01-16382. Airworthiness Directives; Boeing Model 737-600, -700, and -800 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the supersedure of an existing airworthiness directive (AD); applicable to certain Boeing Model 737-600, -700, and -800 series airplanes; that currently requires repetitive inspections of certain elevator hinge plates, and corrective action, if necessary. That AD also provides for an optional replacement of the elevator hinge plates with new, improved hinge plates, which would end the repetitive inspections. This action proposes to require accomplishment of the previously optional replacement of the elevator hinge plates with new, improved hinge plates, as terminating action for the repetitive inspections. This action is necessary to prevent fatigue cracking of the elevator hinge plates, which could lead to the loss of the attachment of the elevator to the horizontal stabilizer, and consequent reduced controllability of the airplane. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by August 13, 2001.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2001-NM-20-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 [phone]. Comments may also be sent via the Internet using the following address: [e-mail]. Comments sent via fax or the Internet must contain “Docket No. 2001-NM-20-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.

FOR FURTHER INFORMATION CONTACT:

Nancy Marsh, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

 

Comments Invited

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-20-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-20-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

On March 15, 2001, the FAA issued AD 2001-06-08, amendment 39-12155 (66 FR 16116, March 23, 2001); applicable to certain Boeing Model 737-600, -700, and -800 series airplanes; to require repetitive inspections of certain elevator hinge plates, and corrective action, if necessary. That AD also provides for an optional replacement of the elevator hinge plates with new, improved hinge plates, which would end the repetitive inspections. That action was prompted by a report that—during flight testing of Boeing Model 737-600, -700, and -800 series airplanes—the elevator hinge plates at elevator hinges 3, 4, 5, 6, 7, and 8 experienced higher-than-expected loads due to buffeting by the spoiler. The requirements of that AD are intended to detect and correct fatigue cracking of the elevator hinge plates, which could lead to the loss of the attachment of the elevator to the horizontal stabilizer, and consequent reduced controllability of the airplane.

Actions Since Issuance of Previous Rule

In the preamble to AD 2001-06-08, the FAA indicated that the actions required by that AD were considered “interim action” and that further rulemaking action was being considered to require the replacement of the elevator hinge plates with new parts, which was provided as optional in AD 2001-06-08, and which would terminate the repetitive inspections currently required by that AD. The FAA now has determined that further rulemaking action is indeed necessary, and this proposed AD follows from that determination.

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 supersede AD 2001-06-08 to continue to require repetitive inspections of certain elevator hinge plates, and corrective action, if necessary. The proposed AD would add a new requirement for replacement of the elevator hinge plates with new, improved hinge plates, which would end the repetitive inspections. Except as discussed below, the actions would be required to be accomplished in accordance with Boeing Service Bulletin 737-55-1067, dated October 19, 2000, which was described in AD 2001-06-08.

Difference Between This Proposed AD and the Service Bulletin

Although the service bulletin specifies to contact Boeing for wear limits during replacement of elevator hinge plates, this AD requires that such wear limits be obtained from the Manager, Seattle Aircraft Certification Office (ACO), FAA, or a Boeing Company Designated Engineering Representative who has been authorized by the Manager, Seattle ACO, to make such findings.

Cost Impact

There are approximately 84 airplanes of the affected design in the worldwide fleet. The FAA estimates that 39 airplanes of U.S. registry would be affected by this proposed AD.

The inspections that are currently required by AD 2001-06-08 take approximately 4 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the currently required actions on U.S. operators is estimated to be $9,360, or $240 per airplane, per inspection cycle.

The new replacement that is proposed in this AD action would take approximately 44 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts would cost approximately $13,116 per airplane. Based on these figures, the cost impact of the proposed requirements of this AD on U.S. operators is estimated to be $614,484, or $15,756 per airplane.

The cost impact figures discussed above are 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.

Regulatory Impact

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.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• 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:

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 removing amendment 39-12155 (66 FR 16116, March 23, 2001), and by adding a new airworthiness directive (AD), to read as follows:

Boeing: Docket 2001-NM-20-AD. Supersedes AD 2001-06-08, Amendment 39-12155.

Applicability: Model 737-600, -700, and -800 series airplanes; line numbers 1 through 84 inclusive; 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 fatigue cracking of the elevator hinge plates, which could lead to the loss of the attachment of the elevator to the horizontal stabilizer, and consequent reduced controllability of the airplane, accomplish the following:

Restatement of Requirements of AD 2001-06-08

Inspections and Corrective Actions

(a) Prior to the accumulation of 7,000 total flight cycles or within 90 days after April 9, 2001 (the effective date of AD 2001-06-08), whichever occurs later, perform high frequency eddy current and detailed visual inspections of the hinge plate at elevator hinge 4, and a detailed visual inspection of the elevator hinge plate lugs (three locations) at elevator hinges 3, 5, 6, 7, and 8. Do these inspections per Part I of the Accomplishment Instructions of Boeing Service Bulletin 737-55-1067, dated October 19, 2000. Repeat the inspections thereafter no later than every 4,000 flight cycles, per the service bulletin, until paragraph (b) of this AD has been accomplished. If any cracking or unusual wear (i.e., elongated holes, loose or missing nuts or bolts, or missing primer or finish) is found during any inspection per this paragraph, before further flight, replace the affected hinge plate with a new, improved hinge plate, and modify the elevator upper skin, the upper and lower hinge covers, and the upper and lower closure panels, as applicable, per the service bulletin, except as provided by paragraph (c) of this AD. Such replacement and modification ends the repetitive inspections for the replaced hinge plate.

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.”

New Requirements of This AD

Replacement of Hinge Plates

(b) Before the accumulation of 15,000 total flight cycles, or within 5 years since the airplane's date of manufacture, whichever occurs first: Replace the elevator hinge plates at hinges 3, 4, 5, 6, 7, and 8, with new, improved hinge plates; per Part II of the Accomplishment Instructions of Boeing Service Bulletin 737-55-1067, dated October 19, 2000, except as provided by paragraph (c) of this AD. The replacement includes modification of the elevator upper skin, the upper and lower hinge covers, and the upper and lower closure panels, as applicable. Doing this replacement ends the repetitive inspections required by this AD.

Exception to Service Bulletin Instructions: Wear Limits

(c) During the replacement of elevator hinge plates per paragraph (a) or (b) of this AD, where Boeing Service Bulletin 737-55-1067, dated October 19, 2000, specifies to contact Boeing for wear limits, before further flight, contact the Manager, Seattle Aircraft Certification Office (ACO), FAA, or a Boeing Company Designated Engineering Representative who has been authorized by the Manager, Seattle ACO, to make such findings. For wear limits to be approved by the Manager, Seattle ACO, as required by this paragraph, the Manager's approval letter must specifically reference this AD.

Alternative Methods of Compliance

(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 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

(e) Special flight permits may be issued in accordance with §§ 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 June 22, 2001.

Kalene C. Yanamura,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.