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Engine Maintenance

• Switching the fuel selector from the presently-selected tank to another tank • Turn on the fuel boost pump • If the engine re-starts locate the nearest airport and land immediately since either fuel planning or a system malfunction has occurred.

The Complete Engine Failure Complete engine failures—the everything’s-fine-clatter-clatter-bang-bangnow-what kind of failures are very rare. The most common causes of complete and sudden engine failures are: 1. A broken crankshaft. 2. One or more spun main or rod bearings—lubrication distress. 3. A broken connecting rod—this is almost always caused by lubrication distress and can also result in the rod or rod cap being ejected through the engine case. 4. A broken or loose accessory drive gear. This failure disconnects the crankshaft from the accessory and magneto drive gearing—when the magnetos stop turning the engine stops turning. These are all true emergencies. Sometimes the failure is trumped by a loss of forward vision due to engine oil on the windscreen. There’s a very slight chance that you may be fighting a sudden out-of-CG situation if the propeller is slung off the airplane following a broken crankshaft. The emotional impact of many engine failure emergencies is further ratcheted off the charts by the cacophony of very loud noises of the failing machinery variety. These emergencies get your attention right now. Steps to take during one of these emergencies include:


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• Control the airplane. Level the wings and trim the airplane as necessary. Set up best glide speed. • Move the fuel selector to the off position—lessens the possibility of a fuel leak and engine fire. • Locate the nearest airport (Even the simplest handheld aviation GPS navigator has a “nearest” function that’s invaluable in an emergency situation) and determine if you can make the runway. • Don’t stall the airplane--seatbelts and shoulder harnesses are built to protect the inhabitants during forward deceleration; most GA airplanes have no protection against vertical deceleration. It’s much safer to fly to a fully-controlled off-airport landing than it is hit the ground in near vertical out-of-control flight cause by stalling the airplane. • If you have a remote switch for your ELT, turn it on. • Put in a radio call to ATC or on 121.5 giving your position and your intentions. • Turn your transponder code to 7700. • Tell your passengers to tighten their seat belts and shoulder harnesses—if you haven’t yet installed shoulder harnesses do it today.

• Open the doors on final approach to landing—if you can, wedge a shoe or towel or flight bag in the opening to prevent the door from jamming during the landing.

Partial Engine Failures Partial power loss is more common than complete engine failures. The most common power loss causes are: • Cylinder head separation (compression loss). • Stuck valve. • Can result in a bent or broken pushrod (compression loss—oil leak). • Detonation-caused piston and ring damage (compression loss). • Burnt Valve (compression loss). With the exception of the cylinder head separation, all these failures provide

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PilotMag-May/June 2010  

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Aviation magazine

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