Airworthiness Directives; Boeing Model 737-300, -400, and -500 Series Airplanes

AGENCY:

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

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for certain Boeing Model 737-300, -400, and -500 series airplanes. This proposed AD would require, among other actions, modifying the door-mounted escape system of the forward right side door slide compartment. This proposed AD results from reports indicating that the forward right escape slide inflated 90 degrees out of alignment after deployment from the forward right side slide compartment. We are proposing this AD to prevent the escape slide from being unusable during an emergency evacuation and consequent injury to passengers or crewmembers.

DATES:

We must receive comments on this proposed AD by October 1, 2007.

ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD.

• 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: (202) 493-2251.
• 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 Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207, for the service information identified in this proposed AD.

FOR FURTHER INFORMATION CONTACT:

Robert Hettman, Aerospace Engineer, Cabin & Environmental Systems Safety Branch, ANM-150S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 917-6457; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to submit any relevant written data, views, or arguments regarding this proposed AD. Send your comments to an address listed in the ADDRESSES section. Include the docket number “FAA-2007-28921; Directorate Identifier 2007-NM-091-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.

We will post all comments we receive, 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 proposed AD. 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 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 (800) 647-5527) is located on the ground level of the West Building at the DOT 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 have received reports indicating that the forward door escape slide inflated 90 degrees out of alignment after deployment from the forward right side slide compartment, on Boeing Model 737-300, -400, and -500 airplanes. During deployment of the escape slide, the escape slide may be temporarily restricted within the slide compartment. This added restriction can delay the escape slide from aligning to a proper orientation before inflation. If inflation begins before the escape slide extends from the door, it can result in a sideways slide deployment. This condition, if not corrected, could result in the escape slide being unusable during an emergency evacuation and consequent injury to passengers or crewmembers.

Relevant Service Information

We have reviewed Boeing Special Attention Service Bulletin 737-25-1567, dated March 21, 2007. The service information describes procedures for modifying the door-mounted escape system of the forward right side door slide compartment. The modification includes:

• Removing the bottle retainer, rubber pad, and window; and cleaning the pan assembly.
• Modifying the window cutout and applying a primer coating and enamel finish.
• Installing a new window.

Boeing Service Bulletin 737-25-1430, Revision 1, dated April 10, 2003, which is required by AD 2004-02-08, amendment 39-13443 (69 FR 4452, January 30, 2004), is necessary to be done prior to or concurrently with Boeing Special Attention Service Bulletin 737-25-1567. Boeing Service Bulletin 737-24-1430 describes procedures for replacing the hinge assembly of the escape slide compartment with a new assembly.

Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition.

FAA's Determination and Requirements of the Proposed AD

We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other airplanes of this same type design. For this reason, we are proposing this AD, which would require accomplishing the actions specified in the service information described previously.

Costs of Compliance

There are about 1,949 airplanes of the affected design in the worldwide fleet. This proposed AD would affect about 660 airplanes of U.S. registry. The modification and installation actions would take about 2 work hours per airplane, at an average labor rate of $80 per work hour. Required parts would cost about $207 per airplane. Based on these figures, the estimated cost of the proposed AD for U.S. operators is $242,220, or $367 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 proposed AD 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.