Bell 206L Main Rotor Cracks

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howey
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Bell 206L Main Rotor Cracks

#1 Post by howey » Wed Nov 09, 2011 7:22 pm

Bell issued an alert service bulletin about two years ago for the B206L, as a result of a main rotor in-flight separation. Is anybody familiar with this SB? It calls for a dye penetrate inspection every 60 cycles. Just wondering if anybody has discovered any cracks in the MR during this inspection.
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Heliian
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Re: Bell 206L Main Rotor Cracks

#2 Post by Heliian » Thu Nov 10, 2011 1:47 pm

The ASB affects several different p/n's and s/n's of 206L blades. Bell determined that a component inside the blade was manufactured out of tolerance and that it put added stress on the spar and could create a void in the bond which could lead to cracking and eventual separation. The basic dye penetrant "wipe check" is to be carried out every 60 starts to check for cracks on the top side of the blade between certain blade stations. A reduction in life limit was also imposed on certain s/n blades. Another part of the ASB recommends an Xray of the affected area that bell helicopter would examine to determine if there is an issue with that particular blade. Once examined, bell will tell you whether you can a) return the blade to normal service(terminating action of the ASB), b)return the blade to service while still complying with the wipe check every 60 starts or c) remove the blade from service. Our blades that were affected did not reveal any cracks during the wipe checks and the xray's came back from bell with a clean bill of health and we no longer have to carry out the wipe checks. There are many longrangers in the country so I couldn't tell you what was found but bell revised the ASB at one point and added a note that approx. 75% of the blades that were xrayed did not need any further action.

Cheers,

I
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helidoug
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Re: Bell 206L Main Rotor Cracks

#3 Post by helidoug » Tue Dec 20, 2011 11:18 am

I just recieved a new Civil Aviation Safety Alert on this subject. CASA 2011-08

Seems another one failed.
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Re: Bell 206L Main Rotor Cracks

#4 Post by North Shore » Tue Dec 20, 2011 9:03 pm

helidoug wrote:Seems another one failed.
*Shudders* :(
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Heliian
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Re: Bell 206L Main Rotor Cracks

#5 Post by Heliian » Thu Dec 22, 2011 4:43 pm

They've reduced the service life of all the affected blades now. The recent 206l accident near kap, was caused by blade failure. We won't know what actually transpired until TSB makes their final report though.
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