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Helicopter Blades Damaged by Storm Otto

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Helicopter Blades Damaged by Storm Otto

Old 4th Mar 2023, 18:10
  #41 (permalink)  
 
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Hard to understand how it could have been in limits if the brake was unable to stop the rotation. How was that certified? Shutting down outside limits with another technical problem is an ever present dilemma, with no guarantees how it will go. But, in limits? You would reasonably expect to be able to stop the rotor!
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Old 5th Mar 2023, 08:03
  #42 (permalink)  

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I’ve seen a situation where the wind was so strong that after shutting down the engines the blades continued to autorotate well above the maximum rpm for the use of the rotor brake.
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Old 5th Mar 2023, 09:35
  #43 (permalink)  
 
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Interesting. Sikorsky rotor brakes (S61, S76, S92) may be applied in emergency immediately after engine shutdown with NR still at 100% / 107%, and the AW139 permits application at 90% NR in that situation.
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Old 5th Mar 2023, 09:43
  #44 (permalink)  
 
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Originally Posted by steve_oc
Interesting. Sikorsky rotor brakes (S61, S76, S92) may be applied in emergency immediately after engine shutdown with NR still at 100% / 107%, and the AW139 permits application at 90% NR in that situation.
Yes but they work...
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Old 5th Mar 2023, 09:45
  #45 (permalink)  
 
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Originally Posted by steve_oc
Interesting. Sikorsky rotor brakes (S61, S76, S92) may be applied in emergency immediately after engine shutdown with NR still at 100% / 107%, and the AW139 permits application at 90% NR in that situation.
They can also be applied with the engines running (as you know)
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Old 5th Mar 2023, 10:28
  #46 (permalink)  
 
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Originally Posted by 212man
Hard to understand how it could have been in limits if the brake was unable to stop the rotation. How was that certified? Shutting down outside limits with another technical problem is an ever present dilemma, with no guarantees how it will go. But, in limits? You would reasonably expect to be able to stop the rotor!
Perhaps it would be more accurate to state that the wind strength reported to the crew was within the shut down limits. As PlasticCabDriver mentions, the rotor brake itself on the H175 isn't the best. Sometimes you select it on and don't perceive any change in the rate of Nr decay!
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Old 6th Mar 2023, 11:58
  #47 (permalink)  
 
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Apologies if this can't be viewed without a subscription:

Video: Footage shows moment Storm Otto rips blades off helicopter
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Old 6th Mar 2023, 12:49
  #48 (permalink)  
 
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Originally Posted by campbeex
Apologies if this can't be viewed without a subscription:

Video: Footage shows moment Storm Otto rips blades off helicopter
Iím guessing itís the same video I posted earlier?
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Old 7th Mar 2023, 08:15
  #49 (permalink)  
 
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Originally Posted by 212man
Pretty sure it doesnít. CF is an inertial, or pseudo force
Newton Three!
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