Many people who have a fear of flying only comprehend the hazards of icing condition involving airplanes taking off. Icing can be a hazard for aircraft in flight too. When it comes to icing, you should always have respect for it. The FAA always emphasize that you must have a clean airplane. That has been hammered into the brains of every pilot since their first days in flight school. Basically, having a clean airplane means having no ice, snow, or frost adhering to the airplane. Airlines make sure that all ground personnel receives yearly training on how to properly deice the aircraft on the ground. Only experience ramp personnel are allowed to deice aircraft. Communication is very important. They get trained on applying the right temperature, mixture ratio, & where to apply it on the aircraft.
Airline pilots are trained to make sure they depart the gate with a clean airplane, & if there is any doubt they will get the airplane deice anyway. Usually in the cockpit both pilots would have time to make an observation if there is any ice on the airplane. Sometimes flight attendants, or ramp personnel will be the first to notice it, & bring it to the crews attention. Departing with a clean airplane is a collective effort with everyone working together as a team to ensure a safe flight. But, ultimately it is the captain's responsibility.
Once you get airborne, your icing problems doesn't just go away. Most turboprop, & jet aircraft have anti-icing systems to prevent the ice build up on certain critical parts of the aircraft. For example, they usually will have engine anti-ice to prevent ice build up in the engine intake. There are wing anti-ice heaters on jets to melt off ice. While turboprops have boots that inflate like a balloon to break off ice on their wing. Other features are windshield anti-ice, fuel heat to prevent ice build up in the fuel lines,& anti-ice that heat certain probes that give pilots instrument readings. Airplanes that have all of these features are approved to fly into icing conditions.
But, just because you are approved to fly into icing conditions doesn't mean pilots will stay leveled at an altitude in prolong icing conditions. As a pilot, you always want to try to get out of icing whenever feasible. Icing degrades aircraft's performance & aerodynamics so there's no incentive to stay in it. Staying in icing conditions produces drag, & makes the airplane heavier therefore wasting more fuel. Furthermore, for airplanes not approved for icing conditions this could be dangerous. For examples of airplanes not approved for icing conditions would be some light general aviation single engine type airplanes & some light twin engines.
Some of the conditions you need to get icing in flight are visible moisture such as clouds, rain, drizzle, and you must be in the right temperature range between plus 6 degrees Celsius & minus 15 degrees Celsius. There are some exceptions when you could still get icing conditions in slightly colder conditions such as flying through cumulonimbus type clouds. But generally, its difficult to pick up icing when beyond minus 20 degrees Celsius. If you are flying in clear blue skies, you will not get in flight icing. Icing is measured on a scale from light, moderate, & severe. Any aircraft that is approved to fly into icing condition will generally not have a problem in moderate conditions.
But, you will probably want to change altitude soon to get out of it. Severe icing can cause a lot of problems for any airplane approved in icing conditions. Basically, it means ice accretion is continuous making the aircraft's anti-ice system ineffective. Severe icing is more of a problem at lower altitudes, but a quick change in altitude will usually get you out of it. In the higher flight levels where most commercial jets fly its generally too cold to pick up icing. If an aircraft in severe icing doesn't change course, or altitude soon it could be in real danger. Fortunately, Severe icing condition doesn't happen that often.
There are basically two types of in flight icing. Rime ice is formed when super cooled water freezes on contact with the airplanes wing. Rime ice looks like granular form white type with entrapped air. The other type is clear air ice. Clear air is a glossy form of ice a little harder to notice visually. Its a slow freezing of large super cooled water droplets. It forms a sheet of ice. Regardless of the ice form there are some clues that trained pilots could notice when they are picking up icing in flight. When pilots fly into visible moisture its almost instinctively to look at the temperature gauge in the cockpit to see if your in that temperature range to get icing. One big clue is the metal rod on the windshield wipers are usually your first clue to icing because they will start to build up ice on it. Also, you will notice a slight decrease in your airspeed. Other clues can come from the autopilot that will start having a harder time maintaining altitude. The autopilot will need more & more trim, or higher pitch to maintain altitude. But, there are so many clues that any professionally trained pilot can recognize very early before the icing becomes dangerous.
Finally, one last icing condition that is dangerous to all aircraft is freezing rain. This is also another rare type of icing. Most civilian aircraft are not approved to fly in freezing rain. Generally, the best thing to do is to avoid that area of freezing rain, or cancel a flight. Freezing rain makes anti-icing systems ineffective.
Captain Simmons is a MD-80 pilot for a major air carrier with over 20 years experience. To learn more please visit our site at [http://www.flyinganxiety.com]
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