Grumman AD

The “tap test” for bondline delamination is supposed to be done every annual according to the maintenance manual. The fact that so many IA’s ignore the checklist is how we ended up with the proposed AD. The Grumman Owners & Pilots Association has provided comments that this AD is redundant with the existing checklist - we’ll see if that sways the FAA. In any case I wouldn’t expect this to take more that a few hours labor for 100-hour compliance.
 
AlleyCat67 said:
The fact that so many IA’s ignore the checklist is how we ended up with the proposed AD
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FYI: its not so much ignore the list as the list is not regulatory with Part 43 Appx D being the requirement. As with other aircraft that have unique issues this is where the owner needs to step in and request the tap test. One Grumman I was familiar with had this test done yearly as a separate line item/sign off vs included in the annual. Plus you'll find a majority of owners do not prefer the OEM inspection references to be used as the annual checklist requirement. This lack of preference and being non-regulatory is the reason for the AD which will make the tap test regulatory for all parties.
 
This is no big deal. Inspection for delamination should ocuur at each annual inspection. It's not very common now. Grummans with actual delamination issues have long since been fixed. A version of this AD was released after a catastrophic failure of the horizontal stabilizer in a Traveler with advanced corrosion. For my aircraft the delamination inspection was a non issue, and anticorrosion spray was used in the horizontal stabilizer for good measure. Done. Very little cost.
 
chemgeek said:
This is no big deal. Inspection for delamination should ocuur at each annual inspection. It's not very common now. Grummans with actual delamination issues have long since been fixed. A version of this AD was released after a catastrophic failure of the horizontal stabilizer in a Traveler with advanced corrosion. For my aircraft the delamination inspection was a non issue, and anticorrosion spray was used in the horizontal stabilizer for good measure. Done. Very little cost.
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The question I always have is "When will the years and exposure cause the glue to fail?" There's a practical life limit to most everything. Apparently, we're not there with the adhesives on the Grumman series, but I struggle to believe they are gonna last forever.
 
kyleb said:
The question I always have is "When will the years and exposure cause the glue to fail?" There's a practical life limit to most everything. Apparently, we're not there with the adhesives on the Grumman series, but I struggle to believe they are gonna last forever.
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I'm not too worried. There has not been a current rash of delaminating Grummans. The most recent incident which prompted an AD was due to advanced and unremediated corrosion which undermined the bonding in a critical structural part of the horizontal stabilizer elevator attachment. It is easily accessible to visual inspection. I've checked this area every preflight for 30+ years.
 
chemgeek said:
I'm not too worried. There has not been a current rash of delaminating Grummans. The most recent incident which prompted an AD was due to advanced and unremediated corrosion which undermined the bonding in a critical structural part of the horizontal stabilizer elevator attachment. It is easily accessible to visual inspection. I've checked this area every preflight for 30+ years.
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Please explain.
 
chemgeek said:
I'm not too worried. There has not been a current rash of delaminating Grummans. The most recent incident which prompted an AD was due to advanced and unremediated corrosion which undermined the bonding in a critical structural part of the horizontal stabilizer elevator attachment. It is easily accessible to visual inspection. I've checked this area every preflight for 30+ years.
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What is the cost to fix.. if it occures in a wing, will this require the whole wing be rived, or just that section?
 
Just that section where the debonding has occurred. Also, the issue, IF any, is typically the pre-1977 aircraft. So the AD maybe written against only those pre-1977 aircraft. After 1976, the process was changed and there has been NO issue with debonding.
 
Bell206 said:
FYI: its not so much ignore the list as the list is not regulatory with Part 43 Appx D being the requirement. As with other aircraft that have unique issues this is where the owner needs to step in and request the tap test. One Grumman I was familiar with had this test done yearly as a separate line item/sign off vs included in the annual. Plus you'll find a majority of owners do not prefer the OEM inspection references to be used as the annual checklist requirement. This lack of preference and being non-regulatory is the reason for the AD which will make the tap test regulatory for all parties.
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If all you IA is doing is the pt 43 required items then you need a new IA.
 
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