Dafydd Llewellyn

You may be getting a kind of "falling leaf" effect, in which first one wing root separates and then the other - and it sets up a rythmic oscillation. I did warn that this might happen with a low-wing machine; with high wings, the initial stall spreads instantly from one wing fence to the other, so the whole centre-section stalls symmetrically, and there is no "tailwagging" effect. You may or may not be able to improve matters by adjusting the stall strips. That can only mean, there is insufficient elevator authority to stall the wing, in the presence of the VGs. However, the elevator authority increases as the CG moves aft; do you have any idea where these aeroplanes are, in the allowable CG range? If there is sufficient elevator authority to stall any part of the wing, within the aircraft's permissible CG range, the stall is likely to be extremely vicious.

Yes, I've noticed that, too. However, any pilot who can get a glider to gain height in a thermal, certainly does not suffer from lazy feet . . . .

The slide card merely provides a simple means of deciding whether you have enough height to make a survivable turn-back without the ground getting in the way. After that, it's up to you. I'd think running off the far end of the runway with your wheels on the ground, a lot more survivable than colliding with the trees at the upwind end - or stalling into the ground in an attempt to stretch the glide. Well, that's Merv's point, isn't it? My question would be, did those pilots have a lot of hours, or the same hour a lot of times?

Well, yes, you DO have to be able to FLY the aeroplane. The loss-of-control issue is surely about basic flying skill, rather than EFATO decision-making, n'est-ce pas?

Um- is this relevant to RECREATIONAL flying? Looks like Twin Otter territory to me.

Well, you are entitled to your opinion, of course. However, when using my aircraft for private business travel, I've made the odd precautionary landing due to weather (PA 28), or oiled-up plugs in one cylinder (Auster), or found that fuel wasn't available where it should have been (Jabiru), because the delivery truck broke down; there are a variety of things that can make it desirable to stop flying for the day, in a place that is not as good as one might wish for the subsequent takeoff. I've also made my share of outlandings in gliders, as well as aero tow retrieves, as a tug pilot; there are cases where one shakes one's head and says "go get the trailer, fellahs". If one is to take into account the added strip length or clearway necessary for safety in an EFATO situation, the airstrip requirements are going to be more demanding than if one is prepared to just scrape over the fence. A precautionary landing in a paddock is surely preferable to trying to push on in marginal VMC. If you do a lot of cross-country flying under VFR, you are going to experience this. I know from these experiences that finding a paddock one can safely fly out of, is much harder than finding one solely to land in; so the freedom to choose what you need right now, rather than what you will need when the weather clears up, can be a considerable safety factor. And even more so, if you take EFATO risk into account. This is what a trailer allows. Yes, it's a nuisance having to go home & get it; however, if you're using the aircraft for recreation, trailering it to where the fun is, is not necessarily such a silly idea. Also, you can perhaps use the trailer as an alternative to a tent under the wing; and have wheels available to go get fuel, or whatever.

Happens all the time, in gliding. The landing area is seldom a worry; you don't have to choose it with an eye to the subsequent takeoff.

13,000 feet at the point of no return and it doesn't need the motor; can glide all the way, either way.

There's a difference between a glider and a typical recreational aeroplane in regard to the airworthiness formalities involved in de-rigging and re-rigging; but maybe simplifying these would be a useful "no cost" way for RAA to reduce accident rates and thus insurance premiums. A good aircraft trailer takes a bit of thought, but it's not all that difficult. We've been considering the alternative merits of flying the motor-glider cross-country all over Australia, versus carting it on the trailer, to gliding sites we fancy visiting, and camping there for a week or so whilst we explore the flying within about 200 Km radius of the site. On the whole, the trailer wins, I think (it's designed to facilitate rigging and de-rigging). We'd probably choose to fly if we go to Tasmania. The availability of the trailer opens a complete set of alternative options. I recall an incident where the Canberra GC Motorfalke suffered some propeller damage whilst flying from a site at the northern end of Lake George - and the club maintenance officer elected to saw the opposite tip off the propeller in order to fly the aircraft back to Lake George South, to collect & fit the spare propeller! Some people cannot think their way out of a paper bag! Having a suitable trailer available is cheap insurance, in my view.

See attached.

And just what do you propose should be done about that, in the context of this thread? One cannot legislate against stupidity, unfortunately. Or perhaps, fortunately, or the population would be greatly reduced, one suspects.

I could not agree more. However, if you know what height you need over the upwind threshold to be able to safely turn back, that gives you a criterion for choosing which airfields you prefer to use, doesn't it? That's just another aspect of reducing the known hazards. Simply flying a single-engine aircraft could be argued to be, to a degree, Russian Roulette; especially when you have to negotiate something like the Sydney Northern Lane. So is driving, and thousands of other things that we do. There's a level below which one cannot reduce the risk; but it seems to me that a good understanding of the risks, puts one in a better position to either avoid them or cope with the unavoidable ones. I've done a certain amount of hazardous flight-test work; but I was not blind to the hazards, and I did what I could to minimise them - I built my own spin recovery parachute system, for example, after a lot of study on the subject and I installed it myself and packed the chute myself. I made sure my personal parachute was serviceable before I undertook that sort of flying. I made sure the door was jettisonable. I did the spin testing over a patch of ground that was suitable for parachute landing; and I had an observer on the ground. So I tend to analyse the situation, and make some effort to prepare for it. Just accepting that it's something to be terrified of, seems to me to be a negative approach. If you plan for a situation, it becomes merely annoying - but not necessarily a cause of incapacitating fear. I believe I could cope with the annoyance of having to put the aeroplane between two trees, without it robbing me of the skill necessary to do so. One of the causes of EFATO accidents has always been taking off with the fuel turned off; in my view, it should be impossible to reach the starter button unless the fuel has been turned on. Another is vapour lock, especially after a series of landings; fuel systems need to be designed to prevent that, and a lot of the ones I see in homebuilt aircraft do not meet that criterion. Another is the form of fuel-injection system that causes a rich-cut if the boost pump is on during takeoff - which is built in to some certificated aircraft, which I avoid flying. A lot of aircraft have empennage designs that will cause blanketing of the vertical tail in a spin. These are all unnecessary hazards. They are something you can fix or avoid, rather than being frightened of. I avoid aircraft with lousy glide performance, by choice. I consider this thread has been most useful, because what I am seeing as a result of it, is that almost all single-engine aircraft have a "non-manoeuvring area" from shortly after lift-off to past the crosswind turn. That means, there really should be a clearway beyond the strip, unless the strip itself is sufficiently long that the aircraft can have adequate height as it crosses the upwind threshold. This is nothing new, but a way of quantifying it was lacking, and we're fumbling our way towards defining what might constitute "adequate height". Clear paddocks adjoining the strip are good - but windscreens on single-engine aircraft, that are vulnerable to penetration by wire fences, are another unnecessary hazard. Oscar is planning to put five-point harness in his Jabiru - that's the right way to look at it, in my books.

The point you are missing, is that if you choose to take off in a single on a runway that has potentially lethal lack of options for an EFATO, you are doing this knowingly. You don't have to. So it behoves you to consider your possible courses of action, and plan accordingly. No, I did not suggest that it's something to be relaxed about; but equally it's not going to help the situation if you freeze or do something stupid. We all face this sort of thing from time to time; I have a very short strip from which to operate our Blanik - so I've gone to the trouble of preparing an emergency strip in the only available location, somewhat downhill and to one side, and my takeoff plan involves moving towards the emergency strip at about the point at which a landing ahead is no longer possible. It's sensible to make the best of the situation, which requires that you remain in control. So fear is NOT your friend.

No, Borman's accident is not relevant to this discussion. I don't think we should distress his relatives by discussing it. I have a question, though; why so much emphasis on fear? Is there some school of thought that says instructors should be teaching their students to fear their aircraft? An aircraft is simply a tool. So is a bicycle, or a motor car, or a tractor, or an adze. Use any of them wrongly, and they can injure or kill you. But they do not attempt to do so of their own volition; it is always due to human error. One needs to understand them and respect their characteristics and limitations; and they all take some skill to use correctly. And practice, to maintain that skill. If you teach people to fear them, you cripple their ability to use them correctly. If you instil a fear of an EFATO turn, you practically guarantee that the person concerned will muck it up. Some people fear spinning; it's a fear of the unknown. Spinning, in an aircraft cleared for that manoeuvre, is not something to fear; it's something to understand and get used to. If the student is terrified of some manoeuvre, there's something desperately wrong with the instruction he's been given. And something bordering on criminal.

OK, good - we're getting some results: Taking the basic figures: Foxbat - 1.5 x 300 +50 = 500 ft. Jabiru J 400 - 500 x 1.5 +50 = 800 ft Blanik motorglider (analysis only) - 250 x 1.5 + 50 = 425 ft. Remember, these are the heights necessary AS YOU CROSS THE UPWIND BOUNDARY FENCE. If you have this height at the upwind boundary of the airstrip and the climb is at a steeper angle than the best glide angle up to the point of engine failure, then a turn-back before the crosswind turn is potentially feasible. The picture that is emerging is, obviously, that the circumstances in which this will be so are few.

A powered aircraft is just a crude glider, when the engine has quit. The Space Shuttle was landed as a glider, dammit. If you read "Modern Airmanship" (if I remember the title correctly) by Van Sickle, he discusses how to do a forced landing in up to an F-104, by a 270 degree turn from a checkpoint directly over the centre of the airstrip. Every aircraft has a "go/no go" height at the checkpoint - I recall he gave it as 12,000 feet for the F-104. If you do not have the height at that point, you eject. Black or white decision. The point I have been trying - evidently quite unsuccessfully - to make, is that it is possible to set-up a go/no go criterion for something like a turnback. You have to establish the numbers by testing with you own technique in your own aircraft - and as that has to be done with engine idling, not dead, you need to add about 50% to whatever height loss you come up with in your tests. THIS PROVIDES A NO-GO CRITERION, SO YOU DO NOT WASTE TIME DITHERING, OR TRY AN IMPOSSIBLE TURN-BACK. I am NOT advocating a turn-back, it's just one option, and you need to know immediately whether it's a viable option. I am simply trying to get the decision-making process to be rational and fast. One has to set similar decision points for critical flight testing - for example, spin-testing a new type. You set a height at which you stop trying to recover the thing, and pop the spin chute; and another height at which you abandon ship if the spin chute doesn't work. These are things one has to have pre-set in one's mind. A turn-back on EFATO is simply another one of these. The principle is the same no matter what you're flying. Only the numbers are different. Go find out the numbers for your aircraft, and add a healthy safety margin on top of them. Provided you do not take-off downwind, a criterion established in essentially still air will normally be conservative. If there's a crosswind component, and you turn back, the initial turn needs to be into wind. Yes, a glider can do it from a remarkably low altitude; but the principle is the same. You may well find that the turn-back height is above 500 ft - in which case, you won't be trying it before the crosswind turn. That's likely to be the case for most GA aircraft, I suspect. But you won't know that unless you go to height and do a few tests. They won't lure you into turning back; more likely convince you that you have no chance before the downwind turn - but at least GO AND FIND OUT. You might just learn something, for a change.

Well, unless you go and test your decision height systematically, you won't know, will you?

Only figuratively; he was a cheerful Bavarian type, very friendly - lovely fellow. They just did not get to be CFIs.

Well, it comes down to getting out there and doing it, n'est-ce pas?

I'm not an RAA instructor; I used to be a GFA instructor, in the '70s and '80s. Back then, we understood that everybody has a "freeze" point, and at ab-initio stage it's likely to be pretty low; and it is the function of the instructor to progressively raise the student's "freeze" point by gradually increasing his level of competence and responsibility; spin training was an important part of that process. So "freezing" IS related to training - but there are varying levels of performance between individuals. An instructor who "freezes" is a clear indication of a failure of the system. This was the reason why the GFA had senior instructors, and (back then) a categorizing instructor who had flown ME 109s in WW2. There weren't any "freezing" instructors who got past him. That's one way, and it works. Maybe there's another, via psychological screening, but does it work?

There are a number of factors that would bear on a simple criterion; however, since it's based on a still-air condition, if you're taking off into a headwind, your upwind climb gradient will be increased and your downwind glide will take you further, so to a degree, the downwash due to the headwind coming over the ridge would be compensated for by the advantage due to the direct wind velocity. The further upwind you get before the engine quits, the greater the effects from both causes, so it all balances out, to a degree. I've outlined the basic principle; the refinements to it will surely become obvious as people start to apply it.

Both. I see this issue as being fundamentally one of inadequate training. It comes down to this: 1. Either you have sufficient height to perform the turn-back manoeuvre at the point of engine failure, or you do not. 2. If you do not, then DO NOT TURN BACK. 3. To know that you have sufficient height to turn back, you need three things: (a) A knowledge of the typical height loss YOUR AIRCRAFT will undergo in the turn-back manoeuvre AS FLOWN BY YOU. You should find this by performing the manoeuvre necessary to get you back to the point at which the engine stopped, heading in the opposite direction. Do this test at 5000 feet AGL, a number of times, average the resultant height loss, and multiply it by 1.5 or so. Add 100 feet for obstacle clearance. This becomes the "safety height" at which you must cross the upwind end of the runway, on climb out, in order to have sufficient height to turn back. (b) A means to readily verify that your height exceeded the "safety height" as you take-off - e.g. a mark on the altimeter glass. © Your climb gradient up to the point of engine failure, must exceed the best glide gradient for your aircraft. This will set a maximum density altitude beyond which the foregoing criteria will not be valid. The necessary information to determine that should be available in the flight manual; if it is not, you will have to determine it by test (something to do whilst you are flying-off the mandatory hours, on a -19 or experimental aircraft). If you change the propeller, this will need to be re-established. One could constitute the criterion in other ways; however it needs to be a black-or-white criterion, so the decision is already made for you as you cross the upwind end of the runway.

There is no substitute for competence.

Most gliders have dive brakes that will limit their airspeed in a steep dive - some even in a vertical dive; 130 knots straight down = 13,000 feet per minute. That will prevent you from being sucked up into most clouds. If you don't have that ability in your aircraft, stay well away from the underside of any active cumulus cloud.

Sorry, but you have some very wrong-headed ideas. The stick position (and elevator angle) at which the wing stalls is entirely variable according to the aircraft CG position. So stick position IS NOT a reliable indicator of the proximity to stall. I know there's a school of thought that imagines that stick position can be used for this purpose, but that is not correct. The best stall warning devices are either (i) an angle of attack indicator, or (ii) a device on the leading edge of the wing that detects when the front stagnation point moves past it; most stall-warning devices work on this principle, and they don't care what the CG position is. I suggest you get hold of a copy of "Flight without Formulae" by Kermode, and read it thoroughly.