EC225 crash near Bergen, Norway April 2016
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Whether or not this was caused by the loss of a pin it still shows the importance of making pin design changes that prevent future insertion of a pin in the wrong hole. 3 very critical parts that can be confused . . . it buggers belief.
It has been pointed out that a small pin in the larger strut hole should be obvious right away on power up / rotor lift or HUMS as happened previously, but that is still no reason not to ask for a redesign of the pins to avoid this possibility.
Edit : post 467 clears up this issue, 225 pins - all three lower pins have the same diam.
It has been pointed out that a small pin in the larger strut hole should be obvious right away on power up / rotor lift or HUMS as happened previously, but that is still no reason not to ask for a redesign of the pins to avoid this possibility.
Edit : post 467 clears up this issue, 225 pins - all three lower pins have the same diam.
Last edited by TylerMonkey; 4th May 2016 at 13:36.
He then says:
«The helicopter flew normal, then i saw it wobble and heard a «bang», after about two seconds i heard one more «bang» and then the helicopter goes straight to the ground»
«The helicopter flew normal, then i saw it wobble and heard a «bang», after about two seconds i heard one more «bang» and then the helicopter goes straight to the ground»
I assume first the bang, followed by the wobbling motion?
skadi
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Eye witness reports all seem to state that they heard bangs and then saw the rotor separate from the helicopter. Given that it would take half a second or more for the sound to reach the ground, it would seem likely that the bangs might have been a prelude to the rotor separation.
So what caused the loud bangs? An engine compresser stall, the gearbox starting to separate and rotor blades hitting the fuselage, suspension tie rods failing sequentially or some other cause?
Given that the sounds are described as loud bangs, it is unlikely to be the sound of metal failing directly, more likely engine related or the sound of impacting rotor blades as some internal brace or the gearbox housing failed.
The Norwegian investigators should be commended for allowing the press so much access to the wreckage and for the open nature of the investigation. That may upset some in the industry but there is a tremendous amount at stake and it is important that there are no allegations of collusion or cover up when the investigation is complete.
So what caused the loud bangs? An engine compresser stall, the gearbox starting to separate and rotor blades hitting the fuselage, suspension tie rods failing sequentially or some other cause?
Given that the sounds are described as loud bangs, it is unlikely to be the sound of metal failing directly, more likely engine related or the sound of impacting rotor blades as some internal brace or the gearbox housing failed.
The Norwegian investigators should be commended for allowing the press so much access to the wreckage and for the open nature of the investigation. That may upset some in the industry but there is a tremendous amount at stake and it is important that there are no allegations of collusion or cover up when the investigation is complete.
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All the lower pins are identical(fwd,LH and RH). The upper pins are a larger diameter and longer than the lower pins. They look very different. The lower pin has 2 flats on the head of the pin and the upper pins have 2 flats on a shoulder which protrudes from the head. The flats are there so you can rotate the pin to insert the nappy pins x2 in an acceptable position where they won't foul on anything.
You would only be able to mistakenly fit a lower pin in the upper (lift housing) holes! Not the other way around! It is unlikely any 225 engineer would not notice this on install or during subsequent after last flight inspections.
You would only be able to mistakenly fit a lower pin in the upper (lift housing) holes! Not the other way around! It is unlikely any 225 engineer would not notice this on install or during subsequent after last flight inspections.
The reports of 2 x loud bags would probably be the engines over-speeding or more specifically the free-turbines. With the head gone, there is no load, so they would run up and most likely experience a turbine burst.
I saw this in a Eurocopter demonstration video once and it is an explosion but contained within the reinforced engine casing. Not that the reinforcement would have helped in this situation sadly as bigger things were in play.
P3
I saw this in a Eurocopter demonstration video once and it is an explosion but contained within the reinforced engine casing. Not that the reinforcement would have helped in this situation sadly as bigger things were in play.
P3
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the epicyclic module is here on the right side of the picture, so now we haven't sen any view of the conical housing and lift housing which are i suppose still attached to the mast...
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Previous post 390 on thread gave the impression lower 3 pins not identical, that the two aft pins had a smaller diameter. It said small one was incorrectly inserted in a larger strut rod hole and gave a clunk noise on rotor lift. VortexR can you please clarify if the lower pins are the same diam ? TIA
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According to MMA the dimensions for the Suspension Bar bolt is the same upper and lower bolts (The outer diameter) 21,975 mm Min
The lenght is different.
Ref MMA 63 32 00 991
The lenght is different.
Ref MMA 63 32 00 991
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Please accept my apologies, everyone. My mind is obviously playing tricks. Vortex is correct, in that it is the upper pins that differ from the lower ones. The incident was also on a 332L, so the whole thing may be a red herring, particular if as Vortex said the pin is too short for installation in the incorrect position.
However, I confirm again, the smaller diameter pin has been inserted, and locked, in the wrong fitting (on a 332). It was not noticed by duplicating engineers. The first hint of something wrong was when the aircraft was powered up.
It is interesting that the ASB/AD require both the pins and the fitting attachments to be checked. Might this indicate that the suspension bar (at least one) has departed the aircraft but it is unknown whether it was via a pin failure/installation error or a fitting attachment failure/installation error.
I had heard a rumour that the forward fitting was replaced recently. Wholly unsubstantiated rumour.
Again, I'm not suggesting that any of this is the cause of the accident, but it is possible.
Apologies again.
However, I confirm again, the smaller diameter pin has been inserted, and locked, in the wrong fitting (on a 332). It was not noticed by duplicating engineers. The first hint of something wrong was when the aircraft was powered up.
It is interesting that the ASB/AD require both the pins and the fitting attachments to be checked. Might this indicate that the suspension bar (at least one) has departed the aircraft but it is unknown whether it was via a pin failure/installation error or a fitting attachment failure/installation error.
I had heard a rumour that the forward fitting was replaced recently. Wholly unsubstantiated rumour.
Again, I'm not suggesting that any of this is the cause of the accident, but it is possible.
Apologies again.
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We always keep the pins in the same position after removal anyway. I've never noticed any difference in diameter between them. This is confirmed by the IPC. All three pins are the exact same p/n.
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That's right. The 332L1 have larger diameter pins on the fwd strut. Not on the 225
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Apologies for a mistake in a previous post 460.
I can confirm (physically) that the 225 upper suspension bar pins are the same diameter as the lower pins. There is no difference in diameter between upper and lower pins. The lower pins are shorter in length than the upper pins.
I too fell foul of confusing the AS332l2 and EC225!
I can confirm (physically) that the 225 upper suspension bar pins are the same diameter as the lower pins. There is no difference in diameter between upper and lower pins. The lower pins are shorter in length than the upper pins.
I too fell foul of confusing the AS332l2 and EC225!
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Ok so a few mistakes and confusion about the suspension bar setup on the forum. Is this indicative of the possibility of confusion/mistake when actually presented with the aircraft? Especially if you have both types on your license or in the hangar? Or is it very obvious when you have the parts in hand? I suspect it is relatively Murphy proof and something has mechanically failed rather than been incorrectly assembled.
