Operating in the Tropics we seem to have many extra challenges compared to more temperate regions - a sort of war against natures natural desire to ensure entropy wins and gravity sucks! Getting around gravity is easy, thanks to Zenith aircraft and their desire to break free from the bonds of the earth - but there are other challenges that Zenith hasn't yet thought of... Here are just some of them - and how we get around them, where possible... (perhaps you have some advice or other challenges to share!)
1. Bugs - it seems that our African insects are on steroids, we regularly remove a significant insect nests from engines, fuselage areas, control cables (yes on the cable itself),etc. It seems that the L angle on the vertical sides of the 701/801 fuselage are ideal nesting grounds for the potters wasps - and they have been known to make nests over a foot long against an L angle - and those nests are heavy. Each pre-flight requires strict attention to insects nests - often built overnight and the knocking away of the mud and removal of larvae and paralyzed caterpillars (there to feed the young) - messy, but necessary.
Spiders like to make nests in every opening they can - the axles get filled with nests, the open ends of the throttle rods, the caps of hex nuts, open threads on the engine block, un used prop mounting holes, etc. Apart from spending time cleaning them out, we find that the best option is to fill the hole with silicon - regular household silicon caulk! WE also do this on the small gaps at the ends of the ailerons, flaps, etc - to avoid adding kilos of extra weight that we would be unaware of!
Of course we cannot block all of the holes - the fuel drains are a bit necessary to not block. This weekend we had about 50 tiny ants that had made the starboard wing fuel drain their home. So much gunge was taken up there to make it home that the only solution left was to remove the drain and spend about 10 minutes flushing and picking with some locking wire to clear it. On other aircraft we have had ants take grass seeds and grass into the fuel tank vent lines - just something to check for!
The pitot tube is not exempt... Of course we put covers on - but not when we are flying or between flights - so one flight we landed and changed passengers, without the pilot (me) leaving the cockpit. After start-up I looked around my airframe as always and as I looked at the pitot I saw an insect carrying a rolled up leaf into the pitot tube. A quick shutdown and a removal game of leaf from pitot. This is why we mount our pitot so that the horizontal tube can be removed, blown through, poked with grass or locking wire and re-installed in a few seconds!!!
When pre-flighting make sure you do not stand on a line of marching ants - at certain times of the year they move across the apron and runways - long black lines of millions of ants migrating from high-to-low or low -to-high ground for water requirements. Stand in the line and they will send teams of commandos up your trouser legs, once they have about 200 installed scouts they give an order to bite - it is like some medieval torture. The ONLY solution is to strip to your underwear (and sometimes that is not enough) and brush off the biting pests - and fast. I have been caught twice - the run to cover (in order not scare the folks at the airfield) to strip down and shake out my clothes is enough for me - I look twice before stepping anywhere on the apron at the season changes. I guess we can say we have two types of pilots - those who have stood in a line of marching ants - and those who are going to!!!
2. Snakes and lizards Snakes like warm engines and will take advantage of sneaking into the engine compartment for a nap - extra precautions are therefore necessary. We have only had snakes in the cockpit a couple of times - but enough to ensure that we look well before embarking on a mission. The rule is not to make a sharp movement if the snake has stowed-away and comes out during the flight. It is also a good reason NOT to fly in shorts - even when the air-on temperature is over 40C (100F)!!! Lizards tend to give more of a fright than snakes - they tend to be faster and able to hang upside down on just about any surface (especially the Geckos) - pre-flight check for lizards and snakes can avoid 'recovery from unusual attitudes' especially the attitude of your passenger should they see it! In fact one student refused to fly after seeing a snake in the plane - he was a little over-wrought for quite a while...
3. Grass seeds. Our grass seeds can puncture tires if you hit them wrong - at least the low pressure big tyres of the 701 seem to stand up quite well to the environment. But be careful, on take off without doors (or even through an air vent) a seed or two may just land on your trousers. work its way through the cloth and start to jab at your skin. Perhaps a seed got in through the side of your shoes as you walked to the plane - and starts to irritate your foot. These seeds can enter your skin like a needle - and they really do irritate. We learn to avoid them and to remove them early to avoid the excitement of the equivalent of a pin being stuck in your leg or foot as you flare to land!.
4. Bats. Bats love the CH701 and CH801 baggage compartments and - if they can get there, the rear fuselage. NEVER leave the inspection panel off overnight or you will get a face full of bats in the morning when you enter the hangar or workshop. We tape brown paper over at night if it is left off and try to fit a little motion detection alarm in the baggage area if no doors are on the aircraft or during build. The bats aren't a problem in themselves, cute little things that eat mosquitoes (helps to keep malaria down) - it is what they leave behind from their behinds... Bat droppings smell and nobody likes cleaning it up. It also stains the metal if a little loose... I am sure you understand...
5. Metal gnawing mice and flying ground squirrels. Yes, mice will gnaw though metal parts - and love electrical wire insulation. We have mice the size rats - remember our rats are the size of rabbits - they make Texan Rats look small (sorry Texas)) - if you don't believe me look up 'Grasscutter' on the web and see a real bush rat. Never leave food or drink in the cockpit - they will send out a team of metal chewing mice-y fiends to get into your plane. To give you an idea, we left a banana in the fridge overnight at the airfield. The next day the door to the briefing room looked as though it had been visited by the Tom and Jerry team and the magnetic strip was gone, the metal, plastic and insulation of the door gone - and a family installed themselves in the salad chilling compartment of the fridge - cheap air-conditioning!!! (remember there is no power when the gen-set is off at the airfield).
The day a ground squirrel tried to make its nest on board was also rather fun - I was right seat as the student taxied out to runway 19 - as I looked over to check the left wing control surfaces I saw this little squirrel sitting just above the students head. Immediate shutdown and a grab for the squirrel - I got the tail - which promptly detached (they do that) and I was left with a 2" fluffy tail as the offending mammal ran away from the area. Where he had been hiding is anybodies guess - or perhaps he had thought that he was a flying squirrel instead of a ground squirrel and wanted the lesson - who knows - but I am glad we got him away before the take off roll!!!
What is useful is that mice, squirrels, snakes and lizards as well as many insects do not like the smell of diesel oil (mind you nor do most non-engineering humans) - so a small channel around the hangar with diesel put in it a couple of times per season will reduce many of the challenges.
I could go on about the grasshoppers on the top of the instrument panel, moths, butterflies the size of small birds, tsetses flies hanging on the wing in flight (something to be amazed at), vultures attacking the aircraft in flight, and more - but I am sure that others have moments to share that we can all learn from - together, as we battle natures desire to challenge us for daring to fly!