Airworthiness Directive · Amendment 39-18037 · The Boeing Company Airplanes
The Boeing Company Airplanes
This AD applies to all The Boeing Company Model MD-90-30 airplanes, certificated in any category.
We are adopting a new airworthiness directive (AD) for all The Boeing Company Model MD-90-30 airplanes. This AD was prompted by reports of cracks emanating from the aft-most barrel nut holes of the left and right upper rear spar caps of the horizontal stabilizer. This AD requires repetitive high frequency eddy current (ETHF) inspections for cracks in the areas around the two aft-most barrel nut holes of the upper rear spar caps, and corrective action if necessary; and repetitive ETHF inspections for cracks in the areas around the two aft- most barrel nut holes of any repaired or replaced upper rear spar cap, and corrective actions if necessary. We are issuing this AD to detect and correct such cracks, which could propagate until the upper rear spar cap severs, and result in failure of the horizontal stabilizer upper center or aft skin panel and adversely affect the structural integrity of the airplane.
At the applicable compliance time specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin MD90-55A017, dated September 27, 2013, except as provided by paragraph (j) of this AD: Do a high frequency eddy current inspection (ETHF) for cracks in the areas around the two aft-most barrel nut holes of the upper rear spar cap; and do all applicable corrective actions; in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin MD90-55A017, dated September 27, 2013. Thereafter, repeat the ETHF inspection at the applicable time specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin MD90-55A017, dated September 27, 2013. Do all corrective actions before further flight.
For airplanes on which a splice repair or replacement was done as specified in Boeing Alert Service Bulletin MD90-55A017: At the applicable compliance time specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin MD90-55A017, dated September 27, 2013, do an ETHF inspection for cracks at the two aft-most barrel nut holes of any repaired or replaced upper rear spar cap, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin MD90-55A017, dated September 27, 2013. Thereafter, repeat the ETHF inspection at the applicable time specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin MD90-55A017, dated September 27, 2013. If any cracking is found, before further flight, do the repair or replacement, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin MD90-55A017, dated September 27, 2013.
The post-repair inspections of the upper rear spar cap of the aft flange that has been splice-repaired specified in Table 1 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin MD90-55A017, dated September 27, 2013, are not required by this AD.
Note 1 to paragraph (i) of this AD: The damage tolerance inspections (post-repair inspections of the upper rear spar cap aft flange) specified in Table 1 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin MD90-55A017, dated September 27, 2013, may be used in support of compliance with Section 121.1109(c)(2) or 129.109(b)(2) of the Federal Aviation Regulations (14 CFR 121.1109(c)(2) or 14 CFR 129.109(b)(2)). The corresponding actions specified in the Accomplishment Instructions of Boeing Alert Service Bulletin MD90-55A017, dated September 27, 2013, are not required by this AD.
Where Boeing Alert Service Bulletin MD90-55A017, dated September 27, 2013, specifies a compliance time “after the original issue date of this service bulletin,” this AD requires compliance within the specified compliance time after the effective date of this AD.
