skipperdan
Joined: 10 Aug 2003
Posts: 1296
Location: Florida
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| Posted: Fri Jul 10, 2009 9:44 pm Post subject: CARB HEAT |
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Here is another good reason for you'all to join AOPA which is a fantastic organization. For less than the cost of a hardware or software addon, you can afford an annual membership.
Here is an excellent article from today's member newsletter.
TRAINING TIPs
Carb heat technique
Warmer temperatures and high humidity create many challenges for pilots, including reduced aircraft performance, thunderstorm development, and rapid fog formation when temperature-dewpoint spreads narrow. These are also the conditions that elevate the risk of aircraft with carbureted engines developing ice in the carburetor throat, with potential for power loss or even engine stoppage. Do you use correct technique to minimize the risk? Can you recognize the signs of carburetor icing’s onset?
Flight training operations requiring multiple power adjustments or sustained flight at low power settings make training aircraft especially susceptible to carb icing, as discussed in the Aug. 23, 2002, Training Tip. If you suspect carb icing because of a gradual power loss or engine roughness, act promptly and aggressively to eliminate it. In most aircraft equipped with carbureted engines, that means applying full carb heat until normal operation has been restored.
If carb icing was present, chances are that the engine’s response to your actions will confirm your suspicions in dramatic fashion. “The first time you experience carb ice can be startling, since application of full carb heat—as recommended—will likely cause brief coughing and choking in the engine as the ice in the carburetor melts and is ingested by the engine,” explains the AOPA Air Safety Foundation’s Safety Advisor Engine Operations. Then engine operation should become smooth, and the power setting you were maintaining before the icing should resume—so let the carb heat do its work.
There are preventive steps you can take when cruising toward your destination on a day when carb icing conditions prevail. “When icing conditions exist, apply carburetor heat often at your cruise throttle setting. Never use partial carburetor heat unless the aircraft is equipped with a carburetor temperature gauge, ice light, or similar instrumentation. Partial heat can possibly make matters worse, unless you know exact carburetor temperatures,” advises the comprehensive discussion of carb ice in the AOPA Online Pilot Information Center. “Remember, full heat or nothing. When below the green band on the rpm or MP gauge, apply carburetor heat. It is good practice to use it on any descent where you have reduced power.” |
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