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Taiwan Coast Guard Dauphin Crash

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Taiwan Coast Guard Dauphin Crash

Old 14th Mar 2016, 12:43
  #41 (permalink)  
cpt
 
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Hello Greeny,

No, on the 365N I was refering to in my post, immersion probes were not installed... and it didn't ditch anyway.

As with this poor Taipei 365, I can't tell as we don't know yet what caused this crash. But the rotation rate looks pretty much what we experience in the sim when we simulate a tail rotor shaft failure on hover.
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Old 14th Mar 2016, 13:04
  #42 (permalink)  
 
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Cpt,
Ok, understood but my point about the floats firing off (if you have an immersion probe) is it could be initiated in flight without submersion.
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Old 14th Mar 2016, 18:57
  #43 (permalink)  
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G'd evening Greeny

Understood too (I'd read your post a little too fast) but the interesting point here, is about uncommanded floats inflation in case of accidental short circuited immertion probe ... BTW, do you know if the so called "AFDS" system is modern enough for not being afected by this fault? (that's the one we have installed on our 76s)
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Old 15th Mar 2016, 08:15
  #44 (permalink)  
 
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Not familiar with S76
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Old 16th Mar 2016, 11:59
  #45 (permalink)  
 
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Once the rotation starts, the continued acceleration of rate as the tail comes back towards the air flow seems to me to make TR shaft failure much more likely than LTE. I have not flown this model, but a 120 will "swap ends" like others say of the Gazelle, and once weather-cocked it all slows and gets considerably less exciting. In this vid, the excitement level just kept going up and up.
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Old 21st Apr 2017, 16:27
  #46 (permalink)  
 
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Originally Posted by John R81 View Post
Once the rotation starts, the continued acceleration of rate as the tail comes back towards the air flow seems to me to make TR shaft failure much more likely than LTE.
It turns out it was neither:

Tail Rotor Pitch Control Loss During Hoisting
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Old 22nd Apr 2017, 08:22
  #47 (permalink)  
 
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So if I read that right - the poor soul on the end of the hoist was flung uno into the main rotor by centrifugal force?
Jesus - that's awful...
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Old 23rd Apr 2017, 11:00
  #48 (permalink)  
 
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So if I read that right - the poor soul on the end of the hoist was flung uno into the main rotor by centrifugal force?
Jesus - that's awful...
Yes, that does seem to be the case. If they has successfully cut the cable it probably would still have been a fatal fall.
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Old 24th Apr 2017, 07:56
  #49 (permalink)  
 
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The ASC note that due to the expense, simulators were not being routinely used by NASC crew.
===>
The copilot also heard the pilot saying, “What is happening to the aircraft?”
The accident was going to happen anyway BUT maybe someone would be alive today...
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Old 25th Apr 2017, 17:21
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Would sim practice of recovery from a TRCF in a relatively low hover have made a big effect on the survival probability, especially if the winch op was not involved?
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Old 26th Apr 2017, 12:13
  #51 (permalink)  
 
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We will never know, it was too expensive to even try...
***facepalm***
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Old 26th Apr 2017, 13:06
  #52 (permalink)  
 
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I seriously doubt you can replicate the exact behaviour of a fenestron failure in a sim. It will simply not rotate in the same manner. Perhaps it will teach the correct response. perhaps it will teach a wrong response that will work in the sim but not on the aircraft (very much like offshore landings).
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Old 26th Apr 2017, 18:11
  #53 (permalink)  
 
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Originally Posted by S76Heavy View Post
I seriously doubt you can replicate the exact behaviour of a fenestron failure in a sim. It will simply not rotate in the same manner. Perhaps it will teach the correct response. perhaps it will teach a wrong response that will work in the sim but not on the aircraft (very much like offshore landings).
That was what I was thinking. I do agree that generally not doing sim raining because it costs money is an indefensible position.
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Old 26th Apr 2017, 18:22
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I would have thought a fenestron failure at low speed is relatively simple to simulate, as the aerodynamic modeling is less complex than forward flight. It's simple physics. The Helisim EC155 always seem to behave in the manner I'd expect, and the stuck TR controls certainly replicated real world training with jammed pedals. One session will always stick in my mind, where the crew were given a TR drive failure in the cruise st 2,000 ft. They decided to do a handling check (on an aircraft that was basically still straight and level). Eventually they washed off the airspeed and the 'thing let go'. Unfortunately, we never reached any 'crash' parameters to 'red screen' and freeze. Conversely, I couldn't reach the stop button as I was hanging on to the grab handle. My colleague had been thrown on the floor from his jump seat and was covered in books and papers. It took a while before we hit the ground. Seemed pretty realistic to me!
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Old 26th Apr 2017, 18:56
  #55 (permalink)  
 
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Simulating tail rotor failures (as well as fenestron failures) have far fewer unknowns in the low speed regime compared to the cruise environment. In general, such failures are relatively straight forward to have the simulator produce an "acceptable" response... acceptable being defined as a response predicted by a physics-based simulation that also satisfies the expectations of pilots.


That being said, the behavior will undoubtedly not be validate against actual aircraft behavior, so there will always be room for uncertainty.
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Old 26th Apr 2017, 19:05
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Originally Posted by 212man View Post
I would have thought a fenestron failure at low speed is relatively simple to simulate, as the aerodynamic modeling is less complex than forward flight. It's simple physics. The Helisim EC155 always seem to behave in the manner I'd expect, and the stuck TR controls certainly replicated real world training with jammed pedals. One session will always stick in my mind, where the crew were given a TR drive failure in the cruise st 2,000 ft. They decided to do a handling check (on an aircraft that was basically still straight and level). Eventually they washed off the airspeed and the 'thing let go'. Unfortunately, we never reached any 'crash' parameters to 'red screen' and freeze. Conversely, I couldn't reach the stop button as I was hanging on to the grab handle. My colleague had been thrown on the floor from his jump seat and was covered in books and papers. It took a while before we hit the ground. Seemed pretty realistic to me!
SIM-Time might help to condition a pilot to react in the right manner instead of asking "what t.. f... is the helicopter doing...."
I found it really impressing, how violent the the movement was even at a fenestron-failure at hover in ground effect.
Not slamming the collective down and bouncing all over the runway would lead to violent movements as noted above with loose parts flying through the SIM and a crash screen....
Wether the height would have been sufficiant for a complete recovery? I doubt it but may be a more controlled crash would have been possible with a slighty higher chance of survival.
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Old 26th Apr 2017, 21:30
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Guess what? - It spins out of control and in a moderately high hover with a man on the wire, someone is going to get badly hurt, there is no good outcome because a crash is inevitable.
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Old 27th Apr 2017, 05:06
  #58 (permalink)  
 
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not doing sim raining because it costs money is an indefensible position
Money was the reason our big oil employer gave for only allowing captains to attend every three years, and copilots not at all, since it involved a trip half way round the world. Their aviation adviser said he saw no value in sim training, yet he attended yearly, but the word "safety" had been mentioned, so the company relented to the above extent. That was twelve years ago I admit though, hope things have changed.
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Old 27th Apr 2017, 06:35
  #59 (permalink)  
 
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Originally Posted by [email protected] View Post
Guess what? - It spins out of control and in a moderately high hover with a man on the wire, someone is going to get badly hurt, there is no good outcome because a crash is inevitable.
You're right, a crash is inevitable.
And the outcome is most likely with badly hurt and even dead crew.
The difference could be in the numbers and the severity of injuries, when the pilot has experienced an failure in the SIM, reacted right in slamming the Collective down while pushing the nose down and into the turn to gain speed which would stabilise a helicopter with a big fin like the Dauphin. It would be nose down - flare- crash, cause the altitude might not be sufficiant for an fly away - but chances of survival would be greater than spinning all the way into the sea.

If a company is thinking, SIM Training is expensive- they should look into the bill of a crash.... 🙁
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Old 27th Apr 2017, 11:42
  #60 (permalink)  
 
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You need at least 40 kts on something like a Dauphin for the fin to be effective and by the time you have slammed the collective down and pushed the nose forward, you are already in the water from the height they were at.

Been through these scenarios in the Sea King sim many times and even from 1000' when you know it is coming you are very lucky to survive.
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