Cessna 340 - lookin' for advice...

[lostpianoplayer]

A few final thoughts

Hi Bookworm.Yep, I take your point, about rejecting takeoffs in twins for minor engine problems. I'm coming to this issue with a fair amount of experience in short field ops in singles, and also maybe 400 hours in piston helicopters, but not a great deal of M/E time, of which I probably only have 150 hours or so. I did train comprehensively for my M/E rating with a very experienced instructor, have read a lot on the subject, and found my flight test to be quite demanding and comprehensive. I appreciate you taking the time to discuss the issue rationally, rather than rushing into ad hominem attacks cos I’m supposedly asking “stupid questions”. I originally decided to stay out of this issue once the shouting started, but perhaps one more post would be pertinent, particularly since you've added some thoughts that are of value. Thank you.

In both the single STOL situation, and taking off in a piston helictoper - or for that matter flying over, say, forests, in either, one is frequently in situations where an engine failure at an inopportune moment could cost you very dearly indeed. The scenario you paint, in terms of a STOL takeoff in a twin, doesn't seem entirely dissimilar, to me, than that of taking off in a single – EXCEPT for the VMC issue. Once you're committed to a STOL takeoff, or a helicopter takeoff on the not unheard of occasions where you can’t stay within the H/V curve, if you have a 'non-immediate failure' engine burp/twitch/whatever, then you're potentially in a world of hurt. In a single, you have a millisecond to decide between the rock and the hard place, and you're certainly not operating on a balanced field. So the real question, it seems to me, is back where we started – does retarding the power on the good engine prevent a VMC roll or not? It would appear the consensus on the answer is no – a VMC roll, or serious loss of directional control, is inevitable, EVEN IF you immediately retarded the power on the good engine. Well, to those who’ve adoped that position, fair enough. I hear ya. I won’t take off below VMC. I was never intending to. It would have been nice to understand exactly why not, rather than take it at face value, and there are one or two answers here that make a strong case in terms of explaining WHY you can’t retard power on the good engine in time. I’ll think more about this issue, and keep picking the brains of those more experience than me. But, just so you know, I ran this by a 30-years-flying M/E guy yesterday, and guess what? He reckons directional control is quite achieveable, provided you cut power on the good engine immediately. I guess that makes him stupid too? Maybe we’re ALL stupid down here in New Zealand. Or maybe the coriolis effect changes the aerodynamics J

Most pilots spend a great deal of time planning & training for engine failures, either partial or total - but my understanding is that statistically speaking, avoidable engine failures - ie not produced by fuel starvation or mismanagement - are extremely rare, which is why some people choose to accept the risks involved in single engine STOL ops, or piston helis. (And, for the record, I HAVE in fact had 2 engine failures, in 12 years of flying, one arguably my fault to some degree, one unavoidable, so I don't believe they're impossible. Just very uncommon.) In terms of this particular issue, I'd have to stand my my initial comment, whatever the angry poster guy thinks of my training, approach to risk, suitability to hold an M/E rating, or whatever. I STILL "can't really see the difference between flying off a short field in a single, and accepting that if the engine fails in the first 5-10 seconds after airborne you're in deep trouble, and doing the same in a twin", EXCEPT insofar as it is affected by VMC. (And no, angry poster guy, save your aggression & go & kick your dog or something - you've made it pretty clear you're here to preach not to listen).

I'm sorry if I appear stupid to the more experienced people here, but I'm used to the concept of relying on my engine, and to minimising as much as possible but never eliminating the risk entirely, if that engine decides to quit. This is why I've been trying to work out if a VMC roll is inevitable if you rotate at a slow speed, by which I don't mean, necessarily, BELOW VMC - but possibly 5 knots or so below the published rotation speed. Or 10 knots, even. My personal opinion is that factory charts are helpful guides but NOT the singular, authoritative and definitive performance indicators that we would like them to be, so I like to augment the published data with actual date, by checking the actual aircraft's real world performance against the charts. The aircraft may or may not be in "as new" condition, for instance, it may be operating off fields that are neither flat concrete nor "firm sod - add 7%" - which are the only two runway surfaces options in my 340’s performance charts - and the published rotation speed of 91 knots may be slightly on the high side if you're operating at very light weights. For instance.

I was considering the possibility that the risk might be basically double that of a single - ie that if you have an engine failure at slow speed, you may accept that you are going down, but straight, level, and in control, but the chances of an engine issue are, of course, doubled. If it was the case that a well handled engine failure, at worst, involved a controlled level crash/overrun, well, that's one thing, and worth considering in terms of operating out of the field I’m considering, which, by the way, is 2400 feet long, so it’s short for a 340, but possibly not exactly a postage stamp. If a VMC roll is inevitable, likely, or even possible, then of course that's a whole different ball of wax. This is what I've been trying to find out. In between the invective, there's been a lot of worthwhile discussion, and I thank you guys for that.

Angry poster guy quoted me on a different thread as "(postulating) that as directional control may not be available on the ground after an engine failure, he sees no reason why one should not take off below Vmca." This illustrates one of the limitations of written communication in general, and particularly where goodwill & respect aren't present. What I actually said was

"What I don't understand is why, if you were hair-triggered to cut power on the live engine, as close as humanly possible, as well as applying immediate opposite rudder (aileron?), then wouldn't the removal of the live power remove the roll/yaw immediately, and thus turn it into a common-or-garden engine failure situation? "

The key being "I don't understand why". I didn't say that I DO understand why, I said I DON'T understand why. I also didn't say that I take off below VMC (I don't) nor that I plan to (I don't.) I was trying to answer a question that I confuses me, and I’m sorry to say I still don't really understand. My original question was “Anyone know what the shortest possible/reasonable/safe takeoff would be for a 340 operating at very low weights?”. One of the posters on the thread has kindly PM’d me with a concise and reasonable answer to that particular question. If I somehow conveyed an intention to fly unsafely, well, it was unintentional. Again, written language, without the non-verbal cues & feedback of a conversation, is easily misinterpreted, which is why I think it’s important to read these anonymous posts with goodwill and an open mind. But having answered that question, I’m STILL not sure why you can’t cut the power on the good engine, and end the assymetric thrust issue, turning your engine failure into a double engine failure, but at least going in under control, and right way up.

Yes, I've read this thread several times, and I understand the definition of VMC ".........critical engine suddenly inoperative with the working engine at maximum rated T/O power in T/O configuration (=gear up)", and I understand why that leads to roll and yaw that cannot be overcome. But I still don't understand why that roll and yaw could not be stopped when you cut power on the operative engine, unless rote adherence to procedure qualifies as understanding. In my experience, I would estimate that power reduction on the good engine would take a about a second or so to take effect, not the four or five seconds referred to by one of the contributors to this thread. (And, of course, the failed engine is likely to spin down at a similar rate, rather than stop dead.) I would have thought that the immediate power reduction, COMBINED WITH opposite rudder/aileron (which will, of course, be effective to some degree, just not enough to overcome the yaw & roll moment of a "working engine at maximum rated T/O power" might, in fact, be enough to prevent the yaw/roll combination that could induce a VMC roll.

I realise that what I "would have thought" isn't enough basis to go and fly the machine in a manner different to that written down in the manual. I'm not suggesting I'm going to. I'm trying to educate myself here. I am mystified by the concept that "conflict hones the skills and allows everyone to reasses their values and opinions". Personally, I find that reasonable discussion is a more effective route to reassessing "values & opinions" than trading barbs about how stupid someone is. And, of course, training in the aircraft - and in the simulator, where some scenarios are too dangerous to enact in the real aircraft. I am indeed heading off to Flight Safety, and will continue to explore the questions raised in this thread, in a safe manner.

It's a shame that these threads, which can be so educational, so easily degenerate into people talking to each other in a manner that I doubt very much they would do so mano o mano, so to speak, unless they were drunk. Actually, maybe that explains it!!! Maybe some of these guys are drunk! I see now

So. I have a great deal to think about. As it happens, VMC on my aircraft is about the same as the stall speed, due to the vortex generators, so it may be that I don't need to even think about this issue. And according to the published charts, the field, at 2500 feet, is long enough for operations at light weights, provided the (grass) surface isn't too soft, and with the caveat that “balanced field” ops aren’t possible. But we'll see. In terms of real world actions, from here on in, I am indeed going to attend a Flight Safety course, where I hope it may be possible to accurately simulate a light weight 340 with VGs operating off a grass field. I doubt if I'll posting the video for Lifeisgood & his friends to scoff at over their beers, but yes, videoing it for later review is a very good idea, and I will do that. I'll then, before I even think of flying out of this particular field, do plenty of flying off a l-o-n-g grass runway, to get completely current on the performance of the machine at light weights. As it happens, whatever misunderstandings angry poster guy et al may have come to, I quite agree about the need for safety in all aircraft operations. And if I have somehow suggested things that seem to belittle airline pilots and airline operations, well, I apologise for that. It wasn’t my intention. I think the safety record of the airlines is outstanding, and that private ops should indeed aim to be as safe as possible. It is my **personal opinion** that many PPLs do have more freedoms and privileges than many airline pilots, in that we are the sole decision-makers, within the bounds of legal regulations, when it comes to go/no-go decisions, routes flown, airstrips/airports used, weights flown at, fuel carried, (often) maintenance carried out/deferred and so on. I’m sure that’s one of the many reasons that private flying has a worse safety record than the airlines, not that I have ever said I think that’s a good thing. Note, however, that I didn’t say that PPLs have more responsibility. Obviously flying with 50, 100, or 300 people’s lives in your hands involved a great deal more responsibility than when you’re just dealing with your own life, and perhaps those of your family and friends.

So thank you, y'all, even angry poster guy, for your responses. There is indeed a lot of wheat amongst the chaff. You've all given me lots to think about, and no, I won't be racing off to kill myself in my 340.