An Example Repair - Revision history

Az gila at 00:22, 10 October 2007

2007-10-10T00:22:54Z

← Older revision		Revision as of 00:22, 10 October 2007
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	'''NOTE:''' This is a major structural repair, and due to the bonded nature of our Grummans, it is hard to find references in the Maintenance Manual and AC 43.13 that cover all cases of damage. A DER was hired... contact Fletchair to find names of DERs that are familiar with our Grumman bonded assemblies.		'''NOTE:''' This is a major structural repair, and due to the bonded nature of our Grummans, it is hard to find references in the Maintenance Manual and AC 43.13 that cover all cases of damage. A DER was hired... contact Fletchair to find names of DERs that are familiar with our Grumman bonded assemblies.

			The DER used for this repair was:-

			Rocky Howard

			AERODESIGN Aircraft Engineering, Inc.

			16006 Canard Circle,

			Austin, TX 78734

			512-266-0610

Az gila at 23:06, 3 September 2007

2007-09-03T23:06:31Z

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	[[Image:Doublers.JPG]]		[[Image:Doublers.JPG]]

	Pilot holes (#40) were drilled in the skin, the doublers cleoced in place, the doublers were then match drilled to the skin holes and clecoed~~. All holes were then drilled out to #30~~.		Pilot holes (#40) were drilled in the skin, the doublers cleoced in place, the doublers were then match drilled to the skin holes and clecoed.

	[[Image:Clecoed.JPG]]		[[Image:Clecoed.JPG]]
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	[[Image:Clecoed-2.JPG]]		[[Image:Clecoed-2.JPG]]

	With everything fitted, the patch and doubler were removed, the patch and skin holes dimpled, and the doubler holes countersunk. The doublers were primed, and then riveted in place. Solid rivets were used were a squeezer would fit, and CherryMax rivets for all other holes. Squeezing the rivets is important, since the repetitive hitting of a rivet gun could damage adjacent bond joints.		With everything fitted, the holes were drilled out to #30, the patch and doubler were removed, the patch and skin holes dimpled, and the doubler holes countersunk. The doublers were primed, and then riveted in place. Solid rivets were used were a squeezer would fit, and CherryMax rivets for all other holes. Squeezing the rivets is important, since the repetitive hitting of a rivet gun could damage adjacent bond joints.

	[[Image:Doublers-rivet.JPG]]		[[Image:Doublers-rivet.JPG]]

Az gila at 23:05, 3 September 2007

2007-09-03T23:05:23Z

← Older revision		Revision as of 23:05, 3 September 2007
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	[[Image:Doublers.JPG]]		[[Image:Doublers.JPG]]

	Pilot holes (#40) were drilled in the skin, the doublers cleoced in place, and ~~then all~~ holes were drilled out to #30.		Pilot holes (#40) were drilled in the skin, the doublers cleoced in place, the doublers were then match drilled to the skin holes and clecoed. All holes were then drilled out to #30.

	[[Image:Clecoed.JPG]]		[[Image:Clecoed.JPG]]

Az gila at 23:03, 3 September 2007

2007-09-03T23:03:54Z

← Older revision		Revision as of 23:03, 3 September 2007
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	[[Image:Doublers.JPG]]		[[Image:Doublers.JPG]]

	#40 ~~Pilot holes~~ were drilled in the skin, the doublers cleoced in place, and then all holes were drilled out to #30.		Pilot holes (#40) were drilled in the skin, the doublers cleoced in place, and then all holes were drilled out to #30.

	[[Image:Clecoed.JPG]]		[[Image:Clecoed.JPG]]

Az gila at 23:03, 3 September 2007

2007-09-03T23:03:06Z

← Older revision		Revision as of 23:03, 3 September 2007
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	[[Image:Doublers.JPG]]		[[Image:Doublers.JPG]]

	Pilot holes were drilled in the skin, the doublers ~~clamped~~ in place, and holes drilled to #30 ~~and clecoed on place~~.		#40 Pilot holes were drilled in the skin, the doublers cleoced in place, and then all holes were drilled out to #30.

	[[Image:Clecoed.JPG]]		[[Image:Clecoed.JPG]]

Az gila at 23:00, 3 September 2007

2007-09-03T23:00:37Z

← Older revision		Revision as of 23:00, 3 September 2007
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	The repair is major since the required patch is over 6 inches in one direction, and the spar cap is damaged, which is defined as a primary structure in the Maintenance Manual.		The repair is major since the required patch is over 6 inches in one direction, and the spar cap is damaged, which is defined as a primary structure in the Maintenance Manual.

	The damaged area was cut away to the marked lines in the picture. First cuts were made with a Dremel tool with a 2 inch ~~[[Tuf-grind disk]~~[ http://www.hobbylinc.com/htm/hou/houac3.htm]] just short of the line. The hole was then trimmed to the line with a 2 inch sanding disk in an angle die grinder. Care was taken over the spar, and the metal was not cut through at this location. A strip of aluminum was left bonded to the spar cap. After the rest of the hole was exposed, this strip was removed with pliers and a peeling motion. Epoxy bonds do not work well in peel, and the strip came off easily. Interestingly, after the hole was cut to the marks, the skin distortions visible in the picture forward of the spar just popped out.		The damaged area was cut away to the marked lines in the picture. First cuts were made with a Dremel tool with a 2 inch [http://www.hobbylinc.com/htm/hou/houac3.htm Tuf-Grind disk] just short of the line. The hole was then trimmed to the line with a 2 inch sanding disk in an angle die grinder. Care was taken over the spar, and the metal was not cut through at this location. A strip of aluminum was left bonded to the spar cap. After the rest of the hole was exposed, this strip was removed with pliers and a peeling motion. Epoxy bonds do not work well in peel, and the strip came off easily. Interestingly, after the hole was cut to the marks, the skin distortions visible in the picture forward of the spar just popped out, and no further enlargement of the hole was needed.

	The repair plan worked out with the DER involved a spar reinforcement and a skin patch similar to that defined for wing leading edges in the Maintenance Manual.		The repair plan worked out with the DER involved a spar reinforcement and a skin patch similar to that defined for wing leading edges in the Maintenance Manual.

Az gila at 22:55, 3 September 2007

2007-09-03T22:55:33Z

← Older revision		Revision as of 22:55, 3 September 2007
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	The repair is major since the required patch is over 6 inches in one direction, and the spar cap is damaged, which is defined as a primary structure in the Maintenance Manual.		The repair is major since the required patch is over 6 inches in one direction, and the spar cap is damaged, which is defined as a primary structure in the Maintenance Manual.

	The damaged area was cut away to the marked lines in the picture. First cuts were made with a Dremel tool with a 2 inch ~~Tuff~~-grind disk just short of the line. The hole was then trimmed to the line with a 2 inch sanding disk in an angle die grinder. Care was taken over the spar, and the metal was not cut through at this location. A strip of aluminum was left bonded to the spar cap. After the rest of the hole was exposed, this strip was removed with pliers and a peeling motion. Epoxy bonds do not work well in peel, and the strip came off easily. Interestingly, after the hole was cut to the marks, the skin distortions visible in the picture forward of the spar just popped out.		The damaged area was cut away to the marked lines in the picture. First cuts were made with a Dremel tool with a 2 inch [[Tuf-grind disk][ http://www.hobbylinc.com/htm/hou/houac3.htm]] just short of the line. The hole was then trimmed to the line with a 2 inch sanding disk in an angle die grinder. Care was taken over the spar, and the metal was not cut through at this location. A strip of aluminum was left bonded to the spar cap. After the rest of the hole was exposed, this strip was removed with pliers and a peeling motion. Epoxy bonds do not work well in peel, and the strip came off easily. Interestingly, after the hole was cut to the marks, the skin distortions visible in the picture forward of the spar just popped out.

	The repair plan worked out with the DER involved a spar reinforcement and a skin patch similar to that defined for wing leading edges in the Maintenance Manual.		The repair plan worked out with the DER involved a spar reinforcement and a skin patch similar to that defined for wing leading edges in the Maintenance Manual.

Bob Steward: changed individual wrenchs to "wrench 4 JPG", spelling correction

2007-09-03T16:37:16Z

changed individual wrenchs to "wrench 4 JPG", spelling correction

← Older revision		Revision as of 16:37, 3 September 2007
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	This page details an example of a Major Repair.		This page details an example of a Major Repair.

	'''Degree of difficulty:''' [[Image:~~wrench.jpg]][[Image:wrench.jpg]][[Image:wrench.jpg]][[Image:wrench.jpg]][[Image:wrench~~.jpg]]		'''Degree of difficulty:''' [[Image:wrench4.jpg]]

	'''As with all Major Repairs, a Form 337 is required, and in this case an FAA Designated Engineering Representative (DER) was involved in the structural analysis.'''		'''As with all Major Repairs, a Form 337 is required, and in this case an FAA Designated Engineering Representative (DER) was involved in the structural analysis.'''
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	The damaged area was cut away to the marked lines in the picture. First cuts were made with a Dremel tool with a 2 inch Tuff-grind disk just short of the line. The hole was then trimmed to the line with a 2 inch sanding disk in an angle die grinder. Care was taken over the spar, and the metal was not cut through at this location. A strip of aluminum was left bonded to the spar cap. After the rest of the hole was exposed, this strip was removed with pliers and a peeling motion. Epoxy bonds do not work well in peel, and the strip came off easily. Interestingly, after the hole was cut to the marks, the skin distortions visible in the picture forward of the spar just popped out.		The damaged area was cut away to the marked lines in the picture. First cuts were made with a Dremel tool with a 2 inch Tuff-grind disk just short of the line. The hole was then trimmed to the line with a 2 inch sanding disk in an angle die grinder. Care was taken over the spar, and the metal was not cut through at this location. A strip of aluminum was left bonded to the spar cap. After the rest of the hole was exposed, this strip was removed with pliers and a peeling motion. Epoxy bonds do not work well in peel, and the strip came off easily. Interestingly, after the hole was cut to the marks, the skin distortions visible in the picture forward of the spar just popped out.

	The repair ~~plane~~ worked out with the DER involved a spar reinforcement and a skin patch similar to that defined for wing leading edges in the Maintenance Manual.		The repair plan worked out with the DER involved a spar reinforcement and a skin patch similar to that defined for wing leading edges in the Maintenance Manual.

	The spar cap was damaged over the center of one of the spar lightening holes, so an 0.040 metal piece was fabricated.		The spar cap was damaged over the center of one of the spar lightening holes, so an 0.040 metal piece was fabricated.

Az gila at 05:20, 3 September 2007

2007-09-03T05:20:59Z

← Older revision		Revision as of 05:20, 3 September 2007
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	~~The~~ damage to the lower side of a Cheetah horizontal stabilizer that had an unfortunate encounter with a runway light. ~~This~~ picture was taken after stripping two layers of paint off an area of the stabilizer, ensuring no stripper came anywhere near an bond lines. PTI stripper proved to be very effective, but read all warning labels, it will damage skin!		This damage is to the lower side of a Cheetah horizontal stabilizer that had an unfortunate encounter with a runway light. The picture was taken after stripping two layers of paint off an area of the stabilizer, ensuring no stripper came anywhere near an bond lines. PTI stripper proved to be very effective, but read all warning labels, it will damage skin!

	[[Image:stab-damage.JPG]]		[[Image:stab-damage.JPG]]

Az gila at 05:19, 3 September 2007

2007-09-03T05:19:21Z

← Older revision		Revision as of 05:19, 3 September 2007
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	'''Degree of difficulty:''' [[Image:wrench.jpg]][[Image:wrench.jpg]][[Image:wrench.jpg]][[Image:wrench.jpg]][[Image:wrench.jpg]]		'''Degree of difficulty:''' [[Image:wrench.jpg]][[Image:wrench.jpg]][[Image:wrench.jpg]][[Image:wrench.jpg]][[Image:wrench.jpg]]

	As with all Major Repairs, a Form 337 is required, and in this case an FAA Designated Engineering Representative (DER) was involved in the structural analysis.		'''As with all Major Repairs, a Form 337 is required, and in this case an FAA Designated Engineering Representative (DER) was involved in the structural analysis.'''


	The damage to the lower side of a Cheetah horizontal stabilizer that had an unfortunate encounter with a runway light. This picture was taken after stripping two layers of paint off an area of the stabilizer, ensuring no stripper came anywhere near an bond lines. PTI stripper proved to be very effective, but read all warning labels, it will damage skin!		The damage to the lower side of a Cheetah horizontal stabilizer that had an unfortunate encounter with a runway light. This picture was taken after stripping two layers of paint off an area of the stabilizer, ensuring no stripper came anywhere near an bond lines. PTI stripper proved to be very effective, but read all warning labels, it will damage skin!