Human Performance and Threat and Error Management

The remote pilot is part of the system

RPA operations can feel screen-based, but the same human performance traps remain: fatigue, time pressure, overconfidence, distraction, heat, dehydration and poor communication.

Airmanship is the habit of keeping the operation safe when the plan meets the real world. For remote pilots, that means aviate, navigate and communicate: keep the aircraft under control, know where it is and where it is going, then keep the right people informed.

• Aviate: keep control, energy, height, battery and recovery options ahead of the aircraft.
• Navigate: maintain orientation, position awareness, airspace awareness and site boundaries.
• Communicate: brief clearly, call threats early and confirm instructions are understood.

RPA pilots have different sensory information

A crewed-aircraft pilot can feel acceleration, vibration, attitude change and aircraft response through the body. A remote pilot receives most of that information through screens, telemetry, sound, sight and crew calls.

That gap matters. System latency, camera delay, map lag or a weak control link can make the aircraft state feel slightly behind the real aircraft. Good remote pilots avoid flying as if the screen is the aircraft.

Split view. Left, labelled REAL: the remote pilot stands on the ground, the drone hovers in the open and a tree stands to the right. Right, labelled SCREEN: the same scene as the pilot's controller screen shows it, a moment late. A gust pushes the real drone towards the tree. The screen still shows the drone in the clear, so the pilot starts the correction late and the real drone gets too close to the tree before it comes back. The screen catches up afterwards. The screen-delay buttons (none, small, large, weak link) change how far the screen lags; the delays are illustrative, not measured values for any system. With a weak link the screen also jumps in steps and the signal bars drop. Look up turns the pilot's head to the aircraft and marks the real position on the screen with a dashed red outline. Look at the aircraft and the site, not only the screen.

• Look at the aircraft and the site, not only the screen.
• Treat telemetry as decision support, not as a substitute for situational awareness.
• Use conservative margins when latency, glare, poor contrast or workload increase.

Read the Latency, senses and personal minimums transcript

Fit to operate comes before fit to fly

A serviceable aircraft does not make a safe operation if the pilot is not fit to operate. Illness, medication, stress, alcohol, drugs, fatigue, dehydration, heat, cold and strong emotion can all reduce attention and judgement.

The professional move is to decide this before launch. If the pilot is tired, unwell, rushed or emotionally loaded, the operation may need another pilot, a delay, a reduced scope or a stop-work call.

An 11 second loop. A remote pilot stands beside a drone that already has a green tick: the aircraft is serviceable. Seven round badges in a row are checked one at a time, with the name of each shown as it is checked: illness, medication, stress, alcohol or drugs, fatigue, dehydration, and heat or cold. With 'Fit' selected, every badge gets a green tick and the decision is GO. With 'Tired' selected, the fatigue badge is flagged in orange, the pilot droops, and the decision is DELAY, SWAP OR STOP. With 'Unwell' selected, the illness and medication badges are flagged, for example a cold treated with an over-the-counter medicine, and the decision is the same. Schematic: no person is being scored or diagnosed. The still frame shows the tired case with the decision.

• Colds, hay fever, congestion, headache and migraine can reduce concentration and comfort.
• Prescription and over-the-counter medicines can affect alertness and judgement.
• Heat, dehydration and fatigue can creep up slowly during outdoor jobs.

Vision is not a perfect sensor

Visual line of sight depends on human vision. Distance, height, glare, background clutter, colour, haze, cloud and low contrast can all make a small aircraft hard to see or orient.

Empty field myopia can occur when the eye has little to focus on, and relative motion can make it harder to judge whether another aircraft, bird or object is moving toward or away from the RPA. The remedy is not bravado; it is scanning, observers, sensible distances and clear lost-visual actions.

A 10 second loop showing the pilot's view of the sky, with a strip along the bottom that shows the pilot's eye and how far away the drone is (schematic, no distances). The drone starts close, large and easy to orient, with its orange nose visible. It then becomes harder to see, depending on the condition selected. Distance: it flies away and shrinks to a dot, so its orientation can no longer be judged. Glare: it moves toward the sun and is washed out. Clutter: it drops in front of a dark tree line and blends in. The drone disappears, the eye in the strip turns red and VISUAL LOST appears. Then the briefed lost-visual action, RECOVER, brings the drone back close where it is clearly visible again. The still frame shows the distance case just before visual contact is lost.

• Use suitable sunglasses or prescription glasses where needed and permitted.
• Brief what the crew will do if the pilot or observer loses visual contact.
• Avoid screen fixation during critical phases, near obstacles or near other airspace users.

Read the Human factors for remote pilots transcript

Stress narrows thinking

Stress can be short-term, such as a sudden aircraft warning, or long-term, such as fatigue, work pressure or conflict at home. Either can narrow attention, reduce memory, rush decisions and make a pilot more likely to press on.

Pressure can come from pride, peer pressure, employer pressure, customer expectation or the desire to get the job done. A good pilot recognises those pressures as threats, not as reasons to lower the standard.

Left: the Yerkes-Dodson curve, performance against arousal, an inverted U. A marker rides the curve. Low arousal is the bored, complacent zone; the middle is the ideal zone; high arousal is overload, with anxiety and tunnel vision. Right: a remote pilot seen from behind, with an attention cone over four cues: the telemetry screen, a crewed aircraft, the drone and a bystander. In the loop the pilot starts bored, so the cues are faint. Arousal rises to the ideal zone and all four cues are bright inside a wide cone. A warning then appears on the telemetry screen, stress pushes the marker into overload, and the cone narrows onto the screen: the aircraft, the drone and the bystander fall outside it and fade. A checklist pulls the marker back to the ideal zone and the cone widens again. Use the stress slider to set the level yourself, and the "Apply a countermeasure" button (a checklist, slowing down or a stop-work call) to pull it back towards the ideal zone. The curve is qualitative; it has no units.

• Use checklists and aide-memoires when workload rises.
• Slow the operation down before overload becomes an error.
• Use stop-work language that every crew member is allowed to call.

Threat and error management is a loop

Threat and error management is the discipline of finding the threat early, trapping the error before it becomes an aircraft state, then recovering while there is still margin.

Strategic risk management happens before flight: site selection, crew, approvals, weather and procedures. Tactical risk management happens during flight: gusts increase, a battery warning appears, a bystander moves, or the aircraft drifts toward a boundary.

An 11 second loop. Four cards sit in a row: threat (a gust of wind), error (a checklist with a missed item), undesired state (the drone drifting toward a boundary) and recover (the drone held clear of the boundary). A red marker follows the chain. With "not trapped" selected, the missed check turns into an undesired aircraft state, the drone drifts toward the boundary, and the crew recovers it while there is still margin. With "trapped" selected, a green barrier springs up after the error and the marker bounces off it, so the error never becomes an aircraft state. Either way the marker then returns along a loop underneath to the threat card, turning blue: the lesson is carried into the next brief. The still frame shows the untrapped case recovering.

• Threat: something outside or inside the crew that can reduce safety margin.
• Error: an action or omission that can move the operation away from the plan.
• Undesired aircraft state: the aircraft or operation is now in a condition that needs recovery.
• Recovery: stop, hold, climb, land, re-brief or otherwise return to a controlled state.

Crew coordination is an operational control

Observers, payload operators and remote pilots need shared words for stop, hold, traffic, lost link, low battery and emergency recovery. If the crew cannot communicate clearly, the operation is already carrying extra risk.

Good crew communication is closed-loop. A person makes a call, the receiver acknowledges it, the action is taken, and the result is confirmed. This reduces assumptions and catches errors early.

An observer on the left and the remote pilot on the right, with the drone flying between them and a crewed aircraft approaching overhead. The observer calls: Traffic, hold. The pilot acknowledges: Copy, hold. The pilot acts and the drone brakes and holds position. The pilot confirms: Holding. A strip below lights Call, Acknowledge, Act and Confirm in turn, and an arrow closes the loop back to Call. In the missed acknowledgement version the pilot does not reply, the Acknowledge step shows a question mark, and the observer repeats the call more assertively before the loop continues. The drone has flown further by the time it holds.

• Use plain, brief calls during critical moments.
• Give observers permission to be assertive when they see traffic, people, hazards or drift.
• Re-brief when the plan changes instead of relying on everyone to infer the new plan.

Read the Crew roles and the observer brief transcript

Build the habit before the pressure arrives

Human performance training is not about blaming people. It is about designing the operation so ordinary human limits are less likely to become safety events.

The practical standard is simple: brief the threats, check personal fitness, use checklists, keep workload manageable, communicate clearly and stop early when the operation is drifting from the plan.

• If the pilot is not fit, delay or replace the pilot.
• If the aircraft is hard to see, bring it closer or land.
• If workload is rising, simplify the task.
• If the crew is confused, hold or land and re-brief.

Practice Questions