Turning off the donkey in flight. Yes or No?
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Sorry to press on this buy if we forget about this exercise for students what about for instructors?
In my limited experience I have had the engine stop on me, once in a spin and once in a stall. Surely there is merit in us having experienced the panic inducing silence at least once under controlled conditions.
WWW
In my limited experience I have had the engine stop on me, once in a spin and once in a stall. Surely there is merit in us having experienced the panic inducing silence at least once under controlled conditions.
WWW
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I agree with WWW, as long as the exercise is done in a controlled situation, ie., over a suitable aerodrome, with altitude to spare(and keys still in the ignition), it should be done. I got the experience of an air restart as part of my initial instructor rating. This was done in a C150 Aerobat.
Like hand-swinging a prop to start the engine, it's something I'm glad I've done once under supervision, but I'm also in no rush to do it again.
Like hand-swinging a prop to start the engine, it's something I'm glad I've done once under supervision, but I'm also in no rush to do it again.
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I still stand by my point about the basic safety of shutting down the engine of a light single. There is no necessity for it. Twins, I had no qualms about the exercise shutting down an engine during my B rating (during a course at OATS) as this was carried out under a definite set of rules (above 3000, nearby suitable diversion airfield, etc) AND you weren't just going downhill with no power, although I do accept safety levels were (acceptably IMHO) decreased.
I'm sure that insurance companies would class a single with a stopped engine as an emergency situation and not as a normal flight manouvre - even if it were stopped deliberately.
What would the exercise demonstrate? That an aircraft flies well with the prop stopped and the difference in drag between a stopped prop and an idling, no power, prop. All very well but why are we doing it? Because it may impact on actual glide performance on the day of a real failure as opposed to what they are used to from their PFL training? Surely, this is down to ensuring that good PFL techniques are taught and maintained post-training. A better way of simulating a degradation of glide performance would be to start the glide with 10 degrees of flap.
I've bemoaned some aspects of JAR as I don't think they've been properly thought through. Taking a narrow PPL / PPL training view the new PPL requirement to fly with an instructor every two years is a good one and should raise the overall standard of PFL's because, whether the risky shutdown and restart procedure is shown or not, if they can't execute a safe forced landing the whole exercise is a waste of time.
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Get there eventually
I'm sure that insurance companies would class a single with a stopped engine as an emergency situation and not as a normal flight manouvre - even if it were stopped deliberately.
What would the exercise demonstrate? That an aircraft flies well with the prop stopped and the difference in drag between a stopped prop and an idling, no power, prop. All very well but why are we doing it? Because it may impact on actual glide performance on the day of a real failure as opposed to what they are used to from their PFL training? Surely, this is down to ensuring that good PFL techniques are taught and maintained post-training. A better way of simulating a degradation of glide performance would be to start the glide with 10 degrees of flap.
I've bemoaned some aspects of JAR as I don't think they've been properly thought through. Taking a narrow PPL / PPL training view the new PPL requirement to fly with an instructor every two years is a good one and should raise the overall standard of PFL's because, whether the risky shutdown and restart procedure is shown or not, if they can't execute a safe forced landing the whole exercise is a waste of time.
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Get there eventually
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You'd be showing (not the same as knowing) instructors-to-be that the engine stopping need not be an instant MAYDAY, panic, look for a field situation. Hell - we have to be able to get out of spins and simulate engine fires. I've experienced neither but have had the engine stop more than once only for a re-start to be completed.
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I can go along- just- with the idea of stopping the engine during the AFI course. I would prefer to do that at altitude, preferably wearing parachutes. I've had too many experiences of a warm Lycoming refusing to start, to want to try that in the air. Embarrassment I can cope with, but I don't want the AAIB to ever know mmy name!
And with all due respect to CFI, if anyone ever gives me an EFATO in a single with the mixture control instead of the throttle, the test is over, I'm treating it as a real emergency- and when I get on the ground, I'm phoning the CAA. Oh, and I won't be paying for the flight, either!
And with all due respect to CFI, if anyone ever gives me an EFATO in a single with the mixture control instead of the throttle, the test is over, I'm treating it as a real emergency- and when I get on the ground, I'm phoning the CAA. Oh, and I won't be paying for the flight, either!
What is the difference between simulating an engine failure by pulling the mixture or the throttle?!
I always used the mixture - a bit less stress on the carby and induction bits (as the throttle buttlerfly remains open), and the chances of the mixture getting stuck in the off position are the same as the throttle getting stuck.
(In fact one of my company's students had a stuck throttle on first area solo, and performed a textbook PFL into a clear paddock with no damage to aircraft or student.)
I always used the mixture - a bit less stress on the carby and induction bits (as the throttle buttlerfly remains open), and the chances of the mixture getting stuck in the off position are the same as the throttle getting stuck.
(In fact one of my company's students had a stuck throttle on first area solo, and performed a textbook PFL into a clear paddock with no damage to aircraft or student.)
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WWW, in Australia they use the mixture control to simulate an engine failure, but only on twins, it is the throttle on single engine PFL's. I found it strange at first, but after getting used to it it makes sense. Personaly I prefer to use the mixture, but our CAA will not allow it of course, and they issued a lengthy AIC to back up their position.
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If you're flying engines that have crankshaft counterweights, (PA31P/LYC-TIGO-541A) for example, the crank counterweights, bushings, and pins take a terrible mechanical beating that can set you up for a catastrophic mechanical failure by rapidly retarding/opening the throttle. Mixture cut-off only deprives the engine of fuel, while not rapidly changing the dynamic loads on the piston/rod/crank interface during the simulated failure (remember the engine is still breathing air during a mixture cut). Rapid throttle movements (even during normal flight ops) is alleged to promote detuning of these critical crank balancing components, leading to their failure. Back in my prior life, I did a lot of C&T with counterweighted engines and never had a failure or complaint from the engineers at overhaul time. Maybe somebody else with time in these machines could share some knowledge/experiences.--CY
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Intersting topic this...I noticed in the opening gambit to the topic that CFS were mentioned. For what it's worth, in my experience both as a stude on several piston/jet aircraft and as an instructor on Tucanos I can quite honestly say that in a single engined aircraft I have never shut an engine down for demonstration purposes or had one shut down on me. (I cannot begin to imagine the subsequent board of enquiry if anything went pear shaped).
The only occasions where engine shutdowns are carried out (in my world anyway - 2 engined FJ) are on convex...one trip only to give you confidence in the ac flying on 1 donk (med/hi level to allow for several relights should the first not succeed) and on engine airtests.
Shutting down your only serviceable engine in flight is, I would say, pretty poor airmanship and could result in egg on your face.
The only occasions where engine shutdowns are carried out (in my world anyway - 2 engined FJ) are on convex...one trip only to give you confidence in the ac flying on 1 donk (med/hi level to allow for several relights should the first not succeed) and on engine airtests.
Shutting down your only serviceable engine in flight is, I would say, pretty poor airmanship and could result in egg on your face.
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I am surprised that many experienced and intelligent people contributing to this forum are missing the point that the CAA REQUIRE an airstart as part of the (now defunct) 509 syllabus! If you want to make an issue of it, have a go at them, do not cast aspertions on the people who have been following syllabus directions.
Also, the point of the exercise is to practise engine re-starts, it has nothing to do with PFL teaching. The exercise has a hard deck of 5000' for re-start.
Soap box retracted...
[This message has been edited by Meeb (edited 22 September 1999).]
Also, the point of the exercise is to practise engine re-starts, it has nothing to do with PFL teaching. The exercise has a hard deck of 5000' for re-start.
Soap box retracted...
[This message has been edited by Meeb (edited 22 September 1999).]
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Airstart as part of 509? Never knew that. In which case things are a wee bit silly. A 509'er is supposed to be being prepared to go straight into airline ops where, forgive my ignorance, air starts are not likely to be required in 20 lifetimes of flying. Whereas being trained to be a FI is leading you to a situation where an air start during just one lifetime career is possible to likely.
Seems an anomaly to me.
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Seems an anomaly to me.
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Lycoming in their 'Lycoming Flyer' recommend using the mixture to simulate a failure. I can't recall if was for m/e only, or included singles.
Their reasoning is along the lines of what Corporate Yank said: The throttle butterfly remains open so there is still mass airflow into the cylinders. This provides a cushioning effect on the piston and associated connections - as would normally be experienced by those engine parts.
Something else it might affect is carby icing probability with a closed throttle but fuel from the idle jet still evaporating, compared to no fuel being evaporated at all? Haven't a clue on this, really, but it seems to make sense. Unless the greater mass airflow with an open throttle has a greater temp. drop of course.
As for the general thread of the topic, I think a properly structured shutdown exercise is beneficial. There are many things we do while teaching that have some level of 'risk' compared to straight & level. I don't believe that a shutdown poses any greater hazard than some of those.
Similarly, I can't see that a shut-down in a fixed-wing is more hazardous than motor-glider or sailplane as long as the aircraft is operated within it's glide performance envelope.
Of course you don't expect the same L/D & therefore glide range, but what does it matter if you're operating within an appropriate albeit different performance envelope? As I recall, gliders could range from (very approx)18:1 up to a modern high performance sailplane's 50 or 60:1. This is a far greater performance change factor than that experienced between a C150/152/172 / PA28 etc.
As with gliding, once the engine is shutdown then treat the flight as commited to land. Judicious choice of an appropriate environment is needed just as it is for any exercise.
Their reasoning is along the lines of what Corporate Yank said: The throttle butterfly remains open so there is still mass airflow into the cylinders. This provides a cushioning effect on the piston and associated connections - as would normally be experienced by those engine parts.
Something else it might affect is carby icing probability with a closed throttle but fuel from the idle jet still evaporating, compared to no fuel being evaporated at all? Haven't a clue on this, really, but it seems to make sense. Unless the greater mass airflow with an open throttle has a greater temp. drop of course.
As for the general thread of the topic, I think a properly structured shutdown exercise is beneficial. There are many things we do while teaching that have some level of 'risk' compared to straight & level. I don't believe that a shutdown poses any greater hazard than some of those.
Similarly, I can't see that a shut-down in a fixed-wing is more hazardous than motor-glider or sailplane as long as the aircraft is operated within it's glide performance envelope.
Of course you don't expect the same L/D & therefore glide range, but what does it matter if you're operating within an appropriate albeit different performance envelope? As I recall, gliders could range from (very approx)18:1 up to a modern high performance sailplane's 50 or 60:1. This is a far greater performance change factor than that experienced between a C150/152/172 / PA28 etc.
As with gliding, once the engine is shutdown then treat the flight as commited to land. Judicious choice of an appropriate environment is needed just as it is for any exercise.
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Surely the 509 requirement for an engine re-start would be met during the m/e part of the syllabus.
I also think that there is an acceptance issue here. If the shutting down of an engine on a single were to become an accepted exercise - on an FI course only or all licences, it would occur more often, and maybe not under ideal, supervised conditions. There's always some nugget who'll push it just too far and end up a statistic.
When shutting down and engine the Seneca checklist requires that cowl flaps are set to closed on the shut down engine in order to slow down engine cooling. I'm no engineer but on some of the simpler (non-cowl-flapped) s/e types aren't we running into the area of shock cooling, a bad habit we normally try to knock out of our students. Hmmmmm, maltreating the donkey too.
I also still think, in UK certainly, that no matter how ideal the situation, you can't account for the unplannable; such as ATZ-busting, conflicting traffic and you've got no options. He may have right of way but he doesn't know you're a glider (not that he'd probably care anyway).
The whole exercise should be the subject of a (thorough) ground briefing and then practiced possibly in a procedures trainer and/or touch drill in the air. Save the actual restart for if it's actually required.
The spin requirement was removed from the UK PPL syllabus because it was causing more accidents than it prevented. If in-flight re-starts were to become an accepted exercise I think there would be a similar correlation.
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Get there eventually
[This message has been edited by climbs like a dog (edited 23 September 1999).]
I also think that there is an acceptance issue here. If the shutting down of an engine on a single were to become an accepted exercise - on an FI course only or all licences, it would occur more often, and maybe not under ideal, supervised conditions. There's always some nugget who'll push it just too far and end up a statistic.
When shutting down and engine the Seneca checklist requires that cowl flaps are set to closed on the shut down engine in order to slow down engine cooling. I'm no engineer but on some of the simpler (non-cowl-flapped) s/e types aren't we running into the area of shock cooling, a bad habit we normally try to knock out of our students. Hmmmmm, maltreating the donkey too.
I also still think, in UK certainly, that no matter how ideal the situation, you can't account for the unplannable; such as ATZ-busting, conflicting traffic and you've got no options. He may have right of way but he doesn't know you're a glider (not that he'd probably care anyway).
The whole exercise should be the subject of a (thorough) ground briefing and then practiced possibly in a procedures trainer and/or touch drill in the air. Save the actual restart for if it's actually required.
The spin requirement was removed from the UK PPL syllabus because it was causing more accidents than it prevented. If in-flight re-starts were to become an accepted exercise I think there would be a similar correlation.
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Get there eventually
[This message has been edited by climbs like a dog (edited 23 September 1999).]
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The current Lycoming guidance for twins is to use mixture above 3000 agl and throttle below 3000 agl. This seems to work OK, the justification is simple: using mixture is less stressful for the engine but below 3000 agl the stress level on the pilot could be raised to an unacceptable level :-)
For singles the only time I deliberately shut down the engine is as a required part of an aerobatic course. It's done using mixture, above 3000 agl, VMC, within range of good fields.
For singles the only time I deliberately shut down the engine is as a required part of an aerobatic course. It's done using mixture, above 3000 agl, VMC, within range of good fields.
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...and that's coz' I'm a wrinkly old PPRuNer who plans to get a lot older and wrinklier!
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In Oz in the old days (DCA etc) engine restarts in singles was part of the syllabus.
Two types were required - a normal shut down & start using the check lists - with some no engine handling & trimming for the glide.
Then you had to do a 'dive' restart. They were a lot of fun, and were always done over a good field, just in case.
I must have done hundreds of them with no hassells.
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'of the varieties of the real & unreal, there are many!'
Two types were required - a normal shut down & start using the check lists - with some no engine handling & trimming for the glide.
Then you had to do a 'dive' restart. They were a lot of fun, and were always done over a good field, just in case.
I must have done hundreds of them with no hassells.
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'of the varieties of the real & unreal, there are many!'
