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Didn't HHL have the same thing happen in front of their hanger in GP 5-6 years ago? Rolled over exactly as described in this case? No collective locked?

 

Yessir.

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I suppose all this input is generally saying that a single hydraulic system machine like an astar has a good potential for incidence with ought diligence on the pilots part. I do know that a double hydraulic system as in a 212, A119 or a 205, the collective is always boosted. I suppose a single system 205 one would need to be careful with that as well. As always, complacency is a risk to us all no matter what the machine. The more diligent we can all be the better...

 

Not fully correct sir...a 205 with a dual hydraulic system will lose boost in the collective with the loss of the #2 system...the cyclic is always boosted in the dual hydraulic 205.

 

I agree with your comments that diligence is paramount, but there are characteristics unique to the astar in this instance that create the problems. You don't generally hear of 206's and 407's jumping into the air during hydraulic checks...although we shouldn't let our guards down when doing hydraulic checks in these machines either.

 

It is the pre load on the spherical thrust bearings in the astar that causes the collective to want to climb. so while it would be out of the ordinary for a 206 or 407 collective to jump up a couple of inches when the hydraulics are turned off....ALL astars will jump into the air with the collective unlocked, throttle at 100% and the hydraulics turned off..

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Max

 

I have a PDF Flight Manual for the B2 VEMD, dated October 15/2010. It states the hydraulic checks are to be done at ground idle. I got it from our training department. I am in now way an expert on A-Star's, so I can only go by what I have.

 

Is there a newer Revision out?

And I kinda guessed the aircraft wouldn't flip over if the hydraulics were depleted at ground idle, with the collective unlocked, but I had to ask.

 

49 Merc

I stand corrected..that's what I get for relying on an old memory! :lol:

Max

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Not fully correct sir...a 205 with a dual hydraulic system will lose boost in the collective with the loss of the #2 system...the cyclic is always boosted in the dual hydraulic 205.

 

I agree with your comments that diligence is paramount, but there are characteristics unique to the astar in this instance that create the problems. You don't generally hear of 206's and 407's jumping into the air during hydraulic checks...although we shouldn't let our guards down when doing hydraulic checks in these machines either.

 

It is the pre load on the spherical thrust bearings in the astar that causes the collective to want to climb. so while it would be out of the ordinary for a 206 or 407 collective to jump up a couple of inches when the hydraulics are turned off....ALL astars will jump into the air with the collective unlocked, throttle at 100% and the hydraulics turned off..

 

I stand corrected and thanks for that... The only 205 I've flown was a single hydraulic system. Good to know.

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FYI

 

AS350 B2 VEMD

 

Sup. 0=>5.1 , EDIT RN3 , April 08 (which is the current revision)

 

Manual Issue Date 23/08/2010

 

4.3.2 Engine Starting

 

yadayadyada...

 

7. FFCL..............Adjust to 67% < ng > 70%

 

yadayada....

 

4.3.3 Run-Up Check

 

1. All necessary systems ON - TEST

2. Hydraulics Checks.....

 

*When engine oil > 0 degrees C

 

3. FFCL ...............FLIGHT detent, maintaining a constant rate of rotor acceleration.

 

 

 

Not assuming this was what happened. Just informing everyone as we dont want to see this happen to anybody.

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One thing which is somewhat strange is that the collective must have been locked upon startup as have started more than one astar with the collective unlocked and it is very apparent so before even getting to idle. So I suspect that the collect lock was probably not adjusted properly thus when the hydraulic switch is turn off and the "jump" in collective occurs the lock disengages and the collective comes up and over she goes. Just a thought. Ensure the lock working properly and if maintenance has been done double check it.

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One thing which is somewhat strange is that the collective must have been locked upon startup as have started more than one astar with the collective unlocked and it is very apparent so before even getting to idle. So I suspect that the collect lock was probably not adjusted properly thus when the hydraulic switch is turn off and the "jump" in collective occurs the lock disengages and the collective comes up and over she goes. Just a thought. Ensure the lock working properly and if maintenance has been done double check it.

 

 

Amen to that....that locking strip can be the source of a lot of issues if it is not adjusted correctly....good point

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Before testing the hydraulics on an Astar I always give the collective a tug to check the lock, then grip the collective with my arm braced while turning off the hydraulics.

 

Glad no one was hurt!

 

D Mitten

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