AD 2001-12-21 Airworthiness Directives; Boeing Model 747 Series Airplanes

Models named: 747 series. Read the applicability below — it usually turns on serial or part numbers too.

All Model 747 series airplanes, 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)(1) 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 contact between the rotating paddle wheel and the stationary end plates within the center wing tank override/jettison fuel pumps or horizontal stabilizer tank transfer pumps due to excessive wear of the pump shaft carbon thrust bearing, which can cause sparks and/or a hot surface condition and consequent ignition of fuel vapor in the center wing tank or horizontal stabilizer tank during dry pump operation (no fuel flowing), accomplish the following: Restatement of Requirements of AD 98-25-52 Airplane Flight Manual (AFM) Revisions (a) Within 7 days after December 29, 1998 (the effective date of AD 98-25-52, amendment 39-10957), revise the Limitations Section of the FAA-approved AFM to include the following procedures. This may be accomplished by inserting a copy of this AD into the AFM. “For Model 747-400 series airplanes equipped with a horizontal stabilizer tank, operation of the horizontal stabilizer tank transfer pumps is prohibited in flight. A tripped circuit breaker of a center wing tank override/jettison pump or a tripped circuit breaker of a horizontal stabilizer tank transfer pump must not be reset until the associated fuel pump has been inspected for damage and any damage has been repaired. The center wing tank override/jettison pumps must be operated in accordance with either option 1 or option 2 below. Option 1 If the center wing tank override/jettison pumps are required for flight, the center tank must contain a minimum of 17,000 pounds (7,700 kilograms) at engine start. The fuel quantity indicating system of the center wing tank must be operative to dispatch with center wing tank fuel intended for use in the flight. Select both center wing tank override/jettison pump switches off at or before the fuel quantity of the center wing tank reaches 7,000 pounds (3,200 kilograms). Note: On Model 747-400 series airplanes, the “FUEL OVRD CTR L” and “FUEL OVRD CTR R” engine indication and crew alerting system (EICAS) messages will be displayed with the switches off. The center wing tank override/jettison pumps may be operated with less than 7,000 pounds of fuel in the center wing tank if required to address an emergency (such as fuel jettison or low fuel quantity). Option 2 If the center wing tank override/jettison pumps are required for flight, the center tank must contain a minimum of 50,000 pounds (22,700 kilograms) at engine start. The fuel quantity indicating system of the center wing tank must be operative to dispatch with center wing tank fuel intended for use in the flight. Select both center wing tank override/jettison pump switches off at or before center wing tank fuel quantity reaches 3,000 pounds (1,400 kilograms). The center wing tank override/jettison pumps may be operated with less than 3,000 pounds of fuel in the center wing tank if required to address an emergency (such as fuel jettison or low fuel quantity).” New Requirements of This Ad Determination of Correct Thrust Washer (b) For airplanes having center wing fuel tank override/jettison pumps and, if installed, horizontal stabilizer tank transfer pumps: If all pumps meet the criteria specified in paragraph (b)(1), (b)(2), (b)(3), or (b)(4) of this AD (i.e., the correct thrust washer is installed), no further action is required by this AD. Accomplishment of this paragraph terminates the requirements of paragraph (a) of this AD. (1) Verify the serial number on the pump data plate. The first four digits of the pump serial number represent the month and year of manufacture (e.g., 0697 indicates a pump manufactured in June 1997). If the serial number date code indicates that the pump was manufactured prior to July 1996, or after November 1998, and if the operator can determine that the pump was not overhauled or repaired after July 31, 1996, then the pump has the correct thrust washer installed. If the pump was overhauled or repaired after July 31, 1996, and the operator has maintenance/overhaul records showing that the thrust washer was not replaced, or was replaced with the correct thrust washer, as specified in paragraph (c) of this AD, then the pump has the correct thrust washer installed. (2) For airplanes having a date of manufacture prior to July 1996, if the operator can determine that the pump was not overhauled or repaired after July 31, 1996; and the pump was not replaced with a new pump manufactured between July 1996 and November 1998, then the pump has the correct thrust washer installed. If the pump was overhauled or repaired after July 31, 1996, and the operator has maintenance/overhaul records showing that the thrust washer was not replaced, or was replaced with the correct thrust washer, as specified in paragraph (c) of this AD, then the pump has the correct thrust washer installed. (3) For airplanes having pumps installed containing a serial number on the pump data plate with the suffix “P,” the pump has the correct thrust washer installed. (4) For airplanes having Crane Hydro-Aire fuel pumps having a thrust washer, part number 60-06561, with a date code of 9848 (“98” indicates the year 1998, and “48” indicates the 48th week in 1998), or higher, etched on the outside diameter of the thrust washer, the pump has the correct thrust washer installed. Terminating Action (c) For airplanes that do not meet the requirements specified in paragraph (b)(1), (b)(2), (b)(3), or (b)(4) of this AD; or if the serial number on the pump data plate of any fuel pump cannot be determined: Within 24 months after the effective date of this AD, replace the applicable center wing fuel tank override/jettison pumps and horizontal stabilizer tank transfer pumps with Crane Hydro-Aire fuel pumps having a thrust washer, part number 60-06561, with a date code of 9848 (“98” indicates the year 1998, and “48” indicates the 48th week in 1998), or higher, etched on the outside diameter of the thrust washer. Accomplishment of this paragraph terminates the requirements of paragraph (a) of this AD. Alternative Methods of Compliance (d)(1) An alternative method of compliance (AMOC) 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. Operators shall submit their requests through an appropriate FAA Principal Operations Inspector or Principal Maintenance Inspector, as applicable, who may add comments and then send it to the Manager, Seattle ACO. (2) With the exception of FAA AMOC letter to Boeing (No. 98-140-437, dated December 9, 1998), AMOCs approved previously in accordance with AD 98-25-52, amendment 39-10957, are approved as alternative methods of compliance with paragraph (a) of this AD. Note 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. Special Flight Permits (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. Effective Date (f) This amendment becomes effective on July 26, 2001. Issued in Renton, Washington, on June 14, 2001. Vi L. Lipski, Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 01-15569 Filed 6-20-01; 8:45 am] BILLING CODE 4910-13-P