[Federal Register Volume 64, Number 161 (Friday, August 20, 1999)] [Proposed Rules] [Pages 45470-45472] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 99-21691] ----------------------------------------------------------------------- DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [Docket No. 99-NM-02-AD] RIN 2120-AA64 Airworthiness Directives; Boeing Model 737 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 737 series airplanes. This proposal would require a one-time detailed visual inspection of the upper decompression panel on the flight deck door to verify that a minimum overlap dimension exists, and corrective action, if necessary. This proposal is prompted by reports indicating that, during production, some upper decompression panels were installed incorrectly on the flight deck door. The actions specified by the proposed AD are intended to detect an incorrectly installed upper decompression panel, which could cause the emergency exit panel on the flight deck door to become inoperable, thereby preventing crewmembers from performing essential duties during an emergency evacuation. DATES: Comments must be received by October 4, 1999. ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 99-NM-02-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal holidays. [[Page 45471]] The service information referenced in the proposed rule may be obtained from Boeing Commercial Airplane Group, 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: Mike Thompson, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-1157; fax (425) 227-1181. 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 notice may be changed in light of the comments received. 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 notice must submit a self-addressed, stamped postcard on which the following statement is made: ``Comments to Docket Number 99-NM-02-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-02-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Discussion During a pre-delivery interior compliance inspection, the FAA discovered that the emergency exit panel installed on the flight deck door of a Boeing Model 737 series airplane did not open properly. The emergency exit panel contains an upper decompression panel that allows pressure to equalize in the event of a rapid decompression. This panel also serves as an alternate escape path from the crew cabin if the flight deck door is damaged during an emergency landing. Subsequent investigation revealed that if the upper decompression panel is installed incorrectly, an interference between this panel and a decorative channel could cause the emergency exit panel to bind. Such binding could cause the panel to become inoperable as an emergency exit; however, the panel would still function properly in the event of a rapid decompression. The FAA found this problem on two airplanes prior to delivery, and has determined that it could also exist on certain Model 737-300/-400/-500 series airplanes, as well as on certain Model 737-600/-700/-800 series airplanes, that have already been delivered. The actions specified by the proposed AD are intended to detect an incorrectly installed upper decompression panel, which could cause the emergency exit panel on the flight deck door to become inoperable, thereby preventing crewmembers from performing essential duties during an emergency evacuation. Explanation of Relevant Service Information The FAA has reviewed and approved Boeing Service Bulletin 737-52- 1128, dated April 22, 1999, which describes procedures to inspect the upper decompression panel on the flight deck door of certain Model 737- 300/-400/-500 series airplanes to verify that a minimum overlap dimension of 0.05 inch exists. If the minimum overlap does not exist, the service bulletin provides instructions to adjust the upper decompression panel and, if necessary, an adjacent decorative channel, to establish the correct overlap dimension. The FAA has also reviewed and approved Boeing Service Bulletin 737- 52-1137, dated May 13, 1999, which describes procedures to inspect the upper decompression panel on the flight deck door of certain Model 737- 600/-700/-800 series airplanes to verify that a minimum overlap dimension of 0.05 inch exists. If the minimum overlap does not exist, the service bulletin provides instructions to adjust the upper decompression panel and, if necessary, an adjacent decorative channel, to establish the correct overlap dimension. Accomplishment of the actions specified in the two service bulletins discussed above, as applicable, 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 service bulletins described previously, except as discussed below. Differences Between Proposed Rule and the Service Bulletins Operators should note that, although the service bulletins recommend that the inspection be performed at the next convenient maintenance opportunity, the FAA has determined that an unspecified maintenance interval would not address the unsafe condition in a timely manner. In developing an appropriate compliance time for this AD, the FAA considered not only the manufacturer's recommendation, but the degree of urgency associated with addressing the 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, the FAA finds an 18-month compliance time for completing the required actions to be warranted, in that it represents an appropriate interval of time allowable for affected airplanes to continue to operate without compromising safety. Operators also should note that, although the service bulletins specify accomplishment of an inspection of the upper decompression panel on the flight deck door to verify that a minimum overlap dimension of 0.05 inch exists, this proposed AD refers to that inspection as a detailed visual inspection. The FAA finds that ``detailed visual inspection'' is the appropriate terminology for the inspection described in the service bulletins. Additionally, a definition of a detailed visual inspection is included in Note 2 of this proposed AD. Cost Impact There are approximately 1299 airplanes of the affected design in the worldwide fleet. The FAA estimates that 901 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 $60 per work hour. Based on these figures, the cost impact of the inspection proposed by this AD on U.S. operators is estimated to be $54,060, or $60 per airplane. [[Page 45472]] 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 AD were not adopted. Regulatory Impact The regulations proposed herein would not have substantial direct effects 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, in accordance with Executive Order 12612, it is determined that this proposal would not have sufficient federalism implications to warrant the preparation of a Federalism Assessment. 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. Sec. 39.13 [Amended] 2. Section 39.13 is amended by adding the following new airworthiness directive: Boeing: Docket 99-NM-02-AD. Applicability: Model 737 series airplanes, as listed in Boeing Service Bulletin 737-52-1128, dated April 22, 1999, or in Boeing Service Bulletin 737-52-1137, dated May 13, 1999; certificated in any category. Note 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (c) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it. Compliance: Required as indicated, unless accomplished previously. To detect an incorrectly installed upper decompression panel, which could cause the emergency exit panel on the flight deck door to become inoperable, thereby preventing crewmembers from performing essential duties during an emergency evacuation, accomplish the following: One-Time Inspection (a) Within 18 months after the effective date of this AD, perform a one-time detailed visual inspection of the upper decompression panel on the flight deck door to verify that a minimum overlap dimension of 0.05 inch exists, as specified in Boeing Service Bulletin 737-52-1128, dated April 22, 1999 (for Model 737- 300/-400/-500 series airplanes); or Boeing Service Bulletin 737-52- 1137, dated May 13, 1999 (for Model 737-600/-700/-800 series airplanes); as applicable. Note 2: For the purposes of this AD, a detailed visual inspection is defined as: ``An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.'' Corrective Action (b) If a minimum overlap dimension of 0.05 inch is not found during the inspection required by paragraph (a) of this AD, prior to further flight, adjust the decompression panel and, as applicable, the adjacent decorative channel, in accordance with Boeing Service Bulletin 737-52-1128, dated April 22, 1999 (for Model 737-300/-400/- 500 series airplanes); or Boeing Service Bulletin 737-52-1137, dated May 13, 1999 (for Model 737-600/-700/-800 series airplanes); as applicable. Alternative Methods of Compliance (c) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO. Note 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. Special Flight Permits (d) Special flight permits may be issued in accordance with Secs. 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished. Issued in Renton, Washington, on August 16, 1999. D. L. Riggin, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 99-21691 Filed 8-19-99; 8:45 am] BILLING CODE 4910-13-U