::[ kampungkai ]::

Tuesday, December 20

Aircraft Snow Removal

Yawn, waking up at 10a.m feels great! For all u working friends haha! are u jealous?? :P bluekkkk... I better enjoy my student life before the working life starts to haunt me. By then, u'll be laughing at me instead because i even have midnight shifts on big days like Xmas, CNY, Raya & Deepavali! (triple pay though haha!)

It's winter season in most of the cold countries, children and maybe SOME adults overseas are playing snowball in their yard and making snowman with carrots cucuk-ed as nose; and back here in Malaysia, children and ALL adults in the northern states are shifting tv, pc monitor, microwave... to higher ground, thank God selangor is fine.

Snow can be fun for us to play with. It's soft, it's cold, it's just oh-so-beautiful to us Malaysians who have not seen snow before, that includes me. However, snow can be disastorous to aircrafts. Not only it is a very effectice aerodynamic spoiler (changes the shape of the surface), but also it adds a significant amount of weight and drag, to name a few.

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Yellow bird - DHL having a hot bath with V.S.O.P

During flights, snow accumulation is quite minimal as the strong on-coming wind will blow the snow off the aircraft surfaces. It is on ground, when the planes are parked, that snow tends to accumulate on the aircraft, especially the wings for its large horizontal surface. Knowing that it is disastorous to fly with snow, so some methods of removing them is compulsory before takeoff is allowed.

Procedures of removing snow range from a low tech broom to sophisticated chemicals. Airlines most commonly use a truck mounted mobile de-icer/anti-icer, just like the picture shown above where DHL is having a hot bath. These units generally consist of one or more fluid tanks, a heater to bring the fluid to a desired application temperature, and a spraying nozzle. The dispensing system is capable of supplying fluid at various pressures and flow rates with an adjustable spray pattern at the nozzle. It's something like the nozzle we use to water our plants in the garden.

So, what chemical is being sprayed as shown? definitely it wouldn't be water, because water freezes easily during winter, which would then form stalagtite on the plane and stalagmite on the airport floor haha! Therefore, some sort of chemical having a freezing point lower than 0 degree (water freezing point) is preferred. Generally, airlines are using a mixture of isopropyl alcohol and ethylene glycol as the chemical. Mind u, these alcohol are not consumable like V.S.O.P or Chivas Regal ya!!! (u need like 1000 bottles of vsop to pour over a plane!)

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When everything is white, the red blue Wau stands out.

If the plane is covered heavily by snow, the ground crews will firstly spray a greater amount of diluted chemical, usually heated, to remove accumulated ice, snow, or frost (de-ice). The dilution must protect from refreezing long enough for the second step (anti-icing) to be completed. During anti-acing, a more concentrated fluid is applied to the uncontaminated surfaces. How concentrated? well that depends upon weather conditions, required holdover time (length of time surface will be protected) and it is applied cold.

De-ice and anti-ice airplanes as close to the departure time as possible, especially when bad weather conditions cause shorter holdover time. Fortunately, we aircraft engineers in malaysia dun need to encounter such problems, and that means less work! But come to think of it, engineers overseas dun do it too. All aircraft engineers do is to order ppl to do things, and when it's done, get to the site and inspect and sign the papers, done! Easy job huh? But dun forget, that signature holds everyone on board's life.


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