GL 10 Human Factors Principles

Rev 12/2024
Disclaimer

Students should use their textbooks, syllabus, and Airman Certification Standards (ACS) as their primary sources of information. EcFlight is an online training tool designed to simplify and enhance your ground school learning experience. However, it is not a substitute for FAA- or school-approved study materials. Before using these slides for study, always refer to your officially approved resources, such as the Jeppesen physical or electronic book and other FAA-approved materials.
Reference Books
- Pilot's Handbook of Aeronautical Knowledge(FAA-H-8083-25B). (2016). Oklahoma City, OK: United States Department of Transportation, Federal Aviation Administration, Airman Testing Standards Branch.
- Private Pilot Syllabus (10001292-002). (2012). Englewood, CO: Jeppesen.
Reference Multimedia
- ERAUSpecialVFR. (n.d.). Motion picture.
- NTSB. (n.d.). Retrieved from https://www.flyingmag.com/technique/accidents/ntsb-no-evidence-bird-strike-phenom-100-crash
- The First Aid Show. (2024, August). Hypothermia and Its Causes. YouTube. https://www.youtube.com/watch?v=ak8lkSFRV2g
Index
Aviation Physiology
Vision in flight
- Light passes through the Lens and falls inside the Retina.
2. Inside the Retina there are Cones and Rods.

Cones are good at detecting color and High detail while Rods are good at detecting movement.

Cones are functioning better when the light is bright, and are sensitive to colors
The eye works the same way as a camera
1
2
3
Night Vision

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Rods are mainly use during night.
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So when you are scanning for traffic use the off- center viewing to focus objects.
- In addition, if you stare at an object at night for more than 2 to 3 seconds, the retina becomes accustomed to the light intensity and the image begins to fade.
- To see an object clearly at night, you must expose the rods to the image. This is accomplished by looking 5º to 10º off the center of the object.

Dark Adaptation
Avoid bright light 30 min before every flight
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Rods are able to detect images in the dark because they create a chemical called rhodopsin, also referred to as visual purple. Rods can take up to 30 min to fully adapt to the dark.
Your health has an important impact on your vision. Factors like drugs, alcohol, smoking, lack of oxygen, and carbon monoxide poisoning can decrease night vision.



Why we need a red light on the cabin?
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The rods are least affected by the wavelength of red light so cockpit lighting has been lighted in red light.
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A low-level white light illuminating the instrument and within the cockpit should be used in flight.
Visual
Autokinesis
- In the dark, a stationary light will appear to move about when stared at for many seconds.
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Caused by staring at a single point or light.
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Focus your eyes on objects at varying distances and not fixate on one target, as well as maintain a normal visual scan.

Flicker Vertigo
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A light flickering at a frequency of 4 to 20 flashes per second can produce flicker vertigo.
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Can occur when you are looking through a slow-moving propeller toward the sun or when the sun is behind you.

False Horizons
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Occurs when the natural horizon is obscured or not readily apparent.
- A Layer of clouds or Lights of boats at night can make the pilot think that he is level off when what is actually hapening is a turn or a dive.
Landing illusions
Can be caused by a wide variety of factors including runway width, sloping runways and terrain, and weather conditions which reduce visibility.

Wider runways will create the illusion of being lower.
Narrower runways will create the illusion of being Higher.

Upslope: illusion that the aircraft is higher than it actually is, "leading to a lower approach".
Downslope: illusion that the aircraft is lower than it actually is, "leading to a higher approach".
Atmospheric Illusions
Haze: create an illusion of being at a greater distance and height from the runway.
Fog: Create an illusion of pitching up.
Rain: create an illusion of being at a higher altitude due to the horizon appearing lower than it is.
How to Prevent Landing Errors
1) Anticipate the possibility of visual illusions during approaches to unfamiliar airports.
2) Make frequent reference to the altimeter, especially during all approaches, day and night.
3) Use Visual Approach Slope Indicator (VASI) or Precision Approach Path Indicator (PAPI) systems
4) Maintain optimum proficiency in landing procedures.
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Here are some Vestibular System Illusions that any pilot can experience.
nversion
oriolis
levator Illusion
eans
omatogravic
Inversion Illusion
- Caused by an abrupt change from climb to straight-and-level flight.
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Create the illusion of tumbling backwards or inversion illusion.

Coriolis Illusion
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When a pilot has been in a turn for a long time any 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.

Elevator Illusion
- An abrupt upward vertical acceleration, usually by an updraft, can stimulate the sensory organs to create the illusion of being in a climb. The disoriented pilot may push the aircraft into nose-low attitude.
- An abrupt downward vertical acceleration, has the opposite effect with the disoriented pilot pulling the aircraft into a nose-up attitude.

False Horizons
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Occurs when the natural horizon is obscured or not readily apparent.
- A Layer of clouds or Lights of boats at night can make the pilot think that he is level off when what is actually hapening is a turn or a dive.
When in a banked attitude is entered too slowly and an abrupt correction of this attitude sets the fluid in motion, creating the illusion of banked attitude to the opposite direction of the turn.
Leans

Reaction
Illusion
Abrupt Correction
Autokinesis
- In the dark, a stationary light will appear to move about when stared at for many seconds.
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Caused by staring at a single point or light.
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Focus your eyes on objects at varying distances and not fixate on one target, as well as maintain a normal visual scan.
- 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 experiences the sensation of turning in the opposite direction. The disoriented pilot may return the aircraft to its original turn. and pulling back on the controls to the point he will lose control.
Graveyard Spin/Spiral

- A rapid acceleration, such as experienced during takeoff, stimulates the otolith organs in the same way as tilting the head backwards. Creating the illusion of pitch up attitude.
Somatogravic

Disorientation
Awareness of your body’s position in relation to our environment is a result of input from three primary sources:
Vision: Eyes, which sense position based on what is seen
Vestibular: Organs found in the inner ear that sense position by the way we are balanced
kinesthetic/Somatosensory sense: Nerves in the skin, muscles, and joints that, along with hearing, sense position based on gravity, feeling, and sound

Disorientation is when the brain receives conflict messages from your senses.
You must rely on the instrument, reduce the workload, and improve management skills.
Spatial disorientation
- Occurs when there is a conflict between the signal relayed by your central vision and your peripheral vision giving the pilot erroneous information about its position.
- Pilots should avoid making significant corrections that result in rapid attitude changes, for this may lead to spatial disorientation
Vestibular System
- The inner ear has two major parts concerned with orientation:
- The semicircular canals.
- Otolith organs.
- The three semicircular canals sense angular acceleration such as roll, pitch, and yaw. Each canal is filled with fluid and contains a gelatinous structure called the cupula.
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When subject to the different forces of flight, the vestibular system can send misleading signals to the brain resulting in vestibular disorientation.

Vestibular Disorientation
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During instrument maneuvers, the vestibular system may send misleading signals to the brain.
Kinesthetic Sense
- Nerves in the body’s skin, muscles, and joints constantly send signals to the brain, which signals the body’s relation to gravity. These signals tell the pilot his or her current position. Acceleration is felt as the pilot is pushed back into the seat.
- Uncoordinated turns, especially climbing turns, can cause misleading signals to be sent to the brain. Skids and slips give the sensation of banking or tilting. Turbulence can create motions that confuse the brain as well.
Respiration
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Respiration is the exchange of gases between an organism and its environment.
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The function of respiration in the human body is to get oxygen into the body and deliver it to the cells and to take carbon dioxide from the cells and remove it from the body.
Hypoxia
Common Symptoms of Hypoxia:
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Headache
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Decreased Reaction Time
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Impaired Judgment
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Visual Judgment
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Euphoria - Prevents the pilot from recognizing a potentially hazardous situation
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Drowsiness
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Numbness
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Tingling in Fingers and Toes
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Blue Fingernails and Lips (Cyanosis)
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Limp Muscles
Major Groups of Hypoxia
- Hypoxic Hypoxia
- Hypemic Hypoxia
- Stagnant Hypoxia
- Histotoxic Hypoxia
Hypoxic hypoxia
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Results in insufficient oxygen available to the body.
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Reduction in the partial pressure of oxygen at high altitude.
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It can be caused by airplanes flying at high altitudes. The percentage of each gas in the atmosphere remains the same. Still, there are fewer molecules available at the pressure required for them to pass between the membranes in the respiratory system.
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This occurs when the blood is not able to take up and transport a sufficient amount of oxygen to the cells in the body.
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Hypemic means “not enough blood.” This type of hypoxia is a result of oxygen deficiency in the blood, rather than a lack of inhaled oxygen, and can be caused by a variety of factors.
- Blood diseases, such as anemia, can cause it. The most common form of hypemic hypoxia is CO poisoning. Hypemic hypoxia can also be caused by the loss of blood due to blood donation.


Hypemic Hypoxia
Stagnant Hypoxia
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Oxygen deficiency in the body due to poor circulation of the blood.
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Caused by shock, the heart fails to pump blood effectively, or a constricted artery. It could result from excessive positive G’s, and cold temperatures reduce circulation and decrease the blood supplied to extremities.
Histotoxic Hypoxia
- The inability of the cells to effectively use oxygen to support metabolism.
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To the pilot, this means that even though there is an adequate supply of oxygen to breathe and that oxygen is being circulated by the blood, the cells are unable to accept or use the oxygen. Alcohol, narcotics, and cyanide are three primary factors that can cause histotoxic hypoxia.



Prevention of Hypoxia
Maintaining good physical condition, eating a nutritious diet, and avoiding alcohol and smoking.
Your body requires more oxygen during increased physical activity. The pilot is at a higher risk for hypoxia if:
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You are flying manually in turbulent conditions compared to a smooth flight on autopilot.
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Fast ascend. The pilot may be less aware of approaching hypoxia.
Decompression Sickness
- Describes a condition arising from dissolved gases coming out of solution into bubbles inside the body on depressurization. Most commonly refers to problems arising from underwater diving decompression.
- Since bubbles can form in or migrate to any part of the body, Decompression Sickness can produce many symptoms, and its effects may vary from joint pain and rashes to paralysis and death. Individual susceptibility can vary from day to day, and different individuals under the same conditions may be affected differently or not at all.
Scuba Diving
The recommended waiting time before going to flight altitudes of up to 8,000 feet is at least 12 hours after diving, which does not required controlled ascent (non-decompression stop diving), and at least 24 hours after diving if controlled ascent is requierd. The waiting time before going to flight altitudes above 8,000 feet should be at least 24 hours after any SCUBA dive.
Hyperventilation
It is a physiological disorder that develops when too much carbon dioxide (CO2) has been eliminated from the body, usually caused by breathing too rapidly or too intensely. Without a sufficient quantity of CO2, normal respiration is disturbed, producing symptoms that resemble hypoxia.
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Corrective Action: Slowing your breathing rate, talking aloud, or breathing into a paper bag restores the body’s proper carbon dioxide level typically. It would be best if you were especially alert of passengers who may feel anxious about flying.

Hypothermia
Hypothermia occurs when the body temperature drops to a dangerously low level, below 95ºF (35ºC), due to heat loss exceeding heat production.
You and your passengers can be at the risk of hypothermia in different cases:
- If you experience a flight cabin heater failure.
- If you are exposed to temperatures colder than your body without suitable clothing.
- If you or your passengers are exposed to cold water after a forced landing or accident.
Symptoms of hypothermia include:
- Shivering.
- Slurred speech or mumbling.
- Slow, shallow breathing.
- Weak pulse.
- Clumsiness or lack of coordination.
- Drowsiness or very low energy.
- Confusion or memory loss.
- Loss of consciousness.
- Bright red, cold skin (in infants)
Single-Pilot Resource Management (SRM)
Defined as the art and science of managing all the resources (both onboard the aircraft and from outside sources) available to a single pilot

- Gather Information
- Analyze It
- Make a Decision
Accidents and Incidents
Definitions
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Aircraft accident: an occurrence associated with the operation of an aircraft which takes place between, and in which any person suffers death or serious injury, or in which the aircraft receives substantial damage.
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Fatal injury: Any injury which results in death within 30 days of the accident.
- Incident: An occurrence other than an accident, associated with the operation of an aircraft, which affects or could affect the safety of operations.
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Operator: means any person who causes or authorizes the operation of an aircraft, such as the owner, lessee, or bailee of an aircraft.
- Serious injury: Any injury which: (1) Requires hospitalization for more than 48 hours, commencing within 7 days from the date of the injury was received; (2) results in a fracture of any bone (except simple fractures of fingers, toes, or nose); (3) causes severe hemorrhages, nerve, muscle, or tendon damage; (4) involves any internal organ; or (5) involves second- or third-degree burns, or any burns affecting more than 5 percent of the body surface.
- Substantial damage: Damage or failure which adversely affects the structural strength, performance, or flight characteristics of the aircraft
The operator of any civil aircraft, shall immediately, and by the most expeditious means available, notify the nearest National Transportation Safety Board (NTSB) office, when:
- A serious accident occurs.
- When the following incident occurs.
Immediate notification §830.5
(1) Flight control system malfunction or failure;
(2) Inability of any required flight crewmember to perform normal flight duties as a result of injury or illness;
(3) Failure of any internal turbine engine component that results in the escape of debris other than out the exhaust path;
(4) In-flight fire;
(5) Aircraft collision in flight;
(6) Damage to property, other than the aircraft, estimated to exceed $25,000 for repair (including materials and labor) or fair market value in the event of total loss, whichever is less.
a) Reports: The operator of a civil, public or foreign aircraft shall file a report on Board Form 6120.
A report on an incident for which immediate notification is required by §830.5(a) shall be filed only as requested by an authorized representative of the Board.
§830.15 Reports and statements to be filed.
b) Crewmember statement: Each crewmember, if physically able at the time the report is submitted, shall attach a statement setting forth the facts, conditions, and circumstances relating to the accident or incident as they appear to him. If the crewmember is incapacitated, he shall submit the statement as soon as he is physically able.
c) Where to file the reports: The operator of an aircraft shall file any report with the field office of the Board nearest the accident or incident.
Aeronautical Decision Making (ADM)
ADM Process
ADM is a systematic approach to the mental process used by pilots to consistently determine the best course of action in response to a given set of circumstances.

ADM Process
- Recognize a change
- Define the problem
- Choose a course of action
- Implement the decision
- Evaluate the outcome
Steps in decision making process
The Model Most Commonly Used

As PIC, you are the final authority of the aircraft.

1. You are the direct responsible for the safety of flight.
2. Understand your own limitations, your health, level of stress or fatigue, attitude , knowledge, skill level.
Crew Resource Management Training
The effective use of all available resources; Human, hardware, and information.
Self Assessment
3P Model
- Perceive: Think about the circumstances related to the Pilot, Aircraft, enVironment, and External pressure. (PAVE)
- Process: Evaluating their impact on flight safety. Think the Consequences, Alternatives, Reality of the situation and External pressure. (CARE
- Perform: Determine the best course of action.

91.3 Pilot-in-command Responsibilities
As PIC you are the final authority of the aircraft.
1. You are the direct responsible for the safety of flight.
2. Understand your own limitations, your health, level of stress or fatigue, attitude , knowledge, skill level.
Hazardous Attitudes
Attitude affects the quality of decisions.
Divided into:
- Anti-authority
- Impulsiveness
- Invulnerability
- Macho
- Resignation

How to identify and cure them?
Risk Management
The ability to identify hazards and associated risk that could cause accidents.

1) Identify risk factors by answering the question on each checklist.
3) Make a Go or No-Go decision.
2) Mitigate risks by modifying your plans if you answer NO to any questions.
Laws Risk Management
The Plane
The Pilot
The Passengers
The Programming
The Plan
5P Model
Prepare all the flight, study the route, weather, Etc.
Aircraft in airworthy condition to flight, (AVIATES).
Check your self. IMSAFE checklist.
Proper briefing before the flight, How and when to fasten the seatbelt?, procedure incase of emergency?.
Electronic instrument displays, GPS, and autopilot reduce pilot workload and increase situational awareness.
The Plane
The Pilot
The Passengers
The Programming
The Plan
You can use the 5P check in different phases of the flight to continue managing risk:
- Before takeoff
- Climb and initial cruise
- Enroute cruise
- Descent
- Before approach and landing
Using the 5P check in flight
Risk Management/ADM are divided into:

Hazards
Hazards that will become a Risk
Mitigate the Risk
Perceive
Verify if aircraft is in airworthy condition to flight, (AVIATES). Documents and pre-flight inspection.
Check your self. Are you in the capacity to perform as a PIC, IMSAFE checklist, and Proficiency
Pilot
Aircraft
enViroment
External pressure
Be familiar with the terrain, airports , airspace and check the weather.
Someone waiting at the airport, passenger disappointed, desire to impress someone, etc.

Process
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Consequences
Alternates
Reality
External Factors
You CARE about the Hazards that will become a Risk
What is going to happen if...?
What are your Options? Delay the flight?
Dangers of fatigue could lead to an accident
Wedding or Business Meeting might be influencing this decision?
Perform
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E
A
M
Transfer
Eliminate
Accept
Mitigate
Mitigate the Risks by performing TEAM WORK
Chief Pilot, CFI, More experienced Airman
Is there a way to eliminate the Risk?
Do the benefits of accepting risk outweigh the costs?
Is there a way to eliminate the Risk?
Task Management
- The process by which pilots manage many tasks that must be performed to ensure the safety and efficiency of flying a modern aircraft.
Planning and Prioritizing
To effectively manage your tasks on the flight deck, it's essential to anticipate and prioritize high-workload moments, such as departures and approaches.
To make informed decisions during flight operations, a pilot must also become aware of the resources found inside and outside the flight deck.
Use of Resources
Internal Resources
External Resources
- Pilot
- Aeronautical Charts
- Passenger
- Checklist

- ATC
- Radar vectors
- FSS

Flight Deck Management
The flight deck serves as your workspace during the flight, making it crucial to keep it organized for safe and efficient operations.
- Ensure all equipment is properly set up.
- Verify that wires and cables do not interfere with the operation of any controls.
- Secure all items in place.
- Make sure nothing obstructs your view.
- Adjust your seat for optimal visibility and reach of the controls.
- Ensure your seat is locked in position.
- Brief all passengers.
Situational Awareness


Situational awareness is the accurate perception and understanding of all the factors and conditions within the five fundamental risk elements (flight, pilot, aircraft, environment, and type of operation that comprise any given aviation situation) that affect safety.
Examples: Proximate terrain, obstructions, airspaces and weather systems.

As you gain experience as a pilot, complacency can become a new risk. To maintain situational awareness, consider the following:
- Keep your focus outside the airplane
- Identify landmarks on a VFR chart
- Cross-check your flight navigation instruments
Obstacles To Situational Awareness
Establish and adhere to standard operating procedures (SOPs).
Airport situational awareness is a crucial focus for the FAA. Before taxiing, you should:
- Check NOTAMs and ATIS
- Review the current airport diagram
- Understand the taxi route, hold-short positions, crossing runways, and runway incursion hotspots
Situational Awareness During Ground Operations
In commercial flight operations, this rule prevents crew members from performing nonessential duties during taxi, takeoff, landing, and other non-cruise activities.
Sterile Flight Deck
Controlled Flight Into Terrain (CFIT) Awareness
Is an accident in which an airworthy aircraft, under pilot control, is unintentionally flown into the ground, a mountain, a body of water or an obstacle.
Caused By: Lack of situational awareness.
CFIT can be avoided with proper training procedures, crew resource management (CRM) and radar surveillance by air traffic services.
Automation Management
- The automation is the use of autopilot, or any automation, to improve situational awareness during the different phases of the flight. The autopilot posses the capability of controlling the aircraft attitude.
- The Pilot must know how to manage the autopilot and navigation sources.
Information Management
Given the large amount of information from GPS devices and paper charts, it's crucial to minimize distractions from less relevant details.
- For VFR operations, fold and store your charts for easy access during flight, and highlight your route and other important information with a color that is easily visible.
Applying Threat and Error Management (TEM)
Threat and Error Management is a safety management approach that assumes that you, as a pilot, will encounter risk and make mistakes during ground and flight operations.
An Undesired Aircraft State (UAS) is a transitional state between a normal operational state and an outcome.
Root Cause Analysis and Risk Anticipation
Before Flight
TEM Strategies
Anticipate and Mitigate Threats
During flight planning, identify any risks and ensure you have all the important information available.
During Flight
Predictive Monitoring
Anticipate and Mitigate Threats
Reactive Monitoring
Identify and Mitigate Unexpected Threats
Detect and Correct Errors
Recognize and Recover from UAS


Managing Startle Event
Root Cause Analysis
Risk Anticipation
Increased Situational Awareness
Decreased Startle Effect
Ability to Manage the Situation





Click to see examples⬇️
Fly Focus Act (FFA)
FLY
- Control your flight path.
- Do not hurry.
FOCUS
- Control your emotions.
- Observe, identify and confirm the situation.
ACT
- Perform the ADM process.
- Implement your decision.
- Communicate with ATC and crew.