Airworthiness Directives; Boeing Model 727 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to all Boeing Model 727 series airplanes. This proposal would require repetitive inspections of the bearing support fitting of the forward trunnion on the main landing gear (MLG) to detect corrosion and cracking; follow-on actions, if necessary; and rework of the support fitting. This action is necessary to prevent failure of the support fitting, which could result in collapse of the MLG during normal operations; consequent damage to the airplane structure; and injury to flight crew, passengers, or ground personnel. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by September 25, 2000.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2000-NM-18-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: 9-anm-nprmcomment@faa.gov. Comments sent via fax or the Internet must contain “Docket No. 2000-NM-18-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:

Walter Sippel, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle Aircraft Certification Office (ACO), 1601 Lind Avenue, SW., Renton, Washington; telephone (425) 227-2028 or (425) 227-2774; fax (425) 227-1181.

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 notice 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 notice must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2000-NM-18-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. 2000-NM-18-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA has received reports indicating collapse of the main landing gear (MLG) during normal operations of certain Boeing Model 727 series airplanes. The affected airplanes had accumulated between 17,000 and 53,000 total flight cycles. Analysis of the MLG revealed that the collapse was caused by fatigue cracking and subsequent breakage of the bearing support fitting of the forward trunnion. The alloy steel trunnion fitting currently installed on these airplanes is susceptible to corrosion and cracking. Such conditions, if not corrected, could result in failure of the support fitting; collapse of the MLG; consequent damage to the airplane structure; and injury to flight crew, passengers, or ground personnel.

Explanation of Relevant Service Information

The FAA has reviewed and approved Boeing Alert Service Bulletin 727-57A0179, Revision 4, dated July 13, 2000, which describes procedures for ultrasonic, visual, and magnetic particle inspections to detect corrosion and cracking of the bearing support fitting of the forward trunnion on the MLG, and rework of the fitting if cracking is detected. The alert service bulletin also describes procedures for eventual rework of the fitting if no cracking is detected. Additionally, the alert service bulletin references Boeing Standard Practices Overhaul Manual, Chapter 20-30-03, as the appropriate source for accomplishment of the cleaning and application of corrosion inhibiting compound to the fitting if no cracking is detected. Accomplishment of the actions specified in the alert 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 alert service bulletin described previously.

Cost Impact

There are approximately 1,375 airplanes of the affected design in the worldwide fleet. The FAA estimates that 912 airplanes of U.S. registry would be affected by this proposed AD.

Should an operator be required to accomplish the proposed ultrasonic inspection, it would take approximately 4 work hours per airplane to accomplish the inspection, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the proposed ultrasonic inspection on U.S. operators is estimated to be $240 per airplane, per inspection cycle.

It would take approximately 6 work hours per airplane to accomplish the proposed detailed visual and magnetic particle inspections, at the average labor rate of $60 per work hour. Based on these figures, the cost impact of the proposed ultrasonic inspection on U.S. operators is estimated to be $328,320, or $360 per airplane, per inspection cycle.

It would take approximately 108 work hours per airplane to accomplish the proposed rework of the trunnion fitting, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the proposed rework on U.S. operators is estimated to be $5,909,760, or $6,480 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.