Sub module 7.17: De-icing/Anti-icing of Aircraft

EASA MODULE 7A
Sub Module 7.17
AIRCRAFT HANDLING AND STORAGE

DE-ICING/ANTI-ICING OF AIRCRAFT
 


 

Ice Types
There are three main types of ice/frost that can affect an aircraft’s performance, Hoar Frost, Rime Ice and Glaze Ice. The temperature and weather conditions will determine the type of ice that forms, but all three types can have a detrimental effect. The Dew Point is the temperature at which moist air becomes
saturated and deposits dew if in contact with a colder surface or the ground. Above ground, condensation into water droplets takes place.

Hoar Frost is a deposit of ice crystals that form on an objectwhen the dew point is below freezing point. High humidity will normally produce hoar frost, as these are similar to conditions
that produce dew. Hoar frost can form when the air temperature is greater than 0°C, but the aircraft skin temperature is less than 0°C. This type of frost produces a very rough surface which
leads to turbulent airflow.

Rime Ice is a light coloured opaque rough deposit that has a porous quality. At ground level it forms in freezing fog from water droplets with very little spreading. It adds very little weight but it can disrupt the smooth flow of air over the wing, and block pitot and static vents.

Glaze Ice can be either transparent or opaque and can form into a glassy surface due to liquid water flowing over a surface before freezing. It is the most dangerous type of ice found on an aircraft and is dense, heavy and tough. It adheres firmly to a surface, is difficult to shake off, and if it does breakaway, it does so in large chunks.  

During cold weather operations, it may be necessary to remove ice and snow from the aircraft, while it is on the ground, and to keep it clear long enough, to allow the aircraft’s systems to cope
with snow or ice removal. This may not occur until the aircraft is flying.

On the ground, the aircraft must be cleared of all snow and ice from its wings, tail, control surfaces, engine inlets and other critical areas before the aircraft can take-off.
Ice formation on an aircraft on the ground may result from a number of causes:
1. Direct precipitation from rain, snow and frost
2. Condensation freezing on external surfaces of integral tanks following prolonged flight at high altitude
3.After taxing through snow or slush, ice may accumulate on landing gear, forward facing surfaces and under-surfaces.

 The formation of ice on aircraft structures can produce many adverse effects, and if allowed to remain may result in some or all of the following:

  • Decreased aerofoil lift
  •  Increased aerofoil drag
  •  Increased weight
  •  Decreased engine thrust
  •  Freezing of moisture in control hinges
  •  Freezing of micro-switches that affect systems such as the landing gear retraction
  •  Ingestion of ice into the engine.

Definitions:
The terms ‘de-icing ‘and ‘anti-icing’ have specific definitions, and it is essential to know the differences.

  • De-icing is the removal of ice that has already formed
  • Anti-icing is the prevention of initial ice formation.

 

 EASA Module 7 Essay Question:
What are the effects of formation of Ice on an aircraft and how this ice can be removed?

(Note: Write your answer in the comment section below)

 

Comments

  1. Iceing is formed due to water particles or direct snow.It is hazardous for an aircraft to fly with iceing.
    There are so many effects of iceing.If there is water in the hinges then it will get freezed and it will become hazard because hinges will stuck and they will not move.Due to iceing the weight of the aircraft will also increase and the drag will also increase because the surface will become rough and it will give more drag.Engine thrust will also decreased because if there is iceing in the engine blades.Lift of an aerofoil decreases because weight of an aircraft increases due to iceing.Iceing can also effect ingestion of engine inlet.
    Iceing can be removed from aircraft by simply using hands or by brush.Ice can also be removed by applying liquids on the surface and if we apply fluids on surface then it can also gives us anti icing for very short interval of time.Deep wet snow can be removed with the brushes and scrapers but we should not damage any component.Light snow is removed by cold blower. Hot blower is not used because snow will melt and there will be some water droplets left and they will re freeze. Ice is also removed by applying chemical on it. There are two types of chemical that can remove ice from the structure. One is thickened and other one is unthickened. In thickened there is glycol that is 50 percent and it is thickened so it can give high protection against re freezing. But as compared to unthickened it have high glycol but it is unthickened so it give protection against refreezing for very short interval of time.There are two types of spraying methods through which icing can be removed. One is cold fluid spray and second is Hot fluid spray. Cold fluid spray is directly applied to the aircraft structure and we can also use brush with them and in hot fluit spraying we can mix FPD with water and then we can apply that.We can also remove ice by applying hot water. We can boil water at 70°C.
    All the procedures are given in AMM everyone should follow that steps carefully and apply that steps to remove icing.

    Hammad Malik

    ReplyDelete
  2. De-icing is the removal of ice that already formed.Anti icing is the initial ice formation.direct from rain. Snow.After taxing the aircraft snow slush snow attach to landing gears etc.
    The ice formation on aircraft is harmful full aircraft and it’s adverse effect.Ice formed in engines and it’s result decreases the engine thrust.ice on aircraft increased the weight of aircraft this ice formed results decreased the airfoil lift.The ice effects the brakes of aircraft.The ice formed in engines and hignes control they effect the landing gear retraction.
    Thera are several methods to remove ice.
    Remove the ice from hand by use of soft brooms, brushes and scrapers.The cold air is used for de-icing.Deep ice remove only by brush or rubber. The ice is light and dry remove by cold air.The hot air not used to remove snow because it may melt snow the water enters the aircraft switches and other sensitive areas.un thickened fluid is best for de-icing because it have high glycol content.The thickened fluid is minimum glycol content it will able remain on aircraft surface on long time.Before de-icing keep in your mind de-icing proceed symmetrically otherwise aircraft unbalanced.Fluid sprayed the aircraft at specific pressure according to maintenance manual of the aircraft.

    ReplyDelete
  3. Ice can have many adverse effects on an aircraft during flying which can cause serious issues and should be removed accordingly.

    The effects of ice on aircraft are not a mystery infact they can produce many adverse effects on flying and many serious problems for the flying crew. Due to formation of ice aircrafts weight tends to increase which inturn produces less thrust and consumes more fuel, due to formation of ice the airflow which was moving smoothly before ice formation may start to become turbulent and in return increase the drag on the aircraft, similarly the aircrafts control hinges may freeze and the pilot would have problems in manouvering the aircraft, just as in microswitches which may freeze and would give us a tough task to retract the landing gears, so could the ice be ingested into tge engine and the engine performance reduced to a great extent.

    The formation of ice may not be such a huge problem because there are ways we can remove it from, particularly 2 ways chemical and mechanical. The mechanical way may be done by the help of a blower, a brush and/or the rubber scrapper. The chemical as the name implies uses a chemical fluid which helps to remove the ice and can provide anti icing for a time period. The period in which the chemical provides protection against ice is called as "hold over time". The chemical way has 2 more methods which may help to remove ice called de icing and then protect it even further called anti icing. One step and 2 step methods, one step is done using a hot fluid which helps remove the ice and gives protection for some time, the 2 step method provides 2 fluids the first when helps in de-icing while the second helps in anti-icing the second step should be done within 3 minutes of the first step.

    Ice formation may have huge problems but they can be rectified by the methods discussed.

    ReplyDelete
  4. Ice on the aircraft can decrease in effectivity of the flight.

    The effect of formation of can be decrease of aerofoil lift and increase of aerofoil drag which can be caused by ice on wings. Weight of aircraft increases due to ice. Engine thrust decreases due to ingestion of ice into the engine. Freezing of moisture in control hinges. Freezing of micro switches that affect the system such as landing gear retraction.

    The ice can be removed by these methods. Removal by hand by using a soft broom brushes hand scraper. It can be de-iced using pressurized hot air from hot air blower. Deep wet snow should be removed by Bush or rubber scrapers, take care as to not damage the components like aerials and pitot probes. Light dry snow should be removed by cold air blower and not hot air blower, hor air blower may melt the which may again accumulate and freeze requiring further treatment.

    Accumulation of ice on aircraft may cause its performance to degrade, so maintenance personnel should follow relevant maintenance manual for removing of ice.

    ReplyDelete
  5. Ice may Form on an Aircraft because of :
    Taxing the Aircraft in snow or Slush. Direct precipitation of rain snow and frost.

    There are three Types of Ice
    Hoar frost, Rime Ice, Glaze Ice
    All of them have individual effects.

    Effects of Ice Formation:

    Ice formation may decrease the aerofoil Lift because of Rough surface due to Ice formed. The Drag of aerofoil may increased due to same reason. The Thrust of Engines will be reduced. The Ice formed on Micro-switches may affect the retraction of Landing gears. It also Effect the Hinges of the control surfaces. May Ice may Enter into the Engine inlet which may effect engine's performance.

    In order to Remove Ice from different parts of the Aircraft it may be done Either by mechanical process by using Soft broms rubber Scrapers or Chemically by using Anit-icing fluids.
    The Whole process of removing the ice is done by Anti-Icing or De-icing.

    Anti-Icing is the process which prevent the initial formation of Ice While de-icing on other hand is the process which remove ice that is already formed.
    To remove Ice it may Be done in two ways
    One step contain the removal of ice that is already formed either and will give a little protection against new ice formation.
    In two step Ice is removed first then Secondly a Anti-ice fluid applied to the structure which give Extra Protection Against new ice formation for long time
    The Time for which The fluid prevent New Ice Formation is Called "Hold over time"
    Attention should be paid to areas like Antennas,Probes, Landing Gears, inlets and Exhaust to protect them from ice formation.

    The Correct Method Detailed in AMM for Anti-Icing and De-icing Should be Followed strictly to Protect the Aircraft from any worst Condition.

    ReplyDelete
  6. There are many things which play a important role in not making the aircraft continuously airworthiness, icing is one of them.
    Icing occurs when the flights are operated on minus degree temperature so that the even moist in the air freeze at that point which effect the controlling surfaces of the aircraft.
    When icing occurs on the aircraft it will decreased the aerofoil lift , it will increased the aerofoil drag, it will increased the weight of the aircraft, it will decreased the engine thrust, it will freeze the moisture in control hinges, it will effect the micro-switches like (WOW) which is on the landing gear.
    There are two methods which we normally follow for the removal of icing. First is Mechanical method and the second method is chemical method.
    In Mechanical method we remove the ice from the aircraft by blowers, brushes, and rubber scrapers.
    In Chemical method we use de icing fluids. There are two types of fluids we use for de icing and anti icing one is unthickened fluid and second is thickened fluid.
    In unthickened fluid we have high quantity of glycol and have low viscosity. It is good de icing agent but have limited protection against refreezing.
    In thickened fluid we have low gycol quantity approximately 50% and have high viscosity due to which it will remain on aircraft for longer period of time. It is also good de icing agent and provides good protection againts refreezing.
    For the removal of ice on aircraft we also use cold fluid spray and hot fluid spray.
    cold fluid spray is a de icing fluid which is used for the removal of icing on the aircraft but in severe conditions we also use rubber scrappers and blowers gor de icing.
    Hot fluid spray is used to normally reduce the turn around time which is normally sprayed at pressure of 100 psi, while using hot fluid spray the nozzel must be kept close to the aircraft.
    By following these procedures we can make our aircraft continuously airworthiness.
    Muhammad Usama

    ReplyDelete
  7. Formation of ice on aircraft can cause serious problems and this is usually a major concern on high altitude. It can be caused on the ground by direct precipitation of ice, snow or rain on the structure.
    Effects of snow:
    If there is ice, snow or frost on an aircraft it can decrease the lift and increase drag on the wings. It will cause the air follow to become turbulent on the aerofoil. It will decrease the thrust on engines and can accumulate in the engine inlet or compressor region. It can effect the functionality of micro switches and sensors like extension and contraction of landing gear. If it get accumulated in hinges and bearings of flight control surfaces then it can cause sever problem and restrict their movements. There are several methods for the removal of ice, frost or snow on the surfaces.
    Deep wet snow can be removed by using mechanical methods, using brush, rubber scraper and soft broom sticks. Care should be taken when removing ice or snow from static probes, antennas, etc. Dry snow can be removed by using cold air from cold air blower unit.
    Heavy and mild snow or frost can be removed by using spraying methods which include Cold fluid spray and Hot fluid spray. Cold fluid spray have great effectiveness but when using in sever cold environment this method should be applied twice or thrice accompanied with mechanical method.
    Hot fluid spray is normally used to reduce turn around time. FPD fluids are applied cold and undiluted. They should be heated at a maximum of 95 degree Celsius and minimum at 60 degree Celsius. They are sprayed at a pressure of 698.5 kN/m2 and the nozzle should be kept close to the surface of the aircraft to reduce the heat loss. When heat transfers and snow melts, it can be removed by sweeping the fluid on the surface.
    When using high pressure precautions must be observed because there is a risk of damaging the aircraft structure.
    When using high pressure care must be taken not to damage pitot probes and aircraft structure. Because high pressure can cause erosion on the structure.
    Hot water should not be used in extreme weather conditions like temperature below -60 degree Celsius. And when applied a de icing agent should be sprayed within 3 minutes of its use.
    Great care should be taken to make sure there is no ice, snow or frost on the surface of the plane.

    ReplyDelete
  8. Muhammad Hamza Ahmed

    Ice may form on Aircraft due to cold weather and temperature in minus ➖.
    Ice build-up on the wings increases weight, and reduces lift. Icing on the aircraft's propeller increases drag and reduces thrust , the wings are very vulnerable to icing the reason is that the ice will effect the airflow over the rest of the wing and sometimes it blocks the components of aircraft to open.
    There are several adverse effects of formation of ice that are decreasing of engine thrust , landing gear retraction problem, ingestion of ice into the engine of an aircraft.
    This ice can be removed by 2 methods One step method and Two step method.
    The One Step method utlises hot fluid to de-ice the aircraft.
    The Two Step method consist of two seperate fluid procedure ,the first step is the de-icing parts and the second step is the anti icing.
    Deicing fluid, a mixture of a chemical called glycol and water, is generally heated and sprayed under pressure to remove ice and snow on the aircraft.
    Anti-icing is a precautionary procedure by which clean aircraft surfaces are protected against the formation of ice and frost and the accumulation of snow and slush for a limited period of time. Cold-soak effect.
    Heavy, wet snow or ice can be removed by placing the aircraft in a heated hangar, by using solutions of heated FPD Muhammad Hamza Ahmed

    Ice may form on Aircraft due to cold weather and temperature in minus ➖.
    Ice build-up on the wings increases weight, and reduces lift. Icing on the aircraft's propeller increases drag and reduces thrust , the wings are very vulnerable to icing the reason is that the ice will effect the airflow over the rest of the wing and sometimes it blocks the components of aircraft to open.
    There are several adverse effects of formation of ice that are decreasing of engine thrust , landing gear retraction problem, ingestion of ice into the engine of an aircraft.
    This ice can be removed by 2 methods One step method and Two step method.
    The One Step method utlises hot fluid to de-ice the aircraft.
    The Two Step method consist of two seperate fluid procedure ,the first step is the de-icing parts and the second step is the anti icing.
    Deicing fluid, a mixture of a chemical called glycol and water, is generally heated and sprayed under pressure to remove ice and snow on the aircraft.
    Anti-icing is a precautionary procedure by which clean aircraft surfaces are protected against the formation of ice and frost and the accumulation of snow and slush for a limited period of time. Cold-soak effect.
    Heavy, wet snow or ice can be removed by placing the aircraft in a heated hangar, by using solutions of heated FPD (freezing point depressants) fluids and water, by mechanical means such as brooms or squeegees, or a combination of all three methods

    And in the end you should see the correct method from AMM to remove the snow and ice.

    ReplyDelete
  9. The weather and temperature is major reason of icing.

    There are main 3 types of ice
    Hoar frost, rimice, glaze ice
    When moist air become in contact with cold surface
    Condensation into water droplets take place.
    When this the dewdrop below the freezing point it become crystal form because the temperature of aircraft is below 0 temperature.
    Hoar frost produce rough surface
    It will disturb air flow which turn into turbulent flow.
    Rim ice is light colour at ground level water droplets form into freezing fog which is effect on weight, and bkock pitot tube and others open surface sensing equipment.
    Glaze ice is the one most dangerous in all over types of icing it may be transparent or opaques form into glassy surface due to liquid water flowing over surface.
    Its heavy, rough, and dense.

    The formation of ice on aircraft structures can produce many adverse effects
    Decrease of lift because the smooth air flow disturb due to rough surface.
    Increase of drag because airflow is not smooth it become turbulent which may occur drag.
    Increases weight is effected on aircraft performance increases os weight consuming more fuel.
    During cold weather is necessary to remove ice from aircraft.
    We can remove ice by mechanical method and chemical method.
    Follow AMM steps to removing ice is more accurate.

    M inam

    ReplyDelete
  10. During the flight in cold whether we sometimes face a very difficult satution that is icing on the aircraft, and it has very adverse effects on the performence of aircraft.

    Icing causes the increase in aircraft weight which is not suitable for aircrafts overall performence, it evently costs much fuel consumption.
    Icing also causes the control hinges to freeze and it effects the controlling abilility of the aircraft.
    It also decreases the aerofoil lift and increased aerofoil drag. Because of the extra layer on the wing it produces drag and effects the performence.
    Moreover icing also causes the freezing of micro-switches that effects the functions such as retraction of the landing gear.
    It is witnessed that icing effects the performence of engines if it ingested into the engine. Turbine engine works on with fuel combustion and mixture of hot air when there is icing inside the engine it effects the engine performence and can cause the engine to chock.

    ReplyDelete
  11. Ice forms on the aircraft when it move from operation areas where temperature is low due to this moist become frost which effect the aircraft.
    Due to iceing the lift of the aerofoil decreased because streamline flow of air disturb bcz of iceing.Engine thrust also decreased due to load. Moisture froze in the control hinges which has large effect on the aircraft the ingest of ice in the engine effect the performance of the engine.Due to the iceing the weight of the aircraft also increased which decreased the engine thrust due to this engine use more fuel.

    The freezing of ice on the micro switches has large effect on the landing gear retraction.Due to the addition of weight the centre of gravity also change it can cause imbalnce.
    Two method are use for the removal of ice mechanical and chemical.In the mechanical process bliowers,brushes and rubber scrapers are use to remove ice.while in chemical process fluid is use which have high content of glycol which provide good protection but limited protection against re-freezing
    And the minimum content of glycol about 50 percent give good protection against re-freezing process .
    For the frost the best fluid for de-icing is kilfrost.
    Only the fluid recommended by the manufacture is used written in the AMM.Attention in the process is necessary for good work.

    ReplyDelete
  12. During flight and on ground due to the temperature changes several types of ice formed on the external body of the aircraft it effects on the movement of aircraft so it should be removed.

    Ice can be formed on the body of aircraft in many types due to rain snow and frost and during flight due to the speed and temperature the external surfaces are effected by ice in forms of crystals and when taxing ice partials may accumulate on landing gear on forward facing and under facing surfaces. It will effect the air craft in many types.it can decrease the lift generation because the shape of aerofoil is effected it will effect engine thrust because ice effect on the rotation of blades.it also effect on the balence of aircraft because of wait shifting during landing it will effect on the performance of landing gear it will increase the drag because it will decrease the sharpness of external parts like wing tips.
    We can remove this ice formation by two mathos machanical and chemical methods called de icing. In machanical method we can remove by using blowers and brushes, rubber,scraps.
    by applying anti icing fluid against ice can is called anti icing.
    To prevent from the structure damage or distrubance in the movement of air craft we should perform the removal of ice according to matainance manual.

    ZOHAIB IJAZ

    ReplyDelete
  13. During the flight in cold weather we come across the problem of icing and if it remains on the aircraft it has some adverse effects on the aircraft performance.

    Icing causes the decreased aerofoil lift and increased aerofoil drag.Because of the extra layers on the wing it produces the drag which effects the lift.
    Icing also causes an extra weight on the aircraft which causes more fuel consumption.It also causes decreased the engine thrust.Moreover icing causes the freezing of the micro-switches.

    The procedure for removal of ice from an aircraft surface by mechanically and chemically.The ice can be removed by these methods. Removal by hand by using soft broom brushes hand scrapers.It can be de-iced using pressurized hot air blower.

    ReplyDelete

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