# AD 99-08-19: APU Fuel Boost Pump - Type: Airworthiness directive - Status: Current - Products: Boeing 747-100 Series, 747-100B Series, 747-100B SUD Series, 747-200B Series, 747-200C Series, 747-200F Series, 747-300 Series, 747-400 Series, 747-400D Series, 747-400F Series, 747SP Series and 747SR Series - Effective: April 27, 1999 - Published: April 12, 1999, 64 FR 17524–17526 - Issued as: Final rule; request for comments - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Large airplane - Amendment: 39-11125 - Docket: 98-NM-292-AD - Registered aircraft: 63 may be affected, by airframe or engine model (OpenAirDocs) - Official PDF: https://openairdocs.org/files/sha256/4c/a8/4ca8c8878e8fde5b09bbb5d6cb0e401fb1c492359e840fb410be199ad4e659c5 (from https://www.govinfo.gov/content/pkg/FR-1999-04-12/pdf/99-8957.pdf) - Federal Register: https://www.federalregister.gov/documents/1999/04/12/99-8957/airworthiness-directives-boeing-model-747-series-airplanes - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/B2A722D6D9C5AA3886256983007241AC.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/99-08-19 ## Summary This amendment adopts a new airworthiness directive (AD) that is applicable to certain Boeing Model 747 series airplanes. This action requires replacement of the auxiliary power unit (APU) fuel boost pump with a serviceable pump. This amendment is prompted by findings from a design review and analysis, conducted as part of an accident investigation, of APU fuel boost pumps installed on certain Boeing Model 747 series airplanes. The actions specified in this AD are intended to prevent potential failures within the electrical motor assembly of the APU fuel boost pump (which could result in leakage of fuel from the electrical connector) or electrical arcing across the connector pins of the pump, and consequent fuel fire. ## The airworthiness directive 99-08-19 BOEING: Amendment 39-11125. Docket 98-NM-292-AD. Applicability: Model 747 series airplanes, line positions 001 through 1150 inclusive; equipped with an auxiliary power unit (APU) fuel boost pump manufactured by Lear Romec and having Lear Romec part number (P/N) RR24640B; 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 (c) 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. Compliance: Required as indicated, unless accomplished previously. To prevent potential failures within the electrical motor assembly of the APU fuel boost pump, which could result in fuel leakage from the electrical connector, or electrical arcing across the connector pins of the pump, and consequent fuel fire, accomplish the following: (a) Within 90 days after the effective date of this AD, replace the APU fuel boost pump as specified by either paragraph (a)(1) or (a)(2) of this AD, in accordance with Boeing Service Bulletin 747-28A2209, Revision 1, dated February 18, 1999. (1) Replace the pump with a pump that has been reworked in accordance with the service bulletin. Or (2) Replace the pump with an FAA-approved pump manufactured by a supplier other than Lear Romec, in accordance with the service bulletin. (b) As of the effective date of this AD, no person shall install on any airplane anAPU fuel boost pump having Lear Romec P/N RR24640B. (c) 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 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. (d) 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. (e) The replacement shall be done in accordance with Boeing Service Bulletin 747-28A2209, Revision 1, dated February 18, 1999. 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. 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. (f) This amendment becomes effective on April 27, 1999. ## Rule preamble ### Supplementary information As part of the accident investigation into the TWA Flight 800 accident of July 1996, the FAA participated in an engineering design review and analysis of the electrical connectors of Lear Romec auxiliary power unit (APU) fuel boost pumps. It has been determined that the Lear Romec component maintenance manual specifies an incorrect part number for that connector. Electrical connectors of Lear Romec APU fuel boost pumps incorporate a silicone insulating material. The results of that review and analysis indicate that contact with fuel can deteriorate the silicone insulating material in the electrical connectors during normal APU operation, due to the silicone material's incompatibility with fuel. Damage to the electrical connectors could cause failures within the electrical motor assembly of the APU fuel boost pump, which is located at the left-hand rear spar-to-landing-gear support beam. Such failures of the APU fuel boost pump could result in fuel leakage from the electrical connector, or the possibility of electrical arcing across the connector pins of the pump, and, if not corrected, could result in a fuel fire. Other Relevant Rulemaking On November 26, 1997, the FAA issued AD 97-25-06, amendment 39-10230 (62 FR 63622, December 1, 1997). (A correction of the rule was published in the Federal Register on January 2, 1998 (63 FR 4).) That AD required disconnection of the electrical connector to the scavenge pump of the center wing tank; a one-time inspection to identify the part number of the electrical connector; and replacement of the pump with a new pump, if necessary. The intent of that AD is to prevent potential failures within the electrical motor assembly of the scavenge pump on certain Boeing Model 747 series airplanes; such failures could result in leakage of fuel from the electrical connector into the main landing gear wheel well, or electrical arcing within the scavenge pump motor, and consequent fuel fire in the wheel well. Since the issuance of AD 97-25-06, the FAA received a report of damage to the internal wiring of a scavenge pump. The connector of that scavenge pump had been replaced with a Lear Romec-supplied connector, in accordance with the requirements of AD 97-25-06. AD 97-25-06 was superseded by AD 98-14-17, amendment 39-10650 (63 FR 36836, July 8, 1998), to require a one-time inspection to identify the scavenge pump motor-impeller unit and to require replacement of a certain Lear Romec pump. Certain electrical connectors on APU fuel boost pumps manufactured by Lear Romec incorporate the same silicone insulating material as that used on those scavenge pump connectors. The unsafe condition and its cause, as identified in AD 98-14-17, are similar to those addressed in this amendment. Explanation of Relevant Service Information The FAA has reviewed and approved Boeing Service Bulletin 747-28A2209, Revision 1, dated February 18, 1999, which describes procedures for a one-time visual inspection to identify the part number of the APU fuel boost pump. The service bulletin also describes procedures for replacement of any Lear Romec APU boost pump having an unacceptable part number, and provides two choices for the replacement pump: a pump that has been reworked, or a pump that has been manufactured by another supplier. Accomplishment of the actions specified in the service bulletin is intended to adequately address the identified unsafe condition, except as described below. Differences Between AD and Relevant Service Information The effectivity of the service bulletin specifies certain line positions. The applicability of this AD is further limited to those airplanes installed with certain boost pumps. (The only action required by this AD is the replacement of those boost pumps.) Explanation of the Requirements of the Rule Since an unsafe condition has been identified that is likely to exist or develop on other airplanes ofthe same type design, this AD is being issued to prevent potential failures within the electrical motor assembly of the APU fuel boost pump, which could result in leakage of fuel from the electrical connector, or electrical arcing across the connector pins of the pump, and consequent fuel fire. This AD requires accomplishment of the actions specified in Boeing Service Bulletin 747-28A2209, Revision 1. Determination of Rule's Effective Date Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days. Comments Invited Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified under the caption "ADDRESSES." All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed. Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket. Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 98-NM-292-AD." The postcard will be date stamped and returned to the commenter. Regulatory Impact The regulations adopted herein will not have substantial direct effects on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. Therefore, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment. The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, may be obtained from the Rules Docket at the location provided under the caption "ADDRESSES." List of Subjects in 14 CFR Part 39 Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. Adoption of the Amendment Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows: PART 39 - AIRWORTHINESS DIRECTIVES 1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. 106(g), 40113, 44701. § 39.13 (Amended) 2. Section 39.13 is amended by adding the following new airworthiness directive: ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS A20WE](https://openairdocs.org/tcds/A20WE): The Boeing Company; names 12 of 14 models: 747-100B Series, 747SP Series, 747-400D Series, 747-400F Series, 747-200B Series, 747-200F Series, 747-300 Series, 747-200C Series… ## Registered aircraft it may apply to (OpenAirDocs) Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment. - Aircraft: 63 (63 by airframe model, 0 by engine model) - Makers: Boeing 63 Models with the most aircraft: - [Boeing 747-446](https://openairdocs.org/model/boeing-747-446): 10 aircraft (airframe model) - [Boeing 747-422](https://openairdocs.org/model/boeing-747-422): 8 aircraft (airframe model) - [Boeing 747-412](https://openairdocs.org/model/boeing-747-412): 5 aircraft (airframe model) - [Boeing 747-400F](https://openairdocs.org/model/boeing-747-400f): 4 aircraft (airframe model) - [Boeing 747-409](https://openairdocs.org/model/boeing-747-409): 4 aircraft (airframe model) - [Boeing 747-481F](https://openairdocs.org/model/boeing-747-481f): 3 aircraft (airframe model) - [Boeing 747-409F](https://openairdocs.org/model/boeing-747-409f): 3 aircraft (airframe model) - [Boeing 747-481](https://openairdocs.org/model/boeing-747-481): 3 aircraft (airframe model) - [Boeing 747-428F](https://openairdocs.org/model/boeing-747-428f): 3 aircraft (airframe model) - [Boeing 747-123](https://openairdocs.org/model/boeing-747-123): 2 aircraft (airframe model) - [Boeing 747-251F](https://openairdocs.org/model/boeing-747-251f): 2 aircraft (airframe model) - [Boeing 747-443](https://openairdocs.org/model/boeing-747-443): 2 aircraft (airframe model) - [Boeing 747-438](https://openairdocs.org/model/boeing-747-438): 2 aircraft (airframe model) - [Boeing 747-428](https://openairdocs.org/model/boeing-747-428): 2 aircraft (airframe model) - [Boeing 747-257B](https://openairdocs.org/model/boeing-747-257b): 1 aircraft (airframe model) - [Boeing 747-283B](https://openairdocs.org/model/boeing-747-283b): 1 aircraft (airframe model) - [Boeing 747-121](https://openairdocs.org/model/boeing-747-121): 1 aircraft (airframe model) - [Boeing 747-131](https://openairdocs.org/model/boeing-747-131): 1 aircraft (airframe model) - [Boeing 747-128](https://openairdocs.org/model/boeing-747-128): 1 aircraft (airframe model) - [Boeing 747-273C](https://openairdocs.org/model/boeing-747-273c): 1 aircraft (airframe model) All 24 models: https://openairdocs.org/ad/99-08-19/models.md Every aircraft: https://openairdocs.org/ad/99-08-19/aircraft.md No proposed rule in this release led to it. Its text cites no advisory circulars or STCs. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.