Physiological Factors: fitness for flight, vision, and night operations

Personal responsibility for fitness 0:01:12

The remote pilot in command determines whether their medical condition permits safe operation. No one else can make that call.

Prohibited under Part 107 - alcohol within 8 hours, being under the influence regardless of elapsed time, BAC of 0.04 or greater, or any drug affecting mental or physical faculties.

Use the IMSAFE checklist before every operation.

Hyperventilation 0:02:13

An abnormally rapid rate of breathing that flushes too much CARBON DIOXIDE from the bloodstream. Most likely during stress or an emergency.

Symptoms - visual impairment, unconsciousness, lightheadedness or dizziness, tingling in the extremities, hot and cold sensations, and muscle spasm.

Treatment - slow the breathing rate, breathe into a bag to re-inhale CO2, or talk aloud.

Muscle spasm matters especially for a pilot holding a controller.

Stress and fatigue 0:04:21

Both degrade attention, concentration and communication. Each has an ACUTE (short-term) and CHRONIC (long-term) form.

Acute fatigue causes - hypoxia (including the pilot at altitude), physical or psychological stress, and energy depletion.

Acute fatigue prevention - proper diet, adequate hydration, and sufficient sleep.

NO amount of training or experience overcomes fatigue. Only rest and diet do.

Chronic fatigue signs - weakness, tiredness, sleepiness, palpitations, breathlessness, headaches and irritability. It warrants a physician.

Chronic stress likewise requires professional help and is disqualifying for flight.

There is no amount of training or experience that can overcome fatigue.0:04:21

Dehydration and heat stroke 0:07:24

A critical loss of body water, which can progress to heat stroke - the body losing the ability to control its temperature.

Causes - high temperature, WIND, low humidity, and DIURETIC drinks (coffee, tea, caffeinated soft drinks, alcohol).

Symptoms - headache, fatigue, cramps, sleepiness and dizziness.

Guidance - 2 to 4 quarts of water per 24 hours; 1 quart per HOUR in severe heat stress, 1 pint per hour in moderate.

THIRST IS ALREADY TOO LATE - it appears at about 2% body-weight loss. Drink periodically on schedule.

When you're thirsty, it's too late.0:07:24

Drugs and alcohol - physiological effects 0:10:33

Beyond the regulatory limits, both substances degrade the specific capacities flying depends on.

OVER-THE-COUNTER drugs count - antihistamines and decongestants cause drowsiness and cognitive deficiency. If the label says do not operate machinery, do not fly.

Alcohol effects - impaired judgement, decreased sense of responsibility, degraded coordination, CONSTRICTED (tunnel) vision, diminished memory, reduced reasoning, and shortened attention span.

A HANGOVER still counts as being under the influence. Alcohol can remain in the body up to 16 HOURS - longer than the 8-hour rule.

The FAA publishes a list of medications; an Aviation Medical Examiner can advise.

Effective visual scanning 0:13:16

Scan in a series of short, regularly spaced eye movements - about 10-degree increments, pausing 2 to 3 SECONDS in each - working from far to near.

The eye only detects movement when it is STATIONARY, which is why a smooth sweep across the sky finds nothing.

HAZE makes objects appear FARTHER away than they are.

Night operations - the regulatory requirements 0:14:51

Since 6 April 2021 night flight is permitted WITHOUT a waiver, subject to knowledge and lighting requirements.

Knowledge - either pass an initial knowledge test covering night operations, or complete the free FAA recurrent training at FAAsafety.gov.

Equipment - an anti-collision light visible for at least 3 STATUTE MILES with a flash rate sufficient to avoid a collision.

The same lighting requirement applies during CIVIL TWILIGHT (30 minutes either side of sunset and sunrise).

No anti-collision light is required between sunrise and sunset.

This course module does NOT substitute for the FAA's own recurrent training for already-certificated pilots.

How the eye works, and why night is different 0:18:46

Light passes through the cornea and lens to the RETINA, which carries CONES (central, colour, detail) and RODS (peripheral, 10,000 times more light-sensitive).

Vision supplies about 80% of flight information.

Cones concentrate centrally; rods concentrate peripherally.

At night the CENTRE of your vision becomes a BLIND SPOT because the cones stop working. Look slightly to the SIDE of an object to see it - off-centre viewing.

The eye is subject to visual illusions and has a physical blind spot at the optic nerve.

Dark adaptation and protecting it 0:23:54

The eye's progressive adjustment to low light. Cones adapt within a few minutes; RODS take roughly 30 minutes to reach full sensitivity.

After about 7-8 minutes the rods overtake the cones - the point to switch to off-centre viewing.

Full adaptation is reached at roughly 25-30 minutes.

ONE exposure to bright light BLEACHES the retina and RESETS the whole process.

Protections - wear sunglasses (ideally neutral density) beforehand, dim screens BEFORE going out, use a RED or GREEN filtered light for preflight, avoid vehicle and street lights, and do not shine lights at your own crew.

At higher elevations supplemental oxygen can improve night vision.

TOBACCO raises blood carbon monoxide and reduces the oxygen available for vision.

The four night illusions 0:29:59

Perceptual errors that occur specifically in darkness.

AUTOKINESIS - staring at a single bright light against a dark background for 8-10 seconds makes it appear to MOVE. Avoid fixating; shift focus periodically.

FALSE HORIZON - lights on terrain, or boats, or a sloping cloud deck align to suggest a horizon that is not level.

REVERSIBLE PERSPECTIVE - an aircraft appears to be moving away when it is actually approaching. Resolved by reading its NAVIGATION LIGHTS.

FLICKER VERTIGO - flashing lights, especially reflected in cloud, can induce nausea and disorientation. Look away.

Depth perception and distance estimation are far worse at night - shadow, colour and texture cues are gone, and objects appear uniform.

Reading aircraft position lights 0:33:10

Standard aircraft lighting reveals another aircraft's direction of travel.

RED nav light on the LEFT wingtip, GREEN on the RIGHT, steady (not flashing).

WHITE nav light facing aft on the tail.

Red flashing BEACON, white flashing STROBES on the wingtips, and a bright white LANDING light near airports.

If you see RED on your right and GREEN on your left, the aircraft is coming TOWARD you. The reverse means it is going away.

This matters because you must yield to all manned traffic, at night as by day.

Practical night operating technique 0:39:40

Field practice for night missions, drawn from the instructor's experience.

PLAN. Scout the site in DAYLIGHT, note obstacles, and if possible fly the planned route by day first.

Charge strobes and carry spares; check sectional and topo maps for towers and power lines, which are effectively invisible at night.

Set the RTH altitude above the tallest obstacle - and understand HOW your aircraft's RTH behaves (DJI models behave differently inside about 65 ft).

The camera is near useless in true darkness; fly on visual line of sight and telemetry.

Visual observers are NOT required at night under the 2021 rules, but remain a good ADM decision.

Cordon the area if possible; people are harder to see and harder to avoid.

Keep monitoring for traffic - and know that when a tower closes, its frequency becomes the CTAF. A closed tower does not mean a closed airport.

Losing visual line of sight at night 0:46:47

The characteristic night emergency, with a defined response sequence.

Possible causes - an obstacle between you and the aircraft, entering cloud or fog, a crash, or failure/loss of the anti-collision light.

RESPONSE - STOP moving immediately. Verify the link and telemetry. If safe and legal, CLIMB. Look for the lights. Send a visual observer toward the last known position. LISTEN for it.

If the anti-collision light has failed, or you cannot regain visual, initiate RTH.

Fog can form after a clear-sky launch, particularly near water.

Choosing and mounting anti-collision lights 0:50:07

The light exists to make you VISIBLE TO OTHER AIRCRAFT - not to help you see your own drone.

Must be visible from 3 statute miles; manufacturers state this, and you can test it.

Any colour is acceptable and you may fit as many as you like. If using colours, follow the red-left / green-right convention.

Mount on TOP for visibility to aircraft above.

A drone's built-in downward LANDING light does NOT satisfy the requirement.

These lights are not really designed for you to see the drone. They're designed for you to be seen by other aircraft.0:50:07

Airspace that changes class when the tower closes 0:52:30

Part-time towered airports revert to a different airspace class after hours - which can change whether you need authorization.

No authorization is needed in uncontrolled airspace. Authorization IS needed in Class B, C, D and E2 - including at night.

The trap - a Class D with a Class E4 extension by day can become one large CLASS E2 at night, so the extension that needed nothing by day now DOES.

The opposite also happens - Winslow's Class E2 reverts to CLASS G after hours, removing the requirement entirely.

The Chart Supplement's airspace remark states the reversion and its Zulu hours.

Night requests go through FAADroneZone - LAANC did not cover them at time of recording.

Apps may not show the after-hours picture; cross-check the sectional, the Chart Supplement and the FAA facility map.