Airworthiness Directives; Lockheed Model L-1011-385 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Supplemental notice of proposed rulemaking; reopening of comment period.

SUMMARY:

This document revises an earlier proposed airworthiness directive (AD), applicable to all Lockheed Model L-1011-385 series airplanes, that would have required repetitive inspections to detect corrosion or fatigue cracking of certain structural elements of the airplane; corrective actions if necessary; and incorporation of certain structural modifications. This new action revises the proposed rule by referencing a new service bulletin that, among other changes, corrects the effectivity and revises the modification threshold of various secondary service bulletins. The actions specified by this new proposed AD are intended to prevent corrosion or fatigue cracking of certain structural elements, which could result in reduced structural integrity of the airplane. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by January 10, 2005.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 99-NM-129-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. 99-NM-129-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 Lockheed Martin Aircraft & Logistics Centers, 120 Orion Street, Greenville, South Carolina 29605. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Atlanta Aircraft Certification Office, One Crown Center, 1895 Phoenix Boulevard, suite 450, Atlanta, Georgia.

FOR FURTHER INFORMATION CONTACT:

William Herderich, Aerospace Engineer, Airframe Branch, ACE-117A, FAA, Atlanta Aircraft Certification Office, One Crown Center, 1895 Phoenix Boulevard, suite 450, Atlanta, Georgia 30349; telephone (770) 703-6082; fax (770) 703-6097.

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 99-NM-129-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. 99-NM-129-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to add an airworthiness directive (AD), applicable to all Lockheed Model L-1011-385 series airplanes, was published as a notice of proposed rulemaking (NPRM) (hereafter referred to as “the original NPRM”) in the Federal Register on December 9, 1999 (64 FR 68960). The original NPRM would have required repetitive inspections to detect corrosion or fatigue cracking of certain structural elements of the airplane; corrective actions if necessary; and incorporation of certain structural modifications. The original NPRM was prompted by new recommendations related to incidents of fatigue cracking and corrosion in transport category airplanes that are approaching or have exceeded their economic design goal. Such corrosion or fatigue cracking in certain structural elements, if not corrected, could result in reduced structural integrity of the airplane.

Comments

Due consideration has been given to the comments received in response to the original NPRM.

Request To Reference Latest Revision of Service Bulletin

One commenter, the airplane manufacturer, provides clarification about the compliance times specified in paragraphs (a)(1), (a)(2), (c)(1), and (c)(2) of the original NPRM as they pertain to certain service bulletins identified in Lockheed Tristar L-1011 Service Bulletin (SB) 093-51-041, dated April 27, 1998 (which is referenced in the original NPRM as the appropriate source of service information for accomplishing the proposed actions; hereafter called the “Collector Service Bulletin”). The commenter states that it will initiate Revision 1 of the Collector Service Bulletin to reflect that continuing inspections are called for by SB 093-57-208; to list the latest revision CN4, dated May 8, 1998, of SB 093-53-260; to reference AD 99-09-14, amendment 39-11147 (64 FR 20144, April 28, 1999); and to revise the threshold of certain modifications.

From this comment, the FAA infers that the commenter is requesting that the original NPRM reference Revision 1 of the Collector Service Bulletin. We agree. The original issue of the Collector Service Bulletin was referenced in the original NPRM as the appropriate source of service information. The original issue describes procedures for certain repetitive inspections to detect corrosion or fatigue cracking of certain structural elements of the airplane; corrective actions, if necessary; and incorporation of certain structural modifications. Since the issuance of the original NPRM, we have reviewed and approved Revision 1 of Lockheed SB 093-51-41, dated March 3, 2000. Revision 1 of the service bulletin corrects the effectivity and revises the “Modification Termination Threshold” of various secondary SBs; revises SB 093-53-260, CN3 to CN4; and contains certain editorial changes. We have revised the supplemental NPRM to include reference to Revision 1 of SB 093-51-041 as the appropriate source of service information.

Requests To Clarify Certain Compliance Times

One commenter, the airplane manufacturer, provides further clarification about the compliance times specified in paragraphs (a)(1) and (a)(2) of the original NPRM for the inspections specified in SB 093-57-058, R5-CN1, dated August 22, 1995, which is listed in the Collector Service Bulletin. The commenter states the SB 093-57-208, Revision 1, dated October 28, 1997, which is also listed in the Collector Service Bulletin, forces inspection of the center box wing spar web at different frequencies. Since both of these SBs will be mandated, the commenter assumes the earlier schedule will take precedence.

From this comment, we infer that the commenter is requesting that the compliance times specified in paragraphs (a)(1) and (a)(2) of the supplemental NPRM be clarified. We agree. We find that paragraph (c)(1) of the supplemental NPRM also needs to be clarified. Those paragraphs refer to the threshold and repetitive intervals specified in the individual service bulletin as listed in Tables 1 and II of the Collector Service Bulletin, as applicable. In the “Inspection Threshold” and “Reinspection Intervals” columns of Tables 1 and II, the Collector Service Bulletin references a total of eight notes (i.e., three notes in Table 1 and five notes in Table II) located at the bottom of those tables. Our intent was that the information specified in those notes be required as part of the applicable compliance time.

As indicated in NOTE (1) of Tables I and II the Collector Service Bulletin, “Inspection thresholds and repeat inspection intervals are shown for convenience, in the event of conflicts the individual service bulletin shall take precedence. Some service bulletins contain inspection options that are not shown here.” Therefore, for the subject inspections, the inspection times listed in SB 093-57-058, R5-CN1, take precedence.

In light of this request and other similar requests below, we find that operators may misinterpret the compliance times specified in the original NPRM. Therefore, for clarification purposes, we have revised the supplemental NPRM by listing the compliance times for each individual service bulletin in a table (i.e., Table 1) and revised paragraphs (a)(1), (a)(2), and (c)(1) to refer to the individual service bulletin listed in Table 1.

One commenter requests that the compliance times specified in paragraphs (a)(1) and (a)(2) of the original NPRM for the initial fatigue-related inspection (i.e., reference SB 093-53-276, Basic, dated June 17, 1996) be clarified as to whether that inspection is to be done at two or four years or is dependent upon corrosion inhibiting compound (CIC) application. The commenter notes that Table 1 of the “Collector Service Bulletin states that the repetitive interval for Service Bulletin 093-53-276 is “CPCP (5).” The commenter states that SB 093-53-276 refers to two Corrosion Prevention and Control Program (CPCP) tasks, which are accomplished repetitively at either two or four years (if 2 part CIC is used).

We do not agree. SB 093-53-276 recommends the use of the initial and repetitive intervals specified in corrosion tasks C-53-120-04 and C-53-160-01, as described in the Lockheed Corrosion Prevention and Control Program (CPCP). In this case, the later of the times is the 15-year threshold and 10-year repetitive interval specified in C-53-160-01. No change to the supplemental NPRM is necessary in this regard.

One commenter requests that SB 093-53-266, which is referenced in the Collector Service Bulletin as an additional source of service information, be revised as described in items 1 through 4 below.

1. The initial threshold should be “prior to the threshold listed in SB 093-53-266, or within one ‘C’ interval after the effective AD date of the AD, whichever occurs later.” From this comment, we infer that the commenter is requesting a grace period for the initial threshold specified in the service bulletin, because the compliance time specified in the subject SB is “within 1 year after receipt of this service bulletin.”

We do not agree. As indicated in “NOTE 2” of the Collector Service Bulletin, “ * * * perform these inspections as specified except substitute ‘Effective Date of Airworthiness Directive’ for ‘After Receipt of Service Bulletin.’ ” Therefore, the initial threshold specified in this supplemental NPRM is within 1 year after the effective date of this AD for that SB. However, for clarification purposes, we have revised the supplemental NPRM by listing the compliance times for each individual service bulletin in Table 1 and revised paragraphs (a)(1), (a)(2), and (c)(1) to refer to the individual service bulletin listed in that table (discussed previously).

2. For airplanes not previously repaired per SB 093-53-264: Within 1 year, do the inspection per paragraph B of the Accomplishment Instructions of SB 093-53-266, and repetitively inspect frames found to be cracked at intervals not to exceed 90 days until modified by the referenced “LCC” drawing.

We do not agree. The 1-year inspection threshold is already identified in paragraph (1)(C)(1) of SB 093-53-266. In addition, it is our policy to require repair of known cracks before further flight (we may make exceptions to this policy in certain cases of unusual need, as discussed below). This policy is based on the fact that such damaged airplanes do not conform to the FAA-certificated type design and, therefore, are not airworthy until a properly approved repair is incorporated. While recognizing that repair deferrals may be necessary at times, our policy is intended to minimize adverse human factors relating to the lack of reliability of long-term repetitive inspections, which may reduce the safety of the type certificated design if such repair deferrals are practiced routinely. Additionally, our policy applies to airplanes certificated to damage tolerance evaluation regulations, as well as those not so certificated.

As noted above, we may make an exception to this policy in certain cases, if there is an unusual need for a temporary deferral. Unusual needs include such circumstances as legitimate difficulty in acquiring parts to accomplish repairs. Under such conditions, we may allow a temporary deferral of the repair, subject to a stringent inspection program acceptable to us. We acknowledge that the manufacturer has specified inspection intervals that are intended to allow continued operation with known cracks, and to prevent the need for extensive repairs. However, since we are not aware of any unusual need for repair deferral in regard to this supplemental NPRM, we have not evaluated these inspection intervals.

We consider the compliance times in this supplemental NPRM to be adequate to allow operators time to acquire parts to have on hand in the event that a crack is detected during inspection. Therefore, we have determined that, due to the safety implications and consequences associated with such cracking, any subject frame that is found to be cracked must be repaired or modified prior to further flight. No change to the supplemental NPRM is necessary in this regard.

3. For airplanes previously repaired per LCC drawings LCC-7622-337 or -325: Within 15,000 flight after repair installation, and thereafter at intervals not to exceed 15,000 cycles, inspect per paragraph C of the Accomplishment Instructions of SB 093-53-266.

We do not agree. The compliance times identified by the commenter are already identified in paragraph (1)(C)(2) of SB 093-53-266. No change to the supplemental NPRM is necessary in this regard.

4. For airplanes repaired or modified per SB 093-53-264 or -266: Every heavy maintenance visit (HMV), do a visual inspection per paragraph C of SB 093-53-266.

We do not agree. The compliance time identified by the commenter is already identified in paragraph (1)(C)(3) of SB 093-53-266. No change to the supplemental NPRM is necessary in this regard.

One commenter, the airplane manufacturer, notes that Table II of the Collector Service Bulletin does not specify a threshold or repetitive interval for SB 093-53-054, Revision 1, dated August 12, 1975. However, the notes of the Collector Service Bulletin say to modify at next HMV. The commenter notes that this SB is a modification only.

From this comment, we infer that the commenter is requesting that the compliance times specified in paragraph (c)(1) of the supplemental NPRM be clarified. We agree. For clarification purposes, we have revised the supplemental NPRM by listing the compliance times for each individual service bulletin in Table 1 and revised paragraphs (a)(1), (a)(2), and (c)(1) to refer to the individual service bulletin listed in that table (discussed previously).

Request for Credit for Previously Approved Alternative Methods of Compliance (AMOC) for Other ADs

One commenter requests that previously approved AMOCs for other ADs (i.e., AD 91-21-51, and AD 99-09-14) that refer to several of the SBs listed in the Collector Service Bulletin be approved for the original NPRM.

We do not agree. We find that any previously approved AMOC must be assessed for its impact on the actions specified by this supplemental NPRM. Paragraph (d) of this supplemental NPRM provides affected operators the opportunity to apply for an AMOC. No change to the supplemental NPRM is necessary in this regard.

Conclusion

Since certain of these changes expand the scope of the originally proposed rule, we have determined that it is necessary to reopen the comment period to provide additional opportunity for public comment.

Changes to 14 CFR Part 39/Effect on the AD

On July 10, 2002, the FAA issued a new version of 14 CFR part 39 (67 FR 47997, July 22, 2002), which governs the FAA's airworthiness directives system. The regulation now includes material that relates to altered products, special flight permits, and alternative methods of compliance. However, for clarity and consistency in this final rule, we have retained the language of the NPRM regarding that material.

Changes to Labor Rate

We have reviewed the figures we have used over the past several years to calculate AD costs to operators. To account for various inflationary costs in the airline industry, we find it necessary to increase the labor rate used in these calculations from $60 per work hour to $65 per work hour. The cost impact information, below, reflects this increase in the specified hourly labor rate.

Cost Impact

There are approximately 235 airplanes of the affected design in the worldwide fleet. The FAA estimates that 117 airplanes of U.S. registry would be affected by this proposed AD.

It would take approximately 32 work hours per airplane (for actions specified in Table I of the Collector Service Bulletin) and 97 work hours per airplane (for actions specified in Table II of the Collector Service Bulletin) to accomplish the proposed inspections, at an average labor rate of $65 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $243,360, or $2,080 per airplane, per inspection cycle (for Table I), and $737,685, or $6,305 per airplane, per inspection cycle (for Table II).

It would take approximately 614 work hours per airplane to accomplish the proposed modifications, at an average labor rate is $65 per work hour. Required parts would cost approximately $142,275 per airplane. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $21,315,645, or $182,185 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 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.

Authority for This Rulemaking

The FAA's authority to issue rules regarding aviation safety is found in Title 49 of the United States Code. Subtitle I, Section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs describes in more detail the scope of the agency's authority.

This rulemaking is promulgated under the authority described in Subtitle VII, Part A, Subpart III, Section 44701, “General requirements.” Under that section, the FAA is charged with promoting safety flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this AD.

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.