EC135 Cyclic Lock incident
 

I heard that ECD have recently published a service bulletin for the cyclic lock on the 135 following someone in the UK taking off with the lock engaged and the weak link feature not being as weak as hoped!! Anyone any idea where this happened and if any damage was done to the aircraft?

I thought it were two incidents in Germany one of them being ADAC but I could be wrong. I do not remember having read anything about such incidents in this country.

There were previous incidents of this happening before, hence the weak link, but this SB came in following a very recent incident where the weak link did not shear, i have heard from a reliable source that it was in the UK but if a similar incident has happened anywhere in the last week it would explain the SB.

There was also anotherEC 135 incident in the USA last year- pilot taking off with the lock installed. Aircraft spread the skids while getting it down on the pad again. The pilot was very lucky... lock did not break, as designed to do.

Interesting that it is happening everywhere?

I'm no test pilot but a good way to prevent these incidents, regardless of whether the weak link works, is to check the cyclic lock is off before taking off.... what do ye think, will it catch on?

Another way of making sure that you don't try to take-off with the cylic lock engaged is not to use the 'naffing' thing in the first place.:}

In the interests of flight safety, with our new aircraft barely a week off the McAlpine red carpet, I tested the cyclic lock release mechanism to see how much force was needed and how much rearward movement would occur once the lock was released. :cool:

Thankfully, and it was intentional, this was done post comp wash drying run/ground power check, with ac shut down! :ok:

Anyway, ready to be corrected, where does it tell you it is a shear pin! Why shouldn't I think it just slips out of the hole with a little force? That little sliver of aluminium surely isn't strong enough to hold it all together :\

Needless to say that if anyone else here has tried it, if you were to take off with the lock engaged and you were to shear the pin, you would have noticed that the rearward jerk once it had sheared would be more than enough to stoof the tail straight into the ground. :eek:

As tbc says....see above :D

Besides, you can't use it if you aint got one no more! So go out and see the effect for yourself! Shutdown of course :E

eurocopter beans you made me laugh!

The comment earlier by 'eurocopter beans' that the weak link feature not being as weak as hoped, is quite interesting.

Looking at the pin;

http://i52.photobucket.com/albums/g11/silsoesid/pin.jpg

You will notice

1. A cutout at the lower part for the cyclic lock to attach to.
2. Above the bulbous part, the thin weak part of the pin.
3. The attachement bolt that attaches the pin to the plate attached to the console


Something I discovered today was;

You can attach the lock 'correctly' into that lower cutout

http://i52.photobucket.com/albums/g1...oesid/pos1.jpg

You can attach the lock into the thin 'weak link' recess

http://i52.photobucket.com/albums/g1...oesid/pos2.jpg

And you can attach the lock right at the top onto the attachement bolt.

http://i52.photobucket.com/albums/g1...oesid/pos3.jpg


The hole size on the cyclic lock is determined by the amount that the 'release mechanism' is operated on application and by the amount of upward force when applying the lock.

Needless to say that when the lock is on the bottom ridge, less force is required to activate the shear pin than if it is 'incorrectly' attached at the weak point.

Worst case scenario is attaching the locking device onto the attachement bolt, where clearly the excessive force required to set free the cyclic, certainly when airborne, would result in an incident.

The weak link feature may well be as weak as designed, but only if the lock is fitted in the correct location!

I'm sure that ECD will say it's there in response to customer demand... :hmm:

What's the betting their engineers would suggest that they install another caption, ambiguously coloured green of course, with some indecipherable abbreviation. This will only illuminate when the cyclic lock is fitted, or only when the cyclic lock is not fitted, or both. Or neither. Just to be sure.

my undertanding silsoeid is that as you have illustrated it is the narrowest part of that silver arrowhead shaped thing that is supposed to shear.

revolutionary, thanks, i try.

Anyhoo... my initial questions stands, does anybody who caused the SB to be issued? Not so we can laugh at him but i would like to know what happened when he took off with a locked cyclic?

How do you get in without barking your shin on the thing in the first place???

I just leave my artificial left leg in the aircraft and hop right out. :}

Locks could be such that if used, the ship key itself is locked onto it, or retained within it (providing the door key is different), and can only be retrieved by removing the control lock.

If the control lock has a barrel and key system, then security for the ship is through taking this control lock key away after flying (plus the lock itself to a point). In fact, looking at the photos posted there, it could be done this way as the brackets already are, with a long-loop padlock... just remove the stupid weak-link pin.

Another way would be a cable looped from the lock round the upper of the cyclic via a sheath (for visibility, not necessarily the primary locking action) that can't be removed 'til unlocked, a la push bike lock.

The whole concept of building in a weak link is assuming the whole design itself is flawed I think, which it is from SilsoeSid's findings. An abortion. Personally, I wouldn't feel comfortable about attaching that thing if I was going to leave the machine for someone else to fly after me, checklists and procedures or not.

As Letsby says, how do you get in without clouting your foot / shin if the lock's in place??

Personally, I never use it but, if I did, and completed my after start checks correctly, I would expect to notice it was locked when either testing the HYD or A/P - if I was also blind enough not to have noticed it beforehand, of course!?:cool:

Overdrive, I think the EC135 control lock is an abhorrent abomination and a miscarriage of justice, but an abortion?

SilsoeSid

ours has a small knurled section that stops you from over inserting the control lock...as it were, i think this is a different style to yours.
PHi had one try to take off with the thing still attached, i remember the pictures of the aircraft several stories up with the back end dangling off the side of the pad/building, the aircraft had to be secured by the fire brigade as it was rather precarious, i don't think the weak link broke away as advertised.

It's a northwest of England coloquialism, an anagrammatic compression of "abhorrent abomination" used to save time :ok:

Old Skool,

Do you have a pic of your 'knurled section'?

It seem quite clear that IF the device is fitted correctly, the weak part of the device is not quite weak enough to do what it should, safely.



Despite all this attention on a weak link that isn't, at the very least, shouldn't one notice that the lock is on when doing the hyd checks (free movement x2), autopilot check (cyclic orbit) and the trim checks (stick response)? :suspect:

It would appear that these 4 checks before take off that would/should identify that the lock is on....don't :hmm: :=

I have my camera and i'll snap a couple of pictures

I have leaned on that thing a couple of times, not during flight or rotors running and i would hate to try and break it in the hover, the resultant snap would surely end in disaster. Our checklist calls for the guard to be re-installed after the hydraulic checks but before bringing the engines to fly and then finally removing it for take off. I did question this and was told it had something to do with a certain rpm (70%/77% sorings to mind) being bad for the blades/mast as the rrpm increases to fly and the cyclic not being centered.
I personally don't re-install the guard after the hydraulic checks, i just keep an eye on the MMI and keep it centered.

anyway as i was saying i'll try to post those pictures