Proper Shutdown procedure

[Daddy O]

When I shut down, after setting the parking brake, I run the engine up to 1200 rpm for a few seconds then back to idle. Once the RPMs get down to idle, cut the mixture and let the engine exhaust the remaider of the fuel in the system. After that shut down the magnetos, then the remainder of the shutdown list.

Is this correct? Xplane does not render backfires if you do it wrong (like cutting mixture @ 1200 rpm) Or has the process changed? Assuming a piston engined craft.

[julio.elizalde]

Every aircraft has a different shut down and secure procedure. Check with a real world checklist.

[Daddy O]

Not really. The aspect i am talking about is the fuel cutoff process. As i said, do it wrong n you can blow off the exhaust manifold. I made a c152 aerobat backfire once (with the owner nearby) .

Just seemed like a topic for the super realists to discuss.

[Keith Smith]

You have right idea, most pistons are shutdown by pulling the mixture. However, it's still possible to shutdown incorrectly even beyond that step. There isn't any mystery, style or technique to it though...it really is just a matter of following the documented procedure for that aircraft.

The only thing I'll add is that I recently found a great article about alternators by someone who appeared to know a ton about it. Since reading that, I've altered my shutdown procedure to include killing the alternator PRIOR to killing the engine. So, now it's avionics, alternator, mixture, mags, master, in that order. That's one of those cases where I'll take field-level expertise on board and modify the checklist.

[Aleks. L.]

It's also a good idea to check the grounding on the magnetos.

[Daddy O]

"avionics, alternator, mixture, mags, master" Just the answer I was looking for.

In your plane do you still run it up to 1700rpm then back to idle before pulling the mixture?

[Keith Smith]

No, just 1000rpm, then pull mixture, but if you were taught something else then pay no attention to me.

[Orest Skrypuch]

... The only thing I'll add is that I recently found a great article about alternators by someone who appeared to know a ton about it.

Do you have a link?

I normally startup with alternator OFF to avoid the extra draw into the field circuit and to avoid the power surge when the engine catches, but have not cycled it OFF before shutdown.

* Orest

[Keith Smith]

Orest,

http://www.nflite.com/ChargingSystem.html (it's pretty long, but there's some great material, particularly just before the trouble tips).

As I read it again, there's minimal value in the shutdown procedure that I described (killing alternator prior to engine shutdown). However, I visualize it as a layering of systems, and still find it to 'tear it down' in the reverse order that I started it up).

It does appear to be better for the battery to have the alternator off prior to engine shutdown, though...to avoid the jump in draw that will occur once the engine shuts down as the voltage regulator tries desperately to pull up to 13.8 volts That's the symptom that he describes while running with master and alternator on with engine off prior to startup (which should be avoided for prolonged periods)

[Orest Skrypuch]

Thanks, I will enjoy reading it.

* Orest