Boeing and GE comments on FAA's 2011 "unsafe condition" qualification of GE80-85B
From FAA AD 2011-15-06 concerning "unsafe condition" of GE90-76B; GE90-77B; GE90-85B; GE90- 90B; and GE90-94B Turbofan Engines
末末末末末末末末末末末末末末末末末
"This AD was prompted by cracks discovered on one HPCR 8-10 spool between the 9-10 stages in the weld joint. We are issuing this AD to prevent failure of the HPCR 8-10 stage spool, uncontained engine failure, and damage to the airplane".
"Request
Two commenters, General Electric Company and The Boeing Company, requested that we remove the ''Unsafe Condition'' paragraph from the AD, and reword the Summary section to resemble the Summary section of AD 2002-04-11. The commenters stated that, by their analyses, cracks in the weld joint would not develop into an uncontained failure. The commenters stated that HPCR 8-10 stage spools, P/Ns 1844M90G01 and 1844M90G02, be inspected by an enhanced inspection, similar to those parts covered in AD 2002-04-11.
Answer
We do not agree. AD 2002-04-11 was issued because of additional focused inspection procedures that had been developed by the manufacturer. Because cracks were discovered on one HPCR 8-10 spool between the 9-10 stages in the weld joint, this unsafe condition is likely to exist or develop in other products of the same type design. The unsafe condition could result in failure of the HPCR 8-10 stage spool, uncontained engine failure, and damage to the airplane. We determined that this unsafe condition requires mandatory repetitive inspections for cracks. We did not change the AD."