00-20246. 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 [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. 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 [phone] or [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 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.

§ 39.13

[Amended]

2. Section 39.13 is amended by adding the following new airworthiness directive:

Boeing: Docket 2000-NM-18-AD.

Applicability: All Model 727 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 (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 failure of the bearing support fitting of the forward trunnion, which could result in collapse of the main landing gear during normal operations; consequent damage to the airplane structure; and injury to flight crew, passengers, or ground personnel; accomplish the following:

Interim Inspections/Follow-On Actions

(a) For airplanes having a bearing support fitting of the forward trunnion installed that has NOT been reworked: Within 1,500 flight cycles or 6 months after the effective date of this AD, whichever occurs first; perform an ultrasonic inspection of the bearing support fitting of the forward trunnion to detect corrosion and cracking in accordance with Part I of the Accomplishment Instructions of Boeing Alert Service Bulletin 727-57A0179, Revision 3, dated September 2, 1999; or Revision 4, dated July 13, 2000, and within 18 months after the effective date of this AD, accomplish the requirements in paragraph (d) of this AD.

(b) For airplanes having a bearing support fitting of the forward trunnion installed that has been reworked in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 727-57A0179, dated March 8, 1990; Revision 1, dated June 13, 1991; Revision 2, dated April 30, 1992; Revision 3, dated September 2, 1999; or Revision 4, dated July 13, 2000: Perform an ultrasonic inspection of the bearing support fitting of the forward trunnion to detect corrosion and cracking in accordance with Part I of the Accomplishment Instructions of Boeing Alert Service Bulletin 727-57A0179, Revision 3, dated September 2, 1999; or Revision 4, dated July 13, 2000; at the later of the times specified in paragraphs (b)(1) and (b)(2) of this AD.

(1) Within 12,000 flight cycles or 10 years after rework, whichever occurs first.

(2) Within 1,500 flight cycles or 6 months after the effective date of this AD, whichever occurs first.

Follow-On Actions/Repetitive Inspections

(i) If no corrosion or cracking is detected, clean the fitting in accordance with the alert service bulletin. Repeat the inspection thereafter at intervals not to exceed 1,500 flight cycles or 6 months, whichever occurs first.

(ii) If any corrosion or cracking is detected, prior to further flight, accomplish the requirements in paragraph (d) of this AD.

Inspections/Rework

(c) For airplanes having a bearing support fitting of the forward trunnion installed that has been reworked in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 727-57A0179, dated March 8, 1990; Revision 1, dated June 13, 1991; Revision 2, dated April 30, 1992; Revision 3, dated September 2, 1999; or Revision 4, dated July 13, 2000: Accomplish the requirements in paragraph (d) of this AD at the later of the times specified in paragraphs (c)(1) and (c)(2) of this AD.

(1) Within 12,000 flight cycles or 10 years after rework, whichever occurs first.

(2) Within 36 months after the effective date of this AD.

(d) At the applicable time specified in paragraph (a), (b)(2)(ii), or (c) of this AD, as applicable: Perform detailed visual and magnetic particle inspections to detect corrosion and cracking of the fitting in accordance with Part II of the Accomplishment Instructions of Boeing Alert Service Bulletin 727-57A0179, Revision 3, dated September 2, 1999, or Revision 4, dated July 13, 2000. Rework the fitting in accordance with the alert service bulletin and repeat the inspections at intervals not to exceed 12,000 flight cycles or 10 years, whichever occurs first. Accomplishment of the requirements in this paragraph constitutes terminating action for the requirements in paragraph (b) of this AD.

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.”

Spares

(e) As of the effective date of this AD, no person shall install on any airplane any bearing support fitting of the forward trunnion identified in the “Existing Part Number” column of Paragraph 2.E. of Boeing Alert Service Bulletin 727-57A0179, Revision 4, dated July 13, 2000, unless that part has been reworked in accordance with Part II of the Accomplishment Instructions of the alert service bulletin. Verify the part number on the fitting prior to installation, and install the subject fitting only if the maximum taxi gross weight (MTGW) limit of the fitting is greater than or equal to the MTGW of the airplane, in accordance with Boeing Drawing 65C37625, as illustrated in the alert service bulletin.

Alternative Methods of Compliance

(f) 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 Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. 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 Permit

(g) 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 August 3, 2000.

Donald L. Riggin,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.