Hello Nige, This was a good call with a successful outcome which may well have saved a catastrophic failure & it just goes to show that, in our game you must stick to your principles even though the decision may be unpopular. As Mike Valentine used to say " In Aviation, It's a damn sight better to be down here wishing you were up there, than to be up there wishing you were down here!!"
Dog members please note that the GFA office will be moving this Thursday 26th June. New address is:- Level 1 / 34 Somerton Road Somerton Vic 3062 Phone:- (03)9303 7805 Fax:- (03)9303 7960 Web: www.gfa.org.au Regards, JGV. Please note my new e-mail address as of 23 Feb 2007: [EMAIL PROTECTED] ------------------------------------------------------ The Gliding Federation of Australia Inc. invites you to visit the web site www.gfa.org.au newcomers to gliding and soaring are invited to visit www.soaring.com.au ------------------------------------------------------------------------ ------------------------------------------- This email transmission may contain confidential or privileged information that is intended only for the individual or entity named in the email address. If you are not the intended recipient, please be aware that any disclosure, copying, distribution or reliance upon the contents of this email is strictly prohibited -----Original Message----- From: Nigel Baker [mailto:[EMAIL PROTECTED] Sent: Friday, 20 June 2008 5:47 PM To: DOGS Cc: Tom Gilbert; Russell White; Redmond Quinn; Michael Shirley; Mark Morgan; Keith Gateley; Hudson, John; graham marsh; Wrigley, Gavin; Colin Turner; Catherine Conway; Baylee Roberts; ANDREW WRIGHT; Ivor Paech; Harry Bache Subject: [DOG mailing list] Crankshaft Damage from prop strike. G'day DOGers I have cc'd this mail to other operators who may be interested in this result. Attached photo's of damage to the blade of a HOV 62 160 prop fitted to an L2000 in a G109 . This is assumed to be from a stone. The owners asked for an opionion from me. I have not seen the Blade damage in person only seen the Photo's. The damge to the leading edge is I thought severe for a stone chip. It seems strange to have such a large bit of damage so far up from the tip. I have trouble understanding how something that big would be picked up by prop wash that high. The damage to the leading edge is quite deep. I have not seen the blade as I said, and Air Props have deemed the damage too bad for them to touch so it went back to Hoffmann. Thus all I have is the photo's and while my immediate reaction is that a strike like this on one blade only does not constitute full stress reversal at the crankshaft journal and likely low stress values anyway therefore unlikley to have done any engine damage, I was reluctant to express more than a general opinion not being directly involved. I was asked to put the question to Limbach. I sent the images to Limbach thinking I was likely to get a negative defensive response and that is exactly what I got. They are of course hiding behind their service bulletin 11.4 which I have also attached. Their reaction to the images was "please comply with SB 11.4". I felt that there was little choice but to bulk strip. JohnViney agreed so that was our isntruction to the owners. The insurance assessor asked the owners to check with the manufacturer re Bulk Strip and that is exactly what we have done. The engine in this aircraft only had 48 hour since overhaul. We did an NDT check on the Crankshaft and Con Rods at that stage and all was well. The engine was removed after I quoted the Spares and someone else quoted also including labour and the insurer gave the go ahead. Well I have to eat my words. I really didn't imagine we were doing anything than arse covering due to the SB. How wrong was I. I knew there was an oustide chance but thought pretty slim of any damage but there is always the unkown and in this case it was just what had caused the prop damage. The answere came back today on the NDT of the crankshaft. There is a crack in the centre main journal. Take this as wake up call guys. Just cause the damage doesn't look too bad and there is no evidence of flange runout don't assume it wil be ok. I have had some people state there is no need to bulf strip when a timber prop is used. Well that's bollicks. There is plenty of evidence to the contrary around but this instance takes me a bit by surprise. I certainly will take a more conservative veiw the next time this comes up. Cheers. Nige. --------------------------------------------------------------------- You are subscribed to the Dimona Owners Group mailing list. To unsubscribe, send email to: [EMAIL PROTECTED]
