E7-11682. Airworthiness Directives; Learjet Model 45 Airplanes

AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Supplemental notice of proposed rulemaking (NPRM); reopening of comment period.

SUMMARY:

The FAA is revising an earlier proposed airworthiness directive (AD) for certain Learjet Model 45 airplanes. The original NPRM would have required revising the Airworthiness Limitations section of the airplane maintenance manual to incorporate certain inspections and compliance times to detect fatigue cracking of certain principal structural elements (PSEs). The original NPRM resulted from new and more restrictive life limits and inspection intervals for certain PSEs. This action revises the original NPRM by changing the applicability to add certain airplanes. We are proposing this supplemental NPRM to ensure that fatigue cracking of various PSEs is detected and corrected; such fatigue cracking could adversely affect the structural integrity of these airplanes.

DATES:

We must receive comments on this supplemental NPRM by July 13, 2007.

ADDRESSES:

Use one of the following addresses to submit comments on this supplemental NPRM.

• DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
• Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
• Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.
• Fax: [phone].
• Hand Delivery: Room W12-140 on the ground floor of the West Building, 1200 New Jersey Avenue, SE., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Contact Learjet, Inc., One Learjet Way, Wichita, Kansas 67209-2942, for service information identified in this proposed AD.

FOR FURTHER INFORMATION CONTACT:

Steve Litke, Aerospace Engineer, Airframe and Services Branch, ACE-118W, FAA, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas 67209; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to submit any relevant written data, views, or arguments regarding this supplemental NPRM. Send your comments to an address listed in the ADDRESSES section. Include the docket number “Docket No. FAA-2006-25174; Directorate Identifier 2005-NM-007-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this supplemental NPRM. We will consider all comments received by the closing date and may amend this supplemental NPRM in light of those comments.

We will post all comments submitted, without change, to http://dms.dot.gov,, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this supplemental NPRM. Using the search function of that web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you may visit http://dms.dot.gov.

Examining the Docket

You may examine the AD docket on the Internet at http://dms.dot.gov,, or in person at the Docket Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Operations office (telephone [phone]) is located on the ground floor of the West Building at the street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the Docket Management System receives them.

Discussion

We proposed to amend 14 CFR part 39 with a notice of proposed rulemaking (NPRM) for an AD (the “original NPRM”) for certain Learjet Model 45 airplanes. The original NPRM was published in the Federal Register on June 26, 2006 (71 FR 36255). The original NPRM proposed to require revising the Airworthiness Limitations section of the airplane maintenance manual to incorporate certain inspections and compliance times to detect fatigue cracking of certain principal structural elements (PSEs).

Actions Since Original NPRM Was Issued

Since we issued the original NPRM, the manufacturer has informed us that the actions in the NPRM apply to serial numbers (S/Ns) 45-005 through 45-302 inclusive, and 45-2001 through 45-2049 inclusive. We issued the original NPRM to apply to S/Ns 45-002 through 45-233 inclusive, and S/Ns 45-2001 through 45-2031 inclusive. The supplemental NPRM includes this change in applicability.

Comments

We have considered the following comments on the original NPRM.

Requests to Withdraw the NPRM

Koch Business Holdings, LLC (Koch), asks if this proposed AD is necessary. Koch states that operators are already required to use the most up-to-date manuals, and wonders if it can expect to see an AD for every make and model of airplane for which a more restrictive change is made to the Airworthiness Limitations section of the airplane maintenance manual (AMM). Koch suggests that we streamline the paperwork instead of increasing the paperwork. Koch further states that the FAA cannot write an AD against a maintenance manual, and that this proposed AD merely adds a requirement to comply with a requirement (the maintenance manuals). Koch states that the proposed AD will not make certain that maintenance items are complied with. Koch suggests, instead of an AD, that we send out the information using advisory wires, service newsletters, and letters from the FAA to the operators. Koch states that it is 100 percent about safety, but believes that the proposed AD just distracts from safety.

McWane, Inc., also states that the proposed AD is unnecessary because the regulatory requirement for complying with the Chapter 4 AMM revisions already exists. McWane explains that the Chapter 4 items are Airworthiness Limitations that are directly tied to the original type certificate; non-compliance places the aircraft outside the requirements of the original type design. McWane feels that using an AD in this case is overkill and an inappropriate use of rulemaking. McWane is primarily concerned that this action would set a precedent that would allow an original equipment manufacturer to let the FAA “become their scapegoat” instead of working with operators to ensure compliance with revised data. McWane suggests getting the information out using other means, and issuing an AD only against non-compliant airplanes.

We infer that the commenters would like us to withdraw the original NPRM. We disagree. We have determined that an unsafe condition exists, and that the actions proposed in the original NPRM are necessary to ensure the continued operational safety of the affected fleet. Compliance with the terms of Airworthiness Limitations sections is required by Federal Aviation Regulations Sections 43.16 (for persons maintaining products) and 91.403 (for operators). Based on in-service data or post certification testing and evaluation, the manufacturer may revise the Airworthiness Limitations section to include new or more restrictive life limits and inspections. Or it may become necessary for the FAA to impose new or more restrictive life limits and structural inspections in order to ensure continued structural integrity and continued compliance with damage tolerance requirements. However, in order to require compliance with these new inspection requirements and life limits, the FAA must engage in rulemaking. Therefore, if we do not issue an AD, the revised limitations in the AMMs cannot be made mandatory. Because loss of structural integrity would constitute an unsafe condition, it is appropriate to impose these requirements through the AD process. We have not changed the supplemental NPRM in this regard.

Clarification of Alternative Method of Compliance (AMOC) Paragraph

We have revised this action to clarify the appropriate procedure for notifying the principal inspector before using any approved AMOC on any airplane to which the AMOC applies.

Addition of Note To Clarify Requirements of Paragraph (f) of the Supplemental NPRM

We have added Note 2 to the supplemental NPRM to clarify that after an operator complies with the requirements of paragraph (f) of the proposed AD, that paragraph does not require that operators subsequently record accomplishment of those requirements each time an action is accomplished according to that operator's FAA-approved maintenance inspection program.

FAA's Determination and Proposed Requirements of the Supplemental NPRM

The changes discussed in the section titled “Actions since Original NPRM was Issued” expand the scope of the original NPRM; therefore, we have determined that it is necessary to reopen the comment period to provide additional opportunity for public comment on this supplemental NPRM.

Costs of Compliance

There are about 347 airplanes of the affected design in the worldwide fleet. This supplemental NPRM would affect about 258 airplanes of U.S. registry. The proposed actions would take about 1 work hour per airplane, at an average labor rate of $80 per work hour. Based on these figures, the estimated cost of this supplemental NPRM for U.S. operators is $20,640, or $80 per airplane.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. 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.

We are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701, “General requirements.” Under that section, Congress charges the FAA with promoting safe 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 rulemaking action.

Regulatory Findings

We have determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD 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.

For the reasons discussed above, I certify that the 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. 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.

We prepared a regulatory evaluation of the estimated costs to comply with this supplemental NPRM and placed it in the AD docket. See the ADDRESSES section for a location to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 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. The Federal Aviation Administration (FAA) amends § 39.13 by adding the following new airworthiness directive (AD):

LEARJET: Docket No. FAA-2006-25174; Directorate Identifier 2005-NM-007-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by July 13, 2007.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Learjet Model 45 airplanes, certificated in any category; serial numbers (S/Ns) 45-002 through 45-302 inclusive, and S/Ns 45-2001 through 45-2049 inclusive.

Unsafe Condition

(d) This AD results from new and more restrictive life limits and inspection intervals for certain principal structural elements (PSEs). We are issuing this AD to ensure that fatigue cracking of various PSEs is detected and corrected; such fatigue cracking could adversely affect the structural integrity of these airplanes.

Compliance

(e) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

Note 1:

This AD requires revisions to certain operator maintenance documents to include new inspections. Compliance with these inspections is required by 14 CFR 91.403(c). For airplanes that have been previously modified, altered, or repaired in the areas addressed by these inspections, the operator may not be able to accomplish the inspections described in the revisions. In this situation, to comply with 14 CFR 91.403(c), the operator must request approval for an alternative method of compliance (AMOC) according to paragraph (g) of this AD. The request should include a description of changes to the required inspections that will ensure the continued damage tolerance of the affected structure. The FAA has provided guidance for this determination in Advisory Circular (AC) 25-1529-1.

Revise the Airworthiness Limitations Section (ALS)

(f) Within 30 days after the effective date of this AD, revise the ALS of the airplane maintenance manual (AMM) to include new life limits and inspection intervals according to a method approved by the Manager, Wichita Aircraft Certification Office (ACO), FAA. Incorporating the applicable chapters in paragraph (f)(1) or (f)(2) of this AD in the AMM is one approved method for doing the revision. Thereafter, except as provided in paragraph (g) of this AD, no alternative life limits or inspection intervals may be approved for the affected PSEs.

(1) For Learjet Model 45 airplanes, S/Ns 45-002 through 45-302 inclusive: Chapter 4 of the Learjet 45 Maintenance Manual, Revision 38, dated April 24, 2006.

(2) For Learjet Model 45 airplanes, S/Ns 45-2001 through 45-2049 inclusive: Chapter 4 of the Learjet 40 Maintenance Manual, Revision 6, dated April 24, 2006.

Note 2:

After an operator complies with the requirements of paragraph (f) of this AD, that paragraph does not require that operators subsequently record accomplishment of those requirements each time an action is accomplished according to that operator's FAA-approved maintenance inspection program.

AMOCs

(g)(1) The Manager, Wichita ACO, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.

(2) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO.

Issued in Renton, Washington, on June 8, 2007.

Stephen P. Boyd,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.