Guest Posted May 10, 2020 Report Posted May 10, 2020 Mooneys aren’t the only ones with spar corrosion issues. I’ve inspected two Piper Arrows, both 1973 200HP models 135 serial numbers apart, both with cracks in the aft spars caused by dissimilar metal corrosion between the aluminum spar and the steel attachment plate. Clarence Quote
StevenL757 Posted May 10, 2020 Report Posted May 10, 2020 Yeah....I’d call that “none-airworthy”. Quote
MB65E Posted May 10, 2020 Report Posted May 10, 2020 That’s crazy. Williams airmotive in Indiana has a great YouTube video on the Piper spar corrosion Issues. They have a kit to fix it. I watched Paul, The founder, cut, match drill, and roll a center Mooney wing skin all by by hand one afternoon. Neat experience that I’ll remember forever. -Matt Quote
EricJ Posted May 10, 2020 Report Posted May 10, 2020 Oof! I'm guessing the economical repair for that would be a replacement (junkyard) wing? Quote
aviatoreb Posted May 10, 2020 Report Posted May 10, 2020 Ugh. Is that as expensive to repair as it is in a Mooney? Quote
Guest Posted May 10, 2020 Report Posted May 10, 2020 5 hours ago, EricJ said: Oof! I'm guessing the economical repair for that would be a replacement (junkyard) wing? No, there is a kit to replace the inner 11”. It’s about $1200 for the kit for left and right wings plus labour. Clarence Quote
bradp Posted May 10, 2020 Report Posted May 10, 2020 Good overview of the piper 28/32 wing spar construction 2 Quote
N201MKTurbo Posted May 10, 2020 Report Posted May 10, 2020 2 hours ago, M20Doc said: No, there is a kit to replace the inner 11”. It’s about $1200 for the kit for left and right wings plus labour. Clarence Is there any way to inspect that if they don't have the inspection plate installed? Quote
Guest Posted May 10, 2020 Report Posted May 10, 2020 47 minutes ago, N201MKTurbo said: Is there any way to inspect that if they don't have the inspection plate installed? On the Arrow there is an inspection plate in each wheel well for access. Some in the Cherokee series had an inspection cover on the lower wing surface by at the rear spar, for those that don’t there is an SB to install one. Even without the inspection cover you can remove the lower wing root strip and use a light and mirror thru lightening holes in the butt rib or slip a borescope in the same opening. Clarence Quote
Guest Posted May 11, 2020 Report Posted May 11, 2020 9 hours ago, bradp said: And we wonder why piper wings fall off. The failure that took place in Florida a few years ago was the main spar and is subject to a soon to be revealed AD. In the mean time Piper has released SB1345 calling for eddy current inspection of the spar. Clarence Quote
N201MKTurbo Posted May 11, 2020 Report Posted May 11, 2020 1 hour ago, M20Doc said: On the Arrow there is an inspection plate in each wheel well for access. Some in the Cherokee series had an inspection cover on the lower wing surface by at the rear spar, for those that don’t there is an SB to install one. Even without the inspection cover you can remove the lower wing root strip and use a light and mirror thru lightening holes in the butt rib or slip a borescope in the same opening. Clarence Thanks, sense I got my IA everybody is pestering me to do annuals. I’m doing a PA-28-180. Spent more time studying than inspecting.... Quote
Ross Taylor Posted May 11, 2020 Report Posted May 11, 2020 Thanks @bradp - that was really interesting. And kudos to the student pilot who tested the wing for movement...and identified that. It could have been tragic. That bolt hole wear was impressive. Quote
carusoam Posted May 11, 2020 Report Posted May 11, 2020 Wow... There wasn’t much of the aluminum left that was in contact with the steal piece... It doesn’t look like inspection can work in a timely fashion... A significant amount of corrosion is in place before it becomes noticeable... on the outside... I was expecting a method of insulating the two different metals from each other... Possibly the next steps are replacing with a similar metal... (?) PP thoughts only not a mechanic... Best regards, -a- If anyone didn’t see the video posted by brad... the first one shows wear of a hole in an aluminum plate that has a steel bolt holding the wing attached... A student tugged on the wing, pre flight... and it moved... Good catch! Thanks for sharing the details gents... Best regards, -a- Quote
ArtVandelay Posted May 11, 2020 Report Posted May 11, 2020 6 hours ago, M20Doc said: The failure that took place in Florida a few years ago was the main spar and is subject to a soon to be revealed AD. In the mean time Piper has released SB1345 calling for eddy current inspection of the spar. Clarence Is that an easy thing to do? Is the equipment relatively inexpensive? I ask because would that be something someone would want to do on a Mooney, maybe even during a prebuy? Quote
Guest Posted May 11, 2020 Report Posted May 11, 2020 6 hours ago, carusoam said: Wow... There wasn’t much of the aluminum left that was in contact with the steal piece... It doesn’t look like inspection can work in a timely fashion... A significant amount of corrosion is in place before it becomes noticeable... on the outside... I was expecting a method of insulating the two different metals from each other... Possibly the next steps are replacing with a similar metal... (?) PP thoughts only not a mechanic... Best regards, -a- If anyone didn’t see the video posted by brad... the first one shows wear of a hole in an aluminum plate that has a steel bolt holding the wing attached... A student tugged on the wing, pre flight... and it moved... Good catch! Thanks for sharing the details gents... Best regards, -a- The new parts in the repair kit from Piper have a layer of sealant type of material between the steel and aluminum. There are a number of places in the Cherokee series where Piper used painted steel against bare aluminium. My guess is the corrosion is caused by paint stripper entry during painting, then water, moisture and time doing the rest. Clarence Quote
Guest Posted May 11, 2020 Report Posted May 11, 2020 4 hours ago, ArtVandelay said: Is that an easy thing to do? Is the equipment relatively inexpensive? I ask because would that be something someone would want to do on a Mooney, maybe even during a prebuy? The inspection requires removal of 4 bolts then inspection of the bolt holes with Eddy current, it requires equipment and training to compete. The wings on Mooney airframes don’t have the same installation method as the Cherokee series so it’s not applicable. Clarence Quote
GeeBee Posted May 11, 2020 Report Posted May 11, 2020 Do you think this Piper Arrow needs a rework? 1 Quote
GeeBee Posted May 11, 2020 Report Posted May 11, 2020 One of the reasons I elected to purchase a Mooney over others was the way it was constructed. I had considered a PA32R or a BE-36. I decided on the Mooney for both performance and structural reasons. The Cherokee wing attach method is not a "50 year" method. It is sad, because the old high wing Pipers had a simple, effective and durable system. I also shy away from Beechcrafts with "bathtub" spar attachments. Believe me, the Beechcraft "bathtub" fitting is no fun.. I had a King Air which was one of the first to get the production installed Monel bolts inspected at the 5 year mark. Deciding I did not want to be on the "bleeding edge" I elected to replace the bolts rather than NDT the factory installed units. When we went to pull the old bolts out found the factory had installed the chamfer washer backwards and gouged the bathtub fitting beyond repair. Ended up hanging a new wing on the airplane. A lot of Beechcrafts out there with mis-torqued and mis-installed wing attach bolts. The methodology required to properly attach the wing is too error prone. Quote
Guest Posted May 12, 2020 Report Posted May 12, 2020 Here is what the Piper rear spar repair looks like. Clarence Quote
EricJ Posted May 14, 2020 Report Posted May 14, 2020 On 5/12/2020 at 9:50 AM, M20Doc said: Here is what the Piper rear spar repair looks like. Clarence That assembly attaches to the existing spar? So you have to remove a significant chunk, eh? Quote
Guest Posted May 14, 2020 Report Posted May 14, 2020 2 hours ago, EricJ said: That assembly attaches to the existing spar? So you have to remove a significant chunk, eh? The instructions say just under 11” have to be cut off. Clarence Quote
Guest Posted May 30, 2020 Report Posted May 30, 2020 So, I picked up the Arrow from the structures shop and took a few pictures of the broken spar. It’s quite bad. Clarence Quote
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