Visual Scanning and Collision Avoidance

Visual Scanning and Collision Avoidance

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Description: We fly in one of the busiest airspaces in the world so it is vital that we develop good visual scanning to avoid a collision. 

 

Objective: To teach the students the elements related to visual scanning and collision avoidance. 

 

Reference: PHAK

 

Equipment: HAndouts, Whiteboard, Airplane toy

 

Instructor Actions :

 

1. Relationship between a pilot’s physical condition and vision 

1. Smoking, stress, illness, alcohol, oxygen deprivation, diet, medication, and age affect vision.

2. Pilots must make sure that they are in the top physical condition so they can safely operate an aircraft. 

2. Environment conditions that degrade vision 

1. Sudden bright lights inflight or from the ground during night operations.

1. Attempt to turn the plane away and fly in the periphery of the lighted areas.

2. Airfield should be as low as possible. 

3. Select approach and departures that avoid lighted areas. 

2. Lack of oxygen due to high altitudes. 

1. Oxygen should be used above 5000 MSL for night operations. 

3. Flightdeck lighting that shines too bright. 

1. Use dim white or red lights in the cabin. 

4. Drugs 

1. Ask AMEs which drugs are approved. 

5. Exhaustion

1. Exhausted pilots tend to only focus on one aspect of a situation. 

6. Poor physique 

1. A good physique will lead to better scanning skills but do not over-exercise also. 

7. Tobacco 

1. Carbon monoxide from cigarettes reduces the blood’s ability to carry oxygen.

8. Alcohol 

1. Impairs coordination and judgment which leads to people staring at objects.

9. Missing meals 

1. Low blood sugar breaks down a person’s attention spans and habits. 

2. Eating vitamin A leads to better night vision. 

3. Vestibular and visual illusions 

1. Vestibular illusions

1. The leans

1. After a prolonged and gradual turn, the pilot abruptly rolls out to level flight leads to the feeling that he has overbanked to the opposite direction which makes him want to correct the turn by turning to the original direction. 

2. The coriolis illusion 

1. During a prolonged and gradual turn, the pilot moves his abruptly moves his head and makes the illusion that the plane’s attitude has changed dramatically so he will maneuver the plane to a dangerous attitude in an attempt to correct the aircraft’s perceived attitude. 

3. Graveyard spiral

1. During a prolonged turn, the pilot rolls out suddenly which makes the illusion of turning in the opposite direction and tries to correct by turning back to the original direction. The pilot then thinks he needs to pull up since the plane tends to lose altitude while turning. So now he is in a spin since he is actually not in level flight and now is pulling up. 

4. Somatogravic illusion: When the airplane accelerates suddenly, the pilot’s head nods up making an illusion of a nose-high and he will react by pushing the nose down. 

5. Inversion illusion: When the plane in a nose-high attitude suddenly levels off and creates a backward tumbling effect which makes the illusion of a nose-high attitude so the pilot will pitch down. 

6. Elevator illusion: Updrafts will make the pilot think the plane is in a nose-high attitude and responds by lowering the nose.

7. False horizons: Upsloping cloud and obscured horizon with city lights and stars will make the pilot confuse on which is the horizon. 

8. Autokinesis: When a pilot focuses on a lighted object at night, it will start to move. 

9. Flicker vertigo: A flickering like or shadow may cause dizziness, nausea, convulsions, and unconsciousness. Sun on the propeller can cause this. 

10. Runway and terrain slopes illusion: A narrower than usual runway creates an illusion that the plane is at a higher altitude than it actually is so the pilot will try to fly a lower approach. A wider than narrower runway will have the opposite effect with the risk of the pilot leveling off high and landing hard or overshooting the runway. 

11. Featureless Terrain Illusion: An absence of surrounding ground features as in an overwater approach over darkened areas or terrain made featureless snow can create the illusion that the plane is too high so they will fly a lower approach. 

12. Water Refraction: Rain on the windscreen creates an illusion of being at a high altitude and results in the pilot flying a lower approach. 

13. Haze: Creates the illusion that we are far and high from the runway so you will be low on the approach. 

14. Fog: Create an illusion of pitching up so pilots often steepen the approach abruptly.

15. Ground lighting illusions: Lights along a straight path, such as road or lights can be mistaken for runways lights. 

4. See and avoid the concept

1. "See and Avoid" is recognized as a method for avoiding a collision when weather conditions permit and require that pilots should actively search for potentially conflicting traffic, especially when operating in airspace where all traffic is not operating under the instructions of ATC.

2.  “See and Avoid.” Part 91, § 91.113 prescribes that when weather conditions permit, regardless of whether the operation is conducted under instrument flight rules (IFR) or visual flight rules (VFR), each person operating an aircraft shall maintain vigilance so as to see and avoid other aircraft. 

3.  Although the task of avoiding other aircraft is often a shared job, the pilot is always responsible to see and avoid traffic (never rely entirely on ATC for collision avoidance)

4. "See and Avoid" requires the application of:

1. Effective visual scanning

2. The ability to gather information from radio transmissions from ground stations and other aircraft,

3. Situational Awareness,

4. The development of good airmanship.

5. Listen to and make radio calls to visualize where other aircraft are located; direction, speed, and altitude

6. Alter your path/speed/altitude if necessary to create adequate spacing with other aircraft

5. Proper visual scanning procedures

1. Before Taking off

1. Scan the approach area for traffic, with appropriate maneuvers to provide a view of the area.

2. Climbs and descents

1.  Execute gentle banks Left and Right at a frequency which permits continuous scanning

3. Traffic patterns 

1. Entries into traffic patterns while descending should be avoided

2. Enter at pattern altitude, scanning for other traffic

3. The aircraft prevents clearing ahead and below the aircraft, descending into the pattern presents the possibility of descending onto another aircraft already in the pattern

4. Straight and level

1. Scan from left to right or right to left. 

2. Begin scanning at the greatest distance an object can be perceived (top) and move inward toward the position of the plane (bottom)

3. For each stop, scan an area of 30 degrees wide.

4. Each stop should not be more than 2-3 seconds. 

5. Pilots should overlap the previous field of view by 10 degrees.

6. Off-center viewing is used for night flying by looking 10 degrees above, below, or to either side of the object. 

7. Peripheral vision is used.

8. Avoid viewing an object for more than 2-3 seconds. 

6. Relationship between poor visual scanning habits and increased collision risk. 

1. Divide your attention between the cockpit and outside, with the vast majority of attention going toward outside the aircraft.

2. Poor visual scanning skills increase the risk of midair collisions. 

3. Keep scanning keeps the eye busy and prevents the pilot from blindly staring off into space.

7. Proper cleaning procedures 

1. Note your initial heading and the heading you wish to roll out on to perform the next maneuver

2. Pick a reference point 90-180° to your left or right

3. Perform a level turn for 90-180° to put the nose of the aircraft on this point

1. If flying a high-wing aircraft, raise your wing first, to clear that direction before turning

2. If flying a low-wing aircraft, apply common sense to bank angle if clearing below you is especially important for an upcoming maneuver (e.g., stalls)

4. Look for other aircraft or hazards through the entire turn in ALL directions

1. This includes up and down, especially if you intend to do any maneuver which will require an excessive change in altitude

5. Once the wings are leveled on your reference point, take another look around and then begin a turn for 90-180° back to the original heading or to the heading of the next maneuver

1. Throughout the entire turn, look in ALL directions

6. Complete the appropriate checklist

8. Importance of knowing aircraft blind spots

1. By understanding where you know you can’t see, you can maneuver the aircraft to see most of these areas.

2. There is a large portion behind and below the aircraft that is never seen from the cockpit, but clearing turns greatly reduce this void temporarily

3. High wing planes have blind spots to the top while low wing planes have blind spots under the plane. 

9. Relationship between aircraft speed differential and collision risk

1. Traveling at higher speeds reduces the time available for detection, decision, and evasive action. 

2. Studies have shown that the minimum time it takes for a pilot to spot the traffic, identify it, realize it’s a collision threat, react, and have the airplane respond is at least 12.5 seconds

10. Situations that involve the greatest collision risk

1. Near VORS

2. Most collisions occur during the day in good VFR conditions below 8000 ft and within 25 miles of an airport. 

3. Practice areas 

4. Traffic patterns 

5. Popular victor airways

Source : https://www.boldmethod.com/learn-to-fly/aeromedical-factors/spatial-disorientation-vestibular-illusions-and-how-to-prevent-each-one-of-them/

The best way to prevent the leans is to avoid super-slow turns in the clouds. You should never over-control your plane, but make sure you are authoritative with your control inputs.

Never move your head quickly, and if you feel like you're getting disoriented, focus on your instrument scan pattern and bring the airplane to straight-and-level flight.

 

Maintain a strong scan pattern, and don't fixate on any one instrument.

Avoid rapid acceleration and deceleration in the clouds.

 

Slow, steady control inputs are the key when you're transitioning from a climb to straight-and-level flight.

 

Maintain a strong instrument scan pattern in turbulence, and if the updrafts and downdrafts become so strong that you are unable to maintain altitude, fly the attitude indicator, keeping your wings straight and level.