Correct Lycoming / Continental engine shutdown procedure (non electrical considerations)

Graham wrote:

Magnetos = check dead cut

That is actually great! It’s on my checklist but had not seen it on an OEM POH before…which aircraft type is it?

I just do it to ensure the mags are actually grounded for subsequent turning the prop for the towbar or maintenance or anyone getting close to the prop on the ground.

IN any case I recently switched to turning the prop backwards to avoid impulse coupling firing.

In general I preferred forwards and that is what I taught for oil scavenging purposes. A friend of mine used to pull the prop through backwards in his Stearman with radial engine, which did not help the smoke clouds on startup (and a bent pushrod on one historical occasion). Switching to forward pulling basically eliminated the problem.

I do not think he ever leaned on the ground and never had an issue, btw.

Peter wrote:

this is not a trivial topic given the wide spectrum of customer abilities in the PPL intake

Yup. I would agree it would be against the interests of GA to filter out the worse 80% of PPL candidates or even 20% , for that matter.

However, do we really need to do that in order to teach basic mixture use while avoiding students from landing themselves on pastures around airfields from lean cuts or, perhaps more likely, damaging cylinders prematurely due to lack of understanding?

I guess the point is this cannot be taught very early in the PPL experience and hence aircraft used for such part of the syllabus are going to suffer constantly rich mixtures, so what’s proposed is simply a way to lower maintenance costs and improve reliability at the expense of some ramp noise…I guess it could be an acceptable trade-off.

I think, however, we should think things over and ensure those getting their PPL’s progress way beyond that into the procedures we are advocating here, ideally before the end of their PPL syllabus. I guess in practice this is not possible for all, but then we should keep on encouraging post-PPL progression as we do here.

Peter wrote:

wide spectrum of customer abilities in the PPL intake

Edited to add that I firmly believe you do not need to be a rocket scientist to be a good pilot (even if sometimes we like to think otherwise).
80% of the times, the ability is there, or is made up for, if you have the right learning attitude.
There was another thread about being humble, having the right attitude and the rest…perhaps we should start making attitude an important part of the syllabus before our flying experience makes us learn the very hard way…
…or perhaps doing that is the equivalent of filtering out the worst 50% in today’s world?

Graham wrote:

You don’t need instrumentation or detailed understanding to do that.

I would agree with the former but not with the later. You really should have clear understanding of what the mixture does, with respect to how you intend to use it. Half way or an inch or so is not satisfactory. On first solo you should have a clear understanding about how each flight control and safety critical items works, sufficient for the task. The question is when you should leaning be introduced into the syllabus.

Peter wrote:

If I was running a school I would install an EDM700 in every plane and go for the ~30% fuel saving

We were told never to fly straight and level for more than 30 seconds in the training area…

“Lights, camera, action” is something I remember from initial pilot training flights, “action” being to enrichen the mixture after receiving takeoff clearance. It didn’t seem complicated at that point to lean the mixture for taxi and then do the reverse for takeoff. I can’t see the issue.

Learning to fly can be somewhat overwhelming for some people.
There’s a massive amount to learn to get you going in the begining.
Some may be very sharp quick learners, well read on general topics etc,
and some may love to learn but take much longer and even take a while to be comfortable being airborne.
I learned to lean from day 1 but kind of in ‘reverse’
We were at 6000ft elevation. If we didn’t lean for max power the poor little 152’s and 172’s would run out of runway. But on the ground we were mostly rich.
I was pretty unhappy at touching the mixture while airborne during my training and for a while after gaining my PPL.
I think there should be an element In the theory requirements and some training in the syllabus somewhere.
Currently perhaps Instructors should be encouraged to include it as soon as a student has capacity to learn to embrace it and do it safely.
For many, the first real introduction to comprehensive leaning techniques and understanding, is during a transition onto higher HP aircraft and or when learning how to best look after their own pride and joy.

Leaning the mixture below 3,000’ was forbidden, and I don’t think I ever leaned, in getting a UK PPL, and then re-doing most of the course in 1986 after letting it lapse.
Four months after passing the second GFT, I was in the US, renting. I learned leaning. Especially in Colorado, in July, with the runway at 4,800’, and the density altitude much higher.

There are quite a few good points made above but a lot are optimised for people’s own operations and come along with dangers for others with most above not based on the operating the O-235 an engine so good production of lead fouling that Champion built a special spark plug to combat these problems.

The reason we are not over keen on people taxing with mixture lean was pointed out by Bathman , if they do get airborne with the mixture only just rich enough to do so there is a good chance that it will cost £20k in engine repairs and down time. There is also the Issue of keeping their eyes out of the cockpit especially in the early hours of flying to build good habits.

We do teach use of the mixture control but only once the student has the capacity for this to be added and get things done correctly, this usually happens at about thirty hours into he sylibus. We don’t want overloaded pilots mis-setting the mixture.

Using the Lycomng shut down process saves £4/hour on maintenance costs while keeping very low time pilots focused on safety issues.

The bottom line is if the perfect world solution championed by some above is not going to work with the very variable quality of student pilots and if I tried the perfect world solution it would cost me £4/hour and at least one trashed engine a year.

So basicly with the economics of GA being as tight as they are the perfect world solution would result in me packing the whole thing in and I would guess that with expert good advice like I’ve seen above most of training industry would reflect my experience. The professional flight training would move on to Fadec controlled diesel power and the flying club as you know it would be gone forever taking recreational aviation along with it.

It all well and good that internet experts tell us what should happen but they don’t have to live with the reality of day to day operation with very inexperienced pilots and the safety/ economic realities that this entails.

Operating rich and the lycomng shutdown works for my training operation and I will continue with what works in the real world, ………………….I do have my own personal aircraft and the operation of that is an entirely different story.

A_and_C wrote:

most above not based on the operating the O-235 an engine so good production of lead fouling that Champion built a special spark plug to combat these problems

I think US students are introduced to leaning on the ground from the first or maybe second training flight because a lot of the planes are 0-235 powered and ‘everybody’ understands these are prone to plug fouling. The other reason is density altitude, and leaning for cruise is subsequently taught for student cross countries – years ago my first solo cross country had me up to about 7,500 ft, probably 9,000 DA. None of this seems like a big deal to me. We leaned by feel/roughness and that works OK for an O-235 in an adequately cooled training plane.

The (U) REM37BY plugs are pretty good in preventing the plug fouling issue, at least they’re good on my (less affected) O-320.

Just one little data point on the reality of GA training in the UK.
The following video shoes a three hour training flight at the end of this chap’s CPL training. They are happily flying along for hours at 4000 feet, on a reduced cruise power setting, yet with the mixture full forward, thus burning 12.5+ GPH. Great, no? Better unfoul your plugs before shutting down…

But they do hours of mental NDB tracking exercises (with both GPS and VOR/DME on board) and even draw lines on a chart using pencel and ruler, whilst not flying on autopilot…