Pilots must consider each of these factors, relative to both their capabilities as the pilot as well as the capabilities of the aircraft they’re flying:

• Visibility—VFR or IFR, both within the airport environment and at the altitude you’ll be flying en route.
• Ceiling—How high are the clouds; can you fly above or around them? If you’re IFR, can you fly through them without risk of icing, severe turbulence, or storm downdrafts?
• Wind—Is the direction and speed conducive to the runway alignment at both the departure and arrival airport? How will the tailwind or headwind impact your ground speed and therefore fuel planning?
• Turbulence and Wind Shear—Ironically, it’s often bumpiest when the skies are the clearest. Can you, your passengers and the aircraft handle the increased structural loads with the sky bumps?
• Thunderstorms—These can be pop-up events or contained with other weather and require a wide berth to fly around—no one should be flying through a thunderstorm.
• Temperatures—Most general aviation aircraft have limited heating and cooling capabilities while still on the ground and rely on airflow over the engine when in the air. This tends to result in extreme conditions.

While more than 80% of all aircraft accidents are put into the “human factors” category, this also includes decision-making, often related to weather and poor flight planning. With all the variables and uncertainty that comes with weather, the number of flights that go uninterrupted and as planned daily is remarkable.

Learn more about making the best decisions based on weather conditions in the Aviation Weather Handbook, available on the ASA website.

The post Aviation Decision-Making and Spring Weather first appeared on Learn To Fly.

When approaching the airport to enter the traffic pattern and land, it is important that the runway lights and other airport lighting be identified as early as possible. If the airport layout is unfamiliar, sighting of the runway may be difficult until very close-in due to the maze of lights observed in the area. Fly toward the rotating beacon until the lights outlining the runway are distinguishable. To fly a traffic pattern of proper size and direction, the runway threshold and runway-edge lights must be positively identified. Once the airport lights are seen, these lights should be kept in sight throughout the approach.

Distance may be deceptive at night due to limited lighting conditions. A lack of intervening references on the ground and the inability to compare the size and location of different ground objects cause this. This also applies to the estimation of altitude and speed. Consequently, more dependence must be placed on flight instruments, particularly the altimeter and the airspeed indicator. When entering the traffic pattern, always give yourself plenty of time to complete the before landing checklist. If the heading indicator contains a heading bug, setting it to the runway heading is an excellent reference for the pattern legs.

Maintain the recommended airspeeds and execute the approach and landing in the same manner as during the day. A low, shallow approach is definitely inappropriate during a night operation. The altimeter and VSI should be constantly cross-checked against the airplane’s position along the base leg and final approach. A visual approach slope indicator (VASI) is an indispensable aid in establishing and maintaining a proper glide path.

After turning onto the final approach and aligning the airplane midway between the two rows of runway-edge lights, note and correct for any wind drift. Throughout the final approach, use pitch and power to maintain a stabilized approach. Flaps are used the same as in a normal approach. Usually, halfway through the final approach, the landing light is turned on. Earlier use of the landing light may be necessary because of “Operation Lights ON” or for local traffic considerations. The landing light is sometimes ineffective since the light beam will usually not reach the ground from higher altitudes. The light may even be reflected back into the pilot’s eyes by any existing haze, smoke, or fog. This disadvantage is overshadowed by the safety considerations provided by using the “Operation Lights ON” procedure around other traffic.

The round out and touchdown is made in the same manner as in day landings. At night, the judgment of height, speed, and sink rate is impaired by the scarcity of observable objects in the landing area. An inexperienced pilot may have a tendency to round out too high until attaining familiarity with the proper height for the correct round out. To aid in determining the proper round out point, continue a constant approach descent until the landing lights reflect on the runway and tire marks on the runway can be seen clearly. At this point, the round out is started smoothly and the throttle gradually reduced to idle as the airplane is touching down. During landings without the use of landing lights, the round out may be started when the runway lights at the far end of the runway first appear to be rising higher than the nose of the airplane. This demands a smooth and very timely round out and requires that the pilot feel for the runway surface using power and pitch changes, as necessary, for the airplane to settle slowly to the runway. Blackout landings should always be included in night pilot training as an emergency procedure.

The post Procedures and Airport Operations: Night Flight Approaches and Landings first appeared on Learn To Fly.

Scanning by Day
The central (foveal) region of the retina provides the best vision, and in full color but only during reasonable daylight. Objects are best seen by day if you can focus their image on the foveal region, and you do this by looking directly at them. The most effective method of scanning for other aircraft for collision avoidance during daylight hours is to use a series of short, regularly spaced eye movements to search each 10° sector of the sky. Systematically focusing on different segments of the sky for short intervals is a better technique than continuously sweeping the sky. This is sometimes called the saccade/fixation cycle, where the saccade or movement takes about one-third of a second.

Relative Movement
If there is no apparent relative motion between you and another aircraft, you may be on a collision course, especially if the other aircraft appears to be getting bigger and bigger in the windshield. Due to the lack of movement across your windshield, an aircraft on a collision course with you will be more difficult to spot than one that is not on a collision course.

Any relative movement of an object against its background usually makes it easier to notice in your peripheral vision. The image of the other aircraft may not increase in size much at first, but, shortly before impact, it would rapidly increase in size. The time available for you to avoid a collision may be quite brief, depending upon when you see the other aircraft and the rate of closure.

If you are flying at 100 knots and it is flying at 500 knots in the opposite direction, the rate of closure is 600 knots, i.e. ten nautical miles per minute. If you spot the other aircraft at a distance of one nautical mile, you only have 1/10 of a minute (six seconds) to potential impact. If you are a vigilant pilot and spot it at 3 nautical miles you have eighteen seconds in which to act.

In hazy or low-visibility conditions, your ability to see other aircraft and objects with edges that might be blurred will be diminished and, if you can see them, they may appear to be further away than their actual distance. You might be closer than you think.

Empty-Field Myopia
When trying to search for other aircraft in an empty sky, the natural tendency of a resting eye is to focus at about six feet. Consequently, distant aircraft may not be noticed. To avoid this empty-field myopia, you should focus on any available distant object, such as a cloud or a landmark, to lengthen your focus. If the sky is empty of clouds or other objects, then focus briefly on a relatively distant part of the airplane like a wing tip as a means of lengthening your focus. Having spotted an airplane in an otherwise empty sky, be aware that it could be closer to you than it appears to be, because you have no other object with which to compare its size.

Specks
A small, dark image formed on the retina could be a distant aircraft, or it could be a speck of dirt or dust, or an insect spot, on the windshield. Specks, dust particles, a scratch, or an insect on the windshield might be mistaken for a distant airplane. Simply moving your head will allow you to discriminate between marks on the windshield and distant objects.

Scanning by Night
The central (foveal) region of the retina containing mainly cones is not as effective at night, causing an area of reduced visual sensitivity in your central vision. Peripheral vision, provided by the rods in the outer band of the retina, is more effective albeit color blind. An object at night is more readily visible when you are looking to the side of it by ten or twenty degrees, rather than directly at it. Color is not perceived by the rods, and so your night vision will be in shades of gray. Objects will not be as sharply defined (focused) as in daytime foveal vision.

The most effective way to use your eyes during night flight is to scan small sectors of sky more slowly than in daylight to permit off-center viewing of objects in your peripheral vision, and to deliberately focus your perception (mind) a few degrees from your visual center of attention (that is, look at a point but look for objects around it). Since you may not be able to see the aircraft shape at night, you will have to determine its direction of travel making use of its visible lighting:

• the flashing red beacon;
• the red navigation light on the left wing tip;
• the green navigation light on the right wing tip; and
• a steady white light on the tail.

Visual Judgment on Approach
The eyes and brain use many clues and stored images of known objects to help in judging distance, size and height. The relative size and relative clarity of objects give clues to their relative distances: a bigger object is assumed to be nearer than a smaller one and a more clearly defined object nearer than a blurry one. When the object is near, binocular vision (the slightly different images of a nearby object relative to its background seen by each eye) assists in depth perception.

Texture also assists in depth perception: the more visible the texture, the closer the object appears to be. On final approach as you near the aim point, the surface texture will appear to flow outward in all directions from the point on which you are focused. This is one means by which you can visually maintain the flight path to the aim point: adjust the attitude and heading so that the point from which the texture appears to be moving outward remains the desired aim point.

Texture is also used for the estimation of height; for instance, as you approach flare height for a landing, the actual texture of the runway or the grass passing by the cockpit becomes increasingly noticeable. Relative motion also aids in depth perception. Near objects generally appear to pass by faster than more distant objects. This helps a visual pilot estimate height above the runway before and during the flare: the closer the airplane is to the runway, the faster the runway surface and the surrounding environment appears to pass by.

Depth perception can be difficult in hazy or misty conditions, where edges are blurred, colors are muted, and light rays may be refracted unusually. This gives the impression of greater distance, an impression reinforced by the fact that we often have to look at distant objects through a smoggy or hazy atmosphere. This illusion is referred to as environmental perspective. In hazy conditions, the object might be closer than it seems; in very clear conditions, the object might be further away than it seems. On hazy days, you might touch down earlier than expected; on very clear nights, you might flare a little too soon.

The post Human Factors: Vision, Scanning, and Judgement first appeared on Learn To Fly.

If you are not already familiar with what a pilot deviation is, it is defined as an action of a pilot that violates any Federal Aviation Regulation. While PDs should be avoided, the regulations do authorize deviations from a clearance in response to a traffic alert and collision avoidance system resolution advisory. Meaning, if a possible collision with another aircraft or vehicle is imminent it is OK to deviate. You must however notify ATC as soon as possible following a deviation.

Piot deviations are broken down into two separate categories, airborne and ground. Airborne deviations result when a pilot strays from an assigned heading or altitude or from an instrument procedure, or if the pilot penetrates controlled or restricted airspace without ATC clearance. Ground deviations (also called surface deviations) include taxiing, taking off, or landing without clearance, deviating from an assigned taxi route, or failing to hold short of an assigned clearance limit.

Ways to Avoid Pilot Deviations:

Plan each flight —you may have flown the flight many times before but conditions and situations can change rapidly, such as in the case of a pop-up temporary flight restriction (TFR). Take a few minutes prior to each flight to plan accordingly.

Talk and squawk —Proper communication with ATC has its benefits. Flight following often makes the controller’s job easier because they can better integrate VFR and IFR traffic.

Give yourself some room —GPS is usually more precise than ATC radar. Using your GPS to fly up to and along the line of the airspace you are trying to avoid could result in a pilot deviation because ATC radar may show you within the restricted airspace.

Stay Alert – This is often overlooked during ground operations. It’s important that whether you are in the air or on the ground you maintain focus and alertness at all times. Keep your head out of the cockpit and on a swivel.

Click the below image to access the FAA Fact Sheet and see the full text on the 4 steps to avoid pilot deviations.

The post CFI Brief: Pilot Deviations, Stay Alert! first appeared on Learn To Fly.

Runway Width Illusion
A narrower-than-usual runway can create an illusion that the aircraft is at a higher altitude than it actually is, especially when runway length-to-width relationships are comparable. The pilot who does not recognize this illusion will fly a lower approach, with the risk of striking objects along the approach path or landing short. A wider-thanusual runway can have the opposite effect with the risk of the pilot leveling out the aircraft high and landing hard or overshooting the runway.

Runway and Terrain Slopes Illusion
An upsloping runway, upsloping terrain, or both can create an illusion that the aircraft is at a higher altitude than it actually is. The pilot who does not recognize this illusion will fly a lower approach. Downsloping runways and downsloping approach terrain can have the opposite effect.

Featureless Terrain Illusion
An absence of surrounding ground features, as in an overwater approach over darkened areas or terrain made featureless by snow, can create an illusion that the aircraft is at a higher altitude than it actually is. This illusion, sometimes referred to as the “black hole approach,” causes pilots to fly a lower approach than is desired.

Water Refraction
Rain on the windscreen can create an illusion of being at a higher altitude due to the horizon appearing lower than it is. This can result in the pilot flying a lower approach.

Haze
Atmospheric haze can create an illusion of being at a greater distance and height from the runway. As a result, the pilot has a tendency to be low on the approach. Conversely, extremely clear air (clear bright conditions of a high attitude airport) can give the pilot the illusion of being closer than he or she actually is, resulting in a high approach that may result in an overshoot or go around. The diffusion of light due to water particles on the windshield can adversely affect depth perception. The lights and terrain features normally used to gauge height during landing become less effective for the pilot.

Fog
Flying into fog can create an illusion of pitching up. Pilots who do not recognize this illusion often steepen the approach abruptly.

Ground Lighting Illusions
Lights along a straight path, such as a road or lights on moving trains, can be mistaken for runway and approach lights. Bright runway and approach lighting systems, especially where few lights illuminate the surrounding terrain, may create the illusion of less distance to the runway. The pilot who does not recognize this illusion will often fly a higher approach.

How To Prevent Landing Errors Due to Optical Illusions
To prevent these illusions and their potentially hazardous consequences, pilots can:

1. Anticipate the possibility of visual illusions during approaches to unfamiliar airports, particularly at night or in adverse weather conditions. Consult airport diagrams and the Chart Supplement U.S. (formerly Airport/Facility Directory) for information on runway slope, terrain, and lighting.
2. Make frequent reference to the altimeter, especially during all approaches, day and night.
3. If possible, conduct an aerial visual inspection of unfamiliar airports before landing.
4. Use Visual Approach Slope Indicator (VASI) or Precision Approach Path Indicator (PAPI) systems for a visual reference, or an electronic glideslope, whenever they are available.
5. Utilize the visual descent point (VDP) found on many nonprecision instrument approach procedure charts.
6. Recognize that the chances of being involved in an approach accident increase when an emergency or other activity distracts from usual procedures.
7. Maintain optimum proficiency in landing procedures.

In addition to the sensory illusions due to misleading inputs to the vestibular system, a pilot may also encounter various visual illusions during flight. Illusions rank among the most common factors cited as contributing to fatal aviation accidents. Sloping cloud formations, an obscured horizon, a dark scene spread with ground lights and stars, and certain geometric patterns of ground light can create illusions of not being aligned correctly with the actual horizon. Various surface features and atmospheric conditions encountered in landing can create illusions of being on the wrong approach path. Landing errors due to these illusions can be prevented by anticipating them during approaches, inspecting unfamiliar airports before landing, using electronic glideslope or VASI systems when available, and maintaining proficiency in landing procedures.

The post Human Factors: Optical Illusions first appeared on Learn To Fly.

In this article we will explore whether or not you can become a pilot if you have diabetes. We will look at piloting for a commercial airline with diabetes and piloting for a private company with diabetes. We will also look at other jobs centered on aviation, such as being a flight instructor, or flying gliders and other small aircraft.

We will look at whether or not you can pilot an aircraft if you have Type 1, Type 2, or pre-diabetes. We will look at whether or not it matters if you are taking insulin, other injections for diabetes, oral medications, or are diet and exercise controlled.

We have already been looking at some promising careers that we can have with diabetes that is well-controlled.

We have looked at being a long-distance truck driver, an EMS/Paramedic, a Firefighter, an air traffic controller, and a law enforcement officer. We have looked at whether or not you can be in the military with diabetes. Now we take on the most difficult career to date.

So what’s up? Let’s look…

You can read the article in it’s entirety by clicking on the image below.

The post CFI Brief: Can you be a pilot with Diabetes? first appeared on Learn To Fly.

Night vision is the ability of the human eye to detect objects at night. The rods and cones that make up the retina of your eye are the receptors which record the image and transmit it through the optic nerve to your brain for interpretation. The cones are concentrated toward the center of your field of vision and are responsible for all color vision and detecting fine detail. Your rods on the other hand are more suited for detecting movement and providing vision in dim light. Unlike cones though, rods are concentrated further away from your center of vision. One downside to rods is the fact they are very light sensitive; any amount of light can overwhelm them and they will need to go through a reset process to adapt to dark. I’m sure this is something you have noticed before. For example when high beam headlights from a car hit you while driving on a dark road you will essentially feel blinded until your rods are able to adjust back to the dim light. It can take the rods up to 30 minutes to fully adjust.

The rods and cones are capable of functioning in both daylight and moonlight, although the process of night vision is placed almost entirely on the rods. It is because of the rods being almost 10,000 times more sensitive to light which makes them the primary receptors for night vision. Since we discussed the cones being concentrated near the fovea (or center of your eye) and rods being concentrated further off center from the fovea it is important to note that the majority of your night vision will be through off-center viewing. Darkness will result in a night blind spot toward the center of your eye where the bulk of those cones are. Rather than trying to look straight on at an object like a plane in the night sky, the pilot is better off looking 5° to 10° off-center exposing the rods to that object as shown in the below image.

The best technique for night scanning is to scan from left to right (or vice versa) starting at the furthest point the eye can see and move inward toward the airplane. While scanning, you will want to spend about 2 or 3 seconds looking at approximately 30° wide sections of the sky, overlapping each section by 10° as you move to the next. This is depicted in the image below.

One of the most important things you must do during night flying is to protect your night vision. Stay away from bright white lights and keep your eyes adapted to the darkness. Chapter 17 of the Pilot’s Handbook of Aeronautical Knowledge (FAA-8083-25) outlines several ways and steps in which you can protect your night vision. If you plan on flying at night it is a must that you fully understand how your eyes function and differ during moonlight then during daylight. This will help to mitigate those inherent risks associated with night flying.

The post CFI Brief: Don’t Be Afraid of the Dark! first appeared on Learn To Fly.

Sunglasses
If a night flight is scheduled, pilots and crew members should wear neutral density (N-15) sunglasses or equivalent filter lenses when exposed to bright sunlight. This precaution increases the rate of dark adaptation at night and improves night visual sensitivity.

Oxygen Supply
Unaided night vision depends on optimum function and sensitivity of the rods of the retina. Lack of oxygen to the rods (hypoxia) significantly reduces their sensitivity. Sharp clear vision (with the best being equal to 20–20 vision) requires significant oxygen especially at night. Without supplemental oxygen, an individual’s night vision declines measurably at pressure altitudes above 4,000 feet. As altitude increases, the available oxygen decreases, degrading night vision. Compounding the problem is fatigue, which minimizes physiological well being. Adding fatigue to high altitude exposure is a recipe for disaster. In fact, if flying at night at an altitude of 12,000 feet, the pilot may actually see elements of his or her normal vision missing or not in focus. Missing visual elements resemble the missing pixels in a digital image while unfocused vision is dim and washed out.

For the pilot suffering the effects of hypoxic hypoxia, a simple descent to a lower altitude may not be sufficient to reestablish vision. For example, a climb from 8,000 feet to 12,000 feet for 30 minutes does not mean a descent to 8,000 feet will rectify the problem. Visual acuity may not be regained for over an hour. Thus, it is important to remember, altitude and fatigue have a profound effect on a pilot’s ability to see.

High Intensity Lighting
If, during the flight, any high intensity lighting areas are encountered, attempt to turn the aircraft away and fly in the periphery of the lighted area. This will not expose the eyes to such a large amount of light all at once. If possible, plan your route to avoid direct over flight of built-up, brightly lit areas.

Flightdeck Lighting
Flightdeck lighting should be kept as low as possible so that the light does not monopolize night vision. After reaching the desired flight altitude, pilots should allow time to adjust to the flight conditions. This includes readjustment of instrument lights and orientation to outside references. During the adjustment period, night vision should continue to improve until optimum night adaptation is achieved. When it is necessary to read maps, charts, and checklists, use a dim white light flashlight and avoid shining it in your or any other crewmember’s eyes.

Airfield Precautions
Often time, pilots have no say in how airfield operations are handled, but listed below are some precautions that can be taken to make night flying safer and help protect night vision.

• Airfield lighting should be reduced to the lowest usable intensity.
• Maintenance personnel should practice light discipline with headlights and flashlights.
• Position the aircraft at a part of the airfield where the least amount of lighting exists.
• Select approach and departure routes that avoid highways and residential areas where illumination can impair night vision.

The post Human Factors: Night Vision Adaptation first appeared on Learn To Fly.

The atmosphere around earth is comprised of gases: 78% nitrogen, 21% oxygen, and 1% various other gases like argon and carbon dioxide. We commonly refer to all these gases that make up the atmosphere as air, fresh crisp air! Out of all these gases, oxygen is the most important to the human body and is vital to all living things. Without the correct amount of oxygen in the human body a person will become sluggish, both physically and mentally, and eventually lose consciousness. We refer to this as hypoxia.

So why is it hard to breathe the higher we go? As altitude increases, the total quantity of each gas reduces; however, the proportions remain the same. This is true up to about 50 miles above the surface. You may have learned in you flight training that as altitude increases, pressure decreases. You can see this by doing a simple experiment with a bag of chips. If you were to bring a bag of chips with you over a mountain pass or on an airplane you will notice that as you go up the bag begins to expand. The bag is not expanding because it is filling up with more air but rather because there is less pressure allowing the air already inside the sealed bag to expand, and yes it will eventually pop if you go high enough. The table below depicts the pressure per square inch at particular altitudes.

The human body takes in oxygen through the lungs, which in turn saturates the blood. From the table above you can see that at sea level (0 feet) the amount of pressure is 3.08 pounds per square inch (psi). This corresponds directly to the pressure within our lungs and is sufficient enough to saturate the blood allowing us to function normally. As we climb, the pressure within the lungs will eventually reach a point that no longer allows for proper saturation of oxygen into the blood stream leading to hypoxia.

For most people, altitudes below 7,000 feet MSL will provide sufficient oxygen quantities and pressure for sufficient saturation. Once we get above 7,000 feet MSL, quantities and pressure become increasingly insufficient and at 10,000 feet MSL oxygen saturation of the blood is at 90% normal. The Aeronautical Information Manual (AIM) recommends using supplemental oxygen above 5,000 feet when flying at night. This recommendation is because decreased oxygen levels will tend to affect your night vision at a greater capacity then vision during daylight hours.

The FAA has established strict regulations for the requirement of supplemental oxygen. As long as you remain healthy and use supplemental oxygen as mandated in 14 CFR Part 91 you should have nothing to worry about.

If you have some free time, you can Google or YouTube oxygen deprivation chambers and get an idea of what happens to the body when deprived of oxygen. You may find some comical videos but in reality it is extremely serious and sometimes a fatal situation for pilots.

Quick recap on why it becomes harder to breath as altitude increases:

1. Quantity of oxygen in the atmosphere decreases with altitude.
2. Pressure decreases as altitude increases, making it harder for oxygen to be delivered into the bloodstream.

The post CFI Brief: Breathing and Oxygen first appeared on Learn To Fly.

The area where the optic nerve connects to the retina in the back of each eye is known as the optic disk. There is a total absence of cones and rods in this area, and consequently, each eye is completely blind in this spot. As a result, it is referred to as the blind spot that everyone has in each eye. Under normal binocular vision conditions (both eyes are used together), this is not a problem because an object cannot be in the blind spot of both eyes at the same time. On the other hand, where the field of vision of one eye is obstructed by an object (windshield divider or another aircraft), a visual target could fall in the blind spot of the other eye and remain undetected.

The figure below provides a dramatic example of the eye’s blind spot.

1. Print the figure below. Hold this page at an arm’s length.
2. Completely cover your left eye (without closing or pressing on it) using your hand or other flat object.
3. With your right eye, stare directly at the airplane on the left side of the picture page.In your periphery, you will notice the black X on the right side of the picture.
4. Slowly move the page closer to you while continuing to stare at the airplane.
5. When the page is about 16–18 inches from you, the black X should disappear completely because it has been imaged onto the blind spot of your right eye. (Resist the temptation to move your right eye while the black X is gone or else it reappears. Keep staring at the airplane.)
6. As you continue to look at the airplane, keep moving the page closer to you a few more inches, and the black X will come back into view.
7. There is an interval where you are able to move the page a few inches backward and forward, and the black X will be gone. This demonstrates to you the extent of your blind spot.
8. You can try the same thing again, except this time with your right eye covered stare at the black X with your left eye. Move the page in closer and the airplane will disappear.

Another way to check your blind spot is to do a similar test outside at night when there is a full moon. Cover your left eye, looking at the full moon with your right eye. Gradually move your right eye to the left (and maybe slightly up or down). Before long, all you will be able to see is the large halo around the full moon; the entire moon itself will seem to have disappeared.

The post Human Factors: The Blind Spot first appeared on Learn To Fly.