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Old 16th Dec 2012, 06:59   #61 (permalink)
 
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Shawn,

As you claim to be an investigator having dealt with several 350 crashes, it surprizes me a great deal that you are so fixed up on just one failure like you are. Most of the crashes I know about does not involve mechanical failure at all, but poor judgement and airmanship, much like the common cause in most EMS accidents in the US.....

Being an investigator with some credibility, one can't draw conclusions before the helicopter has been lifted out of the water like you did in your first post!! And seems to continue to do.

Now, if I would have a Hyd-failure over 4 deg water, I for sure would give a flying f..k about any restrictions zone and head for the nearest dry land to put down on.

As the pictures show very little damage, this looks like a forced landing and a ditching that went well, but since the helicopter appears to not have floats, the crew had to evacuate to not drown inside. With this little damage on the helicopter, and the occupants found outside, I would assume that they were concious and exited the helicopter themselves.

So Shawn, does this accident look like an uncontrolled crash or does it look controlled? If controlled, do you think someone with "only" a hyd failure would elect to ditch a non-float equipped helicopter into 4-5 C deg water?, with a beach or heck the departure airport within 10-15 min of flying??
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Old 16th Dec 2012, 07:22   #62 (permalink)
 
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And, perhaps the crew were non swimmers, but a hasty decision indeed if they embarked on this course without life jackets???
Even good swimmers wont stay at the surface for a long time with watertemps of 4°C and airtemps below 0°. As they were found at the seafloor well clear of the wreck, i assume they had no lifevests...

skadi
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Old 16th Dec 2012, 08:11   #63 (permalink)
 
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Give the guy a break......

...... when Black Max began to contribute his critique on composite structures I don't recall a backlash against his obvious technical experience in that area. We all, after all, have a duty to contribute to the pool of knowledge and experience on any subject that relates to an accident.

Having just read the thread for the first time in detail I find Shawn's contribution balanced and informative insofar as he is sharing his experiences with the rest of us. I don't see Shawn stating that he has identified the cause of the accident, merely pointing up something that might be missed unless the investigation goes into some detail. The S76 accident in the Baltic some years back turned out to be a hydraulic issue and that has a dual hydraulic system. I believe it took some good detective work to establish the cause of that problem.

The thread also contains the experiences of others which is why this forum is so valuable. I suggest a little less emotion (difficult for those who are emotionally involved with the crew and pax I know) and more information and opinion will add to our overall understanding.

G.
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Old 16th Dec 2012, 08:23   #64 (permalink)
 
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Hear hear.
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Old 16th Dec 2012, 22:56   #65 (permalink)
 
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Condolences to the people involved in this tragedy. Shawn keep up the good work, eurocopter should be pushed hard on the subject of their hyd system in the 350. The last two fatal accidents involved with the 350 in Norway have both been concluded by the Norwegian accident investigation board to be due to servo transparency. Hopefully this is not another one..
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Old 17th Dec 2012, 08:55   #66 (permalink)
 
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Mustfly79,


Tragic days for the families and all involved in this last accident.
Hopefully the investigators will find the cause of it as the helicopter seems to be almost intact.

Now, as you refer to servo transperancy, I don't know how much you know about the phenomenon, but it is nothing that will happen to a helicopter in cruise flight. From the accidents you mention,(all of them+a good few others) without going too much into details, they did not fly straight and level just prior to their crashes, but (semi)acrobatic flight with full ship of pax with moderate to high G-turns,High speed,etc. Google: Sundance Helicopter N270SH, or Colin McRae, G-CBHL. Those have also been discussed here before, but the investigation reports are openly availble if you do a search for it. Those are only examples, as there are many more.

In those crashes, I am not too sure the result would have been too different if said individuals was flying a another machine at the time....

Back a few years, there was a video of one of American Eurocopter's testpilots on the BO105, which was practicing for a filmshoot that went badly as well due to the pilot's too agressive handeling at a too low altitude, combined with the flightcaracteristics of the BO-105. I don't feel it is appropriate to blame the helicopter for those accidents, which is related to the individuals aciton behind the controlls.

So, for this accident which we know very little about just now, but the helicopter being almost 100% intact is a good thing for the investigators. I think it is a wrong approach to start focusing on the Hyd system like some are more inclined to do. It is just too early to do that.

All the best.
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Old 17th Dec 2012, 10:19   #67 (permalink)
 
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Official police news statement:
No HYD Problem in this case! The first inspection revealed a T/R driveshaft failure.

Grund für Hubschrauber-Absturz geklärt

Both POBs died from hypothermia and drowning.

skadi

Last edited by skadi; 17th Dec 2012 at 10:20.
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Old 17th Dec 2012, 11:11   #68 (permalink)
 
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Helitrans (Norway) AS-350 missing off coast of Germany

Hi all,

I´d rather wait for the official report.
Broken tailrotordrives are luckily a very very rare occourence.
But the drives they shear, if the tailrotor gets stopped rapidly, i.e. by immersion into water....
The whole wreck seems so intact, that I have my doubts about a failure in flight...
Probably someone on board the vessel heard something about the broken tailrotordrive and sold it to the press...
Lets wait and see...
Greetings Flying Bull
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Old 17th Dec 2012, 11:16   #69 (permalink)
 
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Quote:
Probably someone on board the vessel heard something about the broken tailrotordrive and sold it to the press...
But it was officially distributed by the police with relation to the BFU-inspectors.....

skadi
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Old 17th Dec 2012, 11:19   #70 (permalink)
 
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Looking at how intact the main rotors are, it looks to me as though the rotors were close to stopped when the a/c went into/under the water, which would indicate an engine failure with an auto to ditching and pulling the rpm down to nothing after the flare for splash-down.
Normally when the blades hit the water in a controlled ditching, the torque effect rips everything to pieces and rolls the cabin over...
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Old 17th Dec 2012, 11:32   #71 (permalink)
 
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Helitrans (Norway) AS-350 missing off coast of Germany

Well, they say ""first findings" and you have Seen the pictures?
There are technical issues, which lead to crashes, like the 225 thread shows, but a tailrotorshaftfailure?
That it is broken after the bird landed in the water is what I expect. But as the reason for the crash? Possible but very very unlikely, is what I think and therefore I wait for the final report.
Greetings Flying Bull
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Old 17th Dec 2012, 12:19   #72 (permalink)
 
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It's not inconceivable that a hyd malfunction (hard over or pump failure rather than servo transparency) could cause a some pilots to elect for a ditching rather than continued flight - if you don't really know what has gone wrong but you are struggling to control the aircraft, you are not in a very good place to know what else might go wrong.

Engine failures are far rarer than hyd malfunctions.

Last edited by crab@SAAvn.co.uk; 17th Dec 2012 at 12:21.
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Old 17th Dec 2012, 13:08   #73 (permalink)
 
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Crabs,

Yes, Hyd-failures and more so Hyd-transparencies are certainly more of a problem for this helicopter than engine failures. But engine failures and flame-outs, allthough the result is much the same is not the same thing.
The weather seemed to turn shit, with snowfall and presumably around freezing temperatures. Not a good combination if your aircraft does not have an inlet filter.

But hey, lets keep pushing the Hyd theory...

For Flying Bull or skadi,

According to this news article: Hubschrauber wohl vor Neustadt abgestürzt | shz.de

It says:
Quote:
Vor Fehmarn setzte der Pilot ein Notsignal ab.
Is my German correct by saying that the pilot, managed to send out a Mayday? Or might this be just Journos adding to the story?
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Old 17th Dec 2012, 13:39   #74 (permalink)
 
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Quote:
Quote:
Vor Fehmarn setzte der Pilot ein Notsignal ab.
Is my German correct by saying that the pilot, managed to send out a Mayday? Or might this be just Journos adding to the story?
Your German is correct, but I dont know, whether its Journo stuff or based on other infos.

I agree, that a T/R shaft failure is a rare failure, but if this statement really comes from the BFU-inspectors, they might have some findings to confirm that. The damage to the shaft might be different to a damage, caused by sudden stop when entering the water. Position of the fuel lever? Autorotation? Many points could be important.
On an other german forum was a thread by someone, who spoke to the pilot short prior departure from Lübeck Airport and mentioned, that the helicopter was being deiced prior takeoff. Might that have had an effect?

skadi

Last edited by skadi; 17th Dec 2012 at 17:55.
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Old 17th Dec 2012, 16:19   #75 (permalink)
 
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In both scenarios of hyd failure and t/r failure you would definitely try to keep flying at all costs . I see no difficulty in continuing to fly with hyd failure . T/R failure would require a decent airspeed to be kept which may be difficult if trying to dodge wx ... I would elect to keep flying , or trying , at low level towards dry land regardless of what had gone wrong .
As someone else said , transparency is not an issue in the cruise or if you have a hundred ft or so to recover .
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Old 18th Dec 2012, 14:18   #76 (permalink)
 
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Will be interesting to read the report, choosing to continiue flying depends on the emergency. I dont have any experience in the 350, but i have had an hyd failure in an very old bell47 about 8 years ago. An yes it can happen to you in straight and level flight with you not having any clue whats going on. Used to instruct in the machine an hyd failure training where done daily, in my case there where quite violent low frq vibrations and it did not feel anything like hyd failure. Pulling the mixture solved the problem after 3 failed landing attempts. Looking at the 350, that tailboom is long and if you start loosing parts back there you are quickly running out of cg, hard to see on the pictures if the tail is intact. I have a couple hundred hours in Danish terrotoriy, flying vip between the nordic countrys, i always fly in my survival suit when crossing kattegat\skagerrak area. Do not know if they had survival suits yet, but should be asked when flying out of gliding distance at this time of year?
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Old 18th Dec 2012, 20:12   #77 (permalink)
 
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With regards to the mayday call made from Fehmarn:

There were initial reports of a distress signal, coming from an area near Fehmarn.
Those proved to be false.

Tom
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Old 19th Dec 2012, 00:14   #78 (permalink)
 
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Nigelh

Ever flown a 350 with no hydraulics? I guess not!

Just look at the dance the New York TV ship did before it hit the roof. Hydraulic failure does not end in continued flight, it ends up in whatever patch of earth you are over when it fails.

The Sultan
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Old 19th Dec 2012, 01:27   #79 (permalink)
 
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Quote:
Hydraulic failure does not end in continued flight, it ends up in whatever patch of earth you are over when it fails.
I don't know about the other models, but for a B or BA this is certainly not true. You can fly a good distance to a suitable site for a running landing, or even hover if you really have to, although I certainly wouldn't choose to if there was an alternative.
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Old 19th Dec 2012, 10:18   #80 (permalink)
 
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I think you guy´s are talking about different hydraulic problems.

Hydraulic failure in itself is manageable in the 350 if it´s a loss of hydraulic pressure or even servo transparency if one knows how to handle the problem.

However there are other hydraulic failures that are not as manageable and can very well end in a uncontrolled crash and that´s servo seizure. It has happened.
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