Piston twins, a case of love and serious airmanship

[Pace]

>Which Seneca is that Pace?....I assume it's one of the later ones since I was under the impression that Seneca I single engined ceiling is something like 3000ft. <

Seneca Five twin, Turbocharged intercooled and wastegated. Suggest you go to Piper aircraft and check for yourself?
Seneca 1 is a totally different animal. I have flown them all 1,2,3,4,5

Sternone

>First of all, I DO NOT WANNA FLY WITH YOU, you are completely MESSING UP THE SATISTICS!!! each 900 hours you get an engine faillure ? <

Why do you not want to fly with me? I fly as a captain on Citations with an ATP and have had failures and problems with jets too! but not engine failures.
But isnt that what we are trained for? when things go wrong not the sunny days.

The full engine failure was with an almost new Seneca, 100 hrs total time. Three rocker shafts failed due to incorrect torque of the shafts at Manufacture by continental. Engine replaced within two weeks with an apology.

Second partial was a fuel problem which took a long time to find and required an almost complete replacement of the fuel sytem.

Third was a complete failure of an exhaust manifold pipework which had detached and was found lying at the bottom of the engine cowl.

All luckely for me were handled correctly the full failure occurred at 300 feet in the climb at grosse weight.
So who would you fly with? someone who lost the plot and crashed?

Pace

[Pace]

Sternone

>Why is that ? In a real partial loss (and you know that) it isn't THAT easy to feel what side has failled...the plane just goes from left to right... <

The old dead leg dead engine works well as well as having the ball centre as an early indication. Make sure you disconnect the yaw damper.
then of course check the engine indications!

Its not rocket science but simple piloting skills. From what you are saying many twin pilots are lacking!!! but then that has to be training, currency, or pure panic if you loose it.

Pace

[englishal]

Englishal


Quote:
The new version with ~170HP engines will cruise in the region of 190 kts+ ......

Are you writing from experience? I have flown the single with the new engine and it doesnt add greatly to the performance - certainly nothing like that amount. I have not flown the 42 with the new engines however.

I guess you have flown the 42 at MTOW with a simulated failure after take off. Personally I would not have said on the critical engine the performance is all that great - reassuringly it does climb IF you are on the money, but plenty of margin to get it wrong if climbing away in IMC. In the cruise I would agree it is fine - and I speak from actual experience .

The DA42 is supposed to be coming out with 170HP turbo diesels within a year - or so my friend who runs a Diamond Training Centre said - I'll find out more. I was flying the DA42 with the 2.0 litre diesel a couple of days ago and "failed" the critical engine on approach at near max AUW. No problem at all, could easily climb and managed a nice stable ILS followed by circle to land with no drama....The 2.0Litre has been de-rated to supply same BHP - but I guess you could chip them

[sternone]

The old dead leg dead engine works well as well as having the ball centre as an early indication. Make sure you disconnect the yaw damper.
then of course check the engine indications!

Here you go wrong. Engine instruments like fuel flow/rpm and map will not give you always an indication of an engine faillure.

And ESPECIALLY NOT the inclinometerl.

You see, you just gave me another reason not to fly with you.

Since you have flown the Seneca 1,2,3,4 i would love to hear from you what their SE ceilings are.

Also to keep that SE ceiling at 16500 rpm, how many degrees do you bank into the live engine for that ?

It is during my ME training that i descided that twins aren't what people expect from them. I might not have 999000 hours of multi engine expierence but you can't blame me for having an opinion that is based on what i expierenced myself. For that reason the argument that i'm too low on hours to make an argument stinks.

[Pace]

>Here you go wrong. Engine instruments like fuel flow/rpm and map will not give you always an indication of an engine faillure.

And ESPECIALLY NOT the inclinometerl.

You see, you just gave me another reason not to fly with you.<

Sternone

Dont display your complete ignorance. I am seriously starting to doubt your ability to be voicing a believable opinion here at all.

A complete engine failure will show on your Engine instruments. A loss of power either constant or sporadic will show through unequal thrust.
You need to run through the checks specified in your training (if you have had any?) and positively identify the problem engine before deciding to shut it down or not.

How would you identify an engine problem as I would be interested to hear from such an experienced pilot

>Service Ceiling Two Engines (100 fpm) *25,000+ ft / 7,620+ m
Single Engine (50 fpm) 16,500 ft / 5,029 m
*25,000 ft. is max. approved altitu<

Above are the figures for the Seneca V twin Note the SE quoted as 16500 (50 FPM)

Pace

[sternone]

Pace, I think you should get some updated training, tell me

A complete engine failure will show on your Engine instruments

On what instruments are you always seeing a complete engine faillure ?

And please give me the SE ceiling of the seneca 1,2,3,4 since you flew them all.

[IO540]

My "research" on this topic is as non-exhaustive as it could be but I seem to know a number of twin pilots who have had a staggering incidence of engine failures, yet I know very few SE pilots who have had an engine failure.

One twin (Aztec) pilot I know of has had some huge # of engine failures (10?).

On the Thielers, all bets are off anyway but that is a known problem.

I wonder if twins are more likely (I mean much more than 2x more likely) to get an engine failure? Is there more vibration on the engine and accessories? Or are the engines driven harder, due to the typical operational profile? The control cables are certainly longer.

[Fuji Abound]

I wonder if twins are more likely (I mean much more than 2x more likely) to get an engine failure? Is there more vibration on the engine and accessories? Or are the engines driven harder, due to the typical operational profile? The control cables are certainly longer.

The reverse. At any rate based on FAA statistics the failure rate in twins is considerably less than double the failure rate for singles. Flying published a rate of 1.42 times.

The DA42 is supposed to be coming out with 170HP turbo diesels within a year - or so my friend who runs a Diamond Training Centre said - I'll find out more. I was flying the DA42 with the 2.0 litre diesel a couple of days ago and "failed" the critical engine on approach at near max AUW. No problem at all, could easily climb and managed a nice stable ILS followed by circle to land with no drama....The 2.0Litre has been de-rated to supply same BHP - but I guess you could chip them

Yes, Diamond's own engine is slated to replace the Theilert engines. Personally I doubt the 42 will get close to 190 knots on these but undoubtedly there will be an improvement in performance. The 2.0 litre is as you say currently "de-rated" and offers no noticeable performance gain but does have other advantages.

At what height did you initiate the go around? How was the airframe configured. Did you notice the rate fo climb and how much height was lost between initiating the go around and achieving a stable rate of climb. What rate and speed were you descending at?

[SNS3Guppy]

Obviously the main consideration for choosing a plane may be an economical one. Also there is the ever recurring "increased risk" of twins regarding survivability.

Not necessarily.

Economy may be one reason for choosing an airplane, but it's a poor one in consideration of one's intended mission. If getting from A to B in the least expensive way is most important, then yes, economy is important. That's not necessarily the case if you want to get there quickly, or if performance is an issue, or safety, or avionics, or...you get the idea. There are many reasons to make a flight and many ways to conduct it. Economy is seldom the chief driving criteria in selecting the aircraft.

Ever-recurring increased risk? Not so. "Increased risk" is largely in the purview of the pilot...not a function of the aircraft. How you use the airplane makes all the difference in the world.

On what instruments are you always seeing a complete engine faillure ?

And please give me the SE ceiling of the seneca 1,2,3,4 since you flew them all.

I have to believe Sternone is a troll, or a very, very inexperienced pilot with a very, very inflated opinion of his own training and ability.

My Seneca experience has been primarily in the II and III, and mostly operating from rough dirt airfields in remote locations, always in mountainous terrain. Whatever the book published numbers may be, 8,000 feet at gross weight on a standard day seemed to come closer to the truth when doing engine-out work...which isn't bad for a light twin.

The twin kills you faster, most who get killed while lost of trust on one engine is because they let the plane go below VMC or they feathered the wrong engine. While it doesn't happen with you it happens with other GA ME pilots alot. Why is that ? In a real partial loss (and you know that) it isn't THAT easy to feel what side has failled...the plane just goes from left to right...

Is there some particular benefit to dying slowly in an airplane? If not, then arguing which kills you faster is really a mindless inroad into the airplane decision making process here.

You assert that most fatal mishaps occur due to assymetrical thrust issues, specifically loss of control. Perhaps you could back that up, because if you bother to do a little research I believe you'll find that's not the case at all. Other causal factors such as controlled flight into terrain, fuel mismanagement, and weather related losses account for much higher numbers of mishaps and fatalities.

Now Sternone, based on your VAST experience with simulated and real engine failures in multi-engine airplane, you assert that identification of the failed engine is a difficult task. How many actual engine failures have you experienced in a light twin?

The amount of rudder input is dependent both on airspeed, and on the power setting on the good engine. I've had very pronounced yaw and need for rudder input, with no question which engine failed, and have had no indication in feel when powered back and in a descent, when an engine failed in a twin commander.

Propeller RPM may or may not be an indication, as the propeller when not powered by the engine may be driven by the slipstream at a speed which approximates it's driven speed...or the propeller may experience an decrease in RPM...what occurs depends largely on the airspeed at which the power loss occurs. Further, if it's a blower failure, the RPM will remain unchanged, but manifold pressure will change.

Fuel flow is a good indicator, generally. Not always; the nature of the failure dictates. Same for manifold pressure, etc. An EGT drop is a good indication, however...though it may not show a partial power loss.

Regardless, your assertion that an engine failure is difficult to identify in a multi engine airplane clearly shows that you really don't know what it is you're talking about. Again, that really paints you more in the troll category.

I know some very good pilots who will never fly a twin over mountains.

To each his own. I won't fly single engine IMC. I have spent a lifetime flying single engine airplanes in the mountains, and have even made forced landings in the mountains following an engine failure. I prefer a multi engine airplane for IMC not so much for the redundancy of powerplants, but for redundancy of instrument power (vacum), electrical power, etc. I like the performance a twin gives. A twin can be operated just as safely as a multi engine airplane; the burden comes back to the pilot. I've spent a lot of time in multi engine airplanes and single engine airplanes of all kinds, from light pistons to heavy turbojets to turboprops in the mountains, in IMC, and everywhere you can imagine.

I find that most experienced pilots are reluctant to fly single engine airplanes in IMC, or do single engine night work. Count me among them. I've certainly done it. I've experienced an engine failure in a single engine light piston single in IMC...right to a landing...and yes, in mountainous terrain. For me, experience is a great teacher, and teaches me that I really don't care to experience that again. I find that the willingness to do single engine IMC or night tends to be much greater with low experience pilots, and dwindles considerably as pilots gain experience.

Having said this, single engine IMC and night flying is done regularly, and most often safely by a great many people. I won't. Conversely, I won't fly many light twins IMC either, except under specific circumstances...or at night, or over certain terrain or water...because one needs to consider the limitations that apply to that specific airplane. To assert that one is more safe than the other is ridiculous; it's the pilot that makes the difference between what's safe and what isn't.

A single engine airplane should be flown within the limits of it's capability, just as a multi engine airplane should be.

If you're not comfortable flying a multi engine airplane, then you have no obligation to do so. Your comments that you won't fly with others here, however, smack of an extreme arrogance borne of ignorance, and you seem really proud of your ignorance. Ignorance doth not evidence make...and is hardly an arguement for or against flying a multi-engine airplane. What you're really saying is that you don't like multi engine airplanes because you don't know anything about them and don't understand their capabilities and limitations. Perhaps you should learn a little more before you try to know so much.

[Contacttower]

On what instruments are you always seeing a complete engine faillure?

Although one is not supposed to primarily use the engine instruments to gauge a complete failure they will show different from the live engine; say prior to the failure it was running at 2400rpm.....it won't be any more. The oil pressure will probably have dropped as well and the fuel flow. I agree though sternone....one may not always see those instruments do that.

You do seem to be rather overstating the "twins are dangerous case"....like Pace said mistakes can be made but at the end of the day if one follows the procedures....you know dead leg, dead engine etc you are unlikely to go wrong. Just curious sternone did you actually do the MEP rating?

Ah ha....I see Guppy has arrived....

[FlyingForFun]

Pace,

A complete engine failure will show on your Engine instruments

I demonstrate to my students that this is most definitely not the case. I do it by climbing to a safe height, then switching off the fuel on one engine. Depending on the aircraft (and I mean the exact airframe, not just the type, because they are all slightly different) I can usually demonstrate that the MP has not changed, the RPM has not changed and the oil pressure has not changed. Over time, the temperatures will start to decrease - although if there was a fire that probably wouldn't be true either. Perhaps you should try this some time (but not in something with a turbocharger, unless you want a big bill)?

The only way of identifying a failed engine in a light twin is dead leg, dead engine.

FFF
------------

[IO540]

The only way of identifying a failed engine in a light twin is dead leg, dead engine.

A quicker way would be to look at the EGTs - if you have a multicylinder engine monitor.

Pilots who fly with these watch them all the time, and the combustion upset is immediately obvious.

Or fuel flow - if you have an accurate flow indication.

As you say, the MP, RPM and oil pressure won't change because they are nothing to do with the combustion part of the engine. They are all driven off the rotating mechanism only.

[MIKECR]

And what if the EGT's ar telling porky's? It comes back to good old Dead leg, dead engine.

If an engine go's bang at less than 1000' ft on take off in IMC, there isnt a huge amount of time to go fact finding by hunting around the instruments. Control and identify asap.

[S-Works]

I would like to think that an experienced twin driver will be able to interpret the failed engine by a fluid assessment of all of the information available to them rather than a dogmatic approach to a single method.

I seem to recall a BMI aircraft that crashed due to the good engine being shutdown after an engine failure.

You are not always going to get an immediate dead leg indication on some types so an assessment of all of the data is a perhaps a better approach to the situation.

[shaun ryder]

Thats fine MIKE, but dont forget you will have no peripheral vision to assist with your diagnosis of which engine has failed in IMC. Instruments and not the seat of your pants surely!

[youngskywalker]

It's quite easy really, if the left engine fails on take off you will crash to the left, right engine fails you will crash to the right!

[IO540]

And what if the EGT's ar telling porky's

How is that possible?

With the common EDM-type instrument you get a bargraph for each engine. You can see immediately if there is something wrong.

The only way I can see of getting the "correct" EGTs is if the crankshaft snaps off right behind the prop (the prop comes off) and at the same time there is a fuel flow obstruction which reduces the fuel flow "just right" to maintain the expected EGTs.

[MIKECR]

IO540,

I think thats fine if your at altitude and have time do some kind of fact find. Pooter at the egt's or fuel flow indicators to your hearts content. At low level on take off in IMC and the engine go's bang/fire whatever...then theres a serious urgency to get it sorted. A rapidly decaying rpm needs to be feathered(ideally) before the prop locks. It comes back to control and identify...dead leg, dead engine....check the primary instruments...sort the problem. If you've got time..then fine...try and back up your diagnosis with use of other clues to hand. Im not even remotely an expert, far far from it, but thats what theyre teaching.

[youngskywalker]

...Just buy a King Air! Autofeather and rudder boost, much easier and loads of excess power at hand!

If I had the money, I'd just buy a nice little single engine aeroplane and have fun, if I had loads and loads of money i'd buy the above!

[Squeegee Longtail]

The fact that no-one here can agree on even a basic task like identifying which engine is out kind of answers why assymetric accidents give light twins a bad reputation.

Incidentally, the DA42 with FADEC takes the decision of feathering away, which just leaves you with flying an aircraft with f**k all single engine climb performance to worry about. So no real advance there then.