears before the drone descends. With 'Too close' selected, the drone flies into the bystander's 30 metre dome, which turns red, with the same message. The still frame shows the drone working inside all three limits.

Read the Standard operating conditions transcript

VLOS means more than seeing a dot

Visual line of sight means the remote pilot, or the crew using approved procedures, can maintain direct visual awareness of the aircraft and its surroundings. A tiny dot at the edge of perception is not useful control.

The pilot needs enough visual information to know aircraft orientation, position, movement, proximity to obstacles, other aircraft risk and whether the planned flight path remains safe.

• Do not rely on the screen alone for VLOS.
• Use observers deliberately, with a shared communication plan.
• Stop or recover early when haze, sun angle, distance or background clutter makes orientation uncertain.

Read the VLOS, people and populous areas in practice transcript

Height is measured from the surface below

CASA's headline drone rules use 120 m, or 400 ft, above ground level as the normal maximum height for many operations. The practical point is that height is referenced to the ground or surface below the aircraft, not simply the launch point.

Terrain, structures and job geometry can make this harder than it looks. A mapping run from a hill, a tower inspection or a job near rising terrain needs careful planning so the crew understands the actual height above the surface throughout the flight.

Side view of a drone flying over uneven terrain. Two readouts sit above it: DISPLAY, the height above take-off shown to the pilot, and TRUE, the height above the surface directly below. A dashed line follows the terrain 120 m above the surface, with the zone above it shaded red. Hill launch: the drone takes off from a hilltop, climbs to 120 m on the display and flies out over a valley 80 m lower. The display still reads 120 m, but the true height above the valley floor is 200 m, inside the red zone above the 120 m limit. Rising ground: the drone takes off in a valley and flies toward a hill 80 m higher; the display still reads 120 m, but it is only 40 m above the hill. With "120 m over surface" the drone follows the terrain so the true height stays 120 m, while the display changes. The 80 m terrain difference is illustrative.

People and populous areas are not the same check

Keeping clear of people is a direct separation problem. A populous area is a broader risk question: would an uncontrolled crash create an unreasonable risk to the life, safety or property of someone in the area?

A beach, road, park, worksite, school, event space or built-up area can change quickly. The safe plan is to define the operating area, control access, monitor movement and stop when the people picture no longer matches the briefing.

A 12 second loop, seen from above and not to scale. A drone flies a pattern inside a green operating area, with the crew at the launch point. An orange recovery path leads from the area to a landing point. Uninvolved people walk along a footpath outside, each with a dashed 30 metre ring around them. With 'Walks in' selected, one pedestrian leaves the footpath and walks toward the recovery path. When their 30 metre ring reaches the path, the path turns red and HOLD appears: the drone stops its pattern and holds clear on the far side of the area. Once the pedestrian has crossed and moved away, REASSESS appears and the drone resumes. With 'Stays clear' selected, the pedestrian stays on the footpath and the job continues. The still frame shows the hold.

• Do not fly over people who are not part of the operation unless the operation is specifically authorised and controlled for that risk.
• Keep uninvolved people outside the operating area and recovery path.
• Reassess if pedestrians, vehicles or workers enter the area.
• Treat a site as dynamic, not frozen at the time of the first briefing.

BVLOS, EVLOS, night and special work need a different pathway

BVLOS, extended visual line of sight, night operations, operations near or over people, operations in controlled or restricted airspace, and operations above the normal height limit are not just advanced techniques. They are approval and procedure questions.

For a RePL learner, the key is recognising the trigger. If the job leaves the baseline, pause and identify which approval, operator procedure, risk assessment, equipment, crew role and record is required before the aircraft flies.

Do not fly through emergency response activity

Drone operations must not interfere with police, fire, ambulance, search and rescue or other emergency response activity. The safest plan is to build a simple trigger into every briefing: if emergency aircraft or emergency services activity appears, recover or hold clear and reassess.

This is also a good example of why current-source thinking matters. The legal rule, the local situation and the operator procedure all need to line up before the operation continues.

Make the go/no-go decision explicit

A legal limits check should end in a plain decision. The crew should be able to say whether the operation is inside the baseline rules, which approval pathway applies if it is not, and what operating limits have been briefed.

If that sentence cannot be written clearly, the operation is not ready. More flying skill will not fix an unclear authority or risk position.

Practice Questions