Monday, September 17, 2012

September 17th, 2012

Fresh Air Matters... with Capt. Yaw

In aviation there is no room for ‘cheating the system’. Those who try to make savings ‘here and there’, generally lose a lot more than money. It is not just ‘trimming the edges’ on finances that lead to disaster, but also trimming the edges in build, maintenance and operation – a failure to follow procedures. Travelling around the world, I am often amazed at how many aircraft are out there, flying without the care and attention that they deserve – yet, overall, the world’s flying machines are built, maintained and operated at standards above the rest of the transport sector… which says a lot about the rest!

One of the first things I look for at a maintenance facility is an ‘oil filter cutter’ – and one that is used. The oil filter cutter is an essential maintenance tool when working with any engine with an oil filter. When the oil filter is removed it is can be cut open with a special ‘chip-less cutter’ and then the filter-mat inspected. Time, and time again, I come across engines that are ‘maintained and monitored’ without this tool. What is it that we are looking for when we inspect that filter medium? We are looking for ‘clusters’ and ‘lumps’. It is a sort of ‘blood test’ for the engine. If there is any contamination in the engine, or something is beginning to breakdown in the engine, the evidence will make its way to the oil filter and stay there. Let us imagine that a camshaft cam-lobe gets chipped, the debris will would probably leave a dark, metallic, lump on the filter medium. What if a gear-tooth is wearing rapidly? Well, that may result in a little smattering of shiny metal chip clusters. What does it all mean? It means that we can see a potential mechanical problem BEFORE it becomes a mechanical failure – and can act appropriately. This sort of test could be done on maritime and automotive engines too! Aircraft tend to have another ‘metal wear’ inspection system through a little magnetic plug that collects magnetic materials as they wash past it along the oil ‘veins’ of the machine. As you move up the aircraft engines there may be a ‘chip-detector’ that issues an alarm when a metal chip above a certain size is detected. Do note that it is perfectly normal for small amounts of little filings of metal to collect on the magnetic plug, and also in the filter medium – it is experience that enables us to know when it is ‘needing further investigation’. Experience is built by ‘doing’ – and that means, in aviation, that you expect to inspect thousands of ‘acceptable’ filters in order to spot the very rare ‘unacceptable’ one! Larger aircraft and mining machines often send oil samples for ‘content testing’, where the amount of different elements and compounds can provide insight to material wear inside the engine.

The cost of the time served, and incredibly reliable, manual oil filter cutter is less than $100. The potential saving of major expenses, potential mechanical failure avoidance and peace of mind is many-many-fold the cost of this simple ‘inspection’ tool. Of course, you need to know how to us it too!

Lydia Wetsi, the Ghanaian disabled student pilot/trainee light aircraft engineer, is one of the best ‘oil filter inspectors’ I have ever come across. Even with her disabled arm, she can cut open the oil filter, remove the filter mat and inspect it in a matter of minutes – as well as anybody I have ever come across. I am proud to have that skill in our workshops! (If you would like a demonstration, drop me a line and we may be able to arrange a visit during the next service, or post a you-tube video!)

It is not just maintenance that matters, but also operation. In the operation of an aircraft, we have speeds to respect. We have maximum speeds and minimum speeds. If we fly beyond the maximum speed, the structure of the aircraft may become compromised, as may the reliability of the controls. Each year there are accidents where pilots have exceeded that maximum speed, and paid the price with their lives. Likewise, we have a minimum speed, the stall speed. Nothing to do with the engine stopping, but rather the wing stopping working, i.e., no longer giving lift. The stall speed changes with wing configuration (flaps, slats, etc.), angle of bank and other loading factors. Consequently, the pilot must be very conversant with the speeds, and moreover be ready to ‘feel’ the plane, respond accordingly and preferably stay well within the safe zone. As the plane approaches the stall speed it becomes more challenging to control, with the controls becoming less responsive and possibly one or both wings starting to ‘drop’. All the same, each year people lose their lives from failing to respect the speed requirements of their aircraft.

We have a simple, albeit tongue-in-cheek, formula for operational survival when flying: All you need is TWO out of THREE essential ingredients: SPEED, ALTITUDE, BRAINS.

If you have a SPEED between the minimum and maximum permitted speed and lots of ALTITUDE you have a good chance of survival – it is hard to get it wrong, unless you really try! In fact, we often say ‘we can teach anybody to fly in one hour’ – that is to fly, at a mid-range speed, in calm air, well away from hard objects and controlled airspace! It is not difficult to fly, but it is much more difficult to fly well! Take-offs and landings take even more skills!

If you have plenty of ALTITUDE and the SPEED decays below the stall speed, you will start to lose altitude quite rapidly, and if you are not careful lose control – that is where BRAINS come in. You can ‘spend’ altitude to gain speed, if you know what you are doing – if you don’t… well it may well end in a mess!

The most dangerous configuration is not having much ALTITUDE, that is flying close to the ground – normally, obligatorily, during take-off and landing. At that point, if your SPEED decays into the ‘danger zone’, you need to have lightning fast reactions and a quick working, informed, trained and efficient BRAIN to get the aircraft back under control.

The rules are the rules – break them and you MAY get away with it… however, at some point it bites and something gives – sometimes your life.

This is also applicable on the roads and on the water – respect the speeds, the distance between vehicles (only a fool breaks the two second rule…, etc.), shipping lanes, manoeuvring protocols, sufficient and appropriate power-plants, etc. Failure to do so will not cost you every time, but when it does, it costs you big time – and often it is the innocent that pay the price for your lack of attention to the necessary details.

Fly, drive and sail safely – and remember the rules of build, maintenance and operations are there for a reason – break them at your own risk.

Capt. Yaw is Chief Flying Instructor and Chief Engineer at WAASPS, and lead Pilot with Medicine on the Move, Humanitarian Aviation Logistics ( e-mail

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