AD 99-25-02

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AD Number:
99-25-02
Document Type:
AD Final Rules
Docket Number:
99-NM-332-AD
Subject Heading:
Airworthiness Directives; BOEING Model 737-100, -200, -300, -400, and -500 Series Airplanes,
Subject:
Torque Tube Crank
Status:
Current
Citation:
(Federal Register: November 30, 1999 )
Citation Publish Date:
11/30/1999
Effective Date:
12/15/1999
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Superseded AD: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Superseded By: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 66765 11/30/99)
Comments:
Updated RGL applicability to match AD applicability; CAR C-11-185
AIRWORTHINESS DIRECTIVES FINAL RULES: 99-25-02
CITATION:   [Federal Register: November 30, 1999 ]

PAGE NUMBER:   [Page 66765]

DOCKET NUMBER:   99-NM-332-AD

AMENDMENT:   39-11445

AD NUMBER:   99-25-02

SUBJECT HEADING:   Airworthiness Directives; BOEING Model 737-100, -200, -300, -400, and -500 Series Airplanes,

ACTION:   Final rule; request for comments

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 a one-time inspection to verify correct installation of the fastener that connects the input rod of the spoiler mixer mechanism to the torque tube crank, and corrective actions, if necessary. For certain airplanes, this action requires replacement of the nut, bolt, and cotter pin that connects the input rod of the spoiler mixer mechanism to the torque tube crank with a new or serviceable nut, bolt, and cotter pin. This amendment is prompted by reports indicating numerous discrepancies in the installation of the fastener that connects the input rod of the spoiler mixer mechanism to the torque tube crank. The actions specified in this AD are intended to prevent the linkage between the ratio changer input rod and the aft aileron control quadrant from becoming disconnected, which could result in reduced controllability of the airplane.

DATES:   Effective December 15, 1999. The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of December 15, 1999. Comments for inclusion in the Rules Docket must be received on or before January 4, 2000.

ADDRESSES:  
Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 99-NM-332-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:  
Robert C. Jones, 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) 227-1118; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION:  
The FAA has received reports indicating numerous discrepancies in the installation of the fastener that connects the input rod of the spoiler mixer mechanism to the torque tube crank on Boeing Model 737-100, -200, -300, -400, and -500 series airplanes. These discrepancies include the use of incorrect hardware, the lack of secondary means of retention, and the incorrect (inverted) installation of the bolt. Additionally, the airplane manufacturer has indicated that the torque values specified, in a previously issued service bulletin, for the nut and bolt of the fastener in the spoiler mixer mechanism were too high. The previously specified torque values could cause the nut and bolt to fail, which could result in a disconnection of the linkage between the ratio changer input rod and the aft aileron control quadrant. This condition, if not corrected, could result in reduced controllability of the airplane.

Explanation of Relevant Service Information

The FAA has reviewed and approved Boeing Alert Service Bulletin 737-27A1213, Revision 1, dated May 21, 1998, which describes procedures for a one-time visual inspection to verify correct installation of the fastener that connects the input rod of the spoiler mixer mechanism to the torque tube crank, and corrective actions, if necessary. The corrective actions involve either re-installation of the existing fastener, or replacement of the fastener with a new or serviceable fastener.

For certain airplanes on which the initial issue of the alert service bulletin has been accomplished, the alert service bulletin describes procedures for replacement of the nut, bolt, and cotter pin that connects the input rod of the spoiler mixer mechanism to the torque tube crank with a new or serviceable nut, bolt, and cotter pin.

Accomplishment of the actions specified in the alert service bulletin is intended to adequately address the identified unsafe condition.

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 the linkage between the ratio changer input rod and the aft aileron control quadrant from becoming disconnected, which could result in reduced controllability of the airplane. The actions are required to be accomplished in accordance with the alert service bulletin described previously, except as discussed below. This AD also requires that operators report certain results of the one-time inspections to the FAA.

Differences Between AD and Alert Service Bulletin

Operators should note that the Boeing alert service bulletin recommends that the inspection to verify correct installation of the fastener that connects the input rod of the spoiler mixer mechanism to the torque tube crank be performed at the operator's earliest maintenance opportunity. However, the FAA has determined that such an interpretive compliance time may not address the identified unsafe condition in a timely manner. In developing appropriate compliance times for this AD, the FAA considered not only the manufacturer's recommendation, but the degree of urgency associated with addressing the subject unsafe condition, the average utilization of the affected fleet, the accessibility of the area to be inspected, the time necessary to accomplish the inspection (approximately 1 hour), and the time necessary to accomplish the replacement (approximately 1 hour). In light of all these factors, the FAA finds that inspecting to verify correct installation of the fastener in the spoiler mixer mechanism within a 90-day compliance time is warranted, in that it represents an appropriate interval of time allowable for affected airplanes to continue to operate without compromising safety.

Operators also should note that the Boeing alert service bulletin specifies the effectivity to be Boeing Model 737-100, -200, -300, -400, and -500 series airplanes having line numbers 1 through 2681. However, the FAA has determined that this effectivity would not address all the affected airplanes on which the identified unsafe condition is likely to exist or develop. Therefore, the applicability of this AD includes all Boeing Model 737-100, -200, -300, -400, and -500 series airplanes.

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-332-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:

REGULATORY TEXT:  
99-25-02 BOEING: Amendment 39-11445. Docket 99-NM-332-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 (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 the linkage between the ratio changer input rod and the aft aileron control quadrant from becoming disconnected, which could result in reduced controllability of the airplane; accomplish the following:

Detailed Visual Inspection

(a) Within 90 days after the effective date of this AD, accomplish the actions required by paragraph (a)(1) or (a)(2) of this AD, as applicable, in accordance with Boeing Alert Service Bulletin 737-27A1213, Revision 1, dated May 21, 1998.

(1) For airplanes on which Boeing Alert Service Bulletin 737-27A1213, dated April 23, 1998, has not been accomplished: Perform a one time detailed visual inspection to verify correct installation of the fastener that connects the input rod of the spoiler mixer mechanism to the torque tube crank, in accordance with Revision 1 of the alert service bulletin.

NOTE 2: For the purposes of this AD, a detailed visual inspection is defined as: "An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc. may be used. Surface cleaning and elaborate access procedures may be required."

(i) If the fastener that connects the input rod of the spoiler mixer mechanism to the torque tube crank is installed correctly, no further action is required by this AD.

(ii) If the fastener that connects the input rod of the spoiler mixer mechanism to the torque tube crank is not installed correctly, prior to further flight, either re-install the existing fastener, or install a new or serviceable fastener, in accordance with Revision 1 of the alert service bulletin.

(2) For airplanes on which Boeing Alert Service Bulletin 737-27A1213, dated April 23, 1998, has been accomplished: Replace the nut, bolt, and cotter pin that connects the input rod of the spoiler mixer mechanism to the torque tube crank with a new or serviceable nut, bolt, and cotter pin in accordance with Revision 1 of the alert service bulletin.

Reporting Requirement

(b) Within 10 days after accomplishing the actions required by paragraph (a)(1) of this AD, submit a report of any findings of fasteners that connect the input rod of the spoiler mixer mechanism to the torque tube crank that require corrective action 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.

Alternative Methods of Compliance

(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, 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.

Special Flight Permits

(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.

Incorporation by Reference

(e) The actions shall be done in accordance with Boeing Alert Service Bulletin 737-27A1213, Revision, 1, dated May 21, 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.

(f) This amendment becomes effective on December 15, 1999.

FOOTER: