It has been a long winter, and besides the fact that our piloting skills may have deteriorated since the last time we had the bird out of its roost, there may be other things to consider.  As the temperature and the length of the day on weekends starts to draw our attention away from football, the winter Olympics, and other sedentary pastimes, we soon start to think again about flying.  The question we must ask ourselves is just how ready are we to just go out and jump in our aircraft the first time we get the chance?  This article will provide some reminders about some common sense ideas before we leap back into the air this spring.

Getting the Aircraft Ready

For those of us lucky enough to own our own aircraft, we know how easy it is to drive out to the airport and pull that trusty steed from its stall and head for the sky, but wait, that aircraft has barely moved in almost four months.  Are we really that eager to jump in and go or are there some items that we need to look at first?

An aircraft is a mechanical device whose longevity depends upon frequent use to keep its parts well conditioned for proper operation.  Professional maintenance teams have helped many aircraft owners discover the issues with disuse, and sometimes the costs are more than it would have been to just use the aircraft more frequently.  Despite common perception, many components on an aircraft and other mechanical devices work best when they are exercised frequently, and in fact many mechanics recommend exercise at least once a month to keep systems lubricated and healthy.  Let’s look at a few of the common places trouble can show-up.

Oil and Lubrication:  Aviation oils are designed for a very specific purpose and that oil will perform that purpose when it needs to, but how long has that oil been in your crankcase?  Oils that are allowed to sit for long periods of time and have undergone a wide range of temperature variations have a tendency to trap moisture and carbon particles from combustion in the engine.  This is not the ideal situation for the engine that is going to carry you and your precious payload.  Make an appointment to get your oil changed before the first flight of the season.  Make sure that the technician (or you if you perform preventative maintenance under FAR 43.17 appendix a) cuts open the filter and examines it for metal particles and any signs of excessive wear.  Many people send oil samples off for analysis on a regular basis to see what particulate matter might be floating around inside that engine.  This generally costs about $25 per report.  Not a very high price for a peace of mind, huh?  Excess moisture trapped in an engine can be just as detrimental for engine longevity as the metal particles.  We have seen engines corrode from the inside out when an engine has been left unattended with the same oil for long periods of time.

Seals and Gaskets:  Seals and gaskets located throughout the aircraft remain pliable for many years when they are exercised frequently but begin to dry out and develop dry rot when they are left unused even for periods as short as several months.  This applies to prop seals, landing gear hydraulic components, brake components, lubrication on flight controls, and gaskets throughout the carburetor and fuel distribution system hoses and components.  What can you do about this?  Not much if you have not been running the aircraft at least once a month throughout the winter, but this may explain why things tend to start breaking and leaking after the first flight or two of the year, even though the aircraft just came out of its annual inspection not 20 flight hours ago in the fall!  Perhaps consider rescheduling that annual inspection for the early spring each year to avoid that frustration.

Battery:  Lead acid batteries tend to degrade over time unless they are provided a periodic trickle charge.  Don’t be surprised if the first time you try to turn the engine over in the Spring if the battery does not offer some fundamental protest!  The battery is designed and rated two different ways.  One is an amp-hour (AH) rating and another is a cold cranking amp (CCA) rating.  Aircraft batteries are typically smaller and have less capacity than an auto battery so therefore the ratings are considerably less than a comparable automotive battery so when degradation starts, there simply is not enough reserve capacity to get the aircraft engine started.  I recommend removing or disconnecting the battery if you will not be using it for periods greater than 45-60 days.  Trickle or step-chargers are ok for short periods of time, but are not designed to be left on a battery for weeks at a time.  They should automatically shut down when the battery reaches full charge but the cheaper ones could keep putting that 2 amp charge to the battery for a long period of time and that is not recommended for battery longevity.  After a thoroughly charging, service the battery prior to the first flight of the spring by topping off the fluids, if it has service caps on it.  Do not be tempted to add fluid (use only distilled water) to the battery until it is fully charged or it will just get pushed out the breather drain when it is charged.  Many modern batteries are moving to “maintenance free” designs.  If these are approved for use in your aircraft, I would recommend them even if it costs a little more.  This also eliminates the problems associated with the acid damage found in the battery box caused by the drain hoses oozing excess fluids caused by excess charging.  This is another cause of the lower fuselage corrosion we see on many airframes that we see in inspections and that is an expensive repair.  If you are tempted to “jump start” the aircraft and then immediately taxi to the runway, consider this:  without taking the time to properly charge the battery and be sure there is enough energy without the jump, the battery could quickly go dead after takeoff.  Don’t fly with a battery that is not strong enough to start the aircraft on its own!

Rodents:  What?  How is it that mice and other vermin can figure their way into make a warm winter home in your aircraft upholstery?  Seeing how airports and hangars are frequently surrounded by farm fields, it should not be too surprising until the first time you see the damage in your aircraft!  They are usually long gone by the time you raise the hangar door, but the remains of their feast are still there.  Those little critters eat anything from seat cushion to insulation to wire bundles.  Don’t laugh.  We have seen it more times than we care to count.  It’s probably worth a good look under your seats to see if there are any telltale signs.  If there are signs, don’t assume they only made a snack of your seats!

Birds:  Aircraft are typically prime targets for birds to set up camp in the spring.  They like those quiet places where they can build a nest out of sight.  Too bad a lot of the common places for them to hide their nest are out of sight from a casual preflight inspection.  Better look hard for signs they have entered holes in the cowling baffles or even up underneath the cowling where the nosewheel strut goes to the engine mount.  How many pilots get down on their knees and look up there?  The other place where the birds love to go is the “lightning holes” on the aft side of where flight controls and their piano hinges meet.  We have pulled out 5 pounds of straw before out of Cessna elevators.  The worry here is that the straw could jam in a cable guide or pulley.  Other than blocking or restricting flight control movement, the biggest issue with the birds is when the nest goes undetected and then catches on fire just after liftoff when the engine comes up to temperature.  Just because you have cowling plugs, does not mean the birds won’t find a way in if they want to.  The little rascals are territorial, too.  Once they set up shop, they keep coming back to the same aircraft time after time until they get it out of their system.

Tires:  Tires on aircraft are frequently hidden inside wheel pants and often escape careful consideration on preflights, and this is no exception on the first flight of the year.  Pull that aircraft forward and look carefully at the entire tire looking for flat spots, baldness, or weather checking.  Bring a dependable tire gauge and make sure that the tires are not over or under serviced compared to the recommended numbers shown in the aircraft handbook.

Fuel:  Aircraft fuel (100LL) is not susceptible to the waxy buildups that occur with automotive gas, but it is just as susceptible to the moisture buildups and sediment in the tanks after lengthy inactivity.  If the aircraft you fly is approved for and uses auto gas, then be very wary of deposits that can gum up the fuel distribution system.  Think about how poor your lawnmower runs after sitting with a tank of unstabilized gas for the winter.  Make it a habit to thoroughly drain each and every fuel drain and strainer looking for any sign of moisture or floating sediment.  Small dark colored particles may be dirt or they may be gasket material or tank sealer that has broken free.  Either way, continue draining each strainer until there is no evidence of water or sediment.  This is not the time to be stingy.  Take a full sample and look at it carefully in the light.  Remember to properly dispose of the sample and do not dump the first sample of the year back into the tanks!  If you use auto gas and you know that the aircraft will sit for over three months, then consider filling it with 100LL for the period of inactivity or using an FAA approved gas stabilization compound that will keep the fuel from breaking down over the winter.

I can only urge you to really give the aircraft a complete going over on the first flight of the new flying year.  This is a great time to schedule some preventative maintenance with your local mechanic to make sure that there are no surprises.  Now, after all of this, we just need to make sure that our flying skills are as ready as our aircraft!