Airworthiness Directives; Boeing Model 727, 727C, 727-100, -100C, and -200 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 certain Boeing Model 727, 727C, 727-100, -100C, and -200 series airplanes. This proposal would require an inspection of the forward trunnion attach fittings of the main landing gear (MLG), inspections of the attach fitting holes of the forward trunnion attach fittings if necessary, replacement of the forward trunnion attach fittings if necessary, and corrective actions if necessary. This action is necessary to detect and correct cracks and corrosion on the attach fitting holes of the forward trunnion attach fittings of the MLG, which could result in the collapse of the MLG. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by August 2, 2004.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2003-NM-131-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9 a.m. and 3 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. 2003-NM-131-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 or 2000 or ASCII text.

The service information referenced in the proposed rule may be obtained from Boeing Commercial Airplanes, 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:

Daniel F. Kutz, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 917-6456; fax (425) 917-6590.

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 2003-NM-131-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. 2003-NM-131-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA has received reports of cracks and corrosion in the attach bolt holes of the forward trunnion attach fittings of the main landing gear (MLG) on certain Boeing Model 727 series airplanes. Forward trunnion attach fittings made of 7079-T6 aluminum are prone to stress corrosion cracking even if they have been shot peened. This condition, if not detected and corrected, could result in the collapse of the MLG.

Other Related Rulemaking

On October 2, 2001, the FAA issued AD 2001-20-09, amendment 39-12457 (66 FR 51843, October 11, 2001), applicable to all Boeing Model 727 series airplanes, which currently requires repetitive inspections of the bearing support fitting of the forward trunnion on the MLG to detect corrosion and cracking; follow-on actions, if necessary; and repair/rework of the support fitting, or replacement with a new or repaired/reworked fitting. That AD is to be done in accordance with Boeing Alert Service Bulletin 727-57A0179, Revision 3, dated September 2, 1999; Boeing Alert Service Bulletin 727-57A0179, Revision 4, dated July 13, 2000; or Boeing Service Bulletin 727-57A0179, Revision 5, dated December 20, 2000. The actions specified by that AD are intended 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.

Explanation of Relevant Service Information

The FAA has reviewed and approved Boeing Alert Service Bulletin 727-57A0132, Revision 3, dated March 20, 2003, which describes procedures for an inspection of the forward trunnion attach fittings of the MLG to determine the part number; detailed and high frequency eddy current inspections of the attach fitting holes of the forward trunnion attach fittings having part number 65-19296-1 through -8 (made of 7079-T6 aluminum) for cracks and corrosion if necessary; and corrective actions if necessary. The corrective actions include reworking the attach fitting holes, repairing the attach fitting holes, and replacing the forward trunnion attach fitting with a new forward trunnion attach fitting. Replacement of the 7079-T6 attach fittings with a 7075-T73511 or 7050-T7451 attach fitting is considered terminating action for the service bulletin.

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 Boeing Alert Service Bulletin 727-57A0132, Revision 3, dated March 20, 2003, described previously, except as discussed below.

Differences Between Proposed Rule and Service Bulletin

The compliance time in section 1.E. of the Boeing Alert Service Bulletin 727-57A0132, Revision 3, dated March 20, 2003, specifies to do the actions “For airplanes over 20 years old (since the original airplane delivery date) that have a 7079-T6 MLG forward trunnion attach fitting” at the later time of “two years after the release of Revision 3 the service bulletin” or “ten years after the last inspection/rework of the attach fitting per a prior release of this service bulletin.” However, for these same airplanes, paragraph (b) of this proposed AD specifies to do the actions at the latest of the following times:

1. Prior to airplanes reaching 240 months old since the date of issuance of the original Airworthiness Certificate or the date of issuance of the original Export Certificate of Airworthiness; or

2. Within 18 months after the effective date of this AD; or

3. Within 120 months after the last inspection/rework/repair of the attach fitting per Boeing Service Bulletin 727-57A0132, dated June 28, 1974; Revision 1, dated October 31, 1975; or Revision 2, dated April 24, 1981; or Boeing Alert Service Bulletin 727-57A0132, Revision 3, dated March 20, 2003.

We have determined that “For airplanes over 20 years old” may be interpreted as the AD applies only to airplanes with the stated age as of the effective date of the AD. We have determined that the age of the airplanes is intended to be the initial threshold. Thus, “prior to airplanes reaching 240 months old” will include all affected airplanes. We have also determined that “original airplane delivery date” may be interpreted differently by different operators. We find that “date of issuance of the original Airworthiness Certificate or the date of issuance of the Export Certificate of Airworthiness, whichever occurs first” is generally understood within the industry and records will always exist that establish these dates with certainty. We also did not include the qualifying phrase “that have a 7079-T6 MLG forward trunnion attach fitting” because the first action in the proposed AD is to determine which airplanes have a 7079-T6 forward trunnion attach fitting of the MLG.

Although the service bulletin recommends one option for the compliance time as “two years after the release of Revision 3 the service bulletin,” we have determined that the two year interval would not address the identified unsafe condition soon enough to ensure an adequate level of safety for the affected fleet. In developing this option for the compliance time for this AD, we coordinated with the manufacturer and considered the degree of urgency associated with the subject unsafe condition, the average utilization of the affected fleet, and the time necessary to perform the inspection (1 hour). In light of all of these factors, we find that the compliance time of “within 18 months after the effective date of this AD” represents an appropriate interval of time for affected airplanes to continue to operate without compromising safety.

Although paragraph 7 of “Part II” of the Accomplishment Instructions of the service bulletin only lists part number P/N 65-19296U13 (LH) or P/N 65-19296U14 (RH) as acceptable new attach fittings, paragraphs (d)(2) and (e) of the proposed AD lists the following acceptable new attach fittings: P/N65-19296-9, -10, -13, or -14; P/N 65-99909-1724 or -1727; P/N 65-19296U13 or P/N 65-19296U14.

Although the service bulletin specifies concurrent accomplishment of Boeing Alert Service Bulletin 727-57A0179, Revision 3 or later, this AD does not require concurrent accomplishment of service bulletin 727-57A0179, Revision 3 or later. AD 2001-20-09 already requires accomplishment of the actions in Boeing Alert Service Bulletin 727-57A0179, Revision 3, dated September 2, 1999; Revision 4, dated July 13, 2000; or Boeing Service Bulletin 727-57A0179, Revision 5, dated December 20, 2000.

Cost Impact

There are approximately 523 airplanes of the affected design in the worldwide fleet. The FAA estimates that 309 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 $65 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $20,085, or $65 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.

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.