H O F T E C
With decreasing numbers of certified aircraft and an increasing count of non-certified aircraft, mechanics willing and capable of working on smaller aircraft will be increasingly difficult to find. Therefore, more of the preventive maintenance will fall on the shoulders of the owners. Here are some things to consider as you prepare for another long winter of reduced activity.
- Wiring deteriorates whether you fly or not. Make sure insulation is not cracked, frayed or chafed. Keep contacts, particularly grounds, clean. Have doubtful wiring replaced.
- Engine mount rubbers deteriorate in time and cause the engine to sag. If the spinner no longer lines up with the front of the engine cowling you are overdue for a shock mount change. If you don't change these, you will pay for it in damage due to increased vibration of the airframe and the expensive instrument bearings and avionics. If 10 years have elapsed since a change, you are due. Hardened mount rubbers and engine hoses also increase cabin noise.
- Spray your favourite brand of corrosion inhibitor into the structure any time you open panels or gain access to unusual places. Replace corroded hardware. Remove rust from steel parts and prime and repaint.
- Change engine oil every four months, regardless of the number of hours flown. The additives in the oil, which prevent nastiness, evaporate in time.
- If the aircraft is parked outside, cover the tires so sunlight does not deteriorate the rubber. With the fleet getting older and the mechanics getting fewer, general aviation aircraft owners need to be more active in maintenance.
With the fleet getting older and the mechanics getting fewer, general aviation
aircraft owners need to be more active in maintenance.
- Have your compass swung for real. Whether you fly even thousands plus 500 ft or odd plus 500 ft in cruise above 3000 ft is a function of your magnetic heading, not your compass heading. This is actually a safety item, often made light of. Get it done properly. Have a compass rose surveyed somewhere on your airport if there isn't one already.
- If you have a mode C altitude reporting capability working in your airplane, a pitot-static test and correspondence check must be done every two years. You do not have a choice. It will help air traffic controllers to steer other traffic away from you if your altitude corresponds with the radar read-out.
- How sure are you that your parking area was not flooded out during a heavy rain or spring thaw, immersing the wheel bearings in water? Are you repacking the wheel bearings on your aircraft at least once a year?
- If you pre-heat the whole engine and not just the oil on cold days, that's good. But are you also preheating the cockpit so that the gyros and their expensive bearings will operate at their designed temperatures? Gyros breathe cabin air which is supposed to be warm. Have you checked the price of a gyro overhaul lately? And when was the gyro filter last changed?
- On oleo-equipped aircraft, clean the exposed oleo before you move the airplane. The grit held by the thin film of oil will eventually cost you a seal replacement if you don't clean the shiny area first.
- If you plan not to fly for an extended period, why not remove the expensive avionic boxes for the duration and store them in you temperature controlled home? Moisture and condensation are very costly! Maybe have them tuned up during that period when the shops are less busy.
- Make sure the drain holes in the bottom of the fuselage and other structure are open to let melting snow and rain out.
- Remove snow loads quickly. Make certain that tricycle-geared airplanes are parked so their elevators don't get crunched by something if the tail is pushed down by a snow load. A sawhorse under the tail hardpoint is a great idea.
- Have the tie-down ropes been replaced recently?
There are things owners can do for their airplanes this winter.
Renew your membership to COPA so you can stay up-to-date through aircraft maintenance articles and advertisements. Don't forget to dream about all the neat stuff you could install in your airplane if you had the money.
- If you do fly to keep the oil circulated in the engine, make sure you fly long enough to get the oil temperature to 180 F. Reaching that temperature on the indicator ensures that the oil has actually gone over 212 F and therefore evaporated the water, hopefully out the breather tube. Remember the oil change every four months.
- Maintain proper tire pressure. If you are stuck indoors more this winter, spend some time researching competitive prices for replacement parts. Get to know the part numbers for the spares you will need on the next annual. Buy and read a book on airplane maintenance.
Take your favourite mechanic out for a lunch and or a beer and pump him for maintenance tips. Take notes.