38 - Dodgy Motor?

  • Safety Articles

Human beings are not designed to fly. More importantly for us pilots, our brains are only capable of coping with speeds of around 10 kph (5 knots), with occasional short bursts of up to 30 kph (15 knots). In other words, not surprisingly, our brains cannot go any faster than our bodies. We cannot do anything about this. It is not possible to make the electrons in your head move any quicker than they already do.

So how is it that we can adapt to driving cars at up to 100 kph (50 knots) and flying our aircraft at up to 400 kph (200 knots)? There are of course several answers to this, among them that in cars we very carefully regulate the environment, and moderate our speed accordingly. Driving along a twisting road through a crowded housing complex at 100 kph is very nearly impossible, even to the quickest-thinking youngster.

With aeroplanes, we try to keep our faster periods in the air simple. The cruise segment of most flights is not usually too taxing. The hard work comes when we are slower, but still going faster than our brains can work, and near the ground.

Manufacturers try to ensure their aeroplanes (Pipers, Cessnas, Grobs, Diamonds and the like) are as simple to operate as possible, with comfortably slow landing speeds. But even then, some pilots (particularly the less experienced or those in less than regular practice) find these demanding.

More sophisticated aeroplanes and homebuilts are usually faster on the approach and climb-out, and often far from easy or ergonomic to operate.

The best way our slow-moving brains can cope with this is by training ourselves to think well ahead - all the time.

We should not just think ahead while in the air. For effective foresight, we need to practise this throughout our daily lives, because it does not come naturally.

Only by anticipating problems, and by already having mentally considered and devised sensible solutions, can we deal with emergencies at a critical stage of flight, like during the approach and landing, or soon after take-off.

Another strategy we use in flying to help us stay ahead of our aeroplane is to ensure our aircraft is completely serviceable before departure. To do this we ensure it is properly maintained to a carefully considered schedule.

Then we thoroughly pre-flight check it.

Before arriving at the airfield we will have planned our flight, and thought about what we are going to do if various possible problems occur. We will have regularly practiced engine failures (particularly soon after take-off) and gliding approaches.

Then, after taxying out, we make a comprehensive engine check.

Next we do our pre-take-off check.

Immediately before lining up on the runway, we have a very good look all around the circuit, we consider the weather and wind direction, and we pause for a careful think about what we shall do and where we shall go when the engine stops.

Finally, after opening the throttle, we take a quick glance at the tachometer, to ensure our engine is developing full power.

This pre-flight preparation is all about thinking ahead - and it all helps our slow-moving brains to deal with any problems that might occur, particularly in the more difficult and fast-moving phases of flight, like immediately after take-off.

The whole point of all this rigmarole is to minimise the possibility of having to deal with an engine failure after take-off, because our minds just cannot work quickly enough to cope with it. The best we can hope for is for our brain to revert smartly to a thoroughly practiced and very recently mentally rehearsed series of actions which just might result in an outcome which is a little less than fatal.

So, if there is the slightest suggestion that our engine, or any other part of the airframe, is not working properly, we carefully taxi back to the hangar and get it fixed, however keen we are to fly, and whatever the external pressures.

So why on God's good Earth do members of this club repeatedly insist on taking off with aeroplanes whose engines are not working properly?

In the past year, three of our members' aeroplanes (and possibly more, I don't get to hear about everything) have been seriously damaged after taking off when the pilot knew or suspected there was something wrong with his engine. One member was rich enough to get his aeroplane fixed pretty quickly. The others will take years to repair. It was only by extreme good fortune that none of these blokes (I hesitate to call such poor airmen 'pilots') was killed.

In the past twelve months, I have also witnessed two aeroplanes repeatedly staggering around Serpentine with what was clearly a serious power shortfall. One might expect a pilot to be surprised once by his new aeroplane's lack of performance, but when it's identified, he should be certain he's fixed the problem before flying again.

A while ago, one of our members kept having his engine stop, or its power significantly reduce, after departure. Sometimes this would be immediately after take-off, sometimes it would not be until several minutes later. Sometimes the engine would actually keep going all through the flight, only to fail on the next one. This went on for months, and people kept trying to encourage him to fix it, but he didn't want to spend the money on a proper investigation.

What do you think happened?

Yes, the engine's power eventually reduced to below a level at which it would keep the aeroplane in the air. Very luckily, nobody was seriously hurt in the ensuing crash, although the aeroplane was a total write off. That cost us all a lot of money.

If he got $100,000 dollars from the insurers for his aeroplane, 100 of us other policy-holders each had to provide $1,000 dollars from our premiums. Actually it would have been more than that, because we had to cover the company's costs, wages and profits, too. How do you feel about that?

Please, please, please, the next time you even suspect that there might be something wrong with your engine, its ignition, fuel system or any ancillary component, don't open that throttle.

It doesn't matter if you're taking your new love for the first flight of her life, or whether you've promised all your family you'll fly to that Diamond Wedding Anniversary, or if you're at an airshow and a huge crowd is expecting you to perform, or even if you're flying a donor heart to a dying transplant patient. If your engine shows the slightest abnormal symptoms, turn around, taxi back to your hangar, and get it fixed.

These symptoms might include, but are not limited to: an unusual reluctance to start (fuel, ignition or carburettor problems), rough running immediately after starting from cold, but which soon clears up (a sticky valve), a slightly bigger than usual mag drop (dodgy plug, dodgy HT lead, dodgy mag), or even, as one member had, but ignored, a complete lack of ignition with one mag switched off (dead magneto, but hey, who cares, I've got another one), a drop in rpm, followed by a greater increase when you check the carby heat (ice!), a slight hesitation on opening the throttle (blocked carby jet, vapour lock, carby ice, or any number of other things), less than the usual take-off rpm (I don't know, neither do you, but it's certainly very serious).

If any of these symptoms occurs, or if anything unusual at all happens during the take-off roll, may I respectfully suggest you close the throttle, stop, clear the runway, and go investigate the problem until you are CERTAIN you've solved it.

After all, stopping on take-off is no problem at all, because you practice that at least once a month, don't you?

You don't?

I do.

I also regularly practice engine failures after take-off and glide approaches to land. So do Graham Hewitt, Bob Kingsbury, John Chesbrough and Stewart Maddigan. I haven't noticed anybody else doing it, but maybe I'm unobservant.

If you haven't done one of these for a while, why not go and do a few with an instructor? There are plenty of instructors happy to fly with you for half-an-hour, and that cost is small compared with an aircraft repair.

Please, please, please do not try to fly with a dodgy engine.

I'm fed up with going to unnecessary funerals.

Bob "Bob the Grim" Grimstead
SABC Safety