2014-08605. Airworthiness Directives; Learjet Inc. Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to adopt a new airworthiness directive (AD) for certain Learjet Inc. Model 45 airplanes. This proposed AD was prompted by reports of non-conforming windshield supports (coupe rails). This proposed AD would require a general visual inspection to detect gouging and scratches and to determine if a radius has been removed; an ultrasound inspection to measure the dimensions of the lower coupe rails; an eddy current inspection to detect cracks of the lower coupe rails; replacement of the lower coupe rails if necessary; and revision of the maintenance or inspection program, as applicable. We are proposing this AD to detect and correct non-conforming windshield supports, which could result in uncontrolled cabin depressurization. Non-conforming windshield supports could also compromise the capability of the windshield to withstand a bird strike.

DATES:

We must receive comments on this proposed AD by June 2, 2014.

ADDRESSES:

You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
• Fax: [phone].
• 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.
• Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this proposed AD, contact Learjet, Inc., One Learjet Way, Wichita, KS 67209-2942; telephone [phone]; fax [phone]; email [e-mail]; Internet http://www.bombardier.com. You may view this referenced service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, WA. For information on the availability of this material at the FAA, call 425-227-1221.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2014-0249; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this proposed AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Office (phone: [phone]) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

Paul Chapman, Aerospace Engineer, Airframe Branch, FAA, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Wichita, KS, 67209; phone: [phone]; fax: [phone]; email: [e-mail].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or arguments about this proposal. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2014-0249; Directorate Identifier 2012-NM-211-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the closing date and may amend this proposed AD because of those comments.

We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this proposed AD.

Discussion

We received reports of non-conforming windshield supports (coupe rails). Learjet Inc. identified windshield primary supports that do not meet their type design. The non-conforming windshield supports (coupe rails) might have been compromised during fuselage build or windshield installation. This condition, if not corrected, could result in uncontrolled cabin depressurization. Non-conforming windshield supports could also compromise the capability of the windshield to withstand a bird strike.

Relevant Service Information

We reviewed the following service information. The service information describe procedures for a detailed visual inspection to detect gouging and scratches and to determine if a radius has been removed; an ultrasound inspection to measure the dimensions of the lower coupe rails; an eddy current inspection to detect cracks of the lower coupe rails, replacement of the lower coupe rails if necessary; and revision of the maintenance or inspection program, as applicable.

• Chapter 4, Airworthiness Limitations, of the Bombardier Learjet 45 Maintenance Manual MM-104, Revision 57, dated June 11, 2012.
• Chapter 4, Airworthiness Limitations, of the Bombardier Learjet 40 Maintenance Manual MM-105, Revision 25, dated June 11, 2012.
• Bombardier Recommended Service Bulletin 40-56-03, Revision 1, dated October 15, 2012.
• Bombardier Recommended Service Bulletin 45-56-3, Revision 1, dated October 15, 2012.

FAA's Determination

We are proposing this AD because we evaluated all the relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of these same type designs.

Proposed AD Requirements

This proposed AD would require accomplishing the actions specified in the service information described previously.

Costs of Compliance

We estimate that this proposed AD affects 351 airplanes of U.S. registry.

We estimate the following costs to comply with this proposed AD:

Estimated Costs

Action	Labor cost	Parts cost	Cost per product	Cost on U.S. operators
Inspection	40 work-hours × $85 per hour = $3,400 per inspection cycle	$77	$3,477 per inspection cycle	$1,220,427 per inspection cycle
Maintenance or inspection program revision	1 work hour × $85 per hour = $85	None	$85	$29,835

We estimate the following costs to do any necessary replacement that would be required based on the results of the proposed inspection. We have no way of determining the number of aircraft that might need this replacement:

On-Condition Costs

Action	Labor cost	Parts cost	Cost per product
Replacement	500 work-hours (to replace both coupe rails) × $85 per hour = $42,500	$15,000 (to replace both coupe rails)	$57,500 (to replace both coupe rails)

According to the manufacturer, some of the costs of this proposed AD may be covered under warranty, thereby reducing the cost impact on affected individuals. We do not control warranty coverage for affected individuals. As a result, we have included all costs in our cost estimate.

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 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 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),

(3) Will not affect intrastate aviation in Alaska, and

(4) 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.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Incorporation by reference
• 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 FAA amends § 39.13 by adding the following new airworthiness directive (AD):

Learjet Inc.: Docket No. FAA-2014-0249; Directorate Identifier 2012-NM-211-AD.

(a) Comments Due Date

We must receive comments by June 2, 2014.

(b) Affected ADs

None.

(c) Applicability

This AD applies to Learjet Inc. Model 45 airplanes, certificated in any category, as identified in Bombardier Recommended Service Bulletin 40-56-03, Revision 1, dated October 15, 2012 (serial numbers (S/Ns) 45-2000 through 45-2120 inclusive, and S/Ns 45-2122 through 45-2130 inclusive); and Bombardier Recommended Service Bulletin 45-56-3, Revision 1, dated October 15, 2012 (S/Ns 45-005 through 45-427 inclusive).

(d) Subject

Air Transport Association (ATA) of America Code 53, Fuselage.

(e) Unsafe Condition

This AD was prompted by reports of non-conforming windshield supports (coupe rails). We are issuing this AD to detect and correct non-conforming windshield supports, which could result in uncontrolled cabin depressurization. Non-conforming windshield supports could also compromise the capability of the windshield to withstand a bird strike.

(f) Compliance

Comply with this AD within the compliance times specified, unless already done.

(g) Inspections and Corrective Actions

Within 600 flight hours or 36 months after the effective date of this AD, whichever occurs first: Do the inspections specified in paragraphs (g)(1) through (g)(3) of this AD. Do all inspections and corrective actions specified in paragraphs (g)(1) through (g)(3) of this AD, in accordance with the Accomplishment Instructions of Bombardier Recommended Service Bulletin 40-56-03, Revision 1, dated October 15, 2012 (for S/Ns 45-2000 through 45-2120 inclusive, and 45-2122 through 45-2130 inclusive); or Bombardier Recommended Service Bulletin 45-56-3, Revision 1, dated October 15, 2012 (for S/Ns 45-005 through 45-427 inclusive).

(1) Do a general visual inspection of the coupe rails to detect gouging and scratches and to determine whether a radius has been removed or damaged.

(i) If gouging or scratches are found, before further flight, burnish or blend the gouges and scratches.

(ii) If the radius has been removed or damaged, before further flight, restore the radius.

(2) Do an ultrasound inspection to measure the dimensions of the lower coupe rails.

(i) If the coupe rail has an “X” dimension of 0.246 (6.248 millimeters (mm)) or greater, and a “Y” dimension of 0.148 (3.759 mm) or greater, before further flight, identify the coupe rail, in accordance with table 1 of Bombardier Recommended Service Bulletin 40-56-03, Revision 1, dated October 15, 2012 (for S/Ns 45-2000 through 45-2120 inclusive, and S/Ns 45-2122 through 45-2130 inclusive); or Bombardier Recommended Service Bulletin 45-56-3, Revision 1, dated October 15, 2012 (for S/Ns 45-005 through 45-427 inclusive).

(ii) If the coupe rail has an “X” dimension between 0.246 (6.248 mm) and 0.166 (4.216 mm) or a “Y” dimension between 0.148 (3.759 mm) and 0.134 (3.403 mm), before further flight, identify the coupe rail, in accordance with table 2 of Bombardier Recommended Service Bulletin 40-56-03, Revision 1, dated October 15, 2012 (for S/Ns 45-2000 through 45-2120 inclusive, and S/Ns 45-2122 through 45-2130 inclusive); or Bombardier Recommended Service Bulletin 45-56-3, Revision 1, dated October 15, 2012 (for S/Ns 45-005 through 45-427 inclusive).

(iii) If any coupe rail “X” dimension is below 0.166 (4.216 mm) or “Y” dimension is below 0.134 (3.403 mm), before further flight, replace that coupe rail with a new coupe rail.

(3) Do a flange and radius eddy current inspection for cracks of the left-hand and right-hand lower coupe rails.

(i) If no crack is found, before further flight, mark the new data plate.

(ii) If any crack is found, before further flight, replace the coupe rail with a new coupe rail.

(h) Maintenance/Inspection Program Revision

Within 30 days after the effective date of this AD, revise the maintenance or inspection program, as applicable, by incorporating the applicable inspection reference number (IRN) tasks identified in table 1 to this paragraph, as specified in Chapter 4, Airworthiness Limitations, of the applicable maintenance manual specified in table 1 to this paragraph. The initial task compliance time is the applicable initial compliance time specified in table 1 to this paragraph, or within 30 days after the effective date of this AD, whichever is later.

Table 1 to Paragraph (h) of This AD—IRN Task Revision

Model—	IRN—	Initial Compliance Time—	Chapter 4 of—
Model 40 airplanes	U5323167	Within 600 flight hours or 36 months, whichever occurs first after the effective date of this AD	Bombardier Learjet 40 Maintenance Manual MM-105, Revision 25, dated June 11, 2012.
Model 40 airplanes	U5323168	Within 5,000 flight hours after accomplishment of Bombardier Recommended Service Bulletin 40-56-03, Revision 1, dated October 15, 2012	Bombardier Learjet 40 Maintenance Manual MM-105, Revision 25, dated June 11, 2012.
Model 45 airplanes	U5323167	Within 600 flight hours or 36 months, whichever occurs first after the effective date of this AD	Bombardier Learjet 45 Maintenance Manual MM-104, Revision 57, dated June 11, 2012.
Model 45 airplanes	U5323168	Within 5,000 flight hours after accomplishment of Bombardier Recommended Service Bulletin 45-56-3, Revision 1, dated October 15, 2012	Bombardier Learjet 45 Maintenance Manual MM-104, Revision 57, dated June 11, 2012.

(i) No Alternative Actions and Intervals

After accomplishing the revision required by paragraph (h) of this AD, no alternative IRN task or interval may be used unless the IRN task or interval is approved as an alternative method of compliance (AMOC) in accordance with the procedures specified in paragraph (j) of this AD.

(j) Alternative Methods of Compliance (AMOCs)

(1) The Manager, Wichita Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or local Flight Standards District Office, as appropriate. If sending information directly to the manager of the ACO, send it to the attention of the person identified in paragraph (k)(1) of this AD.

(2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/certificate holding district office.

(k) Related Information

(1) For more information about this AD, contact Paul Chapman, Aerospace Engineer, Airframe Branch, FAA, Wichita ACO, 1801 Airport Road, Room 100, Wichita, KS 67209; phone: [phone]; fax: [phone]; email: [e-mail].

(2) For service information identified in this AD, contact Learjet, Inc., One Learjet Way, Wichita, KS 67209-2942; telephone [phone]; fax [phone]; email [e-mail]; Internet http://www.bombardier.com. You may view the referenced service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, WA. For information on the availability of this material at the FAA, call 425-227-1221.

Issued in Renton, Washington, on April 1, 2014.

Michael J. Kaszycki,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.