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The Aviation Safety Letter (ASL) is published quarterly by Transport Canada, Civil Aviation. The ASL includes articles that address aviation safety from all perspectives, such as safety insight derived from accidents and incidents, information tailored to the needs of maintenance and servicing personnel.

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Demystifying the Instrument Flight Rules (IFR) Visual Climb Departure

What is the SPEC VIS - visual climb?

(Note: "SPEC VIS" stands for specified take-off minimum visibility.)

  • The visual climb procedure gives a pilot the option to fly a departure designed with a standard climb gradient (instead of the depicted non-standard climb gradient).
  • This provides lower performing aircraft the chance to depart IFR when unable to comply with the requirements of the regular routing.
  • This departure procedure is essentially a visual climb to an instrument departure.

Is this option safe?

  • The visibility (SPEC VIS) and cloud ceiling limits must be adhered to.
  • The SPEC VIS is the minimum visibility required to manoeuvre the aircraft safely during the takeoff and initial climb; the cloud ceiling must be greater than the posted climb-to altitude.
  • The SPEC VIS is dependent on aircraft category.

How is it flown?

  • As long as the pilot is operating visually and can safely return to the aerodrome, the aircraft need not manoeuvre near the aerodrome.
  • The pilot needs only to return to the crossover position (usually the aerodrome of departure) at or above the climb-to altitude to end the visual portion of the departure procedure
  • At that point, the pilot can then set the heading and commence the instrument portion of the departure.
  • The pilot is responsible for avoiding all obstructions while climbing visually.
  • The pilot must cross over the selected location, at an altitude that is at or above the climb-to altitude, as that this now places the aircraft in IFR assessed airspace.
  • If the aircraft continues to climb at (or above) the standard rate (200 ft/NM), and remains on the approved routing, the aircraft will safely reach the en route structure and clear the obstacles that necessitated the higher than standard climb gradient.

A few other considerations:

  • Will air traffic control (ATC) allow this manoeuvre with today's traffic?
    • ATC may not be accustomed to departing aircraft that return to the field. It may be best to phone them first.
  • Do you have local area knowledge?
    • Before you take off visually in reduced weather, that you have a general idea of the terrain and obstacles that you may encounter during your climb.
  • Is it night time?
    • Think twice about night time visual climbs - not all obstructions will be lit and terrain is difficult to judge in the dark.
  • Have you considered your alternatives if you are airborne and the weather takes a turn for the worse?
    • If you are unable to regain to the airport, continue to climb and turn towards the predetermined departure point; then you can decide whether it is safer to continue to climb en route or to join an approach procedure to the nearest aerodrome.
  • At which point do you get the IFR clearance?
    • SPEC VIS - visual climb is an IFR departure and therefore the pilot must obtain an IFR clearance from ATC before takeoff.
    • This is not to be confused with an aircraft that departs visual flight rules (VFR) and obtains its clearance after takeoff.
  • If the weather is below VFR but above the minimums for a visual climb departure, do you need special VFR to get airborne?
    • An aircraft departing with an IFR clearance for a visual climb departure from a control zone is not required to obtain special VFR as the airspace has already been checked for other IFR aircraft.
    • Make sure you advise ATC (or traffic) of your intentions BEFORE getting airborne because there is no standard way to do a visual climb.

Seconds to Live

  • Narrative on how taking off on a legal VFR Night Flight with overcast, moonless skies and no ground lighting can result in a fatal crash just 66 seconds into the flight. Why? Because the instruments are showing one thing but your body senses something different,

Spatial Disorientation (SD)

  • Put simply - Spatial disorientation (SD) is the inability to determine which way is up.
  • It is a condition in which a pilot's perception of position, direction and motion does not match reality.
  • Typically, it is a temporary condition brought on by flight into poor weather, or darkness with limited or no visibility.
  • Take away the external visual horizon and a low time VFR pilot is likely to be in big trouble.
  • During an experiment with 20 students - put in simulators with instrument weather conditions - all went into some form of uncontrolled flight that ended with ground impact.
  • The interval ranged from 20 s to 480 s.
  • The average time to impact was 178 s - two seconds short of three minutes.
  • Sensory orientation is provided by our visual system, vestibular system, proprioceptive system, and auditory system.

Visual System

  • Visual perception is often separated into two categories: focal vision and ambient vision.
  • Focal Vision is used for object recognition. This process is dominated by photoreceptors known as cone cells located at the back of the retina.
  • This type of vision relates to the central 30° of the visual field. There are three different kinds of cones and their signals combine to give us colour perception & detail.
  • Ambient Vision is derived from the stimulation of photoreceptors known as rod cells in the periphery of the retina and corresponds to the peripheral visual field.
  • Rods function better than cones in darker environments, but do not perceive colour at all as there is only one kind of rod.
  • Ambient Vision is usually processed subconsciously; it can provide vital information about your position relative to the environment, while your Focal Vision focuses on other unrelated objects.

Dark Adaptation and Night Vision

  • When you first enter a dark area, your vision improves very slowly.
  • After six or seven minutes, your eyes are 100 times more sensitive than when you first entered the dark, but full adaptation takes 30 min or more.
  • After half an hour, the rods in your eyes can be 100 000 times more sensitive!
  • This is due to the buildup of a photosensitive chemical called rhodopsin (or Visual Purple).
  • Visual purple is dependent on vitamin A.
  • Vitamin A cannot be stored by the body so it is necessary to eat well-balanced meals (including eggs, milk, cheese and most vegetables) before night flying.
  • Dark adaptation can quickly be lost by exposure to bright light, so you should minimize the use of white light in the cockpit.
  • However Dark Adaptation can be preserved by the use of Red Lighting.

Scanning Techniques

  • The so-called blind spot at night exists because the cones require a lot of light to work whereas the rods respond to relatively low stimuli.
  • Night vision is weak at the center of the eye, so you should develop a technique called off-centre scanning (Averted Vision).
  • Look away from the object you wish to see and use your peripheral vision.


  • If you stare at one light for an extended period of time, involuntary muscle twitches create the illusion of motion.
  • To avoid autokinesis, use the off-centre scanning technique.

Vestibular System

  • The vestibular apparatus - located in the inner ear - cooperates with the visual system to assist with the stabilization of an image on the retina when the head and/or body is in motion.
  • It also independently to provide sensory information about the body's position and motion in the absence of vision.
  • The cochlea, the vestibule, and the semicircular canals make up the vestibular apparatus in the inner ear.
  • It is sufficient to say that relative motions and accelerations provoke either movement of the fluid in the inner ear and/or other moving parts within the vestibular apparatus. When these materials move, microscopic projections, known as cilia, physically bend.
  • Depending on which way the cilia bend, physical motion and position are converted into a neural signal, which is then transformed by the brain into a spatial map of one's orientation.
  • But, this spatial map may not be accurate, due to different forces acting on the vestibular apparatus
  • So - during night flight - the problem may be that the earth is not where the brain thinks it is and the visual system may not be helping at all.

Proprioceptive System

  • The third way in which humans sense their position and motion is through proprioceptors throughout the body.
  • Sensory receptors relay information about the relative position and interaction of the body's extremities and skin with its environment.

Auditory System

  • Hearing also assists with spatial orientation by perceiving the location of a sound's source.

"Flying by the seat of their pants" describes a situation where sensory cues from the latter three systems are relied upon rather than relying on the dominant sense of vision.

So, SD is the inability to determine one's position, location, and motion relative to the environment and is one of the most common causes of fatal aviation accidents.

As the human body did not develop for the purpose of flight, we must appreciate the anatomy and physiology that allows a person to orient themselves in space.

Each of the four systems have specific minimum thresholds beyond which point a particular sensation initiates a neural input perceived by the mind.

Below a certain signal intensity, inputs will not be perceived and no action will occur.

Studies show that these thresholds - and therefore one's insensitivity to stimuli - increase with inattention.

A pilot who is distracted or not vigilantly monitoring flight instruments is at increased risk of not noticing important sensory information.

These senses also demonstrate both adaptation and habituation, which means that responses to persistent or repetitive stimuli decrease or possibly cease altogether over time.

Barany Chair Training

  • Barany chair training does not really help because the error that produces SD is due to the design of our orientation system, rather than a misinterpretation of it.
  • Experience does not overcome SD. SD training in an aircraft does help because it teaches pilots to rely on their instruments and to ignore their senses.
  • SD remains a constant threat to all pilots. Globally, SD is thought to be one of the leading causes of flight accidents with a very high percentage of them ending in fatalities.

Night Flight Tips and Traps

  • 22 "Tips & Traps" to consider when flying at night.


TSB Issues Advisory on Minimum De-Icing Fluid Quantity Calculations

  • TSB Advisory with full information available here: Guidelines for Aircraft Ground-Icing Operations

Summary of TSB Report A15W0069

  • An amphibious float-equipped Air Tractor AT-802A Fire Boss was operating in support of wildfire management operations when itencountered severe turbulence and pitched to a nose-up attitude .
  • The aircraft climbed to approximately 400-500 ft above ground level (AGL), rolled to the left and entered a nose-down attitude. It struck the ground right-wing low and close to nose level at 16:30 MDT.
  • The pilot was fatally injured as a result of non-survivable impact forces.
  • There was no post-impact fire.

TSB Aviation Investigation Report A14W0181: Severe Icing Encounter and Forced Landing

  • A Cessna 208B departed Yellowknife Airport ( and proceeded to climb on an IFR flight plan.
  • Passing through 6,000' ASL, the aircraft encountered heavy icing.
  • The aircraft continued to climb to 8,000', but when the Cessna began to descend with cruise power , the pilot requested a lower altitude.
  • During the controlled descent, airspeed continued to decline below 120 KIAS even with the application of maximum continuous power.
  • The pilot then requested a return to CYZF, but experienced periods of elevator buffeting and uncommanded forward pitch movements during the turn.
  • As the situation worsened and the aircraft continued to descend, the pilot declared a "Mayday"
  • When the aircraft was 300 ft above ground level (AGL), the pilot experienced a series of wing drops and an associated steep rate of descent.
  • While still in darkness, the aircraft contacted the frozen surface of Great Slave Lake at 7:21 and continued moving for 2,300 ft before it struck a rock outcropping with its nose and left main landing gear.
  • Passenger evacuation was ordered once the pilot had assessed the situation. Passengers attempted to open the main cabin door but were unable to do so. After several failed attempts to evacuate, the passengers succeeded in exiting via the left cockpit door with the aid of cockpit lighting. Cabin lighting had not been turned on.
  • The occupants were not injured, but the aircraft was severely damaged.
  • There was no post-impact fire.

About Canada.ca

  • The Government of Canada is merging department and agency websites into one unified website: Canada.ca.


Let's Stop UNSARs!

  • An "UNSAR" is an unnecessary search and rescue alert.
  • Help minimize this number and amount of time spent dealing with UNSARS by:
  • Making sure the ELT is part of your pre-flight check:
    • Secure, free of corrosion and antenna connections are secure.
    • Armed.
    • Batteries are current
    • Listen on 121.5 to ensure the ELT isn't transmitting
  • After landing - as part of your post-flight routine:
    • Listen on 121.5 to make sure you did not set off the ELT with that bounce on landing.
    • Turn your ELT function switch to "OFF" if practical.
  • To prevent the unnecessary launch of search aircraft, let an air traffic service (ATS) unit or Joint Rescue Coordination Centre (JRCC) know if your ELT does go off accidentally.
  • Advise them of the ELT location and how long it was activated.
  • Any testing of an ELT that transmits on 121.5 MHz must be conducted only during the first 5 minutes of any hour UTC and restricted in duration to not more than 5 seconds.
  • Most 406 MHz ELTs are equipped with an integral self-test function. The manufacturer's instructions describe how to carry out this self-test and interpret its results. The instructions should be followed closely to avoid false alerts.
  • If your self-test will cause a transmission on 121.5 MHz then it should also only be conducted during the first 5 minutes of any hour UTC.
  • When shipping your ELT for maintenance, turn the ELT function switch to "OFF" and remove the batteries if possible.

SmartPilot proudly works with.

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We would like to acknowledge the financial support of the Government of Canada for this initiative through the Search and Rescue New Initiative Fund (SAR NIF).