Airworthiness Directive · Amendment 39-17789 · Thrust reverser
The Boeing Company Airplanes
This AD applies to The Boeing Company airplanes, certificated in any category, powered by General Electric (GE) CF6-80C2 engines, as identified in paragraphs (c)(1) and (c)(2) of this AD.
(1) Model 747-200B, 747-300, 747-400, 747-400D, and 747-400F series airplanes, as identified in Boeing Alert Service Bulletin 747-78A2185, dated October 26, 2010.
(2) Model 767-200, -300, -300F, and -400ER series airplanes, as identified in Boeing Alert Service Bulletin 767-78A0100, dated October 26, 2010.
We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 747-200B, 747-300, 747-400, 747-400D, 747-400F series airplanes, and Model 767 series airplanes, powered by General Electric (GE) CF6-80C2 engines. This AD was prompted by reports of failure of the electro mechanical brake flexshaft (short flexshaft) of the thrust reverser actuation system (TRAS). This AD requires replacing the short flexshaft on each engine with a new short flexshaft, testing of the electro mechanical brake and center drive unit (CDU) cone brake to verify the holding torque, and performing related investigative and corrective actions if necessary. We are issuing this AD to prevent an uncommanded in-flight thrust reverser deployment and consequent loss of control of the airplane.
Within 60 months after the effective date of this AD, replace the short flexshaft on each thrust reverser half of each engine with a new short flexshaft, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-78A2185, dated October 26, 2010; or Boeing Alert Service Bulletin 767-78A0100, dated October 26, 2010; as applicable; or Middle River Aircraft Systems CF6-80C2B Service Bulletin 78-1168, Revision 2, dated April 19, 2011.
Note 1 to paragraph (g) of this AD: The torque value for the short flexshaft installation specified in paragraph (g) of this AD is lower than the torque value described for the part specified in AD 2000-09-04, Amendment 39-11712 (65 FR 25833, May 4, 2000).
Within 2,000 flight hours after accomplishment of the short flexshaft replacements required by paragraph (g) of this AD: Do a functional test on the electro-mechanical brakes and the cone brake of the center drive unit (CDU) to verify the holding torque, on all thrust reversers and on all engines, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 747-78A2166, Revision 3, dated July 29, 2004 (for Model 747 airplanes); Boeing Alert Service Bulletin 767-78A0081, Revision 2, dated April 19, 2001 (for Model 767-200, -300, and -300F airplanes); or Boeing Alert Service Bulletin 767-78A0088, dated April 19, 2001 (for Model 767-400ER airplanes). Repeat the functional test thereafter at intervals not to exceed 2,000 flight hours.
If any functional test required by paragraph (h) of this AD fails: Before further flight, do related investigative and corrective actions, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 747-78A2166, Revision 3, dated July 29, 2004 (for Model 747 airplanes); Boeing Alert Service Bulletin 767-78A0081, Revision 2, dated April 19, 2001 (for Model 767-200, -300, and -300F airplanes); or Boeing Alert Service Bulletin 767-78A0088, dated April 19, 2001 (for Model 767-400ER airplanes); and repeat the applicable test or check until successfully accomplished.
(1) Accomplishment of the initial test specified in paragraph (h) of this AD terminates the requirements of paragraphs (a) and (e) of AD 2003-16-16, Amendment 39-13269 (68 FR 51439, August 27, 2003), for Model 747-400 series airplanes powered by GE Model CF6-80C2 series engines.
(2) Accomplishment of the initial test specified in paragraph (h) of this AD terminates the requirements of paragraph (g) of AD 2000-15-04, Amendment 39-11833 (65 FR 47252, August 2, 2000), for Model 747-200 and -300 series airplanes powered by General Electric Model CF6-80C2 series engines.
(3) Accomplishment of the initial test specified in paragraph (h) of this AD terminates the requirements of paragraphs (e) and (f) of AD 2000-09-04, Amendment 39-11712 (65 FR 25833, May 4, 2000), for Model 767 series airplanes powered by General Electric Model CF6-80C2 series engines.
