# AD 99-18-17: Airplanes - Type: Airworthiness directive - Effective: September 16, 1999 - Published: September 1, 1999, 64 FR 47656–47658 - Issued as: Final rule; request for comments - Superseded by: Nothing supersedes this AD - Amendment: 39-11283 - Docket: 99-NM-187-AD - Official PDF: https://openairdocs.org/files/sha256/7c/f0/7cf02bd71f1d415a033bc7b561a95101883bca975457de49e0e935470ff3b899 (from https://www.govinfo.gov/content/pkg/FR-1999-09-01/pdf/99-22531.pdf) - Federal Register: https://www.federalregister.gov/documents/1999/09/01/99-22531/airplanes - Page: https://openairdocs.org/ad/99-18-17 ## Summary This amendment adopts a new airworthiness directive (AD) that is applicable to all Boeing Model 737-100, -200, -300, -400, and -500 series airplanes. This action requires repetitive replacements of the airplane battery with a new or reconditioned battery, and for certain airplanes, replacement of the battery charger with a new or serviceable battery charger. This action also requires performing repetitive tests to determine the condition of a certain diode of the Generator Control Units (GCU); and corrective actions, if necessary. This amendment is prompted by an incident during which all electrical power was lost due to a combination of a weak or depleted battery and the failure of a certain diode of the GCU. The actions specified in this AD are intended to prevent failure of all electrically powered airplane systems, which could result in the inability to continue safe flight and landing. ## The airworthiness directive ### 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. ### Sec. 39.13 [Amended] 2. Section 39.13 is amended by adding the following new airworthiness directive: 99-18-17 Boeing: Amendment 39-11283. Docket 99-NM-187-AD. Applicability: All Model 737-100, -200, -300, -400, and -500 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 (f) 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 failure of all electrically powered airplane systems, which could result in the inability to continue safe flight and landing, accomplish the following: ### (a) (a) For Model 737-100 and -200 series airplanes equipped with battery charger Boeing part number (P/N) 10-60701-1: Within 90 days after the effective date of this AD, accomplish the requirements of paragraphs (a)(1) and (a)(2) of this AD. (1) Replace the airplane battery charger with a new or serviceable airplane battery charger, Boeing P/N 10-60701-3, in accordance with Chapter 20-10-111 of the Boeing 737 Airplane Maintenance Manual (AMM); and (2) Replace the airplane battery with a new or reconditioned airplane battery in accordance with Chapter 24-31-11 of the Boeing 737 AMM. Thereafter, replace the airplane battery with a new or reconditioned airplane battery at intervals not to exceed 750 flight hours. ### (b) (b) For Model 737-300, -400, and -500 series airplanes: Within 90 days after the effective date of this AD, replace the airplane battery with a new or reconditioned airplane battery in accordance with Chapter 24-31-11 of the Boeing 737 AMM. Thereafter, replace the airplane battery with a new or reconditioned airplane battery at intervals not to exceed 750 flight hours. ### (c) (c) For all airplanes: Within 90 days after the effective date of this AD, perform a test to determine the condition of diode CR910 of the Generator Control Units (GCU) in accordance with Boeing Telex Message M-7200-99-01528, dated March 5, 1999. Note 2: Any tests performed prior to the effective date of this AD, in accordance with Boeing Telex Message M-7200-99-01528, dated February 19, 1999, or dated March 4, 1999, are not considered acceptable for compliance with the applicable action specified by this AD. (1) If all diodes pass the test, repeat the diode test thereafter, at intervals not to exceed 600 flight hours. (2) If any diode fails the test: Prior to further flight, replace the GCU with a new or serviceable GCU, and if necessary, the airplane battery with new or reconditioned airplane battery, and repeat the diode test for the replaced GCU in accordance with the telex message until successful completion of the test is achieved. Repeat the diode test thereafter, at intervals not to exceed 600 flight hours. ### (d) (d) As of the effective date of this AD, no person shall install a battery charger having P/N 10-60701-1 on any Model 737 series airplane. ### (e) (e) Within 10 days after accomplishing the initial diode test required by paragraph (c) of this AD, submit a report of the test results (negative findings) to the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; fax (425) 227-1181. Information collection requirements contained in this regulation have been approved by the Office of Management and Budget (OMB) under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have been assigned OMB Control Number 2120-0056. ### (f) (f) 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 ACO. 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 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. ### (g) (g) 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. ### (h) (h) Except as provided by paragraphs (a) and (b) of this AD, the test shall be done in accordance with Boeing Telex Message M-7200-99-01528, dated March 5, 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. 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. ### (i) (i) This amendment becomes effective on September 16, 1999. Issued in Renton, Washington, on August 24, 1999. Vi L. Lipski, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. ## Rule preamble ### Dates Effective September 16, 1999. The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of September 16, 1999. Comments for inclusion in the Rules Docket must be received on or before November 1, 1999. ### Addresses Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 99-NM-187-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. The service information referenced in this AD may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. This information may be examined 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. ### For further information contact Stephen S. Oshiro, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, FAA, Transport Airplane Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2793; fax (425) 227-1181. ### Supplementary information The FAA has received a report of an incident during which all electrical power was lost due to a combination of a weak or depleted battery and the failure of a certain diode of the GCU on a Boeing Model 737-200 series airplane. The electrical configuration of a Boeing Model 737-200 series airplane is similar in design to that of Boeing Model 737-100, -300, -400, and -500 series airplanes. Therefore, Boeing Model 737-100, -300, -400, and -500 series airplanes maybe subject to the same unsafe condition revealed on the Model 737-200 series airplane. The report revealed that, during an approach for landing, all electrical power was lost while the flight crew attempted a routine, in-flight start of the Auxiliary Power Unit (APU). Following from that incident, an assessment of airplane battery maintenance was conducted, which resulted in the determination that some operators have extended the maintenance intervals beyond those recommended by the manufacturer. Such extended maintenance intervals increase the likelihood of allowing an airplane to operate with a weak or depleted airplane battery. The risk of a weak or depleted battery is greater on Model 737-100 and -200 series airplanes than the Model 737-300, -400 and -500 series airplanes because some of these airplanes utilize an older version of a battery charger. This older version of a battery charger has charging characteristics (overcharges and dries out the battery) that are not compatible with the extended airplane battery maintenance intervals. Additionally, certain diodes of the GCU have exhibited a susceptibility to short-circuit failure. The cause of these failures is under investigation. If an attempt is made to start the APU during flight with a weak or depleted battery, and a short-circuit failure of a certain diode of the GCU has occurred, all electrical power could be lost for all airplane systems. Such failure could result in the inability to continue safe flight and landing. ### Explanation of Relevant Service Information The FAA has reviewed and approved Boeing Telex Message M-7200-99-01528, dated March 5, 1999, which describes procedures for performing repetitive tests to determine the condition of a certain diode of the GCU; and corrective actions, if necessary. The corrective actions include replacement of any GCU with a new or serviceable GCU if a failed diode is detected, and for certain conditions, replacement of the airplane battery with a new or reconditioned airplane battery. The FAA also has reviewed and approved Boeing 737 Airplane Maintenance Manual (AMM) Chapters 20-10-111 and 24-31-11. These service documents describe the following: AMM 20-10-111: For Model 737-100 and -200 series airplanes, this AMM describes procedures for removal and installation of black box units. For these airplane models, the airplane battery charger is considered to be a black box unit. AMM 24-31-11: For all Model 737-100, -200, -300, -400, and -500 series airplanes this AMM describes procedures for removal and installation of the airplane battery with a new or reconditioned airplane battery. Additionally, the AMM describes procedures for cleaning and checking any installed airplane battery. ### Explanation of the Requirements of the Rule Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design, this AD is being issued to prevent failure of all electrically powered airplane systems, which could result in the inability to continue safe flight and landing. This AD requires accomplishment of the actions specified in the service documents described previously. This AD also requires that operators report results of inspection findings to the FAA. ### Interim Action Since the cause of the failures of the GCU's is under investigation, this is considered to be interim action until final action is identified, at which time the FAA may consider further rulemaking. ### 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 99-NM-187-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: 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.