Heli ditch North Sea G-REDL: NOT condolences
OH?
Helimutt,
Your statement.....
should have read.....
I don't know anyone I fly with who would knowingly fly an aircraft which they thought wasn't safe.
Your statement.....
I don't know anyone I fly with who would fly an aircraft which they thought wasn't safe.
I don't know anyone I fly with who would knowingly fly an aircraft which they thought wasn't safe.
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Connell Flyer
I will try to answer your question as best I can.
The AAIB has made reccomendations in its interim report and EASA have issued an AD, I believe to increase the frequency of the mag plug checks in the epicycil MGB module.
I fly an L2 and you might feel it is a bit strange that I have not paid too much attention to the actual actions taken by the engineering staff.
This is because I know that my Company have an EASA approved Continuining Airworthiness Department who I trust completely to carry out all necessary actions required not only by the regulations but also their own internal monitoring functions and any increased actions that department feel is necessary until the full report and investigation is complete.
I have 100% faith in the engineers who service the machines I fly because if I did not...I would not fly them.
I like to feel that I have some experise in the operation of the helicopter and I know that my engineers have an expertise in maintaining them. I feel we shopuld be a little careful not to "cross-over" into areas that neither party have the depth of knowledge or experience to comment on as it not helpful and sometimes damn-right misleading.
It is tempting to want to pester the engineers to know what they are doing, have done, but in essence nothing has really changed procedurally because the procedures in place are there to assess, implement and review maintenance in the aftermath of an incident just as they always have been.
Having said all that, the jury really is out on the accident and until they return with a more detailed "verdict" I will remain positive and confident in the L2 machine.
Flying is, and has always been, subject to certain risks. Normally these are assessed, calculated and thereafter controlled. In essence thats exactly what a system of continued airworthiness strives to achieve.
When something like this happens it is easy to jump to the conclusion that the machine or the system is not safe. The truth is that safety is a concept and not an absolute and that the real mechanism employed is the management of risk.
Sometimes the risk is not managed correctly. Who knows that may be the case here. Or sometimes the risk factors (million-to-one-chance) actually occur ie...it was a chance in a million failure. Who knows..that might be the case here.
Suffice to say that taking the performance of the L2 fleet worldwide as a whole, supported by the many 1000s of hours of trouble free operation in my logbook...I, like many of my collegues temper our response proportionally.
This incident was very close to home...same fleet...same type of ops...same hemisphere...same airspace. This does not change the fact that it is the risk factors invloved that will ultimatley have caused the accident...one way or the other.
Hope that helps!!
The AAIB has made reccomendations in its interim report and EASA have issued an AD, I believe to increase the frequency of the mag plug checks in the epicycil MGB module.
I fly an L2 and you might feel it is a bit strange that I have not paid too much attention to the actual actions taken by the engineering staff.
This is because I know that my Company have an EASA approved Continuining Airworthiness Department who I trust completely to carry out all necessary actions required not only by the regulations but also their own internal monitoring functions and any increased actions that department feel is necessary until the full report and investigation is complete.
I have 100% faith in the engineers who service the machines I fly because if I did not...I would not fly them.
I like to feel that I have some experise in the operation of the helicopter and I know that my engineers have an expertise in maintaining them. I feel we shopuld be a little careful not to "cross-over" into areas that neither party have the depth of knowledge or experience to comment on as it not helpful and sometimes damn-right misleading.
It is tempting to want to pester the engineers to know what they are doing, have done, but in essence nothing has really changed procedurally because the procedures in place are there to assess, implement and review maintenance in the aftermath of an incident just as they always have been.
Having said all that, the jury really is out on the accident and until they return with a more detailed "verdict" I will remain positive and confident in the L2 machine.
Flying is, and has always been, subject to certain risks. Normally these are assessed, calculated and thereafter controlled. In essence thats exactly what a system of continued airworthiness strives to achieve.
When something like this happens it is easy to jump to the conclusion that the machine or the system is not safe. The truth is that safety is a concept and not an absolute and that the real mechanism employed is the management of risk.
Sometimes the risk is not managed correctly. Who knows that may be the case here. Or sometimes the risk factors (million-to-one-chance) actually occur ie...it was a chance in a million failure. Who knows..that might be the case here.
Suffice to say that taking the performance of the L2 fleet worldwide as a whole, supported by the many 1000s of hours of trouble free operation in my logbook...I, like many of my collegues temper our response proportionally.
This incident was very close to home...same fleet...same type of ops...same hemisphere...same airspace. This does not change the fact that it is the risk factors invloved that will ultimatley have caused the accident...one way or the other.
Hope that helps!!
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OK, for our "nervous offshore workers", let's tell it like it is.
We don't have the details yet but everyone believes that the mechanical failure in this case was the Main Gearbox (MGB) and it is fairly obvious that the situation was never going to be survivable, for anyone.
Could it happen again? - Yes.
Could the wing fall off your 747 when you go on holiday? Yes.
Could your oil rig/platform collapse into the sea while you're asleep? Yes.
Could a drug-crazed maniac burst into your house and massacre your family? Yes.
Is it likely? Statistically it is neither more likely nor less than it was before.
As I see it there are four major considerations for any mechanical failure - Design, Construction, Maintenance and Operation:
Design: The MGB design has not changed much since the Super Puma was first put into service. The L, L2 and 225 are all pretty much the same and this design has "gazillions" of hours without significant problems - there is nothing wrong here.
Construction: Yes, they are manufactured differently, and so they should be. Technology has moved on and so has the way these things are made. I am fairly sure that Eurocopter do not source their metal from different suppliers according to which aircraft they are going to build. I am also sure that when they manufacture the individual gear wheels in the factory they do not assign any particular individual to each fleet. The worldwide fleet is large and mature, so if this was an issue we could expect to have had some indication of problems before this.
Maintenance: I don't care what colour t-shirt they wear or what shape logo is embroidered on their t-shirt, Aircraft Engineers are Professionals. If this turns out to be a result of maintenance error, then that's just it - a tragic error. If it is, then we should all remember that all companies rely on outside agencies to do complex work - it does not necessarily stop at the door of the Operator.
Operation: Pilots are also Professionals - although it has happened that a pilot has decided to commit suicide and take his entire aircraft with him, let's be frank, unless the rest of the workforce is also nuts there is not much chance of it happening again.
Fly relaxed (or don't fly at all) - it was a freak accident - they happen.
Of course, we need to find out why it happened and try to make sure this particular freak can't happen again.
We don't have the details yet but everyone believes that the mechanical failure in this case was the Main Gearbox (MGB) and it is fairly obvious that the situation was never going to be survivable, for anyone.
Could it happen again? - Yes.
Could the wing fall off your 747 when you go on holiday? Yes.
Could your oil rig/platform collapse into the sea while you're asleep? Yes.
Could a drug-crazed maniac burst into your house and massacre your family? Yes.
Is it likely? Statistically it is neither more likely nor less than it was before.
As I see it there are four major considerations for any mechanical failure - Design, Construction, Maintenance and Operation:
Design: The MGB design has not changed much since the Super Puma was first put into service. The L, L2 and 225 are all pretty much the same and this design has "gazillions" of hours without significant problems - there is nothing wrong here.
Construction: Yes, they are manufactured differently, and so they should be. Technology has moved on and so has the way these things are made. I am fairly sure that Eurocopter do not source their metal from different suppliers according to which aircraft they are going to build. I am also sure that when they manufacture the individual gear wheels in the factory they do not assign any particular individual to each fleet. The worldwide fleet is large and mature, so if this was an issue we could expect to have had some indication of problems before this.
Maintenance: I don't care what colour t-shirt they wear or what shape logo is embroidered on their t-shirt, Aircraft Engineers are Professionals. If this turns out to be a result of maintenance error, then that's just it - a tragic error. If it is, then we should all remember that all companies rely on outside agencies to do complex work - it does not necessarily stop at the door of the Operator.
Operation: Pilots are also Professionals - although it has happened that a pilot has decided to commit suicide and take his entire aircraft with him, let's be frank, unless the rest of the workforce is also nuts there is not much chance of it happening again.
Fly relaxed (or don't fly at all) - it was a freak accident - they happen.
Of course, we need to find out why it happened and try to make sure this particular freak can't happen again.
Last edited by ppng; 14th Apr 2009 at 16:48.
There are no limits
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Construction: Yes, they are manufactured differently, and so they should be. Technology has moved on and so has the way these things are made. I am fairly sure that Eurocopter do not source their metal from different suppliers according to which aircraft they are going to build. I am also sure that when they manufacture the individual gear wheels in the factory they do not assign any particular individual to each fleet. The worldwide fleet is large and mature, so if this was an issue we could expect to have had some indication of problems before this.
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As far as the construction of the MGB's is concerned, while the design may be similar between types, infact, all eurocopter types, the 225 will undoubtedly be different in construction. the MGB was one of the big problems encountered when developing the aircraft. i have heard, though cannot confirm, that is why the L2 came out as an iterim measure, till these problems were overcome. The 225 has a 5 bladed head and a significantly more powerful pair of engines, so the main gearbox will have been beefed up to handle the extra torque from the engines and the load from the head. And of course has an emergency glycol lube system, as has been talked about alot after the S92 crash
incidently, the lateral vibe that our offshore friend was talking about, sounds more like a main rotor imbalance. maybe just needed a bit of tuning?
incidently, the lateral vibe that our offshore friend was talking about, sounds more like a main rotor imbalance. maybe just needed a bit of tuning?
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I offer my apologies to Flaps 5.
I thought you were inferring that the engineers were unwilling to fly on test flights.
In 22 yrs as a mechanic & engineer I have never released a helicopter to service after a major component change/disturbance without flying (myself or another engineer involved in the work) on the required check ride.
I feel it is my professional duty.
However, I accept that if 3 or 4 people say they work in companys where this is normal, then it must be true.
As for the luxury of manpower, I have regularly been the only licenced engineer on duty with 8 clunky workhorses to supervise.
If there's more work than I can handle, some of the machines stay U/S until I'm ready. Airtest req'd or not.
Treat you engineers with respect & they'll treat you likewise.
I thought you were inferring that the engineers were unwilling to fly on test flights.
In 22 yrs as a mechanic & engineer I have never released a helicopter to service after a major component change/disturbance without flying (myself or another engineer involved in the work) on the required check ride.
I feel it is my professional duty.
However, I accept that if 3 or 4 people say they work in companys where this is normal, then it must be true.
As for the luxury of manpower, I have regularly been the only licenced engineer on duty with 8 clunky workhorses to supervise.
If there's more work than I can handle, some of the machines stay U/S until I'm ready. Airtest req'd or not.
Treat you engineers with respect & they'll treat you likewise.
epicycle gearbox
"Split Torque Epicyclic Helicopter Gearing
ivor the driver "
Sorry should have written this a couple of days ago.
I'm no engineer, as you can tell from my title, I was looking at the above link posted by ivor the driver a few days ago trying to understand how the 332 gearbox works. I coudn't help thinking that there's something wrong with the drawing, specifically the rotation.
The main shaft seems to be rotating against the rest of the gearing.. and comparing it against the rotation of an L2 the shaft in the drawing seems to rotate the wrong way??
ivor the driver "
Sorry should have written this a couple of days ago.
I'm no engineer, as you can tell from my title, I was looking at the above link posted by ivor the driver a few days ago trying to understand how the 332 gearbox works. I coudn't help thinking that there's something wrong with the drawing, specifically the rotation.
The main shaft seems to be rotating against the rest of the gearing.. and comparing it against the rotation of an L2 the shaft in the drawing seems to rotate the wrong way??
ExLatcc - Think you will find that is just a "generic" view of an epicyclic geartrain, it certainly looks very little like the AS332(L1) main box in my course notes, and as you suggested, some of the rotation directions do not add up, for instance shaft 28 and 30 are shown turning in opposite directions while driving the same gear ring.
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Here is a link to a simplified diagram of an epicyclic.
Epicyclic gearing - Wikipedia, the free encyclopedia
In a chopper the yellow sun gear shaft would be on the opposite side to the green planet gear carrier. The sun gear shaft would of course be vertical, driven by the input bevel gear, and the green shaft would drive the rotor mast, (or another epicyclic stage and then the rotor mast). The red ring gear is fixed to the gearbox casing.
Epicyclic gearing - Wikipedia, the free encyclopedia
In a chopper the yellow sun gear shaft would be on the opposite side to the green planet gear carrier. The sun gear shaft would of course be vertical, driven by the input bevel gear, and the green shaft would drive the rotor mast, (or another epicyclic stage and then the rotor mast). The red ring gear is fixed to the gearbox casing.
Thanks for that farsouth I had assumed that input 28 was driving the upper gear and 30 was driving the bottom.
It always struck me looking down on the engineers when the cowls are open, just how small the engines and gearbox are and what a huge load is going through them.
Its certainly very interesting to learn just how the power is transferred into the rotor.
Shame the authorities couldn'd see this a few years back when Bill Lear was trying to certify his Learfan.
It always struck me looking down on the engineers when the cowls are open, just how small the engines and gearbox are and what a huge load is going through them.
Its certainly very interesting to learn just how the power is transferred into the rotor.
Shame the authorities couldn'd see this a few years back when Bill Lear was trying to certify his Learfan.
dipperm0 - good diagram of the MGB (from the THM I think?) but just to point out that it only shows 1 planet gear on each epicyclic stage, when in fact there are a number (not sure how many).
HC
HC
widgeon
If you look to the left of where it says "LH Accessories" you will see a blue shaft, where that gets fat and meshes with the pink tail rotor drive shaft, is the torque sensor (measures twist in the solid-looking inner shaft), keep going left and where it thins out again looking a bit like a splined coupling is the freewheel - a bit to the right of the 8011 rpm callout. Same place for the other engine obviously.
HC
If you look to the left of where it says "LH Accessories" you will see a blue shaft, where that gets fat and meshes with the pink tail rotor drive shaft, is the torque sensor (measures twist in the solid-looking inner shaft), keep going left and where it thins out again looking a bit like a splined coupling is the freewheel - a bit to the right of the 8011 rpm callout. Same place for the other engine obviously.
HC
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AAIB statement on BBC Radio 4 News tonight!
It was announced that the AAIB have said that they are still unsure as to the failure and damage sequence which occured within the gearbox, and due to the nature and extent of the damage (the gearbox broke apart) it may not be possible to find out!
This would leave questions and doubts unanswered and unresolved!
This would leave questions and doubts unanswered and unresolved!