How much different is it than a engine failure?

Take off is not the phase of flight I worry about with this failure it's low and slow where it can kill you or in a idle descent.

There are dozens if not hundreds of Bendix -10 conversions in the fleet.

Edit spelling

I agree. You may be able to land a crippled, under winged, underpowered Metro or other plane with one at full power, and so probably want that mode given the lack of performance on takeoff, etc, but not so much in a Commander.

Agree! Steve - more pics of that bad boy!!

Except the engine indications are confusing. The engine has not flamed out.

Except the NTS system has not activated. You are in higher drag than flight idle with no help from the NTS system.

Except the engine does NOT spool down in RPM. No change in RPM, thus no audible cue pilots are used to getting with an engine failure.

In a true engine failure, it flames out AND the engine spools down AND you get NTS.

So NOT THE SAME AT ALL.

It would be MUCH BETTER if the FCU DID flame out, but no, they modified it so it keeps the engine running for no sane reason.


Yes, but handling this is natural. Unbriefed pilots handle the emergency without training or warning. Witness the SDR I quoted of a true life example ON APPROACH, where the fail high condition is WORST.


Not true. The prop governor will hold engine RPM by loading the engine. The engine will not exceed prop governor RPM.

If you have a torque/temp limiter enabled (I don't have one), then it MAY help to reduce the torque. But even if it doesn't, engine will not self destruct.


Not true. The FCU runaway failure has been given as a surprise to unbriefed pilots at random times.


No big deal, I've had it maybe 20 times over the last 8 years. I can't recall a single case of all the pilots we have had in the sim failing to handle it properly even when given as a surprise and even when not discussing FCU failure.


My opinion is that you have greatly overestimated the fail high scenario risks.

Have you experienced it? I have at least 20 times.

I have fail high FCUs. They are safer by far, IMO.

Mike C.

Surely you realize that no one is suggesting you land with one engine at full power.

What the fail high FCU does is give you a chance to get to a safe altitude and airspeed, shutdown the broken engine, and then land OEI.

Mike C.

Takeoff is when you are low and slow. If you can handle that, then you can handle it on approach.

You are not on approach at flight idle power.

In a flight idle descent, you have airspeed which makes the event very benign.

Even if you have fail low FCUs, there ARE other failure modes which can cause the engine to fail at high power. This is a failure mode EVERY turbine pilot should know about and be able to handle.

Mike C.

Except the engine indications are confusing. The engine has not flamed out.

Except the NTS system has not activated. You are in higher drag than flight idle with no help from the NTS system.

Except the engine does NOT spool down in RPM. No change in RPM, thus no audible cue pilots are used to getting with an engine failure.

In a true engine failure, it flames out AND the engine spools down AND you get NTS.

So NOT THE SAME AT ALL.

It would be MUCH BETTER if the FCU DID flame out, but no, they modified it so it keeps the engine running for no sane reason.


Yes, but handling this is natural. Unbriefed pilots handle the emergency without training or warning. Witness the SDR I quoted of a true life example ON APPROACH, where the fail high condition is WORST.


Not true. The prop governor will hold engine RPM by loading the engine. The engine will not exceed prop governor RPM.

If you have a torque/temp limiter enabled (I don't have one), then it MAY help to reduce the torque. But even if it doesn't, engine will not self destruct.


Not true. The FCU runaway failure has been given as a surprise to unbriefed pilots at random times.


No big deal, I've had it maybe 20 times over the last 8 years. I can't recall a single case of all the pilots we have had in the sim failing to handle it properly even when given as a surprise and even when not discussing FCU failure.


My opinion is that you have greatly overestimated the fail high scenario risks.

Have you experienced it? I have at least 20 times.

I have fail high FCUs. They are safer by far, IMO.

Mike C.

Maybe it's the difference in OEI performance.

You feel the fail high FCU is better because of the MU-2s performance during take off. It is very critical time of flight for a MU-2. You are right, I would want the fail high in a MU-2 also.

In a commander a engine out on take off is a very easy thing to handle. I don't worry about that as much as being surprised by a single engine going to full throttle.

I was unsure about completing the FCU upgrade. It was expensive and the failure is something I couldn't train for.

I tried to talk myself out of doing it until I asked myself this, (would I do the upgrade if it was free). That made it a easy decision.

The FCU failure on take off with the upgraded FCU is very similar to a engine failure or say a loss of thrust at take off. My concern is the other 99.9% of the flight. The upgrade improves safety throughout the rest of the flight.

It also eliminates an inspection every 1000hrs and a 3000hr parts replacement.

If the loss of thrust on take off does not trigger the NTS then its even easier to handle than a engine out! Thats less drag than a normal engine failure on take off.

Your example using a professional crew of two does not work for me.

I am a typical owner pilot who flies his plane about a 100 hours a YEAR not a 100 hours a MONTH like those pro guys.

The sim is not REAL! You are never, or you should never be surprised in the sim!

That sim experience is great for Muscle memory but does not simulate a real emergency environment.

Then an FCU fail high is easy to handle on approach, too.

I fail to see why the Commander is so benign on a takeoff engine failure and deadly with an FCU fail high on approach. Either it handles asymmetric thrust well, or it doesn't.


No Commander simulator exists that has FCU failure as an option? I find that hard to believe.

Even when we put green pilots in the sim, not briefed on FCU failures at all, they handle it pretty well. The key, like anything in a turboprop is to fly the plane first, and then deliberately handle the failure carefully.


Cruising is at high power, so not that big a deal. Nobody should have any problems handling a failure above 1000 AGL of any kind.


The FCU AD (new version AD 2015-12-04 or old version 2006-15-08) has no 3000 hour parts replacement. What parts do you think have to be replaced?

The spline inspection isn't invasive.

The new FCUs with plastic splines fail at a higher rate than the old steel ones.


That's a common misconception. An engine at 0% torque is significantly more drag than an engine in full NTS. You'd think that 0% torque would mean the prop is not draggy, but that's not the case. You can tell this is so because simulated feather is well above 0% torque, around 14-18% torque or so.

The FCU fail low torque might be as low as -5%, small negative torque. This is just small enough not to trigger NTS. Even if it does trigger NTS, the NTS will immediately release and the prop will oscillate in nearly flat pitch, high drag. NTS won't get anywhere near mostly feathered like it would for a true engine failure.


I provided one instance where an FCU failed high on approach. Handled.

I provided one instance where an engine failed, not FCU, but had all the same characteristics of fail low FCU failure, and people died.

Both cases are Metros.

If you want to argue that your situation isn't like theirs, that's fine, but the confusion of having a not NTSing failed engine exists and you should not discount it. It confused a pro crew.


The sim is a lot more real than you give it credit. When we do LOFT based training, no failures are telegraphed. They can occur suddenly, without warning, in the worst possible situations. The pilot has to diagnose the problem and deal with it.

Indeed, in airplane training is a LOT LESS REAL. The instructor telegraphs which engine failed because he has to move controls right in front of you. He can't do numerous failures simple because he can't fail some system with the controls he has.

If you have not taken sim training, I strongly recommend that you do. It will open your eyes.

Mike C.

Read the Red Lake Metro accident. A pro crew couldn't handle it.

http://www.tsb.gc.ca/eng/rapports-repor ... 3c0150.pdf

BTW, the then director of maintenance for Bearskin Airlines, Clark Blumberg, was part of the team that I was on that worked on getting the FCU AMOC approved which ultimately led to the revised AD allowing the fail high steel spline FCUs to remain in service. They felt the fail high FCU was more reliable to start with, and was safer when it did fail. It was a Bearskin Metro which crashed at Red Lake.

Mike C.

It's the unexpected happening at the worst time. That's what I want to avoid.

Engine failure on take off, everbody is ready for that.

Not so much a runaway FCU when you are concentrating on shooting an approach in difficult weather. You are in a vulnerable position for an engine to go to full throttle for no apparent reason. That's goes for any airplane, because of the timing, but you are right I would much prefer a commander if it did happen.

Same with a idle descent. Sure you have airspeed but you are unlikely to be ready if somebody shoved a throttle to 130% torque. Particularly in weather and if busy setting up an approach.

I like training in a sim as much as the next guy. I have also had loft scenarios. It's not the same as a real emergency!

How could it be, you study the night before you go in. So you will be ready for some kind of problem.

Duh! It's simulated.

i would expect simulated feather to be at 14% torque but that's not what we were taking about.

There is a diaphragm that gets changed at 3000hours if you don't upgrade.

Read the Red Lake Metro accident. A pro crew couldn't handle it.

http://www.tsb.gc.ca/eng/rapports-repor ... 3c0150.pdf

BTW, the then director of maintenance for Bearskin Airlines, Clark Blumberg, was part of the team that I was on that worked on getting the FCU AMOC approved which ultimately led to the revised AD allowing the fail high steel spline FCUs to remain in service. They felt the fail high FCU was more reliable to start with, and was safer when it did fail. It was a Bearskin Metro which crashed at Red Lake.

Mike C.

Fail low FCUs can also fail at high power. The mod changes the way it behaves only on spline failure, not the other possible failure modes.

You always have to be ready for engine failure be it flame out or more than full power.

The Red Lake accident shows that going into high drag, no NTS, partial engine failure puts you in a vulnerable position. They were in visual conditions when the failure occurred at 500 AGL.


Ah, now I know what you are talking about. The old style rolling P3 diaphragm. Yes, this has a 3,500 hour replacement from what I understand.

My FCUs are middle generation with P3 piston style (no diaphragm) but with fail high and steel splines.

The diaphragm to piston change has nothing to do with fail high or low behavior.

One of the problems with later FCUs is that the piston style isn't always better than the diaphragm style. There are problems with corrosion in the piston style and P3 air bypassing the seal sometimes. Not all improvements turn out to be so in the end. There are those who think the diaphragm style is superior to the piston style.

Mike C.

Yes. We know they can.

I offer the SDR of a crew having a fail high FCU failure on a Metro. They went around, climbed, shutdown engine, landed single engine, no accident.

Two nearly identical situations, two different engine behaviors, two different outcomes.


That's not what happens. The thrust asymmetry is less than a takeoff engine failure and you are at higher airspeed, so it is easily handled. It is also not ambiguous which engine has the problem, something that afflicted the Red Lake accident.


Quite the opposite. Bearskin had converted their entire fleet to the new fail low FCUs for some time and he was reporting the problems they were having. The AMOC did not apply to him (he was in Canada for one thing, not under FAA jurisdiction), he was just providing data to help in the root cause analysis.

I can see you are resolute in your belief in the fail low FCUs and will invent defenses against all logic and evidence I can present, so keep them. But if you get a chance to sim fly the various scenarios, I think you will change your mind.

Mike C.