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As we move into the colder part of the year, we begin to consider winter weather and its implications for aviation here at GoFly. Whilst it’s not all extra chores and precautions – the winter months offer some of the most spectacular and breathtakingly beautiful flying days – there are a few key extra points that all students and private hirers should be aware of. In the third of a four-part article series on winter aviation, we look at winter engine starts.

Part of the GoFly engine start checklist is to switch the engine master on, and allow the glow plugs to warm up to a sufficient temperature before engaging the starter motor. “Sufficient temperature” is indicated by the glow plug light; it should illuminate when the engine master is switched on (see photo above; the glow plug light is show illuminated top centre) and then go off when the glow plugs are warm enough.

The glow plugs aid diesel engine starting in cold weather; because a cold engine block will absorb the heat generated by cylinder compression, the fuel-air mix may not ignite & start the engine. The glow plugs provide a source of heat inside the engine, warming the fuel-air mix sufficiently to allow ignition.

If the weather is cold enough to warrant carrying out the ‘cold start’ engine checklist (and if you’re chilly by the time you’ve made it into the cockpit, it’s probably cold enough that you’ll need to) then the only change to the GoFly engine start procedure is to turn the engine master off, then on again, until the glow plug indicator light goes out – essentially re-heating the glow plugs again. This warms up the glow plugs more than the normal procedure, allowing a much better chance of a first time engine start.

If this procedure isn’t followed during cold weather, then it can be a lot harder or impossible for the engine to start. Because the engine is started using an electric starter motor, which is powered by the battery, multiple attempts to start will result in a severely drained or flat battery! We find this is not very conducive to going flying, as it necessitates a battery change (Our FADEC-controlled diesel engines must not be started using ground power).

The cold weather start procedure is outlined in the checklist and is relatively simple to follow. If you’re not sure whether or not it’s a cold weather start, the answer is “it probably is”. Please do follow the checklist and preserve the aircraft battery. The checklist is reproduced here;


As for normal start but perform Engine Master Switch ON /OFF twice to ensure glow plug heating is maximal. Repeat as necessary.

 Do not run starter motor continuously for more than 10 secs

Wait 20 seconds before further attempt.

 If no start after several attempts leave for 30 minutes.

Do not flatten the battery.

 Starting with an external power source is not permitted.


Happy winter aviating!

Ben Koprowski, FI