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Old 4th Jan 2017, 07:32   #41 (permalink)
 
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Reply to John's last post:

John, the loss of T/R drive anecdote that I had heard did not achieve balanced or prolonged controllable flight. From recollection they had to enter a lowish power descent with right turn and I would guesstimate some degree of slip but personally uncertain.......but importantly ....it bought them time so say a few Chinese expletives (ie "ahh F..k") and to make a few decisions and pull off a relatively safe landing/termination with all on board safe as I recall...

I know...growing old ain't for the faint hearted...

Cheers
RG
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Old 4th Jan 2017, 10:26   #42 (permalink)
 
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The S92a hums system New and old does have green amber red indicators as in other systems.
It also has a "toolbox " which in the early hums you had to upload separately in the later it is done with the main download of the card.
In the tool box is specific programs which look at tail gearbox bearing energy, tail rotor dis-bond, Mgb foot skew and engine drive shafts.
These programs give you another green or red indicator to simplify and speed up hums analysis of critical previous problem areas.
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Old 4th Jan 2017, 14:23   #43 (permalink)
 
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And some others





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Old 4th Jan 2017, 15:45   #44 (permalink)
 
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Quote:
Mitchaa - It is my understanding that HUMS was effective with a warning in this case
I need help with your logic...your helicopter is almost spun off a deck in a near catastrophe. Surely if the HUMS was effective in warning then the aircraft would not have made that last flight to the rig.
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Old 4th Jan 2017, 16:08   #45 (permalink)
 
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Close Calls do not count statistically.

I would say the Crew deserves a "Well Done! for getting the aircraft onto the Deck!
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Old 4th Jan 2017, 16:46   #46 (permalink)
 
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Looking at the deck there may be a hard landing check in order.
Well done that crew in anycase.
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Old 5th Jan 2017, 09:35   #47 (permalink)
 
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Quote:
Originally Posted by SASless View Post
I would say the Crew deserves a "Well Done! for getting the aircraft onto the Deck!
+1.

Plus the relatively wide track of the main gear of the S-92 probably was a good thing in this case as well. Had it fallen on its side the outcome might have been different.
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Old 5th Jan 2017, 14:13   #48 (permalink)
 
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It doesn't add much, but the AAIB says it is now sending a team to investigate. (An hour earlier, it said merely that it was looking into reports of an incident.)
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Old 5th Jan 2017, 14:36   #49 (permalink)
 
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Yes Henra the 92 is like a flat iron compared to some other helicopters.
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Old 5th Jan 2017, 15:27   #50 (permalink)
 
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Interesting to see the nosewheel at 90 - I wonder what effect it would have had if it had been lockable? Might have either resisted the rotation, or exacerbated the tendency to roll over!
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Old 5th Jan 2017, 17:16   #51 (permalink)
 
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If there was some loss of tail rotor control, would the canted tail rotor and its complex yaw/pitch coupling of control inputs have compounded attempts to control the aircraft and get it planted onto the deck? A loss of lift at the tail might explain the slice in the aluminium alloy decking, seen in 2 of the photos, roughly radial to the landing circle.

The crew did well to keep it on deck, once it had made initial contact, and not hit the nearby crane. Or worse.
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Old 5th Jan 2017, 17:16   #52 (permalink)
 
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Just speculating but are the cuts in the deck caused by the wheel rim?
If so the tires must have nearly been rolled off the rim.
Must have been an interesting few seconds.
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Old 5th Jan 2017, 17:18   #53 (permalink)
 
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Nice to see a happy ending to someone’s really really bad day.
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Old 5th Jan 2017, 17:20   #54 (permalink)
 
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They don't call them poopy suits for no good reason!
212 man: not an expert by anymeans but I suspect that the ability of the 92 nose gear to castor was beneficial, in this case, to keeping the aircraft upright. A locked nosewheel would, I think, have contributed to any rolling movement. I wonder how much the aircraft actually tilted. Thoughts?

Last edited by albatross; 5th Jan 2017 at 19:22.
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Old 5th Jan 2017, 19:37   #55 (permalink)
 
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If you allow the aircraft to yaw freely (castoring nosewheel) then I wonder if it has more tendency to roll in the opposite direction to the turn than if the nosewheel is sliding (resisting the yaw) - just a thought.
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Old 5th Jan 2017, 20:44   #56 (permalink)
 
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When landing a heavy plank wing with a steerable nosewheel when you let the nose drop and there is substantial weight on the nose wheel then the cams will ensure that you can only control its direction with nosewheel steering. In a severe crosswind this can lead to some deft fiddling with the tiller to keep it straight.

In this case I would have thought that the castoring nosewheel would have been a help rather than a hindrance.
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Old 6th Jan 2017, 00:53   #57 (permalink)


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Think there will be some concern about the deck surface failing. Wonder if the CAA will have some changes to CAP 437 regarding 'punching'.
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Old 6th Jan 2017, 02:01   #58 (permalink)
 
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Energy has to go somewhere: 12 tonnes flailing around. In this case, a significant amount has gone into deforming the deck.

Where else do you want it to go? We can have glass hard deck but then it's more likely that energy will carry the aircraft over the edge.
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Old 6th Jan 2017, 02:19   #59 (permalink)
 
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Crab,

Is there a difference between the reaction of an aircraft to the Castoring Wheel being in front of the mast or behind the mast as say in a 92 and a Wessex/61.....re Tipping Tendency?
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Old 6th Jan 2017, 04:10   #60 (permalink)
 
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PC2DLE.......

Is the 92 operated to PC1 or still the PC2DLE fudge?
From all accounts very fortuitous (!) the failure happened when it did and well done to the crew.


NOT SAYING IT IS THE CASE HERE - but got me thinking - intrigued on bearing load factors with a regular practice I have seen - almost a 'snatch' application of power as crews decelerate with min torque set (quickstop-esque) then apply power just before decision to 'make' the DPBL - albeit with a pinch of salt. Evident from 'newcomers' from other companies.
Cannot help but feel such a manoeuvre does not help situation.
Does CHC track such parameters on HOMPs - I ask because it is something our customer insist we monitor.......
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