Heli down

[500E]

Glasgow UK police EC 135 down on bar, reports of 8 dead including 3 crew sad day.

Condolences to bereaved & hope those in hospital recover ok

[HeliNomad]

Was the helicopter a BO105 or an EC-145?

[Flying Pig]

135

[avbug]

Two days ago. Old news.

[TomPPL]

Avbug, two days old yes, but as of today they are still removing bodies from the site.

[JCM5]

Any idea yet what caused this?

[aeroscout]

There is a lot more about this crash that I would like to know. I'm sure I'm not the only one. I'm glad the story didn't get shelved after a day or two.

[rubidug]

Heli looks to have come straight down.

MR blades seem to be not damaged, heli on its side (retreating blade stall)....looks to me they didnt get into autorotation. Aft cyclic!!!

My condolences with the deceased and their families...

[JCM5]

Heli looks to have come straight down.

MR blades seem to be not damaged, heli on its side (retreating blade stall)....looks to me they didnt get into autorotation. Aft cyclic!!!

My condolences with the deceased and their families...

 

As a Robbie pilot I don't know much of anything about EC flight dynamics.

 

What sort of things would cause a twin engine 135 to need to enter an auto?

 

Could this be 100% pilot error? What kind of mechanical failures are possible and/or likely to create this scenario?

[500F]

Running out of fuel will do it, Though usually it’s not simultaneous. TR drive fail can cause you to need to enter an auto, especially at a hover. I'm not sure either is the case here. In many twins. Loose one engine at high weight in a hover and its not much different than a single, more time to pick you spot and more cushion, but you are still going down.

 

I've never flown a 135 but one possibility on my mind would be a single engine failure in a hover or low speed maneuvering followed by a raised collective resulting rotor stall.

 

A lot of things can cause a single engine to fail in a twin. All of the same things as a single, X2.

 

[iChris]

Heli looks to have come straight down.

MR blades seem to be not damaged, heli on its side (retreating blade stall)....looks to me they didnt get into autorotation. Aft cyclic!!!

 

 

Are you confusing “blade stall” with “retreating blade stall”? Retreating blade stall occurs during high forward speed flight and is a tangential velocity issue at the retreating blade. Overall blade stall (due to low RPM), were the aircraft literally falls from the sky, is likely to result in the damage you speak of.

Edited December 2, 2013 by iChris

[rubidug]

Usually a helicopter has some motion, whether it be forward or otherwise laterally.

When the rotor starts to lose RPM, one side will stall first. Its the retreating blade, because of the higher angles of attack.

Two accidents that have been studied significantly by the school I am attending have shown that when there is engine failure (or other power failure), and the RRPM drops, the aircraft will fall from the sky sideways, because retreating blade stall occurs before overall blade stall.

[Wally]

 

As a Robbie pilot I don't know much of anything about EC flight dynamics.

 

What sort of things would cause a twin engine 135 to need to enter an auto?

 

Could this be 100% pilot error? What kind of mechanical failures are possible and/or likely to create this scenario?

 

Fuel issues. Antitorque and plain drive train failures. Uncontained catastrophic engine failures have taken the other engine out. Pilots pull the wrong engine off-line and/or mismanage systems. Twins can be complicated.

It's not certain that the aircraft landed from an auto. Witnesses claim various things, low/no rotor, vertical descent, tumbling, various odd noises. No mayday call on record is interesting, too.

[500E]

The AAIB man stated on tv tonight that,

No distress calls made,
From the radar data the a/c came straight down,
The a/c was intact when it crashed.

 

Low fuel very unlikley, engins fed from diferent tanks of diferent sizes, + numerous warning prompts.

[500F]

I am told catastrophic rotor system failures often break occupant’s necks nearly immediately due to the inbalance. Perhaps if the head did fail it could explain the no mayday call. How high was he?

 

[iChris]

Usually a helicopter has some motion, whether it be forward or otherwise laterally.

When the rotor starts to lose RPM, one side will stall first. Its the retreating blade, because of the higher angles of attack.

Two accidents that have been studied significantly by the school I am attending have shown that when there is engine failure (or other power failure), and the RRPM drops, the aircraft will fall from the sky sideways, because retreating blade stall occurs before overall blade stall.

 

Is that what you're planning on teaching as a CFI on retreating blade stall? Moreover, is that all your school teaches on retreating blade stall?

Edited December 3, 2013 by iChris

[rick1128]

This is going to be an interesting accident investigation. Europe is firmly in the two engines are safer camp. Personally all the extra engine does is double your chances of an engine failure. No or minimum damage to the blades leads be to suspect that the rotor was not turning when it hit.

 

Not sure about the T2, but the P2 allows the other engine to go to a higher power setting when one engine has failed. Would suspect that the T2 does the same.

[rubidug]

 

Is that what you're planning on teaching as a CFI on retreating blade stall? Moreover, is that all your school teaches on retreating blade stall?

 

Thanks for your insightful input.

[Dnr032]

Thanks for your insightful input.

iChris asked a question. Are you going to answer the question? I would like to know the answer also.

[rubidug]

Well, there is obviously more to RBS than stated above.

I have not started my CFI training yet. I'll have to get back to you!

 

 

I stated that it 'looked' to me...should i have said dissemetry of lift? I was comparing this accident to ones that we have looked at.

Maybe you could be a little nicer, and explain what I said that was incorrect?

I certainly don't want to spread incorrect information....

 

 

iChris asked a question. Are you going to answer the question? I would like to know the answer also.

 

 

Seems like more than one of us didn't know

[Dnr032]

Thanks for your insightful input.

 

Seems like more than one of us didn't know

 

Maybe you could be a little nicer, and explain what I said that was incorrect?

 

Since it appears to me you are the one who is started the sarcasm when iChris asked a question, and no I don't think I can be nicer in my reply, I will just jump out of this conversation. I will leave it to you and your vast experience.

 

I will offer, however, if you want to PM me, I will be nice and maybe pass along some useful and helpful knowledge and advice. But I will do it in a private manner not in this public forum.

 

Good Luck to you.

[JDHelicopterPilot]

The EC135 has multiple warning/caution lights when it comes to low fuel state. This in addition to a graphical and numeric display of fuel level. Also the EC fuel systemis designed so that both engines wont flame out at the same time.

 

Will be interesting to see the final report.

[rubidug]

 

Is that what you're planning on teaching as a CFI on retreating blade stall? Moreover, is that all your school teaches on retreating blade stall?

 

So, I asked the instructors at my school tonight to look at this post. The answer to your question, is yes, that is what they are teaching at my school.

 

"Retreating blade stall occurs during high forward speed flight and is a tangential velocity issue at the retreating blade. "

 

Yes, that is true. But, retreating blade stall can also occur at ANY speed, under low RRPM. I was told that no placards, charts, or POH's talk about this. Why? Because they expect the pilot to ALWAYS be in the green on RRPM. If anyone could find that chart, it would be you iChris!

Maybe you can produce one!?! I would certainly earn some extra credit points if I could use it

 

And, as I told dnr032 privately, I am NO expert. I am a >50 hour student. I was simply offering a suggestion that was passed along to me by someone with whom I respect as having an expert opinion. Simply put, it is our goal to save lives.

[pilot#476398]

tangential velocity

 

 

[Nearly Retired]

Rubidug, there is a guy on Facebook who posts in that "Helicopter Pilots" page. He is also a student pilot but he comes across and portrays himself as someone who is very knowlegeable (expert even!) about how helicopters fly. Only...he gets things wrong. When challenged, he claims to have been verbally taught said material by instructors whom he trusts implicity and who have more flight time than me and Avnut and iChris and Chuck Yeager/Aaron and every other "old-timer" on this board combined. I mean, these guys are Gods! Thus, he considers the information he's gained to be of tremendous value, and that there can be no other way (or method, or theory, or whatever), and he transmits this material as if he learned these things himself by his own experience. Only he hasn't. In other words, he's a parrot but not even a very good one.

 

As we gain experience, we (hopefully) learn that there is a time to talk, and a time to keep quiet. More and more, I find myself biting my tongue (along with a good deal of eye-rolling) as young pilots pontificate grandly about this or that, as if they in their vast experience should have a Ph.D in helicopter flying.

 

Not saying this is you. Just sayin'.

 

But in general, when you want to ask a question, it's best to just ask the question and not add any "qualifying statements." For instance, your original post submitted that the helicopter rolled left (although that has not been shown to be true as far as I know) and went on to postulate that it could be because of retreating blade stall because of something you've been taught - which might not have been extremely complete. Ahhhhh...well...you know...

 

Sure, a helicopter with very low rotor could roll-off to the retreating side...*IF* it had some forward speed. Then it would crash inverted or at least on its side. To most of us who've seen a helicopter crash scene or two, it was clearly apparent from the get-go that at the point of impact the EC-135 in question had very little forward speed at all...maybe none. And no rotor rpm either, judging by those pristine blades. And it looked like it hit pretty level.

 

It's always interesting to speculate - especially for pilots who fly the '135. We like to...no, strike that...we need to know what happened, so we can file it away in the back of our minds in case a similar situation happens to us. But the need to know must be tempered with caution. Let's not jump any guns before the wreckage is even cold.

 

So okay, what could have caused this crash? Most of us who've been around a while know better than to even hazard a guess. Why not? It's too puzzling! Nearly zero rotor rpm? Vertical descent at extremely high rate? No apparent fuel at the crash site?? We will assume that the helicopter had been in forward flight, not in a hover when the Bad Thing happened, so that kind of rules VRS out. Of course, that could be wrong, but we generally don't see police helicopters hovering in place like ENG helicopters do. Police ships orbit.

 

We could presume that he ran out of fuel, but the EC-135 is designed so that both engines don't flame out at the same time (i.e. one feed or "supply" tank is larger than the other). We could presume that he had a catastrophic transmission failure, but why then would there be no fuel in the ship? (That would be some incredibly bad timing for one unlucky crew.) And no matter what the emergency, why go for a roof? That's puzzling because I'm not sure I would, even at night. (My own speculation is that the aircraft was *not* under control as it came down.)

 

So far, Tuesday night here, there are still so many unanswered questions. Too many to be throwing out wild theories. Time will tell. And probably quickly. We just have to be patient enough to wait a bit.

 

I know that young pilots want to know everything. They're big sponges, absorbing as much as they can about flying. Which is great! The problem comes when the young pilot feels that he's absorbed enough to actually know something about helicopters. Let me tell you something: As long as I've been doing this, I'm still learning. And maybe the most important thing I've learned is that I don't know everything. Often, when I think I *know* something, even something I've *known* for years, I'll get some evidence or information to the contrary. It usually leaves me scratching my (balding) head, going, "How have I not crashed and killed myself yet?" (Oh, sorry, that's more of that insecure, introspective crap that Avnut says I should just keep to myself.)

 

As the Scottish investigators do their job, there is no doubt that we will soon learn more details about this puzzling crash. I'm sure all of us will be very interested to hear what they have to say. Me? I'll wait.