AD 2015-05-01 Airworthiness Directives; The Boeing Company Airplanes

Models named: 757-200, -200PF, -200CB, -300 series, 767-200, -300, -300F, -400ER series. Read the applicability below — it usually turns on serial or part numbers too.

This AD applies to all The Boeing Company Model 757-200, -200PF, -200CB, and -300 series airplanes; and Model 767-200, -300, -300F, and -400ER series airplanes; certificated in any category.

Comply with this AD within the compliance times specified, unless already done.

Prior to the next RAT backdrive test, or within 24 months after the effective date of this AD, whichever occurs first: Do an inspection to determine the part number and serial number of the RAT hub assembly, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 757-29A0066, Revision 1, dated March 8, 2010 (for Model 757 airplanes); or Boeing Alert Service Bulletin 767-29A0110, Revision 1, dated March 8, 2010 (for Model 767 airplanes). A review of airplane maintenance records is acceptable in lieu of this inspection if the part number and serial number of the RAT hub assembly can be conclusively determined from that review. (1) If the part number or serial number of the RAT hub assembly is missing, or if the part number and serial number are specified in paragraphs (g)(1)(i) and (g)(1)(ii) of this AD, and the hub assembly has not been reworked and re-identified as specified in Hamilton Sundstrand Service Bulletin 730814-29-12, dated November 30, 2005 (for Model 757 airplanes); or Hamilton Sundstrand Service Bulletin 729548-29-15, dated November 30, 2005 (for Model 767 airplanes): Prior to the next RAT backdrive test or within 24 months after the effective date of this AD, whichever occurs first, replace the RAT or RAT hub assembly with a new, serviceable, or reworked and re-identified RAT or RAT hub assembly, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 757-29A0066, Revision 1, dated March 8, 2010 (for Model 757 airplanes); or Boeing Alert Service Bulletin 767-29A0110, Revision 1, dated March 8, 2010 (for Model 767 airplanes); except as provided by paragraphs (g)(2) and (g)(3) of this AD. (i) Model 757-200, -200PF, -200CB, and -300 series airplanes having part number (P/N) 733785A or 733785B, and serial number (S/N) 0410 through 0413 inclusive, 0415, 0417 through 0430 inclusive, 0432, or 0434. (ii) Model 767-200, -300, -300F, and -400ER series airplanes having P/N 734350A, 734350B, 734350C, or 734350D; and S/N 0666, 0673 through 0684 inclusive, 0686, 0687, or 0689. (2) Where Boeing Alert Service Bulletin 757-29A0066, Revision 1, dated March 8, 2010 (for Model 757 airplanes); or Boeing Alert Service Bulletin 767-29A0110, Revision 1, dated March 8, 2010 (for Model 767 airplanes); specifies to contact Hamilton Sundstrand for a replacement unit, this AD does not require that action. (3) Where Boeing Alert Service Bulletin 757-29A0066, Revision 1, dated March 8, 2010 (for Model 757 airplanes); or Boeing Alert Service Bulletin 767-29A0110, Revision 1, dated March 8, 2010 (for Model 767 airplanes); specifies to return all RAT hub assemblies to Hamilton Sundstrand for rework and test, operators may return the RAT or RAT hub assembly to Hamilton Sundstrand or to an FAA-approved repair facility that has the capability to disassemble, repair, balance, and test the RAT or RAT hub assembly.

This AD was prompted by reports indicating that the counterweights in some hub assemblies of the ram air turbine (RAT) could be understrength and fracture when the RAT is rotating, and that some RAT hub assemblies were delivered with balance washer retention screws that were incorrectly heat-treated, and therefore, susceptible to fracture and cracking. We are issuing this AD to prevent an inoperative RAT, which, following a dual engine shutdown in flight, will cause loss of all hydraulic power to the primary flight controls, resulting in subsequent loss of control of the airplane.

None.