Airworthiness Directive · Amendment 39-17573 · Flight controls
Airbus Airplanes
This AD applies to all Airbus Model A318-111, -112, -121, and -122 airplanes; Airbus Model A319-111, -112, -113, -114, -115, -131, -132, and -133 airplanes; Airbus Model A320-111, -211, -212, -214, -231, -232, and -233 airplanes; and Airbus Model A321-111, -112, -131, -211, -212, -213, -231, and -232 airplanes; certificated in any category.
We are adopting a new airworthiness directive (AD) for all Airbus Model A318, A319, A320, and A321 series airplanes. This AD was prompted by reports that certain trimmable horizontal stabilizer actuators (THSA) were found with corrosion that affected the ballscrew lower splines between the tie-bar and screw-jack. This AD requires repetitive inspections of the THSA; ballscrew integrity tests, if necessary; and replacement of affected THSAs. We are issuing this AD to detect and correct corrosion in the ballscrew lower splines, which, if the ballscrew ruptured, could lead to transmission of THSA torque loads from the ballscrew to the tie-bar, prompting THSA blowback, and possible loss of control of the airplane.
You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
For the purposes of this AD, the definition of THSA first flight is the THSA “entry into service date,” which is the date of the first flight of the airplane on which the THSA was originally fitted in production. All entry into service dates are included in the table that appears after the Accomplishment Instructions in Goodrich Service Bulletin 47145-27-16, Revision 2, dated January 7, 2013. If the entry into service date is not included in this table, use the manufacturing date engraved on the THSA's identification plate as the “entry into service date.”
At the later of the times specified in paragraphs (h)(1) and (h)(2) of this AD: Do a detailed inspection of the gaps between the ballscrew shaft and tie-rod splines on any THSA having P/N 47145-XXX (where XXX stands for any numerical value) to determine if the corrosion category is Type I, Type II, or Type III, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A320-27-1214, including Appendix 01, dated February 23, 2012; and the Accomplishment Instructions and the flowchart following the Accomplishment Instructions of Goodrich Service Bulletin 47145-27-16, Revision 2, dated January 7, 2013. Repeat the inspection thereafter at intervals not to exceed 24 months.
(1) Within 22 years accumulated by the THSA since the THSA's first flight, but no earlier than 20 years accumulated by the THSA since its first flight.
(2) Within three months after the effective date of this AD.
If, during any inspection required by paragraph (h) of this AD, it is determined that a THSA has Type II or Type III corrosion: Before further flight, do a ballscrew integrity test, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A320-27-1214, including Appendix 01, dated February 23, 2012; and the Accomplishment Instructions and the flowchart following the Accomplishment Instructions of Goodrich Service Bulletin 47145-27-16, Revision 2, dated January 7, 2013. If Type I corrosion is found, no action is required by this paragraph.
(1) For THSAs having Type II or Type III corrosion and for which the results of the ballscrew integrity test are not correct, as specified in Airbus Service Bulletin A320-27-1214, including Appendix 01, dated February 23, 2012: Before further flight, replace the affected THSA with a THSA that meets the criteria specified in paragraph (l) of this AD, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A320-27-1214, including Appendix 01, dated February 23, 2012.
(2) For THSAs having Type III corrosion and on which the results of the ballscrew integrity test are correct, as specified in Airbus Service Bulletin A320 27-1214, including Appendix 01, dated February 23, 2012: Within 10 days after the most recent inspection, replace the THSA with a THSA that meets the criteria specified in paragraph (l) of this AD, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A320-27-1214, including Appendix 01, dated February 23, 2012.
(3) For THSAs having Type II corrosion and on which the results of the ballscrew integrity test are correct, as specified in Airbus Service Bulletin A320 27-1214, including Appendix 01, dated February 23, 2012: Within 24 months or 5,000 flight cycles after the most recent inspection, whichever occurs first, replace the THSA with a THSA that meets the criteria specified in paragraph (l) of this AD, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A320-27-1214, including Appendix 01, dated February 23, 2012.
Replacement of a THSA, as required by paragraph (i) of this AD, does not constitute terminating action for the repetitive inspections required by paragraph (h) of this AD.
If any corrosion type is found during any inspection required by paragraph (h) of this AD, at the applicable time specified in paragraph (k)(1) or (k)(2) of this AD, report the findings to Airbus, Customer Services Engineering—SEEL5, Flight Control Systems A320 Family, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France; fax +33 5 61 93 44 25. The report must include the information specified in Appendix 01 of Airbus Service Bulletin A320-27-1214.
(1) If the inspection was done on or after the effective date of this AD: Within 90 days after that inspection.
(2) If the inspection was done before the effective date of this AD: Within 90 days after the effective date of this AD.
As of the effective date of this AD, no person may install a THSA having P/N 47145-XXX (where XXX stands for any numerical value) on any airplane, unless that THSA meets the applicable criteria specified in paragraph (l)(1) or (l)(2) of this AD.
(1) The THSA must not have accumulated 20 years or more since the THSA's first flight, and after installation must be inspected as required by paragraph (h) of this AD, at the later of the times specified in paragraphs (h)(1) and (h)(2) of this AD, and be inspected thereafter at intervals not to exceed 24 months as required by paragraph (h) of this AD; and any applicable actions specified in paragraph (i) of this AD must be accomplished.
(2) If the THSA has accumulated 20 years or more since the THSA's first flight, it must have been inspected before installation as required by paragraph (h) of this AD and determined to have Type I corrosion (if the screw shaft lower splines thread condition does not meet the Type II or Type III condition), and be inspected thereafter at intervals not to exceed 24 months as required by paragraph (h) of this AD; and any applicable actions specified in paragraph (i) of this AD must be accomplished.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
Aircraft
