Deathtrap MU-2 BANNED

[Berkut]

Assumption that the majority of the pilots are below average is a stretch.

I'd say probably half of them are below average.

 

[Hung Start]

I think Lead was pretty much right on with his description of the airframe idiosycrises of the MU-2. If I may expand on that a bit, lets look at the differences with the Garrett engine.
I have over 3,000 hours with a TPE in a King Air. And never had any problems with it. But, it will not windmill and sometimes not "feather" automaticaly like most turboprops. It has a fine system called NTS, or Negative Torque Sensing, which if rigged and operating correctly will help drive the prop to about 88% feather, certainly helping alleviate a lot of the drag. But, if it is not working, or not handled correctly, you are driving THE ENTIRE ENGINE. No free turbine here. And, as opposed to a lot of multi-training, where we are taught to "test" the dead engine by slowly pulling the power back to idle, that only tricks the NTS into thinking YOU WANT TO GO TO IDLE!!! So, the NTS will then bring the blades back to flat pitch. Just look at the radius of those big 4 blades (or 3 sometimes) and imagine all that wing area cut off from airflow, and you are dragging that entire engine also. Just try spinning the engine by hand sometimes, you get the idea. So, picture this, the left engine is in flat pitch, killing lift on that wing, and to try to raise the wing you use the yoke instead of rudder, now you have raised the spoiler on the right wing and killed lift there too. The correct drill in an engiine failure is to push the failed engine power up full, not retard. And rudder, then trim.
I think little things like this, plus the spoilers have caused more than a few accidents out there. Still a great plane/engine combo, just needs to be learned and respected a bit better than most.

Hung

 

[avbug]

But, it will not windmill

Oh, it does. Trust me on that. I found out the hard way. I also use the braking effect to good advantage during steep descents down terrain faces...but it definitely does windmill. NTS at idle during steep descents will pulse in and out as the system seeks to put a load back on the blades. The governor is attempting to move the blades to flat pitch, whereas NTS is trying to move it out of flat pitch and toward feather to put a load on the blades.

I'd say probably half of them are below average.

Hard to argue with logic. One out of every ten are probably also in the top ten percent...

And you'd be right. The Avanti is 67 lb/sq ft.

Which begs the question as to w(h)eather the wing loading is particularly relevant to the accident record of the MU-2. The Avanti has a high wing loading (I believe the wing area is the same, or roughly so, as the Cessna 182...you're a lot better at math...you might know)...clearly this of itself isn't the defining factor. But it's often cited in arguements agains the MU-2.

 

[Fearless Tower]

Why? The Beech 18 is an airplane just like any other airplane. If you have basic conventional gear skills and a head on your shoulders, it is operated just as safetly as any other airplane...and insurance treats it accordingly. Operating it is basic stick and rudder (and instrument) skill...not rocket science. It's just an airplane.

That's just it.....I haven't had the privilege of flying in an 18, but everything I've heard on the Beech 18 bulletin boards is that the airplane is a relatively easy to fly and fairly dependable. Many who have flown it liken the old twin beech to a mini-DC-3. However, in recent years, the insurance rates for said airplane have gone through the roof and many pilots with less than 2000 hours time are finding it very difficult to get insured. Some say it's because of the tailwheel, others claim it has more to do with the twin 450 hp engines and still others claim it is related to the track record of freight operators. Regardless of the reason, the bottom line is that a low time individual owner operator is going to have some trouble getting insurance for the bird even though most pilots who have flown them find them very safe, reliable aircraft.

That MU-2 pilots don't seem to have the same trouble getting insurance seems to me to lend credibility to exactly what you are saying, Avbug: that the reality of the situation is that the plane isn't as dangerous as some would claim. I don't have the experience to say either way, but I find the subject rather interesting.

 

[Hung Start]

Avbug:

I guess I was not clear on that. When I say "it will not windmill", what I was saying is it will not windmill like a PT-6. Not a free turbine type of free wheeling. Yes, it windmills, but as a very heavily loaded set of blades that are in very flat pitch and driving the entire engine.
Agreed that you can use that to very good purposes, like landing in a very, very short distance, or descend in ways that ATC can't believe. And,,, if properly adjusted, they should not pulse. But most are never adjusted that well.
But, if you are in a loaded situation with a bad engine, and allow it to go flat instead of towards feather,, well,, your just going from bad to worse.

Hung

 

[Swass]

Awesome discussion guys.

Refreshing to see on this board again.

 

[A Squared]

I'd say probably half of them are below average.

Well, no, half are below the median. It doesn't necessarily follow that half are below average.

Let's say you have 100 people. 99 are 4' 6" tall. the other guy is 7 ft tall. The average height is 4' 6.3". 99% of that group is below average height.

 

[CrimsonEclipse]

What a ridiculous way to cloud the issue. Nobody ever tried to correlate a wing failure with pilot error, nor incude a wing failure in the pilot error statistics. A wing which separates might be construed to be pilot error if it were the result of something the pilot might have found during a preflight, or if the pilot elected to fly through a thunderstorm. However, when we speak of pilot error and issues involving basic airmanship skills we're not speaking of wing separations.

Wow, someone takes themselves too seriously.
It's called SARCASM!

100% of the MU-2's could be involved in accidents...and this still wouldn't make it a dangerous airplane, seeing as the overwhelming majority of accidents and fatalities are the result of pilot error. This would make it a field of dangerous pilots...which not conincidentally is the leading causes of why the King Air crashes, too. Further, 100% of the MU-2's could be involved in fatal accidents and still not brush the fatalities caused from the wreckage of B737's.

Um, yes...it would.

Nobody argues that the B737 is dangerous, despite the number of fatalities. Yet the MU-2, frequently involved in fatalities when flown by untrained, inexperienced pilots with a common identifiable thread of deficiencies in background and experience, causes a sensation.

It's not the total, it's the number of accidents per flight hour, and it's
MUCH higher in the MU-2.

This web board was dominated for a time with the last spat of MU-2 fatalities, lorded over by wives and sisters of the deceased. Not experienced individuals who had a clue whence they spake, but by people who were presed by emotion and not knowledge or understanding. These same individuals were responsible for the lobbying that has lead the FAA to once more set it's political foot forward to "investigate" the airplane.

True, but doesn't change the facts.

Three separate panels of FAA investigators examining the airplane, it's history, it's accidents, it's everything, and putting 60 hours of flight testing on the airframe last year, and the official observation that "with reasonable training, an average pilot can operate the MU-2 safely if operated within the AFM guidlines." One might reasonably infer that either the MU-2's involved in accidents were being operated overwhelmingly by below average pilots, that average pilots had less than average training, or that average pilots (some better than others) failed to adhere to the AFM guildelines. Perhaps a combination thereof.

Of course, it's everythig BUT the airplane.

Assumption that the majority of the pilots are below average is a stretch. A given is that training by and large, particurly statistically among those involved in fatal accidents, is inadequate. That pilots have failed to adhere to AFM guidelines is also often borne out in accident investigations. Obviously far more flights are conducted successfully by pilots who are adhering to the aircraft manufacturer's guidelines than not, else we'd see a higher percentage of losses. Here we have everyman's airplane that really shouldn't be flown by every man...but legally can be until newly mandated training takes place.

The airplane requires MANDATED training but is not different from every
other airplane. Um, ok...

As proper training and oversight is mandated, a decrease in the accident rate and record is inevitable; this is exactly what we shall see. Again, there's nothing wrong with the airplane; it's a poor carpenter that blames his tools.

Except my tools don't kill 10 at a time.

All things mechanical can fail. As pilots, much of our training is spent not learning to fly operating equipment, but to deal with the failures. And therein, so said Sir William, lies the rub.

Rub all you want, just look at the numbers.

CE

 

[Hung Start]

Swass:

You were saying????,,,,,,,,

But we made it to 4 pages.

Hung

 

[Swass]

Waiting.......... for..................the................



"brightspark" comment that is sure to come.........

 

[avbug]

I hate to disappoint you, swass. Actually, that's not entirely true, but I'm going to disappoint you, and deal with the self-loathing, anyway. No sparks of brightness for you, today.

Agreed that you can use that to very good purposes, like landing in a very, very short distance, or descend in ways that ATC can't believe. And,,, if properly adjusted, they should not pulse. But most are never adjusted that well.

The Garrett may be set up in many ways, and all may be proper. The design of the airplane, and the maintenance documents attached to it, enable it be set up not only for a particular installation, but for a particular operator.

Ours were set up such that bringing the power levers to idle nearly tossed you out of your seat; the airplane could be pointed practically straight down and nearly stall out...that much braking action. When I first got in the airplane I had been in the same type with a PT6 engine on it, and out of habit pulled the power lever to idle during the landing. The airplane fell out of the air. During an hour and a half introduction to the airplane, I did a record number of go-arounds as I tried to find the sweet spot on that power lever.

In that condition, which is properly set up for that application, in a very steep dive down a canyon or hillside, the airplane will be felt very strongly to pulse as the NTS pushes the blade angle toward coarse. The flip side of it was found when I flew an airplane that hadn't been rigged quite right. The fuel control and the underspeed governor were discovered to fight each other if the speed control backed off the forward stop at 100%. We had to readjust the speed control bottom end (underspeed gov) to 98% instead of 96% because it was fighting the fuel control and causing massive engine surges. This wasn't learned until a throttle quadrant developed some play and the speed control backed off in flight. Power rolled right back to idle then surged up again, and kept doing it in increasing cycles.

It was a definite attention-getter.

 

[Berkut]

Well, no, half are below the median. It doesn't necessarily follow that half are below average.

Hence the "probably"

 

[Say Again Over]

Nts

I agree with the previous post that flight idle fuel flows can be set up to Pulse or not to Pulse, it's really an operator preference. As far as whether the system is working properly, it's very easy to check during start up, if you don't verify that it's working, you get what you get, I've turned engines off at a safe altitude without the system working properly and there is tremendous yaw, not something you'd ever want to see just after takeoff.

 

[Bringupthebird]

The Cessna 208 Caravan deserves far more scrutiny than any MU-2. Mr. Tancredo should look at the abyssmal accident rate of that thing first. IMHO, no single engine should be allowed in commercial service at night, IMC or in icing.

 

[GoingHot]

no single engine should be allowed in commercial service at night, IMC or in icing.

That would take out a lot of airplanes currently flying everyday in those environments. The 208s alone, number several hundred.

CE-208
CE-210
CE-207
PA-32
PA-46
TBM-700
PC-12
others

 

[avbug]

I agree with the previous post that flight idle fuel flows can be set up to Pulse or not to Pulse, it's really an operator preference.

The pulsing on descent is actually the Negative Torque Sensing (NTS) system, which isn't a fuel adjustment. It's the governor driving the prop to coarse to apply positive torque, or a load, to the driveshaft.

The fluctuations that take place due to the speed adjustment interference occurs when the bottom end of the low speed governor is set close enough that when the power is pushed up (and the speed lever set back to lower RPM), the prop governor tells the fuel control to pull the power back, and then causes a reduction in fuel flow. The fuel control senses this as going underspeed and applies extra fuel, and the surge is interpreted by the governor as an overspeed and it takes away even more fuel. The engine begins to surge. The simple soloution is to set the bottom end of the propeller governing range up a little.

Personally I think it's a poor design that's capable of getting to that point as a function of normal positioning of the engine controls...but it is possible, even within a properly adjusted engine set according to the manufacturer.

 

[Hung Start]

Once again, I understand about the fuel flows and the pulsing. I know it can be set up either way, and having flown at least one that was not set up well,,, oh yeah, it grabs your attention. Especially if one is a "hard" low pitch and the other is not. Talk about yaw!
But (and I am the first to defer to Avbug on this, because I am no mechanic) I believe Garrett or Mitts came out with a S/B on setting either the fuel flows or blade angles recently to help counter that.
Still,,,, a well seasoned and qualified pilot who knows the systems will be able to counter any rigging/setting/flow problem.
Just my .002 with a fair amount of Garrett time.

Hung

 

[siucavflight]

IMHO, no single engine should be allowed in commercial service at night, IMC or in icing.

Wow, I would hate to see that happen.

 

[Hung Start]

Well, if we put into our OPSPECS, as not allowed, it obviously cannot happen.
Why was this not thought of before????

Hung

 

[Rally]

As far as insurance goes. I have a '56 C-172 and a '54 C-170. Same exact airplane except for the position of the gears. Double the insurance. Lots of accidents in a C-170. It can be slightly tricky on occasion, but really when it comes down to it you just gotta steer and not let up on it. Probably the same way for the MU-2 in laymans terms. Problem is old habits die hard with the hold 3 degrees of bank etc into the good engine, according to what most people say your probably gonna end up in the dust.