EH101 crash
Guest
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Well, what a charmer!
It is obvious from the previous threads that Max's venom is directed at some other gripe, as there is no evidence at all to support him on this topic.
What really saddens me is that he is (according to previous threads) a colleague of Patrick, but has to hide behind anonymity to express his thoughts. In all probability, given the fleet sizes etc, he actually flies with Pat. We see constant reference to the management of the two North Sea companies on this forum, and their deficiences, how nice to see the back-stabbing going on from our fellow pilots.
For the record, Patrick is highly a experienced helicopter pilot, with over 25 years in the business both military and commercial. More particularly, he is one of only a small number in any way qualified to discuss the EH 101s flying abilities.
What a crass and unecessary remark.
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Another day in paradise
It is obvious from the previous threads that Max's venom is directed at some other gripe, as there is no evidence at all to support him on this topic.
What really saddens me is that he is (according to previous threads) a colleague of Patrick, but has to hide behind anonymity to express his thoughts. In all probability, given the fleet sizes etc, he actually flies with Pat. We see constant reference to the management of the two North Sea companies on this forum, and their deficiences, how nice to see the back-stabbing going on from our fellow pilots.
For the record, Patrick is highly a experienced helicopter pilot, with over 25 years in the business both military and commercial. More particularly, he is one of only a small number in any way qualified to discuss the EH 101s flying abilities.
What a crass and unecessary remark.
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Another day in paradise
Guest
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4Rvibes,
First, I want to point out that PP8 and PP9 were not fitted with rotorbrake,nor with a sonar winch.However, the hydraulic system remains the same.Looking at the diagrams, I tried to understand what you said.
In your Dec 09 comment, you write that the rotorbrake was hydraulically disabled. To me, it means that even in the event of the r/b being activated,there is no hydraulic power to operate it. Furthermore, I fail to see why another hydraulically powered system could activate the rotor brake. Many other systems are powered by IHPS 3 ( n3 Integrated Hydraulic Power System). Again, they only use hydraulics as a way to be powered, and all have their own independant way to be activated. In the same way, we could say that any action on the cyclic would move the commands servos, and in some way drop the undercarriage!!!!!
To finish, you state " A hideous amount of burning.........made the pilot to ditch [ and so say all of us]". What does the pilot himself has to say? No matter what all of us can say, only the crew flying the a/c on the day can tell us what happened. Then again, I
was also guilty to speculate on the reasons of the ditching.........
[This message has been edited by Pat Gerard (edited 15 December 2000).]
First, I want to point out that PP8 and PP9 were not fitted with rotorbrake,nor with a sonar winch.However, the hydraulic system remains the same.Looking at the diagrams, I tried to understand what you said.
In your Dec 09 comment, you write that the rotorbrake was hydraulically disabled. To me, it means that even in the event of the r/b being activated,there is no hydraulic power to operate it. Furthermore, I fail to see why another hydraulically powered system could activate the rotor brake. Many other systems are powered by IHPS 3 ( n3 Integrated Hydraulic Power System). Again, they only use hydraulics as a way to be powered, and all have their own independant way to be activated. In the same way, we could say that any action on the cyclic would move the commands servos, and in some way drop the undercarriage!!!!!
To finish, you state " A hideous amount of burning.........made the pilot to ditch [ and so say all of us]". What does the pilot himself has to say? No matter what all of us can say, only the crew flying the a/c on the day can tell us what happened. Then again, I
was also guilty to speculate on the reasons of the ditching.........
[This message has been edited by Pat Gerard (edited 15 December 2000).]
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To: Pat Gerrard
What you said in jest about moving the command servos and causing the landing gear to drop is not beyond the realm of possibility. What you described as applied to electrical systems is called a sneak circuit and it could depending on the system design apply to a hydraulic system.
These were the types of failures I instructed the analysts at Agusta to look for. I don't know if they were ever able to find any that would be catastrophic or not but in any event, the manager of the Reliability department had all catastrophic failures removed from the FMEAs.
One of the failure modes I highlited was an internal leak of the electrical control valve causing the rotor brake to come on in flight. I suggested that the valve body incorporate a controlled leak back to return so that system pressure would not be applied to the rotor brake unless the pilot commanded it.
However, if there were an electrical sneak circuit, this could cause the application of the rotor brake when the pilot commanded another unrelated electrical unit either on or off.
This internal leak condition is what caused the Lauda Air 767 thrust reverser to come on in flight. The hydraulic actuator did not incorporate a controlled leak to return and when the pressure built up, the reverser deployed.
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The Cat
[This message has been edited by Lu Zuckerman (edited 15 December 2000).]
[This message has been edited by Lu Zuckerman (edited 15 December 2000).]
What you said in jest about moving the command servos and causing the landing gear to drop is not beyond the realm of possibility. What you described as applied to electrical systems is called a sneak circuit and it could depending on the system design apply to a hydraulic system.
These were the types of failures I instructed the analysts at Agusta to look for. I don't know if they were ever able to find any that would be catastrophic or not but in any event, the manager of the Reliability department had all catastrophic failures removed from the FMEAs.
One of the failure modes I highlited was an internal leak of the electrical control valve causing the rotor brake to come on in flight. I suggested that the valve body incorporate a controlled leak back to return so that system pressure would not be applied to the rotor brake unless the pilot commanded it.
However, if there were an electrical sneak circuit, this could cause the application of the rotor brake when the pilot commanded another unrelated electrical unit either on or off.
This internal leak condition is what caused the Lauda Air 767 thrust reverser to come on in flight. The hydraulic actuator did not incorporate a controlled leak to return and when the pressure built up, the reverser deployed.
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The Cat
[This message has been edited by Lu Zuckerman (edited 15 December 2000).]
[This message has been edited by Lu Zuckerman (edited 15 December 2000).]
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One of the problems associated with rotor brakes (or wheel brakes for that matter) is the problem of pressure self generation as a result of friction.
Should inadequate clearance exist between the rotor brake pucks and the disc, the resultant friction will generate heat, causing increasing pressure, greater friction, etc, etc. The brake just comes on harder and harder until it catches fire. This situation is extremely dangerous if there is no way of relieving the hydraulic pressure generating in the system, and the cycle is thus self-sustaining.
The situation can be caused by maintenance action, corrosion, slippage prior to rotor engagement, incorrect adjustment and various other causes. I can think of similar rotor brake problems on just about every type of helicopter that has ever flown. The S76 brake problems of long ago related to the brake system itself, but also required that should the brake be immobilised that the lines removed and the brake itself vented to atmosphere, so it could relieve any pressure that might build in the event of a fricion/pressure build up.
This is not to suggest what has occurred here, simply some previous information.
Surprised that the commercial EH-101 did not have a rotor brake installed for North Sea ops. Assume it does for shipboard Naval operations?
Should inadequate clearance exist between the rotor brake pucks and the disc, the resultant friction will generate heat, causing increasing pressure, greater friction, etc, etc. The brake just comes on harder and harder until it catches fire. This situation is extremely dangerous if there is no way of relieving the hydraulic pressure generating in the system, and the cycle is thus self-sustaining.
The situation can be caused by maintenance action, corrosion, slippage prior to rotor engagement, incorrect adjustment and various other causes. I can think of similar rotor brake problems on just about every type of helicopter that has ever flown. The S76 brake problems of long ago related to the brake system itself, but also required that should the brake be immobilised that the lines removed and the brake itself vented to atmosphere, so it could relieve any pressure that might build in the event of a fricion/pressure build up.
This is not to suggest what has occurred here, simply some previous information.
Surprised that the commercial EH-101 did not have a rotor brake installed for North Sea ops. Assume it does for shipboard Naval operations?
Guest
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To Cyclic Hotline
The two EH101 flying from Aberdeen were pre-production and not commercial aircrafts.It was an Intensive Flying Operation Program for the Maturity and Reliability Enhancement of the EH101. They were not fitted for North Sea ops. The flying was only for testing and development of the a/c. One was military registered ( Navy 101 ), the other one Italian registered ( I-LIOI).
The two EH101 flying from Aberdeen were pre-production and not commercial aircrafts.It was an Intensive Flying Operation Program for the Maturity and Reliability Enhancement of the EH101. They were not fitted for North Sea ops. The flying was only for testing and development of the a/c. One was military registered ( Navy 101 ), the other one Italian registered ( I-LIOI).
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Pat,
I will confess that I have never been closer to an EH101 than in Westlands factory in 1986, and that was a wooden mock-up of the civil version.
Nonetheless, uncommanded rotorbrake pulls are not unknown in the helicopter world.
Embarassingly I have to direct you to Lu's and Cyclic's posts because I have been off-line for a couple of days and these guys have said what I wanted to say.
To summarise, Murphy's law prevails. A fail-safe valve will always fail once, an idiot-proof check valve will always be fitted by a bigger idiot than the idiot who designed it, a fire-proof decking will light up like a candle due to unforseen media leaking on it.
I have no beef against the EH 101 as some others posters on this thread have (yes you Chin Chin) although I personally don't see it as a big success in the North Sea. A sad shame. From the one person I know who flew it he thought it was the proverbial "terriers testicles", not my phraseology I must admit.
4R
I will confess that I have never been closer to an EH101 than in Westlands factory in 1986, and that was a wooden mock-up of the civil version.
Nonetheless, uncommanded rotorbrake pulls are not unknown in the helicopter world.
Embarassingly I have to direct you to Lu's and Cyclic's posts because I have been off-line for a couple of days and these guys have said what I wanted to say.
To summarise, Murphy's law prevails. A fail-safe valve will always fail once, an idiot-proof check valve will always be fitted by a bigger idiot than the idiot who designed it, a fire-proof decking will light up like a candle due to unforseen media leaking on it.
I have no beef against the EH 101 as some others posters on this thread have (yes you Chin Chin) although I personally don't see it as a big success in the North Sea. A sad shame. From the one person I know who flew it he thought it was the proverbial "terriers testicles", not my phraseology I must admit.
4R
Guest
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Latest buzz on the demise was that a strong smell of burning was apparent whilst in the dip, so the ball was raised and the P1 turned for dry land. Tight feeling around the backside urged the driver to carry out a controlled ditching, and on finals into wind all went pear shaped. As discussed, the r/b had either not backed off completely, or had come on uncommanded, and started a fire forward of the MGB. Following the Italian fatal the control rods are now stainless steel, unlike the previous composite construction, so they were OK, but as the fire progressed back around the MGB it took out the tail rotor drive shaft, which let go just before ditching. Water entry was about 15 degrees off wings level, and the rest is history.
It's only a rumour network, if anyone asks.
It's only a rumour network, if anyone asks.
Guest
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Good info John.
Only question is what happened to the floats ? , were they torn off in the ditching . The picture on the news didn't seem to show any attatched floats.
I guess the pilot made the all the right decisions ditching into terra firma would have been a complete disaster.
Only question is what happened to the floats ? , were they torn off in the ditching . The picture on the news didn't seem to show any attatched floats.
I guess the pilot made the all the right decisions ditching into terra firma would have been a complete disaster.
Guest
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Well, I have been speaking to one of the Italian engineers who was part of the IFOP program.
He confirmed what I had known for sometime.
I am happy to say that I agree with Widgeon and Chin Chin, and satisfied that the aircraft was not to blame. To quote Chin Chin, "procedures used to clear the aircraft for flight" were probably at fault.
Happy New Year to you all for 2001.....
[This message has been edited by Pat Gerard (edited 31 December 2000).]
[This message has been edited by Pat Gerard (edited 31 December 2000).]
He confirmed what I had known for sometime.
I am happy to say that I agree with Widgeon and Chin Chin, and satisfied that the aircraft was not to blame. To quote Chin Chin, "procedures used to clear the aircraft for flight" were probably at fault.
Happy New Year to you all for 2001.....
[This message has been edited by Pat Gerard (edited 31 December 2000).]
[This message has been edited by Pat Gerard (edited 31 December 2000).]
