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Owner's Corner

Lloyd Stephens, Aircraft Owner and Board Member WVFC


Of Batteries and Starters

A few weeks ago my Archer, N3576J, had a problem with starting the engine.  That has been fixed now (it turned out that the primer was only injecting fuel into one of the three cylinders it was supposed to be feeding), but this problem brought up a discussion with maintenance about the need to protect starters and batteries.  One of the things that happened with my plane was that a member ran the battery down trying to start the engine.  He returned the book with a note that he was unable to start the engine, but did not mention that the battery had been run down by his attempts to do so.  The next person scheduled to fly it, came out on Saturday morning and found that the battery was completely dead.  The plane was then grounded for the weekend until the battery could be recharged on Monday.  When I talked to maintenance about this, they told me that there were five planes grounded over the weekend because of dead batteries, and this seems to be an ongoing problem.  As club members, we need to be more careful not to run down the aircraft batteries when we are preflighting and starting the engines.

When you preflight, you should not turn on all of the electric equipment (radios, lights, pitot heat, etc.) and leave them on while you are conducting the preflight.  This causes a serious drain on the battery.  It is best to check these items one at a time and to turn them off (and turn the master switch off) as soon as you have checked each of them.  If someone else is flying with you, enlist their help to check the external items like lights and pitot heat.  If you are not going to be using these items during a flight it is not essential to check them every time.  (If a number of people fly the plane during daytime VFR conditions and all of them check the lights and pitot heat, there is a lot of drain on the battery for no effective purpose.)  Learn to be conscious of minimizing the time that the master and the individual switches are on, to protect the battery.  And if either you, or someone else, have run down the battery, make a note in the file and tell the person at the front desk about it.  You’re not going to get charged for running the battery down, but the battery will need to be charged.  If you don’t let us know, it’s not very nice for the next person scheduled to find that he or she does not have an airplane to fly because you didn’t tell us that the battery was dead.

Starting an aircraft engine has been described as “one part science, one part art, one part folklore, and two parts luck.”  Most of the time we are able to get the engine started without too much of a problem, but if we can’t, it not only can result in running down the battery, but also in overheating and damaging the starter.  I have frequently heard someone (hopefully not WVFC members) cranking the starter for well over 30 seconds in an attempt to start a recalcitrant engine.  Starters are not designed for such extended use.  Excessive starter cranking without allowing enough time for the starter to cool between attempts results in overheating.  Although the recommended time of use can vary somewhat with the starter, generally it is recommended that to avoid damage from overheating the starter be engaged for up to 10 seconds followed by a 30 second cool-down.  This cycle can usually be repeated up to three times.  After that the starter should be cooled down for at least one minute before another start attempt.

Difficulty starting an engine is generally due to either not enough fuel available to the engine, or too much fuel.  When the engine is cold, I find the best way to start my plane is with the throttle about 1/4” to 1/2” open, mixture full rich, and the electric fuel pump on, give it two shots of the primer (pull the knob out and wait a couple of seconds for it to fill before pushing it in) and then one shot of the throttle, then engage the starter.  This usually results in a perfect start.  If it doesn’t, try a little more priming.  If the engine is warm you may not need to prime it.  This procedure may vary depending on the airplane you are flying.  Consult the Pilot’s Operating Handbook for the specific instructions for your plane.  The POH usually contains information on starting engines that are flooded and also those that are hot, as well as normal starts.  Learning to start the engine of the plane that you are flying, without excessive cranking of the starter, will protect both the starter and the battery, minimizing down time and maintenance costs.

Here are a couple of articles from the AOPA Flight Training magazine that you might find interesting.