AD 99-01-16
final rule
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | The Boeing Company | 737-100 Series | Airworthiness Directives; BOEING Model 737-100, -200, -300, -400, and -500 Series Airplanes |
| aircraft | The Boeing Company | 737-200 Series | Airworthiness Directives; BOEING Model 737-100, -200, -300, -400, and -500 Series Airplanes |
| aircraft | The Boeing Company | 737-300 Series | Airworthiness Directives; BOEING Model 737-100, -200, -300, -400, and -500 Series Airplanes |
| aircraft | The Boeing Company | 737-400 Series | Airworthiness Directives; BOEING Model 737-100, -200, -300, -400, and -500 Series Airplanes |
| aircraft | The Boeing Company | 737-500 Series | Airworthiness Directives; BOEING Model 737-100, -200, -300, -400, and -500 Series Airplanes |
Unsafe Condition
Damage to the horizontal stabilizer, engine flameout caused by ice formed from water drained inadvertently through a mispositioned selector valve.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Install a placard warning cabin crew not to put the selector valve for the forward lavatory water supply in the 'DRAIN' position during flight. Install an isolation valve in the drain line downstream of the selector valve, which terminates the placard requirement.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
within 6 months for placard installation; isolation valve installation must be accomplished within the compliance time required for the placard to preclude the need for the placard.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Boeing Model 737-100, -200, -300, -400, and -500 series airplanes with forward lavatories installed.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Lvatory Water Supply
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_99-01-16.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 99-01-16 Document Type: AD Final Rules Docket Number: 97-NM-238-AD Subject Heading: Airworthiness Directives; BOEING Model 737-100, -200, -300, -400, and -500 Series Airplanes Subject: Lvatory Water Supply Status: Current Citation: (Federal Register: January 08, 1999 (Volume 64, Number 5)) Citation Publish Date: 01/08/1999 Effective Date: 02/12/1999 Make: The Boeing Company Model: 737-100 Series | 737-200 Series | 737-300 Series | 737-400 Series | 737-500 Series Product Type: Aircraft Product Subtype: Large Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 (64 FR 1112 No. 5 01/08/99) Comments: Updated RGL applicability to match AD applicability; CAR C-11-185 AIRWORTHINESS DIRECTIVES FINAL RULES: 99-01-16 CITATION: [Federal Register: January 08, 1999 (Volume 64, Number 5)] PAGE NUMBER: [Page 1112] DOCKET NUMBER: 97-NM-238-AD AMENDMENT: 39-10981 AD NUMBER: 99-01-16 SUBJECT HEADING: Airworthiness Directives; BOEING Model 737-100, -200, -300, -400, and -500 Series Airplanes ACTION: Final rule. SUMMARY: This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 737-100, -200, -300, -400, and -500 series airplanes, that requires installation of a placard that warns the cabin crew not to put the selector valve for the forward lavatory water supply in the "DRAIN" position during flight. This amendment also requires installation of an isolation valve in the drain line downstream of the selector valve, which would terminate the requirement for the placard installation. This amendment is prompted by reports of damage to the horizontal stabilizer, and engine flameout caused by ice formed from water drained inadvertently through a mispositioned selector valve. The actions specified by this AD are intended to prevent damage to the engines, airframe, or horizontal stabilizer, and/or to prevent a hazard to persons or property on the ground, as a result of ice that could dislodge from the airplane. DATES: Effective February 12, 1999. The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of February 12, 1999. ADDRESSES: 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: Don Eiford, 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) 227-2788; fax (425) 227-1181. SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to all Boeing Model 737-100, -200, -300, -400, and -500 series airplanes was published in the Federal Register on November 13, 1997 (62 FR 60810). That action proposed to require installation of a placard that warns the cabin crew not to put the selector valve for the forward lavatory water supply in the "DRAIN" position during flight. That action also proposed to require installation of an isolation valve in the drain line downstream of the selector valve. Consideration of Comments Received Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received. Request to Delay Issuance of AD Pending Release of Service Information Several commenters request delay of the issuance of the AD pending the release of appropriate service information that provides technical details for installation of the isolation valve. The commenters state that, without such service information, they are unable to provide meaningful comments regarding the technical content of the proposed AD. The FAA partially concurs with the commenter's request. The FAA recognizes that a service bulletin would provide technical details and procedures for accomplishing the actions proposed by the notice of proposed rulemaking (NPRM). However, the issue subject to public comment was the general requirement for the placard and valve installations. Further, because the valve installation is not expected to be technically complicated or difficult to accomplish, the FAA does not anticipate receiving any comments addressing the technical aspects of the valve installation. In light of this information, the FAA has determined that it is unnecessary to delay issuance of the final rule. Request to Revise Applicability One commenter states its understanding of the applicability as being limited to those models on which forward lavatories are installed. The FAA infers that the commenter is requesting that the FAA revise the applicability to include that limitation. The FAA concurs with the commenter's request, having determined that an affected airplane without a forward lavatory installed would not be subject to the identified unsafe condition. The applicability of the final rule has been revised accordingly. Request to Consider Valve Installation as Terminating Action One commenter requests that the proposed AD be revised to require installation initially of either the placard or the valve. That commenter considers the valve installation as the primary solution to address the identified unsafe condition; therefore, valve installation (if accomplished within the compliance time required for the placard installation) would preclude the need for the placard installation. That commenter suggests some airlines may choose to incorporate the valves within the 6-month window and forgo the placard installation. As further justification for its request, the commenter adds that production airplanes now include the isolation valve but not the placard. The FAA concurs with the request to require installation initially of either the placard or the valve. The FAA's intent behind installation of a placard, as proposed by the NPRM, was to provide an expeditious means to achieve an acceptable level of safety pending installation of the isolation valve. However, the FAA agrees that the isolation valve is considered the primary design solution to the identified unsafe condition. Therefore, the placard would not be needed if the valve is installed within the 6-month compliance time required to install the placard. The final rule has been revised to specify this, and to indicate that installation of the valve terminates the requirement for installation of the placard. Request to Remove Requirement for Valve Installation One commenter reports that it has not experienced the problem addressed in the proposed AD. The commenter states that the proposed requirement to install an isolation valve in the drain line is unnecessary, and installation of a placard should be sufficient to address the unsafe condition. The FAA infers that the commenter is requesting removal of the requirement to install the valve. The FAA does not concur. The FAA has determined that long-term continued operational safety will be better assured by design changes to remove the source of the problem, rather than by reliance on the cabin crew following additional procedures. This determination, coupled with a better understanding of the human factors associated with following such procedures, has led the FAA to consider placing less emphasis on the use of informational placards and more emphasis on design improvements. The valve installation requirement is in consonance with these conditions. No change to the final rule in this regard is necessary. Concern Regarding AD Effectiveness One commenter generally supports the proposal, but urges the FAA to continue to monitor occurrences of airframe damage and engine flameout due to inadvertent or erroneous drain valve activation in flight. The commenter states that the proposed corrective action would reduce but not eliminate the possibility of this unsafe condition, and urges the FAA to determine if a more active means of preventing the unsafe condition would be appropriate. The FAA acknowledges the commenter's concern and will continue to monitor such occurrences of airframe damage and engine flameout. The FAA may consider further rulemaking activity if additional corrective actions are deemed necessary. Actions Since Issuance of NPRM Since the issuance of the NPRM, the FAA has reviewed and approved Boeing Service Bulletin 737-38-1043, dated January 8, 1998, which provides procedures for the installation of the placard. Paragraph (a) of the final rule has been revised to incorporate the service bulletin as the appropriate source of service information for the placard installation. In addition, Figure 1 of the NPRM (which depicts the placard) has been removed from the final rule because an appropriate figure is provided in the service bulletin. Conclusion After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes described previously. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD. Cost Impact There are approximately 2,830 airplanes of the affected design in the worldwide fleet. The FAA estimates that 1,037 airplanes of U.S. registry will be affected by this AD. It will take approximately 1 work hour per airplane to accomplish the required placard installation, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of this installation required by this AD on U.S. operators is estimated to be $62,220, or $60 per airplane. It will take approximately 6 work hours per airplane to accomplish the required installation of an isolation valve, at an average labor rate of $60 per work hour. Required parts will cost approximately $300 per airplane. Based on these figures, the cost impact of this installation required by this AD on U.S. operators is estimated to be $684,420, or $660 per airplane. The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. 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. For the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it 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: REGULATORY TEXT: 99-01-16 BOEING: Amendment 39-10981. Docket 97-NM-238-AD. Applicability: Model 737-100, -200, -300, -400, and -500 series airplanes; having forward lavatories installed; 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. Compliance: Required as indicated, unless accomplished previously. To prevent damage to the engines, airframe, or horizontal stabilizer, and/or to prevent a hazard to persons or property on the ground, accomplish the following: (a) Except as provided by paragraph (c) of this AD: Within 6 months after the effective date of this AD, install a placard on the door beneath the forward lavatory sink, that warns the cabin crew not to put the selector valve for the forward lavatory water supply in the "DRAIN" position during flight. The installation shall be accomplished in accordance with Boeing Service Bulletin 737-38-1043, dated January 8, 1998. (b) Within 36 months after the effective date of this AD, install an isolation valve in the drain line downstream of the selector valve for the forward lavatory water supply, in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. Once the valve is installed, the placard described in paragraph (a) of this AD may be removed. (c) For airplanes on which the valve installation required by paragraph (b) of this AD is accomplished within the compliance time specified in paragraph (a) of this AD, the placard installation required by paragraph (a) is not required. (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 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 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) The placard installation shall be done in accordance with Boeing Service Bulletin 737-38-1043, dated January 8, 1998. 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. (g) This amendment becomes effective on February 12, 1999. FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_99-01-16.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 99-01-16 Document Type: AD Final Rules Docket Number: 97-NM-238-AD Subject Heading: Airworthiness Directives; BOEING Model 737-100, -200, -300, -400, and -500 Series Airplanes Subject: Lvatory Water Supply Status: Current Citation: (Federal Register: January 08, 1999 (Volume 64, Number 5)) Citation Publish Date: 01/08/1999 Effective Date: 02/12/1999 Make: The Boeing Company Model: 737-100 Series | 737-200 Series | 737-300 Series | 737-400 Series | 737-500 Series Product Type: Aircraft Product Subtype: Large Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 (64 FR 1112 No. 5 01/08/99) Comments: Updated RGL applicability to match AD applicability; CAR C-11-185 AIRWORTHINESS DIRECTIVES FINAL RULES: 99-01-16 CITATION: [Federal Register: January 08, 1999 (Volume 64, Number 5)] PAGE NUMBER: [Page 1112] DOCKET NUMBER: 97-NM-238-AD AMENDMENT: 39-10981 AD NUMBER: 99-01-16 SUBJECT HEADING: Airworthiness Directives; BOEING Model 737-100, -200, -300, -400, and -500 Series Airplanes ACTION: Final rule. SUMMARY: This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 737-100, -200, -300, -400, and -500 series airplanes, that requires installation of a placard that warns the cabin crew not to put the selector valve for the forward lavatory water supply in the "DRAIN" position during flight. This amendment also requires installation of an isolation valve in the drain line downstream of the selector valve, which would terminate the requirement for the placard installation. This amendment is prompted by reports of damage to the horizontal stabilizer, and engine flameout caused by ice formed from water drained inadvertently through a mispositioned selector valve. The actions specified by this AD are intended to prevent damage to the engines, airframe, or horizontal stabilizer, and/or to prevent a hazard to persons or property on the ground, as a result of ice that could dislodge from the airplane. DATES: Effective February 12, 1999. The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of February 12, 1999. ADDRESSES: 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: Don Eiford, 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) 227-2788; fax (425) 227-1181. SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to all Boeing Model 737-100, -200, -300, -400, and -500 series airplanes was published in the Federal Register on November 13, 1997 (62 FR 60810). That action proposed to require installation of a placard that warns the cabin crew not to put the selector valve for the forward lavatory water supply in the "DRAIN" position during flight. That action also proposed to require installation of an isolation valve in the drain line downstream of the selector valve. Consideration of Comments Received Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received. Request to Delay Issuance of AD Pending Release of Service Information Several commenters request delay of the issuance of the AD pending the release of appropriate service information that provides technical details for installation of the isolation valve. The commenters state that, without such service information, they are unable to provide meaningful comments regarding the technical content of the proposed AD. The FAA partially concurs with the commenter's request. The FAA recognizes that a service bulletin would provide technical details and procedures for accomplishing the actions proposed by the notice of proposed rulemaking (NPRM). However, the issue subject to public comment was the general requirement for the placard and valve installations. Further, because the valve installation is not expected to be technically complicated or difficult to accomplish, the FAA does not anticipate receiving any comments addressing the technical aspects of the valve installation. In light of this information, the FAA has determined that it is unnecessary to delay issuance of the final rule. Request to Revise Applicability One commenter states its understanding of the applicability as being limited to those models on which forward lavatories are installed. The FAA infers that the commenter is requesting that the FAA revise the applicability to include that limitation. The FAA concurs with the commenter's request, having determined that an affected airplane without a forward lavatory installed would not be subject to the identified unsafe condition. The applicability of the final rule has been revised accordingly. Request to Consider Valve Installation as Terminating Action One commenter requests that the proposed AD be revised to require installation initially of either the placard or the valve. That commenter considers the valve installation as the primary solution to address the identified unsafe condition; therefore, valve installation (if accomplished within the compliance time required for the placard installation) would preclude the need for the placard installation. That commenter suggests some airlines may choose to incorporate the valves within the 6-month window and forgo the placard installation. As further justification for its request, the commenter adds that production airplanes now include the isolation valve but not the placard. The FAA concurs with the request to require installation initially of either the placard or the valve. The FAA's intent behind installation of a placard, as proposed by the NPRM, was to provide an expeditious means to achieve an acceptable level of safety pending installation of the isolation valve. However, the FAA agrees that the isolation valve is considered the primary design solution to the identified unsafe condition. Therefore, the placard would not be needed if the valve is installed within the 6-month compliance time required to install the placard. The final rule has been revised to specify this, and to indicate that installation of the valve terminates the requirement for installation of the placard. Request to Remove Requirement for Valve Installation One commenter reports that it has not experienced the problem addressed in the proposed AD. The commenter states that the proposed requirement to install an isolation valve in the drain line is unnecessary, and installation of a placard should be sufficient to address the unsafe condition. The FAA infers that the commenter is requesting removal of the requirement to install the valve. The FAA does not concur. The FAA has determined that long-term continued operational safety will be better assured by design changes to remove the source of the problem, rather than by reliance on the cabin crew following additional procedures. This determination, coupled with a better understanding of the human factors associated with following such procedures, has led the FAA to consider placing less emphasis on the use of informational placards and more emphasis on design improvements. The valve installation requirement is in consonance with these conditions. No change to the final rule in this regard is necessary. Concern Regarding AD Effectiveness One commenter generally supports the proposal, but urges the FAA to continue to monitor occurrences of airframe damage and engine flameout due to inadvertent or erroneous drain valve activation in flight. The commenter states that the proposed corrective action would reduce but not eliminate the possibility of this unsafe condition, and urges the FAA to determine if a more active means of preventing the unsafe condition would be appropriate. The FAA acknowledges the commenter's concern and will continue to monitor such occurrences of airframe damage and engine flameout. The FAA may consider further rulemaking activity if additional corrective actions are deemed necessary. Actions Since Issuance of NPRM Since the issuance of the NPRM, the FAA has reviewed and approved Boeing Service Bulletin 737-38-1043, dated January 8, 1998, which provides procedures for the installation of the placard. Paragraph (a) of the final rule has been revised to incorporate the service bulletin as the appropriate source of service information for the placard installation. In addition, Figure 1 of the NPRM (which depicts the placard) has been removed from the final rule because an appropriate figure is provided in the service bulletin. Conclusion After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes described previously. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD. Cost Impact There are approximately 2,830 airplanes of the affected design in the worldwide fleet. The FAA estimates that 1,037 airplanes of U.S. registry will be affected by this AD. It will take approximately 1 work hour per airplane to accomplish the required placard installation, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of this installation required by this AD on U.S. operators is estimated to be $62,220, or $60 per airplane. It will take approximately 6 work hours per airplane to accomplish the required installation of an isolation valve, at an average labor rate of $60 per work hour. Required parts will cost approximately $300 per airplane. Based on these figures, the cost impact of this installation required by this AD on U.S. operators is estimated to be $684,420, or $660 per airplane. The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. 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. For the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it 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: REGULATORY TEXT: 99-01-16 BOEING: Amendment 39-10981. Docket 97-NM-238-AD. Applicability: Model 737-100, -200, -300, -400, and -500 series airplanes; having forward lavatories installed; 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. Compliance: Required as indicated, unless accomplished previously. To prevent damage to the engines, airframe, or horizontal stabilizer, and/or to prevent a hazard to persons or property on the ground, accomplish the following: (a) Except as provided by paragraph (c) of this AD: Within 6 months after the effective date of this AD, install a placard on the door beneath the forward lavatory sink, that warns the cabin crew not to put the selector valve for the forward lavatory water supply in the "DRAIN" position during flight. The installation shall be accomplished in accordance with Boeing Service Bulletin 737-38-1043, dated January 8, 1998. (b) Within 36 months after the effective date of this AD, install an isolation valve in the drain line downstream of the selector valve for the forward lavatory water supply, in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. Once the valve is installed, the placard described in paragraph (a) of this AD may be removed. (c) For airplanes on which the valve installation required by paragraph (b) of this AD is accomplished within the compliance time specified in paragraph (a) of this AD, the placard installation required by paragraph (a) is not required. (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 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 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) The placard installation shall be done in accordance with Boeing Service Bulletin 737-38-1043, dated January 8, 1998. 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. (g) This amendment becomes effective on February 12, 1999. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
This site is not affiliated with or endorsed by the FAA. Always verify with official sources.
Related Airworthiness Directives
2025-02-02 Recurring
final ruleAirworthiness Directives; The Boeing Company Airplanes
Unsafe Condition: cracks in the frame inner chord and web at station (STA) 727 between S-11L and S-13L, which could result in the inability of a principal structural element to sustain limit load, and adversely affe...
2023-13-12 Recurring
final ruleAirworthiness Directives; The Boeing Company Airplanes
Unsafe Condition: premature aging of certain passenger chemical oxygen generators, which could fail to deliver oxygen during an emergency, possibly resulting in injury to the airplane occupants.
2023-12-13
final ruleAirworthiness Directives; The Boeing Company Airplanes
Unsafe Condition: Radio altimeters cannot be relied upon to perform their intended function if they experience interference from wireless broadband operations in the 5G C-Band. This interference can cause other airp...
2023-10-02
final ruleAirworthiness Directives; Transport and Commuter Category Airplanes
Unsafe Condition: Radio altimeter anomalies that are undetected by the automation or pilot, particularly close to the ground (e.g., landing flare), could lead to loss of continued safe flight and landing. Additional...