Airworthiness Directive · Amendment 39-17549 · Flight controls
Airbus Airplanes
This AD applies to Airbus Model A330-301, -302, -303, -321, -322, -323, -341, -342, and -343 airplanes; and Model A340-211, -212, -213, -311, -312, and -313 airplanes; certificated in any category; all manufacturer serial numbers; if fitted with a trimmable horizontal stabilizer actuator (THSA) having part number (P/N) 47147-500 or P/N 47147-700.
We are adopting a new airworthiness directive (AD) for certain Airbus Model A330-300, A340-200, and A340-300 series airplanes. This AD was prompted by a determination that ballscrew rupture could occur on certain trimmable horizontal stabilizer actuators (THSAs). This AD requires repetitive THSA ballscrew shaft integrity tests, and replacement if necessary. We are issuing this AD to detect and correct ballscrew rupture, which, along with corrosion on the ballscrew lower splines, may lead to loss of transmission of THSA torque loads from the ballscrew to the tie-bar and consequent THSA blowback, which could result in 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.
At the later of the times specified in paragraph (g)(1) or (g)(2) of this AD, as applicable, do a THSA ballscrew shaft integrity test, in accordance with the Accomplishment Instructions of Airbus Mandatory Service Bulletin A330-27-3191, dated June 7, 2012; or Airbus Mandatory Service Bulletin A340-27-4186, dated June 7, 2012; as applicable. Repeat the integrity test thereafter at intervals not to exceed 12,000 flight hours or 4,400 flight cycles, whichever occurs first.
(1) At the latest of the times specified in paragraph (g)(1)(i), (g)(1)(ii), or (g)(1)(iii) of this AD.
(i) Within 12,000 flight hours since the airplane's first flight; or
(ii) Within 12,000 flight hours since the most recent THSA ballscrew shaft integrity test was done as specified in maintenance review board report (MRBR) Task 274000-12; or
(iii) Within 12,000 flight hours since the most recent THSA ballscrew shaft integrity test was done, as specified in Airbus Mandatory Service Bulletin A330-27-3179 or Airbus Mandatory Service Bulletin A340-27-4175, as applicable. (These service bulletins specify testing in case of type II or type III findings).
(2) Within 1,000 flight hours after the effective date of this AD, but without exceeding the latest of the times specified in paragraph (g)(2)(i), (g)(2)(ii), or (g)(2)(iii) of this AD.
(i) 16,000 flight hours since the airplane's first flight.
(ii) 16,000 flight hours since the most recent THSA ballscrew shaft integrity test was done, as specified in MRBR task 274000-12.
(iii) 16,000 flight hours since the most recent THSA ballscrew shaft integrity test was done, as specified in Airbus Mandatory Service Bulletin A330-27-3179, or Airbus Mandatory Service Bulletin A340-27-4175, as applicable. (These service bulletins specify testing in case of type II or type III findings).
If the result from any test required by paragraph (g) of this AD is not correct, as specified in the Accomplishment Instructions of Airbus Mandatory Service Bulletin A330-27-3191, dated June 7, 2012; or Airbus Mandatory Service Bulletin A340-27-4186, dated June 7, 2012; as applicable: Before further flight, replace the THSA with a serviceable THSA, in accordance with the Accomplishment Instructions of Airbus Mandatory Service Bulletin A330-27-3191, dated June 7, 2012; or Airbus Mandatory Service Bulletin A340-27-4186, dated June 7, 2012; as applicable. Replacement of a THSA, as required by this paragraph, with a THSA having P/N 47147-500 or P/N 47147-700, is not terminating action for the repetitive tests required by paragraph (g) of this AD.
