Q-WINTER OPS Flashcards
De-Icing and Anti-Icing Fluids
De-icing/anti-icing fluids are a solution consisting principally of water and a glycol freezing point depressant. Although there are several manufacturers of these fluids they are generally divided into four
types; Type I, Type II, Type III and Type IV. A list of approved fluids authorized for use on Porter Airlines aircraft can be found on the Transport Canada website. Type I Type I is used as a de-icing fluid; it provides limited protection against an accumulation of contamination
after the application. (Kilfrost ABC-3 Type II fluid may be heated, diluted and used for de-icing.) Type IV Type IV are used as anti-icing agents. They are applied after the aircraft has been de-iced and the
primary purpose of this application is to prevent further accumulations (for a limited time), of ice or snow when continuing precipitation exists. Propylene Glycol may also be used as a de-icing fluid but is restricted
to temperatures not less than -29°C. Type III Clariant Safewing MP III 2031 ECO is a one-step de-icing and anti-icing fluid that provides longer holdover times than Type I and is applied heated if de-icing is required.
Pre-Takeoff Contamination Inspection
- A Pre-Takeoff Contamination Inspection (PCI) is a pre-flight inspection of the critical surfaces carried out by a qualified person to determine if they are free of contamination, immediately prior to takeoff.
- This inspection is mandatory in all cases when an aircraft has been de-iced/anti-iced. This inspection must occur within 5 minutes of starting the takeoff roll.
Note: In the case of a minimum holdover time less than 20 minutes, takeoff must occur within the minimum holdover time, unless an external critical surface inspection is conducted by a qualified
person and the aircraft is deemed acceptable for flight or the aircraft returned for de-icing.
Note: In the case of a minimum holdover time 20 minutes or more, takeoff may occur beyond the minimum holdover time as long as a PCI has been conducted within 5 minutes of beginning the takeoff roll. Takeoff after the maximum holdover time listed is prohibited.
Note: When using a Holdover Time Determination Report (HOTDR) provided by an approved Holdover Time Determination System (HOTDS) that outputs a single value Holdover Time, the single
value Holdover Time shall be considered limiting unless an external critical surface inspection is conducted by a qualified person and the aircraft is deemed acceptable for flight.
Note: Fluid effectiveness may decrease at a faster rate when planning a takeoff near the maximum holdover time listed. Pilot judgement is critical.
- This check must be carried out from a vantage point and under lighting conditions that permit an accurate assessment of the existence or non-existence of contamination on the wings and leading
edges. The inspection can be conducted from inside the aircraft or from outside the aircraft. The use of wing lights or a flashlight may be required to accurately determine if the wings are clean. If the wing
leading edges and representative surface (outboard spoiler) are clearly visible and suitable for takeoff, it may be assumed that the other critical surfaces that were de-iced/anti-iced are also suitable for
takeoff. Additional consideration should be given when snow commences and the aircraft is clean, cold and not de-iced in subzero temperatures. A visual check alone may not be enough to ensure that
snow is not adhering to the critical surfaces. The procedure to be followed is to raise the spoilers; if no snow adheres, you may assume that the remaining surfaces are free of contamination.
An indication of loss of effectiveness is any snow that lands on the surface and does not melt. If contamination is noted on the surface of the fluid, it must be assumed that ice has formed and a
takeoff not be attempted.
Type I – De-Icing Fluid
Fluid Characteristics
- Type I is a de-icing fluid. Its primary purpose when used is to remove ice, frost or snow from the aircraft critical surfaces. It is a red fluid and is applied hot for de-icing, (60°C to 80°C).
- Type I, when used by Porter Airlines comes from the manufacturer pre-mixed approximately 50/50 and is used as received. This mix gives Type I a freezing point of -43°C. The freezing point of Type I fluid must be at least 10°C below the ambient temperature, therefore, Type I cannot be used alone at temperatures below -33°C. This is to protect the fluid from freezing during initial application. It also provides a buffer to allow for variations in the freezing point of the fluid.
- Type I is formulated with a wetting agent to provide quick and uniform wetting and spreading on the surface of the aircraft, maximizing the efficiency and effectiveness of its application.
- Type I fluid does not corrode, stain or deteriorate steel, aluminium, cadmium or composite materials used in aircraft construction. It conforms to the requirements of major air carriers and aircraft
manufacturers.
Type III – De-Icing/Anti-Icing Fluid
Fluid Characteristics
Type III fluid is a new de-icing and anti-icing fluid designed for use on low rotation speed aircraft. It consists of 50% propylene glycol and is a green fluid. The fluid is applied hot for de-icing and provides longer holdover times than Type I.
Aerodynamic Effects
The fluid has a much lower viscosity than Type II or Type IV fluids allowing it to flow off the aircraft at lower takeoff speeds. No correction to the takeoff distances and speed is needed until the temperature drops below -16.5°C. Below this temperature, V1/VR/V2 will require a speed increase of 2 KTS to 7 KTS based upon takeoff weight and this will impact TODA, ASDA and Accelerate-Stop Factors. See Section 5.7.6 for details where Type II and IV fluid penalties are applied to Type III fluid below -16.5°C.
Holdover Time
The lowest operational use temperature (LOUT) is -16.5°C (2°F) for aircraft with rotation speeds less than 100 knots or -29°C (-20°F) for aircraft with higher rotation speeds.
Type IV – Anti-icing Fluid
Fluid Characteristics
Type IV is an anti-icing fluid. It was developed as an improved Type II fluid with superior holdover time characteristics. It is a green fluid and is applied undiluted and hot for anti-icing. It has a freezing point of -
49°C (-56°F) or lower.
Aerodynamic Effects
Type IV Anti-icing fluids share similar aerodynamic characteristics as Type II fluids. Some residual fluid may be anticipated during rotation and lift-off and consequent short-term loss of lift. V1/VR/V2 will require a speed increase of 2 KTS to 7 KTS based upon Takeoff weight and this will impact TODA, ASDA andAccelerate-Stop Factors. See Section 5.7.6 for details.
Note: Type IV fluid must be applied within 3 minutes of the Type I application. This may necessitate deicing/anti-icing the aircraft one area at a time.
Supplement 76
All takeoffs on Porter aircraft use Supplement 76 (Takeoff into icing conditions to 1000 FT AGL with REF SPEEDS switch OFF) regardless of the ambient conditions. As per this supplement in an engine failure scenario, normal V2speeds are held until 1000 FT AGL at which time the aircraft is accelerated to normal VFRI speeds and the flaps can be retracted to 0. Pilots must continue to accelerate to VCLIMB ICE (VCLIMB+ 20 KTS) before continuing the climb. Once established at this speed, the airframe mode select can be selected to FAST and the REF SPEEDS switch can be selected to INCR. Caution: selecting the REF SPEEDS switch to INCR prior to V CLIMB ICE may result in premature stick shaker activation. In a normal two-engine climb, the V
CLIMB ICE speed should be briefed prior to takeoff and the REF SPEEDS switch should be selected to INCR when at or above this speed if icing conditions are encountered in the climb.
Descent and Approach
Visual detection of ice on aircraft surfaces is the primary means of ice detection (wings, windshield wiper spigot etc.). Ice Detector probes are a secondary means of ice detection. This is due to the software level that the system was certified to. As a result, the Ice Detector probes are useful for first indication of ice only. ICE DETECTED will annunciate and flash on the ED following ice detector probe ice sensing.
Upon initial detection of ice, the AIRFRAME MODE SELECT shall be selected to FAST and the REF SPEEDS switch selected to INCR.
When the ICE DETECTED annunciation extinguishes, crews shall perform a visual inspection of the leading edges and wing tip to confirm that the wing is aerodynamically clean. It is the pilot’s discretion to turn the REF SPEEDS switch OFF and land at normal approach speeds. There is no requirement to turn off the prop de-ice or windshield heat as there is no performance penalty with these systems activated. If the aircraft cannot be considered aerodynamically clean by 1000 FT AGL, the landing must be
conducted at V REF+ 20 KTS (flap 15) or VREF+ 15 KTS (flap 35). When landing at these higher speeds, the ICE ACC figure must be added to the demonstrated landing distance for a dry or wet runway. If this calculated distance is greater than the runway available, adjustments for headwind may be used to decrease the required landing distance. A diversion to a suitable alternate is required if the runway distance required exceeds the runway distance available. Careful planning for fuel and payloads must be made in conjunction with SOCC during conditions where landing with ice accretion is likely.
Level 1 Sanding Water
Heavy Rain
Level 1
Slush
less then 1/8
Level 1
Wet Snow
Less then a 1/4
Level 1
Dry snow
Less then 1/2
Level 1
Compact Snow
100% of coverage
Level 2
Standing Water
25%-50%
1/8 to 1/2
Level 2
Slush
1/8 to 1/4
Level 2
Wet Snow
1/4 to 1/2
