Mag Checks

[dutchroll]

There seems to be a train of thought from some RAAus circles that actually shutting the engine off is good training because it will prepare you better (presumably for the "sound of silence") if it really happens.

 

I totally disagree with this.

 

The single biggest shock, I believe (from experience), when you have an emergency of any type is when you are the one who is responsible and who has to do something. When an instructor is sitting next to you, there's always that thing in the back of your mind: "oh well he can take over if we really get in trouble". It's the same type of psychology at play when, for example, you first do solo stalling or spinning. Nagging away is this thought of "well it's all up to me to get out of it now - no-one to help me, so I better remember the procedures".

 

I think people are way over-estimating how much the style of training which is the topic of this thread will prepare you. The issue is how you're going to deal with it when you're on your own and have no-one to turn to for advice or who can take control. That's the single biggest psychological hurdle, not whether the engine is stopped or turning.

 

No one actually knows how they will behave in an emergency.

That is absolutely true. So training should not be focused on trying to modify a "possible" (but relatively unpredictable) behaviour, but on drilling in the right techniques and procedures which the pilot can turn to in order to survive when he's on his lonesome and it goes wrong. Because when the crap hits the fan, it's generally true that pilots will revert to whatever procedures have most thoroughly stuck in their mind from training.

 

 

[KRviator]

If an instructor ever turned off the ignition (note, NOT magnetos) during a BFR in my RV he would be sporting a bloody and probably broken nose once we landed.

 

Not every engine has magnetos, not every engine will restart when you advance the mixture - and that is assuming the student completes the activity correctly to actually get to that point without having fluffed something along the way.

 

The PMags I installed in the -9 have an internal alternator that doesn't require ships power above approximately 900RPM, however below that speed they require an external electrical source. The Sensenich prop likewise will probably stop somewhere around best glide speed, especially with a high-compression engine (one day I'll actually test it overhead somewhere suitable). The Rotec TBI manual contains a caution that if you lean-cut the engine, it won't restart by simply readvancing the mixture. Put that together and if you fall short, or overshoot and you have an issue with the starter, or its contactor (happens often enough that it would form part of a risk assessment for the activity) and you will be having a very bad day, very quickly.

 

There is no excuse for shutting down a perfectly good engine in the name of "training". Not at our level, anyway. Far too many pilots have died during training as compared to the real thing.

 

 

[rage83]

if your short final and the mags or mixture is cut what is your option? LAND THE PLANE at short final you should be able to make the field with or without an engine.

 

if you are to have a real engine issue be it mag or otherewise its not going to wait untill you have sufficent height. Engine failures happen at any and all times during flight.

 

Thats why you are trained to deal with it. I kind of disagree with the posts here about being less than impressed. I would rather have it happen when i have an instructor on board the first time to at least be a back up in the event i can't bring it down safely.

 

At what point in the takeoff roll do you practice an engine failure after takeoff?

 

Engine failures at altitude are easy because you have time but that doesen't test you when it counts. The only way to test some one is in a real situation and if an engine fails just after lift off and you cant recover it because you havent been shown it then your in trouble. If the engine fails short final and you havent done it before your in trouble.

 

The reason you have to spend more time and money to learn to fly a plane is because it is a complex process. Emergency procedures are part of that process and emergencies can happen at any time. I for one would prefer to have experienced it under simulated conditions with an experienced instructor beside me then having family or friends sitting beside me and not being full over the best way to get the aircraft down safely.

 

 

[Teckair]

I kind of disagree with the posts here about being less than impressed. I would rather have it happen when i have an instructor on board the first time to at least be a back up in the event i can't bring it down safely.

And what about all the reasons given as to why it is a bad idea do you disagree with them to? Don't have blind faith in the instructor it could still go wrong. With a dead engine the instructor might have trouble getting you both out of trouble.

 

 

[01rmb]

All the discussion disregards all the things that can go wrong on final that requires power for a go around. I have aborted landings and done a go around to avoid birds, kangaroos, a glider that took longer than expected to clear the runway as well as a preceding aircraft that had run off the runway. Why kill the power completely and remove safe options to avoid much more serious consequences? Flying has enough risks - no need to unnecessarily make it more hazardous when simply pulling the power back pretty well does the same thing.

 

 

[rage83]

And what about all the reasons given as to why it is a bad idea do you disagree with them to? Don't have blind faith in the instructor it could still go wrong. With a dead engine the instructor might have trouble getting you both out of trouble.

Its not about blind faith. Do they let you jump in an aircraft on your own without training? My reasoning is based on myself liking to have been showed how to do something correctly, then being tested. Yes it increases risk however that is why i prefer to do it when i have someone else in an aircraft for the first time. I would rather know that i can handle it and how to handle it than just having someone say aw yeah by the way if the engine stops short final just land it. Most people i know and fly with would prefer me to have been trained in a particular event as apposed to purely winging it when it happens. Cutting mags is probably overkill but it drives home the reason why you need to be able to fly a plane well without an engine. When you are in a situation when the engine stops for real you want to know you can get it the first time because there is no engine so you cant say oh well you butchered that so lets go around and try agin.

 

All the discussion disregards all the things that can go wrong on final that requires power for a go around. I have aborted landings and done a go around to avoid birds, kangaroos, a glider that took longer than expected to clear the runway as well as a preceding aircraft that had run off the runway. Why kill the power completely and remove safe options to avoid much more serious consequences? Flying has enough risks - no need to unnecessarily make it more hazardous when simply pulling the power back pretty well does the same thing.

As for aborting landings yes there are times when you need to abort but that is where the threat and error management of the instructor will need to come into play to decide if it is appropriate. I'm pretty confident there is going to be no instructor on the planet that is going to switch mags off if there are birds or other aircraft on the runway.

 

 

[anjum_jabiru]

Thanks for contributing your posts. On the same note what would would you do if you were flying at say at 2000 feet AGL and your engine became too hot at cruise speed. Would you rather put the nose down and allow the speed to build up into the yellow arc (thus stressing the airframe), allowing more air over the engine to cool the engine down, or would you rather reduce the power and raise the nose to maintain altitude but sacrifice your speed a little (still remaining in the green arc)? It seems like a catch 22 to me.

 

- My instructor has suggested that I lower the nose to improve airflow over the engine, in the Jabura LSA that I fly. But that would mean increasing the engine power to maintain altitude, which would in turn generate more heat. Sorry if I sound confusing. The choice is between raising the nose and decreasing power vs lowering the nose and increasing power. Have your pick.

 

- On the contrary if the engine is running cold, I believe pulling the carb heat out would solve the problem with icing as directed by my flight instructor.

 

 

[rage83]

Thanks for contributing your posts. On the same note what would would you do if you were flying at say 3000 feet and your engine became too hot at cruise speed. Would you rather put the nose down and allow the speed to build up into the yellow arc (thus stressing the airframe), allowing more air over the engine to cool the engine down, or would you rather reduce the power and raise the nose to maintain altitude but sacrifice your speed a little (still remaining in the green arc)? It seems like a catch 22 to me.- My instructor has suggested that I lower the nose to improve airflow over the engine, in the Jabura LSA that I fly. But that would mean increasing the engine power to maintain altitude, which would in turn generate more heat. Sorry if I sound confusing. The choice is between raising the nose and decreasing power vs lowering the nose and increasing power. Have your pick.

 

- On the contrary if the engine is running cold, I believe pulling the carb heat out would solve the problem with icing as directed by my flight instructor.

Flying a plane at a speed into the yellow arc will NOT stress the airframe. Flying above Turbulent air Penetration Speed in turbulent conditiions will stress the airframe. Aircraft often descend at speeds within the yellow arc in the right conditions.

Your instructor is right lowering the nose increasing airflow may assist in cooling. However i would be reducing power as well and increasing airspeed obviously height permitting. If my temperature is getting close to or above the upper temp limit i would attempt to cool in then look at cutting flight short landing at nearest suitable. Just remember unless its turbulent you can fly a plane right up to Vne without damage.

 

 

[anjum_jabiru]

It is generally pretty bumpy where I fly most of the time. Hence I tend not to go above the cruise speed which is about 90 knots in a Jab LSA (upper limit of green arc). Field Elevation is about 1000' and I fly at around 2500' - 3000'. Since the minimum height should be 1000' AGL and if I am flying at 2500' (ie 1500' AGL), it leaves me with only 500'at my disposal in which I need to cool the engine down without losing any more altitude. The aim is to keep the cylinder head temperature between 100 - 150 'C...

 

And then what? Climb back up to 1500' AGL?!

 

 

[rage83]

if engine temp isnt coming down then you have a problem its that simple find the nearest suitable spot to land.

 

 

[Fishla]

at cruise power and attitude you shouldn't be overheating.

 

Are you flying your own aircraft or the school's?

 

 

[anjum_jabiru]

It is the school's aircraft. The cylinder head temps are touching the 150 mark just after a climb to 1000' AGL, and hover just under that mark for a while. I guess I am a bit over cautious (or you may call me obsessive) and would like the needle to point exactly in between the 100 - 150 mark, hence I try and get it there whenever possible. It does not overheat but I don't like the idea of the needle hovering just under the 150 mark for a long time in cruise flight.

 

 

[Fishla]

Tell the school. Perhaps the cooling duct needs a look.

 

But to answer your question, to cool an engine you lower the nose.

 

Don't close the throttle, fly slower and hold the nose up to maintain altitude.

 

 

[facthunter]

Overheating when you can increase the speed to assist, usually relates to climbing. If you are overheating in level flight where you have much more airspeed and usually 1/4 less power in cruise means you have a problem. You certainly wouldn't be able to climb in those circumstances. the plane would be U/S really, so land soon and rectify it. I take as much notice of the rate of temp increase as the actual temp. If it's rapidly rising to a higher temp limit and looks as if it will overshoot don't wait till it gets there. Take corrective action .Nev

 

 

[biggles]

It is the school's aircraft. The cylinder head temps are touching the 150 mark just after a climb to 1000' AGL, and hover just under that mark for a while. I guess I am a bit over cautious (or you may call me obsessive) and would like the needle to point exactly in between the 100 - 150 mark, hence I try and get it there whenever possible. It does not overheat but I don't like the idea of the needle hovering just under the 150 mark for a long time in cruise flight.

What engine temp monitors do you have and which cylinders are the hottest, also what fuel are you using and its flow during climb-out if known ? ..... Bob

 

 

[Romeo Juliet Whiskey]

Roscoe & Happy Flyer - Yes, there seems to be not much point in posting these issues here or bouncing of ideas and getting the opinions of other people. Just to let you know that opinions of different people tend to differ on the same issues. I wonder if you have heard anything about group discussions and brain storming. 1 to 1 teaching may or may not be the best form of learning strategy as one is limited to the opinion of a single person rather than sharing ideas and experiences of other people who may have been involved in a similar situation.I adore my CFI as he is a lovely person, experienced pilot and an excellent teacher. If my CFI shuts the engine off to check the student's reaction in a controlled environment and see if they can bring it down safely then I believe this is the best form of training.

I also enjoy your posts mate. I also like to get different opinions from other people, such as those here from this forum... not just from my instructor. Best way to learn IMO.

 

 

[myshed2]

Why is everyone missing the point here?

 

Anjun asked a simple question about the engine of his aeroplane and people leap in with opinions that have nothing to do with his question.

 

The question was, "will turning off both maggies cause damage to one or both of them?" There was no mention of the legalities or otherwise of the instructors actions.

 

How can this question prompt a response like, " Anjun you appear to have a poor response to aircraft systems".

 

These forums are to help pilots of all levels of experience to be better pilots.

 

If you don't want to help but just want to show how clever you are, go on "who wants to be a millionaire".

 

 

[anjum_jabiru]

Hi Biggles, I am not very sure. I will find out next time and let you know buddy :)

 

 

[facthunter]

Shutting the mags by earthing some part of the (usually ) primary circuit won't damage anything. The switch itself may become faulty at any time like anything mechanical.

 

If the engine is very hot there could be some running on from hot parts like the exhaust valve or a bit or incandescing carbon so shutting off the ignition only, may subject the engine to a few uncontrolled hard hits internally. It's a good thing to close the throttle as well to reduce the severity of this possibility, or eliminate it.. A restart in the air is like on the ground. Easier if the throttle set to idle rather than large throttle setting. Some carburetters won't have enough speed through the venturi to flow fuel if the throttle is well open. It relies on the idle system and the choke on a CD carb only works when the throttle is closed (or nearly so). Nev

 

 

[Dick Gower]

Engine restarts were in the PPL syllabus years ago. They were a hangover from the days where aircraft had no starters and have long since been discontinued. One of the problems was getting the prop to stop in the first place.

 

If the mags are off and the prop windmilling there is a risk of plug fouling from all of the fuel that is still passing through the engine without being ignited. Then there is carburetor icing to consider: it can still ice up while the mags are off but now there is no exhaust heat to melt it. This is why, if you must fail the engine, it is better done with the idle cut-off (if there is one!)

 

If, on the other hand, the prop has been stopped, icing or plug fouling won't happen but you are then at the mercy of the starter to get going again unless there is enough altitude to dive-start it.

 

Either way, the engine has also been rapidly cooled so restarting and going to full power is not a great idea either.

 

So these are the reasons I gave up teaching engine re-starts forty-something years ago.

 

Your question is really whether starting on one or both creates the situation described: it doesn't. Starting on one magneto (the impulse one) is only done to prevent kick-back from the (advanced) non-impulse magneto during start.

 

I hate to suggest finger trouble Anjum but it sounds awful likely.

 

 

[Teckair]

Why is everyone missing the point here?

Everybody is not missing the point read the posts again. People were rightly concerned about the dangerous practice of shutting down the the engine in flight.

 

The question was, "will turning off both maggies cause damage to one or both of them?"

That was not the question as silly as that would be, read it again. My understanding is Jabirus are not fitted with 'maggies'. Turning the engine off close to the ground has the potential to damage everything including both ignition systems the plane and the people in it.

 

 

[anjum_jabiru]

The question really is that - Is shutting off both mags at the same time on finals (with ROM around 1800) cause any damage to the magnetos? The reason for asking is that after doing a full stop landing and parking the aircraft, a few minutes later when wanting to go up again after a break, the right magneto seemed to be giving some problems. After starting the engine with both switches / magnetos on in the Jab LSA, I taxied to the holding area to perform the pre-take off checks. While doing a pre-take off check at 1800 RPM, on shutting "off" the left switch / magneto, the engine shut down completely, although the right magneto was switched to "on" position.

 

This sort of a thing has never happened before. On doing the checks a second time to make sure that I had done the checks correctly, the engine shut down again on switching "off" the left switch / magneto in the Jab LSA. I then restarted the engine leaving both magnetos on as usual and taxied back to the parking area. I told my instructor, who also maintains the aircraft himself about the problem. When he performed the checks, the mags seemed to be ok and the engine did not shut down. However as a precautionary measure he changed the right magneto on the aircraft as it had behaved inappropriately.

 

As Dick Gower rightly pointed out - "If the mags are off and the prop windmilling there is a risk of plug fouling from all of the fuel that is still passing through the engine without being ignited." [Thanks Dick for your contribution. I see that you don't post often but when you do, it makes a lot of sense!]

 

In that case I am wondering if the magnetos were actually ok but it was plug fouling of the spark plugs supplied by the right magneto which actually led to the problems. And once I taxied back to the starting point, the plug fouling might have cleared up, as any excess fuel might have got burnt up, hence the problem was never repeated!

 

 

[Teckair]

The question really is that - Is shutting off both mags at the same time on finals (with ROM around 1800) cause any damage to the magnetos?

I don't think so but you would be best to check with Jabiru.

 

As Dick Gower rightly pointed out - "If the mags are off and the prop windmilling there is a risk of plug fouling from all of the fuel that is still passing through the engine without being ignited." [Thanks Dick for your contribution. I see that you don't post often but when you do, it makes a lot of sense!]

That does not sound right to me plugs usually get fouled with carbon or oil I highly doubt that was your problem. It sounds like the right ignition system had a intermittent fault.

 

 

[anjum_jabiru]

I was thinking in terms of an overflow. I had similar problems from a motor bike and the engine would not start. But when the excess fuel evaporated it was good to go. (As you can see, I am not a mechanical engineer.)

 

 

[Teckair]

I was thinking in terms of an overflow. I had similar problems from a motor bike and the engine would not start. But when the excess fuel evaporated it was good to go. (As you can see, I am not a mechanical engineer.)

The motor bike sounds like it was flooded but your plane ran on one ignition which it would not do if it was flooded.