Federal Aviation Administration, DOT.
Notice of proposed rulemaking (NPRM).
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. This proposal would require a one-time inspection to determine whether the lower bearing support of the aileron transfer mechanism directly below the first officer's control column has a “pocket,” and follow-on corrective actions, if necessary. This action is necessary to prevent jamming of the first officer's control wheel due to the presence of a foreign object on the lower bearing support of the transfer mechanism, which could result in reduced controllability of the airplane. This action is intended to address the identified unsafe condition.
Comments must be received by March 28, 2002.
Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2001-NM-344-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal holidays. Comments may be submitted via fax to (425) 227-1232. Comments may also be sent via the Internet using the following address: firstname.lastname@example.org. Comments sent via fax or the Internet must contain “Docket No. 2001-NM-344-AD” in the subject line and need not be submitted in triplicate. Comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 for Windows or ASCII text.
The service information referenced in the proposed rule 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.Start Further Info
FOR FURTHER INFORMATION CONTACT:
Doug Tsuji, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-1506; fax (425) 227-1181.End Further Info End Preamble Start Supplemental Information
Interested persons are invited to participate in the making of the proposed 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 above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this action may be changed in light of the comments received.
Submit comments using the following format:
- Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.
- For each issue, state what specific change to the proposed AD is being requested.
- Include justification (e.g., reasons or data) for each request.
Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this action must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2001-NM-344-AD.” The postcard will be date stamped and returned to the commenter.
Availability of NPRMs
Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2001-NM-344-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.Start Printed Page 6213
The FAA has received a report indicating that the first officer's control wheel on a Boeing Model 737-300 series airplane jammed during landing rollout. Investigation revealed that a foreign object jammed between the lower bearing support of the aileron transfer mechanism and the lost motion arm. A similar incident in 1984 prompted a change in the design of the lower bearing support of the transfer mechanism to remove a “pocket.” “Pocket” is the term given to the area on the upper surface of the lower bearing support (aft of the bearing, in the area of the rig pin holes) that is surrounded by the ribs of the lower bearing support. A foreign object could become trapped in this pocket and interfere with the movement of the first officer's control wheel at large deflections, causing the control wheel to jam. This condition, if not corrected, could result in reduced controllability of the airplane.
The lower bearing support of the aileron transfer mechanism is the same on all Model 737-100, -200, -200C, -400, and -500 series airplanes as it is on certain Model 737-300 series airplanes. Therefore, all of these airplanes may be subject to the same unsafe condition described above. Model 737-600, -700, -800, and -900 series airplanes have a different transfer mechanism for the aileron; thus, these models are not affected.
As stated previously, a design change to remove the pocket on the lower bearing support was implemented. This change was made during production on airplanes with line numbers 1249 and subsequent. However, since the aileron transfer mechanism and lower bearing support are interchangeable between airplanes, it is possible that the lower bearing support on any Model 737-100, -200, -200C, -300, -400, or -500 series airplane with a line number 1 through 3132 inclusive could have a pocket. Thus, all of these airplanes may be subject to the identified unsafe condition.
Explanation of Relevant Service Information
The FAA has reviewed and approved Boeing Alert Service Bulletin 737-27A1238, dated July 13, 2000, which describes procedures for a one-time visual inspection using a mirror to determine whether the lower bearing support of the aileron transfer mechanism directly below the first officer's control column has a pocket. If a pocket is found on the lower bearing support, the service bulletin specifies to accomplish a modification of the ribs of the lower bearing support. The procedures for modification include machining the ribs, accomplishing a dye-penetrant inspection to detect cracking of the lower bearing support, or, as an option, replacing the lower bearing support. The service bulletin also describes follow-on actions to the modification, which include a functional test of the transfer mechanism and testing of the aileron control mechanism for interference. If any cracking of the lower bearing support is found during the dye-penetrant inspection, or if any resistance is found during the follow-on testing of the aileron control mechanism, the service bulletin specifies to contact Boeing. Accomplishment of the actions specified in the service bulletin is intended to adequately address the identified unsafe condition.
Explanation of Requirements of Proposed Rule
Since an unsafe condition has been identified that is likely to exist or develop on other products of this same type design, the proposed AD would require accomplishment of the actions specified in the service bulletin described previously, except as discussed below.
Differences Between Proposed AD and Service Bulletin
Operators should note that, although the service bulletin specifies that Boeing may be contacted for disposition of certain repair conditions, this proposal would require the repair of those conditions to be accomplished per a method approved by the FAA.
Operators also should note that the service bulletin characterizes the inspection therein as a visual inspection using a mirror. For clarification, this proposed AD identifies the inspection described in the service bulletin as a “detailed inspection.” Note 3 of this proposed AD defines such an inspection.
There are approximately 3,101 airplanes of the affected design in the worldwide fleet. The FAA estimates that 1,244 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 1 work hour per airplane to accomplish the proposed inspection, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $74,640, or $60 per airplane.
The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the proposed requirements of this AD action, and that no operator would accomplish those actions in the future if this proposed AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions.
The regulations proposed herein would not have a substantial direct effect 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, it is determined that this proposal would not have federalism implications under Executive Order 13132.
For the reasons discussed above, I certify that this proposed regulation (1) is not a “significant regulatory action” under Executive Order 12866; (2) is not a “significant rule” under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) if promulgated, 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 copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.Start List of Subjects
List of Subjects in 14 CFR Part 39
- Air transportation
- Aviation safety
The Proposed Amendment
Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:Start Part
PART 39—AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
2. Section 39.13 is amended by adding the following new airworthiness directive:Start Printed Page 6214
Boeing: Docket 2001-NM-344-AD.
Applicability: Model 737-100, -200, -200C, -300, -400, and -500 series airplanes; line numbers 1 through 3132 inclusive; certificated in any category.
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 (e) 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 jamming of the first officer's control wheel due to the presence of a foreign object on the lower bearing support of the transfer mechanism for the aileron, which could result in reduced controllability of the airplane, accomplish the following:
(a) Within 2 years after the effective date of this AD, do a one-time detailed inspection to determine whether the lower bearing support of the aileron transfer mechanism directly below the first officer's control column has a “pocket,” according to Boeing Alert Service Bulletin 737-27A1238, dated July 13, 2000. (The upper surface has a raised stop at the end opposite the rig pin hole.) If no pocket is found, no further action is required by this AD.
“Pocket” is the term given to the area on the upper surface of the lower bearing support, aft of the bearing in the area of the rig pin holes, that is surrounded by the ribs of the lower bearing support.
For the purposes of this AD, a detailed 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.”
(b) If a pocket is found on the lower bearing support of the transfer mechanism for the aileron: Before further flight, do paragraphs (b)(1) and (b)(2) of this AD according to Boeing Alert Service Bulletin 737-27A1238, dated July 13, 2000, except as provided by paragraph (c) of this AD.
(1) Do all actions associated with the modification of the ribs of the lower bearing support (including performing a dye-penetrant inspection for cracking of the lower bearing support and any necessary corrective actions, machining the ribs, and changing the part number of the lower bearing support). Replacement of the lower bearing support with a new, improved support is optional as specified in the service bulletin.
(2) Do the follow-on actions to the modification, including a functional test of the transfer mechanism, a test of the aileron control mechanism for interference, and corrective actions, if necessary.
(c) If any cracking of the lower bearing support is found during the dye-penetrant inspection, or if any resistance is found during the test of the aileron control mechanism, and the service bulletin specifies to contact Boeing for appropriate action: Before further flight, repair per a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA. For a repair method to be approved by the Manager, Seattle ACO, as required by this paragraph, the Manager's approval letter must specifically reference this AD.
(d) As of the effective date of this AD, no person may install a lower bearing support, part number 65-55476-1 or 65-55476-9, on any airplane, unless the actions in paragraphs (a), (b), and (c), as applicable, of this AD have been accomplished.
Alternative Methods of Compliance
(e) 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.
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
(f) 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.
Issued in Renton, Washington, on February 5, 2002.
Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 02-3273 Filed 2-8-02; 8:45 am]
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