How often do we see the starter motor limits exceeded during a hot start, resulting in no start?
Chances are most don’t give the starter limitations* a second thought, especially when there are others watching and the pilot’s pride is on the line! Ignoring the limitations could well result in a premature replacement of the engine starter.
Until aviation catches up and we have Full Authority Digital Engine Control (FADEC) with electronic ignition, hot starts will always be problematic in typical fuel injected aircraft.
Ok, so you’ve had your $100 hamburger, refuelled, and the aircraft has been parked in the hot sun – it’s time for the acid test. Did I mention you are in a Cirrus, and of course everyone is watching?
This technique will reliably produce a hot start on the first attempt in a SR aircraft.
1. Mixture … FULL RICH
2. Power Lever … CLOSED
3. Fuel Pump … BOOST
4. Starter … ENGAGE
5. Power Lever … SLOWLY MOVE FORWARD
The engine will start, run for a bit, then die!
When it dies immediately move the power lever FULL FORWARD.
The engine will fire again whereupon the power lever must be moved quickly towards the IDLE position to keep the RPM around 1000.
Keep the fuel pump on BOOST for up to a minute if the ambient temperature is high.
Some SR22 aircraft are fitted with a lightweight composite propeller which means the engine will accelerate very quickly when it starts, even during a cold start. It is not uncommon to see the RPM climb from zero to 1500 RPM in seconds. On gravel or loose seal the propeller can be very easily be damaged, and in any case it is not very sympathetic to a cold engine.
I also prefer starting a cold (primed) engine from idle, gradually moving the power lever forward while cranking, and then initially maintaining 800 to 900 RPM. As the engine warms the engine will soon enough settle at 1000 RPM. Of course this is the same technique as the hot start except for the bit when the engine dies.
If you find yourself unable to start a hot engine that has been over primed follow the procedure in the POH under Starting Engine.
• Turn fuel pump off.
• Allow fuel to drain from intake tubes.
• Set the mixture control full lean and the power lever full open.
• Crank the engine through several revolutions with the starter.
• When engine starts, release ignition switch, retard power lever,
and slowly advance the mixture control to FULL RICH position.
I should probably add the words ‘good luck’ at this point. Hot starts are never fun but they shouldn’t be a problem.
SR20/22 G3/G5: Limit cranking to intervals of 20 seconds with a 20 second
cooling period between cranks.
SR22T: During start, limit cranking to intervals of 10 seconds with a 20
second cooling period between cranks. This will improve
battery and contactor life.
(Charles Gunter is a Cirrus Standardised Instructor Pilot with over 13,000 flying hours and is the CEO of Cirrus Melbourne and Avia Aviation)