Shutting off the fuel in a Seneca I

[Skaz]

wow, there's a lot of 'great spirits' sharing their wisdom with us lesser aviators
One of my personal mottos since I became a pilot, has been that, as soon as you start to think you know everything about flying and cant learn from anybody anymore, you become a liability, to yourself, your passengers, crew, people in the airspace with you and people below your flightpath.

I only have 45....ok, 44.9 hours on the PA34 Seneca I, and 1100ME, but I'd like to chip in my 2 cents....

During training, my instructor did fail an engine using the fuel cutoff. I think he did it more because of the position of the fuel selector switches and being able to reach them surreptisiously than anything else! But, he never failed an engine below ....say 3000'? (this is in South Africa b.t.w.)

My personal SOPs, for every aircraft, be-it SE or ME, that has the capability to select one tank only, or crossfeed, I check that this function will work.
On the C402C I fly regularly, early during the taxi, I crossfeed, then select normal feed and test the aux pumps on high, well before I get to the holding point and do my runups. This way I know that the crossfeed will work, the aux pumps will provide fuel at high pressure to the engines if an engine driven pump will fail, and during the runup I can see the engines feeding off their respective tanks without problems.

One instructor, during my F406 rating, had me do single engine circuits and landings, with one SE go-around. The 'failed' engine was set at zero thrust only, on the landings I got the failed engine back to use, but the go-around was SE only.....,man was that some hairy s-h-i-t ! Not fun at all, luckily it is a pretty powerfull machine and empty with the two of us one engine's 500horses was enough....but still not cool.

During upper air work the one engine was feathered (at idle) and we did Vmca and steep turns etc. Sweating like a pig, I was.

A ME aircraft on one engine is not a beast to play around with.
Especially an underpowered one like a Seneca I.

 

[Lead Sled]

OK, I've got a little time on my hands and I'm thinking that my fingers need a little exercise, so me thinks that I'll climb up on my soapbox for a few minutes...

I've had the feeling, for a long time, that many pilots don't properly respect the capabilities of light twins. They're just so excited about flying them that they really don't spend enough time thinking about what they've really got themselves into, but it doesn't matter - they're finally able to have "a fist full of throttles".

In most cases, light twins have pretty good performance - on both engines. However, it must be understood that, WITHOUT EXCEPTION, they have two engines because they need two engines. Single-engine performance in any piston-powered light twin is abysmal. Loss of power is the primary culprit. Remember, normally aspirated aircraft lose power with altitude. An aircraft's climb ability is directly proportional to the amount of "excess" power that it has available vs. what is needed to maintain level flight. For example, if a 200 HP normally aspirated airplane requires 100 HP to maintain level flight it would (at SL, ISA day) have 100 "excess" HP to use for climb. At 10,000' MSL, the engine might only be able to produce 130 HP, leaving it with a 30 HP surplus. This is the reason why turbocharged aircraft perform so well - you would be able to maintain SL power up until you reached the "critical altitude" for the particular engine. In some cases, this can be as high as 18,000' MSL.

This is also why light twins typically perform so poorly on one engine. Take, as an example, a Twin Comanche with two 160 HP engines. If that airplane required, say, 150 HP to maintain level flight it would have 170 "excess" HP to climb with. If it lost an engine, it would have lost 50% of its available power, but with just 10 "excess" HP, it may have lost 95% of its ability to climb. This, of course, will also appliesy to all other light twins. If you only learn one thing from this post, it should be that light twins have two engines because they need two engines.

There are some other operational differences that you should be aware of…

If you're in a single and you loose the engine, the laws of physics dictate what will happen next. Leaving the gear down until you have no more "usable" runway left only makes sense. It will leave the airplane in much better condition should the engine decide to pack it on while you're still over the runway. (By the way, I've had it happen to me once.) I've seen some "hotdoggers" rotate and immediately suck the gear up. A while back, I even heard of a guy who would place the landing gear in the up position as he took the runway. His thinking was that the squat switch would keep the gear from coming up while the airplane was on its takeoff roll and immediately start the retraction process as soon as he broke ground. What a weenie - his practice came to light one morning when he rotated a bit too early and the airplane settled back onto the runway. You don't need a PhD in Physics and Aeronautical Engineering to figure out what happened next.

(By the way, these are usually the same guys who immediately pull the throttle back to climb power as soon as the gear is in the wells. Statistically, that's the time when you’re most likely to have an engine come apart.)

Multiengine aircraft are an entirely different matter - you want to get the airplane cleaned up as soon as possible. In the case of most piston twins, their ability to maintain controlled flight depends upon the pilot getting the gear up, the propeller feathered, and the flaps up. Failure to this often results in the airplane being turned into a lawn dart.

I don't want anyone misunderstanding my comments on the need to get gear up on light-twins ASAP. I'm not implying that you need to get the gear cycling the moment the aircraft breaks ground. You don't need to be cocked and on a hair trigger - just get to it as soon as you can get around to it. Sure, there will be situations where you can delay it; I used to fly out of an ex-military airportwith a 10,300-foot runway and there was no need to be in a rush with the gear. You could takeoff and land most twins 3 times on this runway. However, I believe that on a more typical runway, once the airplane's up and climbing, having the gear out becomes more of a liability than an asset if and when an engine decided to "go south" on you.

We tend to take engine reliability for granted, but I believe that this is a very dangerous thing to do. Most light twins simply won't maintain altitude with a windmilling propeller and/or the gear down. The old Metroliners had a rocket bottle in the tail to buy the flight crew enough time to get the gear up in the wells. Auto-feather systems are on most, if not all, turboprop twins. The manufacturers wouldn't put up with the increased costs and complexity of doing this if there wasn't a true need for it. They put this stuff on the turboprops that have significantly better single-engine performance than piston-twins. It really ought to be on the "little" twins, but no one is willing to pay for it. Like I said, light twins lose up to 90%+ of their climb capability. The figure is probably even higher than that - I've seen several non-turbo'd twins that wouldn't climb out of ground effect and several turbocharged twins that could barely achieve climb rates of 100 fpm or so. But never the less, the point is that twin engine aircraft have two engines because they need two engines and under certain conditions they can maintain controlled flight on one engine IF THE PILOT DOES EVERYTHING RIGHT. You don't have time to dawdle, it has to be done right and right now.

OK, my fingers are cramping - it's time to climb down off of my soapbox.

Lead Sled

 

[PC12Cowboy]

Lead sled...let me help you down!

Well said lead sled...Uhhmmmm(best throat clearing)

Pulling the fuel flow to the engine is the WORST thing you can do to the motor, it will run near its maximum temp for a minute or two and then shut down...losing all heat rapidly. This alone is major concern for the engine to make TBO, but alas it can do great damage to the ignition system as well as spark plugs over temp can and often do change their gaps. now you have a cold engine that doesnt want to run, due to plugs not doing their jobs.
Yes it is required to shut down and engine in ALL the multi PTS's, but the POH has procedures for this devised by Test pilots and engineers to reduce the stress on the system.

I am in complete agreement that training hould be made as realistic as possible........but not to the point of increasing your exposure to a REAL emergency...........Not something that ME students and MEI's do well when its real. The stats prove that!
I have witnessed 4 fatal accidents and DO NOT want to see yours! Please remember we teach so that they might learn....not scare the hell out of them or jeapordize our students, or for that matter our own lives!!! just follow the procedures of the manufacturer and FLY SAFE!

Humble and always learning,
Kevin
PC12Cowboy

 

[nosehair]

Realistic Training

Two (2) things I've noticed over the years of training students how to fly and control airplanes and helicopters:
Sometimes; not usually, but sometimes, a student who I have trained with safe simulation, when experiencing the real thing will go completely berserk and react hysterically to the situation.
(1) When sneaking the fuel valve off and the engine actually quits.
(2) When first encountering actual IMC conditions.
(3) Oh - and also accidentally entering a spin.
Some of the accidents that occur are a direct result of this lack of training in our system. I say some, but I believe most. There are no statistics to reveal it. Pilots don't admit it. "I was so scared when I actually went IMC that I just couldn't focus on the instruments - I was consumed by the wierd feelings in my body which I had never felt before - next thing I knew, evrything was spinning around! Lucky I broke out high enough to recover."
They don't say - or even remember that.
Exposure to the real thing may not be required to get the rating, and usually it isn't required - most people will respond with their trained habits - but the once-in-a-while guy who loses it in the initial exposure to a real engine cut, a spin, or actual weather, and then recovers with a few exposures to the actual - well, I bet you just saved his life.
And more than that - you made him confront his fear and overcome it.

 

[labbats]

Good post nosehair. But unless you are suggesting cutting the engine for real below 3000' AGL, you're arguing the same point as everyone else.

 

[tathepilot]

My initial question has risen a great deal of insight on teaching in a twin, as well as instructing in general. I flew with my first multi engine student the other day and boy let me tell you it felt like I just got my cfi all over again.
But to say the least it was great! The guy I flew with just wanted to do some checkride prep.

And 'yes' I did shut the fuel off below 3000'.

 

[labbats]

Some people never learn....

 

[tathepilot]

Some people never learn....

That is the reason for training, to learn right?

As the localizer starts to come alive fuel goes off. Normally around 2300' ish. After he goes through his procedure fuel goes back on, zero thrust simulated. I feel that is the best way to go. If the engine doesn't want to come back alive there is plenty of time to call home and talk about it.

Although my time is low, I'm very safety concious. If you read my first post. I was concerned about the practice that the mei was using. I didn't feel it was the safest way to go.

 

[avbug]

Pulling the fuel flow to the engine is the WORST thing you can do to the motor, it will run near its maximum temp for a minute or two and then shut down...losing all heat rapidly. This alone is major concern for the engine to make TBO, but alas it can do great damage to the ignition system as well as spark plugs over temp can and often do change their gaps. now you have a cold engine that doesnt want to run, due to plugs not doing their jobs.

While shutting off fuel does have the potential to cause damgae to fuel-lubricated wetted components, it does not do any of the things you described.

Shutting off the fuel will not change the mixture setting; it will not therefore change the temperature while the engine is producing power. Only when the fuel runs out will the temperature change; it will then drop. Once shut down, you are correct, temperature then decreases.

Spark plugs do not overtemp when shutting of an engine using the fuel control (mixture or fuel selector, in this case).

Spark plugs do not vary their gap according to temperature, except in cases when excessive electrode errosion has taken place. Electrode errosion takes place based on the firing of the plug itself, not the burning that takes place in the cylinder.

Excessive temperatures in a cylinder lead to burned valves and occasionally a melted piston...but the primary problem with running at critical temperature settings isn't the temperature, it's the potential for detonation...which does the real damage. During a fuel shutoff, power drops drastically, and any variances that might briefly occur in fluctuation with fuel flow won't lead to any damage caused by temperature, or detonation. Detonation issues are critical at power settings above 75%, not below, and with loss of fuel flow, power drops and any attendant danger of detonation and associated damage drops with it.

Tatheplilt, having heard the testimonies and information from many pilots here more experienced than yourself, and having heard the recommendations from the FAA, including those posted in the practical test standards, why did you do that??

As the localizer starts to come alive fuel goes off. Normally around 2300' ish.

Is there any valid earthly reason why you would do this instead of setting zero thrust on one engine? Not only are you shutting off fuel below 3,000, you are doing it while flying an approach, descending. Not smart.

After he goes through his procedure fuel goes back on, zero thrust simulated. I feel that is the best way to go.

Why do you feel this way? Perhaps it's time for you to listen to virtually every other professional pilot in the business, the FAA, the industry, etc...don't try to reinvent the wheel. There's a reason that many of today's practices are conducted the way they are...because when it was done the way you seem to want to go, a lot more people got killed in training than in actual accidents. That's not right.

If the engine doesn't want to come back alive there is plenty of time to call home and talk about it.

You really think so? What do you do in the meantime if the other engine quits, or the student screws up and fails the wrong engine. Don't think it can happen? Think again. And don't do that any more.

Although my time is low, I'm very safety concious.

Possibly so, but it doesn't show. Don't try to make a name for yourself by reinventing the wheel, or you'll end up making a name for yourself...if you know what I mean. You don't have the experience right now to be innovative in trying what you think might be best or safest. Don't try. Stick with what is safest, and that is exactly what we've been talking about here. Simulate those failures on the approach with the throttle, set zero thrust, and don't go around on one engine. Land, taxi back, warm the engine up again, and go try it once more.

 

[tathepilot]

One good reason why I did that was because it has been done with me and I do feel that it is a safe way to go. Another reason was because when I did do my mei check ride I asked the examiner what did he reccomend and do you know what he told me? He said don't do fuel cut-off's below 500' feet agl!

I do respect his advice him being a CP for CO. And a 35k hour pilot, although I would never cut the fuel that low. I don't listen to advice that 'everybody' gives me, even this examiner. If I don't feel like something is safe than I won't do it. (In the case of my first post.)

Is there a valid reason why I would shut off the fuel durning localizer intercept? Sure. To give the applicant the chance to think.
Is it me or has anyone here had a cfi do partial panel in the clouds? I did, and the first time it bugged me out. When the cfi first covered up the instruments in imc I said, you guys really do that *hit. But you know what I guess he was confortable doing that. And after doing it for a while I thanked him because I got to see how it was do shoot a real partial panel approach. During more of my mei training I flew with a different mei a couple of times and do you know what this guy did? You got it he shut the fuel off as the localizer came alive... in 'IMC'

reinvent the wheel? No sorry I don't have that much time to do so? am I the only one that has gone through this type of training. Is FRG that far from the rest of the world, because this is the type of training that I have been through since day one since becomeing a pilot.

What if the other engine quits? Nah not too likely.
What if he fails the wrong engine? What exactly does that mean?

 

[avbug]

What if the other engine quits? Nah not too likely.

You really think so? You don't have the experience to be thinking that kind of foolishness. Wake up.

What if he fails the wrong engine? What exactly does that mean?

You don't know? Then what on earth are you doing sitting in the position you're in? You shut down one engine and the student identifies and feathers the other...don't think it can't happen? I've been in working professional cockpits and prevented it from happening. It can happen. And while it's happening, you have nothing to fall back on because guess what? You just shut down the only powerplant you had left. Good guess.

I recall watching the Smothers brothers years ago. One had done something foolish. The other said, "If I told you to go jump off a cliff, would you do it?" The first thought for a moment and said, "Well, not again."

You do everything the way you were taught? I hate, absolutely hate, to hear someone say, "but that's how I was taught." I don't give a rats umbillical cord weather you were taught something. My only reply is, "but what do you know?" I don't care what you can parrot from a former instructor. The flying world is filled with a heritage of inexperience. One new instructor teaching another...each passing on "but that's what I was taught" to the next. That's a chain of emptiness if ever there was one.

Always leave yourself an out. Don't ever make the stupid mistake of thinking that something is unlikely, or it won't happen to you. It will. And you won't like it.

Ever seen an airplane break apart in flight? I just watched two aircraft I flew do just that. Don't think it can't happen? Ever watched your engine catch fire? I have. It happens. Ever had a two engine failure? My fist tanker job was being drafted into an airplane that had just lost it's crew...who quit after all four engines failed in IMC, enroute from a fire. It happens. But apparently not to you, because it's "not too likely." Do you base all your safety of flight decisions on what's likely?

During my last sim recurrent, I was climbing out on departure, and an engine failed. A moment later, the sim instructor, parroting ATC, wryly asked me where I bought my fuel. I could see that one coming, and immediately started a turn around. The other engine failed post haste. He was making a point, and it was a valid one. Don't think it can happen. Probably not. Not to you, anyway.

Your thirty five thousand hour examiner can toot all he wants. A great deal of my flight experience has been at and below 500' in all sorts of airplanes, all sorts of weather, and almost always in less than favorable circumstances. Much of it in multi engine airplanes. Even in four engine airplanes, shutting one down low isn't something we ever did frivolously...even with a fire, a separated cylinder, smoke, a wing covered in oil or other fluids, etc. I'd stack any single hour of that time up against five hundred of your examiner's point to point (presumably airline) hours, and still tell him he's a bloody fool if he's shutting engines down without need at low altitudes.

And you, a brand new instructor who should be sticking to the syllabus, what are you thinking?

 

[tathepilot]

Dear Mr Avbug. Did you even read my last post? I don't think so because if you did you would clearly understand that I'm not being a parot. (doing only as I'm taught)
You said fail an engine, that didn't make sense because I was looking for the term feather. When I was with the student it was clear before we even left the ramp that if and emergency arose I would take the a/c and handle it. If something happend during training and I did nothing, than it would be considered training. And we made it clear that if an engine needed to be feathered, that I would do it.

Mr. Bug I do thank you for your insight as it all helps. Although your tone seems to be quite condescending. Yo tote inexperience, inexperience, inexperience towards me yet I look to people like you for advice. I never said that I do what I want to neither did I say I'll do things exactly as people do them. If you read my last post you will understand that.

 

[Cat Driver]

Tathepilot.

I would suggest you listen to what avbug's message is rather than dissect how he presented it.

Because he is correct in what he is trying to tell you.

None of us who know this business want to see some new commer get killed because of being wrong headed and just plain wrong about the safe way to train.

Cat Driver

 

[DCitrus9]

tathepilot said: "When I was with the student it was clear before we even left the ramp that if and emergency arose I would take the a/c and handle it"
So you are actual single engine at the marker, the student f's up, engines chokes, whatever... yet you're 5 miles from the runway at1500 agl
And what, exactly, will you do to "handle" that glider you just built?

Let me attempt to summarize for you what has been laid out in great detail and with wise words.

Don't paint yourself into a corner!

Shutting off an engine, voluntarily, down low is NOT NECESSARY. Furthermore it is foolish and dangerous. It serves absolutely no purpose.
Do you really think you are fooling an applicant by using the fuel rather than simulated? If so, that applicant is already in over his head and needs to be doing remedial airwork- not engine failures. He should be trained to always expect an engine failure, especially on a stinking training flight. There is benefit to an actual inflight shutdown. Therefore it is included in the PTS. But do it with a safety net, ie. altitude to spare.
I challenge you to prove, to yourself, that it is more beneficial than dangerous to shut down an engine.
I don't care if you try to save face on this stupid message board. All that really matters is how you fly that next flight. Think it over before you endanger your next student. Fly smart.

 

[Lead Sled]

I'm the new kid on the block, but I've been around the block a few times. A while back, someone told me a story about a fellow aviator who, after a royal screwup, found himself waiting in line at the Pearly Gates (behind his passengers). Saint Peter asked him how he got there. His reply, "I have no idea, It's never killed me before."

I have little patience for "high time" pilots who do stupid tricks and I consider pulling an engine below 3,000' AGL a stupid trick. Tathepilot, I've known 20,000 hour airline captains that were total screwups (Thankgoodness for ALPA.) and 500 hour pvt pilots that were very competitent and consciencious. Personally, your friend may have a bazillion turbine hours, but that might only give him a false sense of security when it comes to the dangers of flying piston-twins. If I seem a bit touchy about this it is because I am. I've had three friends killed pulling those kinds of stunts in two separate accidents.

Bottom line is this, if you induce an emergency and you end up in an accident or incident you will be liable. Period. Simulated zero thrust will not only protect your fanny, it will protect your license. Save the engine shutdowns for the simulators.

Lead Sled