Georgetown, DE
- Aircraft Year
- 1975
- Aircraft Type
- 112-390
- Reg Number
- N1410J
- Serial Number
- 410
Re: Safety Alert
10J looks fine...
10J looks fine...
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Safety Alert
- Thread starter jrichards
- Start date
Moultonboro, NH
- Aircraft Year
- 1976
- Aircraft Type
- 112/A
- Reg Number
- N101DM
- Serial Number
- 391
Re: Safety Alert
101DM is OK
Thanks
John
101DM is OK
Thanks
John
South Burlington, VT
- Aircraft Year
- 1978 580
- Aircraft Type
- Super Commander
- Reg Number
- N555LP
- Serial Number
- 14405
Re: Safety Alert
Hi All,
Update.
Gary has sent me two sets of candidate replacement shaft assemblies for his 112, and we have rejected both sets.
We are now up the learning curve a ways. Here's what we know:
1. Gary's "good" side was also cracked. Just a hairline that I could only see at my bench under my carbon arc microscope, but it WAS there.
2. It is fairly evident that Rockwell was aware of unacceptable welds on these assemblies as early as 1975 (when Gary's original assembly was repaired by someone... I guess by the factory, or its subcontractor).
3. BOTH of the two candidate replacement sets we have inspected thus far have had unacceptable welds: the first set had an apparent repair weld at the same place, and the 2nd set had a seemingly OEM weld that had fully perforated the tube wall (large voids and large affected area) only evident by interior examination of the tube.
4. Sometime in 1976, Rockwell changed the design, making the "claws" of the control arm reach further around the tube, and increasing the fillet width of the weld.
5. CAC changed the design again, circa 1992, beading down the well upper skin to make room for the control arms to have full wrap-arounds on the shafts and returned to a more normal weld fillet width.
6. It is virtually impossible to visually observe hairline cranks except under well-lit high-power magnification and it is definitely impossible to observe the tube interior for weld perforation without doing some disassembly.
Jim
Hi All,
Update.
Gary has sent me two sets of candidate replacement shaft assemblies for his 112, and we have rejected both sets.
We are now up the learning curve a ways. Here's what we know:
1. Gary's "good" side was also cracked. Just a hairline that I could only see at my bench under my carbon arc microscope, but it WAS there.
2. It is fairly evident that Rockwell was aware of unacceptable welds on these assemblies as early as 1975 (when Gary's original assembly was repaired by someone... I guess by the factory, or its subcontractor).
3. BOTH of the two candidate replacement sets we have inspected thus far have had unacceptable welds: the first set had an apparent repair weld at the same place, and the 2nd set had a seemingly OEM weld that had fully perforated the tube wall (large voids and large affected area) only evident by interior examination of the tube.
4. Sometime in 1976, Rockwell changed the design, making the "claws" of the control arm reach further around the tube, and increasing the fillet width of the weld.
5. CAC changed the design again, circa 1992, beading down the well upper skin to make room for the control arms to have full wrap-arounds on the shafts and returned to a more normal weld fillet width.
6. It is virtually impossible to visually observe hairline cranks except under well-lit high-power magnification and it is definitely impossible to observe the tube interior for weld perforation without doing some disassembly.
Jim
Last edited:
Micky Grana
New member
Thermal
- Aircraft Year
- 1978
- Aircraft Type
- 114
- Reg Number
- N5879N
Re: Safety Alert
5879n just got out of annual and she is also good
5879n just got out of annual and she is also good