AD 98-21-29 Airworthiness Directives; Boeing Model 747-100, -200, -300, -400, 747SP, and 747SR Series Airplanes

Models named: 747-100, -200, -300, -400, 747SP, 747SR series. Read the applicability below — it usually turns on serial or part numbers too.

Model 747-100, -200, -300, -400, 747SP, and 747SR series airplanes, having line numbers 629 through 1006 inclusive, and powered by General Electric or Rolls Royce engines; certificated in any category. Note 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (d) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Required as indicated, unless accomplished previously. To prevent high fuel pressure in components between the fuel shutoff spar valve and the engine fuel shutoff valve, which could result in failure of the fuel system components, lead to fuel leakage, and, consequently, lead to a possible engine fire, accomplish the following: (a) Within 18 months after the effective date of this AD, perform a one-time visual inspection to determine the part number of the fuel shutoff valve installed in the left- and right-hand outboard engines, in accordance with Boeing Alert Service Bulletin 747-28A2199, dated August 1, 1996. (1) If a valve having part number (P/N) S343T003-40 (ITT P/N 125334D-1) is installed, no further action is required by this AD. (2) If a valve having P/N S343T003-40 (ITT P/N 125334D-1) is not installed, prior to further flight, accomplish either paragraph (a)(2)(i) or (a)(2)(ii) of this AD. (i) Replace the valve with a new valve, in accordance with the alert service bulletin. Prior to further flight following accomplishment of the replacement, align the valve(s), perform a check to detect leaks, and correct any discrepancy, in accordance with the alert service bulletin. Or (ii) Modify the valve body assembly of the fuel system in accordance with ITT Service Bulletin SB125120-28-01, ITT Service Bulletin SB107970-28-01, and ITT Service Bulletin SB125334-28-01; all dated July 15, 1996. (b) Except as provided in paragraph (c) of this AD, prior to further flight following accomplishment of paragraph (a)(2) of this AD, perform a one-time inspection to detect fuel leaks of the components between the fuel shutoff spar valve and the engine fuel shutoff valve on all four engines, in accordance with the applicable section that pertains to Rolls Royce RB211 series engines or General Electric CF6-80C and CF6-45/50 series engines in Chapter 71 of the Boeing 747 Airplane Maintenance Manual (AMM). If any leak is detected, prior to further flight, replace the part with a serviceable part. (c) For airplanes having maintenance records that positively demonstrate that the inboard engines have never been located in the outboard position: Prior to further flight following accomplishment of paragraph (a)(2) of this AD, perform a one-time inspection to detect fuel leaks of the components between the fuel shutoff spar valve and the engine fuel shutoff valve on the outboard engines only, in accordance with the applicable section that pertains to Rolls Royce RB211 series engines or General Electric CF6-80C and CF6-45/50 series engines in Chapter 71 of the Boeing 747 AMM. If any leak is detected, prior to further flight, replace the part with a serviceable part. (d) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. Operators shall submit their requests through an [[Page 55520]] appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO. Note 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. (e) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished. (f) Except as provided by paragraphs (b) and (c) of this AD, the actions shall be done in accordance with Boeing Alert Service Bulletin 747-28A2199, dated August 1, 1996; or ITT Service Bulletin SB125120-28-01, ITT Service Bulletin SB107970-28-01, and ITT Service Bulletin SB125334-28-01; all dated July 15, 1996. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207; or ITT Aerospace Controls, 28150 Industry Drive, Valencia, California 91355. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. (g) This amendment becomes effective on November 20, 1998. Issued in Renton, Washington, on October 6, 1998. Darrell M. Pederson, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 98-27459 Filed 10-15-98; 8:45 am] BILLING CODE 4910-13-P