Human Factors Review ATC Chapter 8

Aim To review principals of human factors to a BAK level of knowledge

Objectives 1.State the effects of alcohol and medication on pilot performance 2.Describe the physiological factors and illusions associated with flying 3.Define threat and error management and describe its importance during flight

1. Alcohol and Medication Alcohol Even small amounts of alcohol can impair a pilots performance and severely affect their judgement The law states you must not fly for at least 8 hours after consuming alcohol and must have a blood alcohol level less than 0.02 Realistically if you have been drinking heavily it may take longer than 8 hours for you to be safe to fly

1. Alcohol and Medication Medication All drugs will effect the body and/or mind, this may limit you physical or mental ability to preform your duties as a pilot Combining various medications may have unknown consequences and individuals reactions will vary Illegal drugs must never be taken before flight Any legal prescription or non prescription drugs must be approved by a qualified DAME

To remain spatially aware the human brain uses data inputs from three different sources Somatosensory system – Nerves in the skin, muscles, and joints, which, along with hearing, sense position based on gravity, feeling, and sound. Spatial awareness Visual system – Eyes, which sense position based on what is seen. The brain interprets signals from these three systems and from this orientates the body in space Vestibular system – Organs found in the inner ear that sense position by the way we are balanced. 2. Physiological Factors

However the brain does not consider all of these information systems equal, and relies much more heavily on information from the visual system over anything else Visual system 80% Vestibular and Somatosensory system 20% Spatial awareness During flight in visual meteorological conditions (VMC), the eyes are the major orientation source and usually prevail over false sensations from other sensory systems When these visual cues are removed, as they are in instrument meteorological conditions (IMC), false sensations can cause a pilot to quickly become disoriented. 2. Physiological Factors

Sends signals from the skin, joints, and muscles to the brain that are interpreted in relation to the Earth’s gravitational pull These signals determine posture. Inputs from each movement update the body’s position to the brain on a constant basis. The Somatosensory system “Seat of the pants” flying is largely dependent upon these signals. Used in conjunction with visual and vestibular clues, these sensations can be fairly reliable, however, the body cannot distinguish between acceleration forces due to gravity and those resulting from manoeuvring the aircraft This can lead to sensory illusions and false impressions of an aircraft’s orientation and movement. 2. Physiological Factors

Anatomy of the Eye The eye is similar in construction to a digital camera, its main components are the lens, retina and optic nerve The leans is used to focus incoming light and filter it to the retina The retina is a light sensitive area on the back of the eye used to turn light signals coming through the lens into electrical signals ready to send up to the brain The Retina is made up of cones and rods Cones are sensitive to colour, small details and distant objects. They provide the best visual acuity and are more effective during the day Rods are sensitive to movement and only see in black and white. They are more effective at night The optic nerve links the eye to the brain which processes the signals 2. Physiological Factors

Empty field myopia The eye, like the rest of the human body, is naturally lazy and tries to do as little work as possible When not actively looking at an object the eye will naturally focus at a distance of about 2 meters This can mean you may not notice an approaching aircraft To overcome this limitation you must try to actively lookout at distance objects 2. Physiological Factors

Anatomy of the Ear The Ear is divided into three sections, outer middle and inner The outer ear channels sound waves to the middle and inner ear. Any obstruction, whether intentional or unintentional, of the outer ear will reduce the sound pressure waves reaching the ear drum The middle ear contains three small bones which turn the sound pressure waves into mechanical motion which increase the initial movement of the ear drum The cochlea in the inner ear turns movement of the bones in the inner ear into electrical signal which are the transmitted to the brain It also contains the vestibular system 2. Physiological Factors

Allows the pilot to sense movement and determine orientation in the surrounding environment In both the left and right inner ear, three semicircular canals are positioned at approximate right angles to each other, similar to the axis of our aircraft. Each canal is filled with fluid and has a section full of fine hairs. The vestibular system 2. Physiological Factors

Acceleration of the inner ear in any direction causes the tiny hairs to deflect, which in turn stimulates nerve impulses, sending messages to the brain. The vestibular system Our brain receives all of these inputs during normal flight, the visual sense resolves any errors. When we loose our visual sense we loose 80% of our ability to maintain spatial awareness leading to a number of illusions 2. Physiological Factors

The Leans Occurs when a banked attitude is entered too slowly to set in motion the fluid in the “roll” semicircular tube. An abrupt correction of this attitude sets the fluid in motion, creating the illusion of a banked attitude in the opposite direction. This is a very common illusion and most pilots will experience it at some point 2. Physiological Factors

Coriolis Illusion Occurs when a pilot has been in a turn long enough for the fluid in the ear canal to move at the same speed as the canal. A movement of the head in a different plane, such as looking at something in a different part of the flight deck, may set the fluid moving and create the illusion of turning or accelerating on an entirely different axis. This action causes the pilot to think the aircraft is doing a manoeuvre that it is not. 2. Physiological Factors

Graveyard Spiral As in other illusions, a pilot in a prolonged coordinated, constant-rate turn, will have the illusion of not turning. During the recovery to level flight, the pilot will experience the sensation of turning in the opposite direction. If the pilot is disoriented they may return the aircraft to its original turn. Because an aircraft tends to lose altitude in turns unless the pilot compensates for the loss in lift, the pilot may not notice a loss of altitude The absence of any sensation of turning creates the illusion of being in a level descent. The pilot may pull back on the controls in an attempt to climb or stop the descent. This action tightens the spiral and increases the loss of altitude 2. Physiological Factors

Somatogravic Illusion A rapid acceleration stimulates the otolith organs in the same way as tilting the head backwards. This action creates the illusion of being in a nose-up attitude, especially in situations without good visual references. If the pilot is disorientated they may push the aircraft into a nose-low or dive attitude. A rapid deceleration by quick reduction of the throttle(s) can have the opposite effect, with the disoriented pilot pulling the aircraft into a nose-up or stall attitude. 2. Physiological Factors

Threats Threats are defined as external events or errors that occur outside the influence of the pilot, increase the operational complexity of the flight and require pilot attention or management if safety margins are to be maintained. Threats are considered to be external or internal Some typical external threats to operations include: Adverse weather Weight and balance Density altitude Runway length Some typical internal threats include: Fatigue Complacency Over or under confidence Lack of flight discipline Impulsiveness Lack of currency and proficiency Machoism Other traffic High terrain or obstacles The condition of the aircraft Invulnerability Resignation Anti-authority 3. Threat and Error Management

Errors Threat and Error Management accepts that it is unavoidable that pilots, as human beings, will make errors Errors are defined as pilot/flight crew actions or inactions that lead to a deviation from pilot or organisational intentions or expectations, reduce safety margins and increase the probability of adverse operational events. Errors can be classified as handling errors, procedural errors or communications errors. While errors may be inevitable, safety of flight requires that errors that occur are identified and managed before flight safety margins are compromised. Typical errors might include: Incorrect performance calculations Inaccurate flight planning Non-standard communications Aircraft mis-handling Incorrect systems operation or management Checklist errors 3. Threat and Error Management

Undesired aircraft state The definition of undesired aircraft state is pilot induced aircraft position or speed deviations, misapplication of flight controls or incorrect systems configuration associated with a reduced margin of safety. An undesired aircraft state can still be recovered to normal flight but, if not managed appropriately, may lead to an outcome such as an accident or incident. Safe flight requires recognition and recovery from an undesired aircraft state in a very short timeframe before an outcome, such as loss of control, failure to achieve optimum performance or flight into terrain occurs. Examples of errors and associated undesired aircraft states include: Loss of directional control during a stall (error) resulting in an unusual attitude (state) Inappropriate or ineffective scan of aircraft instruments (error) resulting in flight below best climb speed 3. Threat and Error Management

Undesired aircraft state TEM requires the pilot to plan and use appropriate countermeasures to prevent threats and errors leading to an undesired aircraft state. Countermeasures used in TEM include many standard aviation practices and may be categorised as follows: Planning countermeasures, including flight planning, briefing, and contingency planning Execution countermeasures, including monitoring, cross or rechecking, workload and systems management Review countermeasures, including evaluating and modifying plans as the flight proceeds, and inquiry and assertiveness to identify and address issues in a timely way Once an undesired aircraft state is recognised, it is important to manage the undesired state through the application of the correct remedial solution and prioritise aircraft control for a return to normal flight, rather than to fixate on the error that may have initiated the event. 3. Threat and Error Management

Questions?