E9-30902. Airworthiness Directives; The Boeing Company Model 737-200, -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 supersede an existing airworthiness directive (AD) that applies to certain Model 737-300, -400, and -500 series airplanes. The existing AD currently requires an inspection to determine the manufacturer and manufacture date of the oxygen masks in the passenger service unit and the lavatory and attendant box assemblies, corrective action if necessary, and other specified action. This proposed AD would expand the applicability in the existing AD. This AD results from a determination indicating that additional airplanes may be subject to the identified unsafe condition. We are proposing this AD to prevent the in-line flow indicators of the passenger oxygen masks from fracturing and separating, which could inhibit oxygen flow to the masks and consequently result in exposure of the passengers and cabin attendants to hypoxia following a depressurization event.

DATES:

We must receive comments on this proposed AD by February 16, 2010.

ADDRESSES:

You may send comments 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: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this proposed AD, contact Boeing Commercial Airplanes, Attention: Data & Services Management, P. O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone [phone], extension 1, fax [phone]; e-mail [e-mail]; Internet https://www.myboeingfleet.com. You may review copies of the referenced service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information on the availability of this material at the FAA, call 425-227-1221 or 425-227-1152.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov;​; 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 (telephone [phone]) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

Robert Hettman, Aerospace Engineer, Cabin Safety and Environmental Systems Branch, ANM-150S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or arguments about this proposed AD. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2009-1224; Directorate Identifier 2009-NM-118-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

On March 9, 2008, we issued AD 2008-06-24, Amendment 39-15436 (73 FR 14666, March 19, 2008), for certain Model 737-300, -400, and -500 series airplanes. That AD requires an inspection to determine the manufacturer and manufacture date of the oxygen masks in the passenger service unit and the lavatory and attendant box assemblies, corrective action if necessary, and other specified actions. That AD resulted from a report that several passenger masks with broken in-line flow indicators were found following a mask deployment. We issued that AD to prevent the in-line flow indicators of the passenger oxygen masks from fracturing and separating, which could inhibit oxygen flow to the masks and consequently result in exposure of the passengers and cabin attendants to hypoxia following a depressurization event.

Actions Since Existing AD Was Issued

Since we issued AD 2008-06-24, we have determined that the oxygen masks on the affected Model 737-300, -400, and -500 series airplanes have the same flow indicators as those installed on certain Model 737-200 series airplanes; therefore, Model 737-200 series airplanes may be also subject to the identified unsafe condition.

Relevant Service Information

We have reviewed Boeing Special Attention Service Bulletin 737-35-1099, Revision 1, dated April 23, 2009. The specified actions are essentially identical to those specified in Boeing Special Attention Service Bulletin 737-35-1099, dated April 9, 2007 (which we cited in the existing AD). Revision 1 of Boeing Special Attention Service Bulletin 737-35-1099 expands the effectivity of the service bulletin by adding Model 737-200 series airplanes that may have been delivered with B/E Aerospace oxygen assemblies, identified in B/E Aerospace Service Bulletin 174080-35-01, before January 1, 2002, and that have had the oxygen mask assemblies replaced with assemblies manufactured between January 1, 2002, and March 1, 2006. B/E Aerospace Service Bulletin 174080-35-01 was referred to in the existing AD as an additional source of guidance for modifying the oxygen mask assembly.

FAA's Determination and Requirements of the Proposed AD

We have evaluated all pertinent information and identified an unsafe condition that is likely to develop on other products of the same type design. For this reason, we are proposing this AD, which would supersede AD 2008-06-24 and would retain the requirements of the existing AD. This proposed AD would expand the applicability to include Model 737-200 series airplanes.

Costs of Compliance

There are about 1,981 airplanes of the affected design in the worldwide fleet. This proposed AD would affect about 666 airplanes of U.S. registry.

The actions that are required by AD 2008-06-24 and retained in this proposed AD affect about 646 airplanes of U.S. registry. The required actions take about 16 work hours per airplane, for an average of 180 oxygen masks per airplane distributed in about 45 PSUs/oxygen boxes, at an average labor rate of $80 per work hour. Required parts cost about $6 per oxygen mask, or $1,080 per airplane. Based on these figures, the estimated cost of the existing AD for U.S. operators is $1,524,560, or $2,360 per airplane.

This proposed AD would be applicable to approximately 20 additional airplanes. Based on the figures discussed above, we estimate the costs for the additional airplanes imposed by this proposed AD on U.S. operators to be $47,200, or $2,360 per airplane. This figure is based on assumptions that no operator of these additional airplanes has yet done any of the proposed requirements of this AD, and that no operator would do those actions in the future if this AD were not adopted.

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
• 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 removing Amendment 39-15436 (73 FR 14666, March 19, 2008) and adding the following new AD:

The Boeing Company: Docket No. FAA-2009-1224; Directorate Identifier 2009-NM-118-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by February 16, 2010.

Affected ADs

(b) This AD supersedes AD 2008-06-24, Amendment 39-15436.

Applicability

(c) This AD applies to The Boeing Company Model 737-200, -300, -400, and -500 series airplanes, certificated in any category; as identified in Boeing Special Attention Service Bulletin 737-35-1099, Revision 1, dated April 23, 2009.

Subject

(d) Air Transport Association (ATA) of America Code 35: Oxygen.

Unsafe Condition

(e) The existing AD results from a report of a sudden decrease in cabin pressure and deployment of the passenger oxygen mask assemblies; several masks had broken in-line flow indicators. The Federal Aviation Administration is issuing this AD to prevent the in-line flow indicators of the passenger oxygen masks from fracturing and separating, which could inhibit oxygen flow to the masks and consequently result in exposure of the passengers and cabin attendants to hypoxia following a depressurization event.

Compliance

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

Restatement of Requirements of AD 2008-06-24, with New Service Information

Inspection and Related Investigative/Corrective Actions if Necessary

(g) For airplanes identified in Boeing Special Attention Service Bulletin 737-35-1099, dated April 9, 2007: Within 60 months after April 23, 2008 (the effective date of AD 2008-06-24), do a general visual inspection to determine the manufacturer and manufacture date of the oxygen masks in the passenger service unit and the lavatory and attendant box assemblies, and do the applicable corrective action and other specified action, by accomplishing all of the applicable actions specified in the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-35-1099, dated April 9, 2007; or Revision 1, dated April 23, 2009; except where the service bulletin specifies repairing the oxygen mask assembly, replace it with a new or modified oxygen mask assembly having an improved flow indicator. The corrective action and other specified action must be done before further flight. As of the effective date of this AD, use only Revision 1 of Boeing Special Attention Service Bulletin 737-35-1099.

New Requirements of This AD

Inspection and Related Investigative/Corrective Actions if Necessary

(h) For airplanes other than those identified in paragraph (g) of this AD: Within 60 months after the effective date of this AD, do a general visual inspection to determine the manufacturer and manufacture date of the oxygen masks in the passenger service unit and the lavatory and attendant box assemblies, and do the applicable corrective action and other specified action, by accomplishing all of the applicable actions specified in the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-35-1099, Revision 1, dated April 23, 2009; except where the service bulletin specifies repairing the oxygen mask assembly, replace it with a new or modified oxygen mask assembly having an improved flow indicator. The corrective action and other specified action must be done before further flight.

Note 1:

Boeing Special Attention Service Bulletin 737-35-1099, dated April 9, 2007; and Revision 1, dated April 23, 2009; refer to B/E Aerospace Service Bulletin 174080-35-01, dated February 6, 2006; Revision 1, dated May 1, 2006; and Revision 2, dated May 28, 2008; as additional sources of guidance for modifying the oxygen mask assembly by replacing the flow indicator with an improved flow indicator.

Parts Installation

(i) As of the effective date of this AD, no person may install a B/E Aerospace oxygen mask assembly having a part number in the 174080 series or 174095 series with a manufacturing date after January 1, 2002, and before March 1, 2006, on any airplane, unless it has been modified in accordance with the requirements of paragraph (g) or (h) of this AD.

Credit for Actions Done In Accordance With Previous Issue of the Service Bulletin

(j) Actions done before the effective date of this AD, in accordance with Boeing Special Attention Service Bulletin 737-35-1099, dated April 9, 2007, are acceptable for compliance with the requirements of paragraph (g) of this AD.

Alternative Methods of Compliance (AMOCs)

(k)(1) The Manager, Seattle 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. Send information to ATTN: Robert Hettman, Aerospace Engineer, Cabin Safety and Environmental Systems Branch, ANM-150S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone [phone]; fax [phone]. Or, e-mail information to [e-mail].

(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 principal maintenance inspector (PMI) or principal avionics inspector (PAI), as appropriate, or lacking a principal inspector, your local Flight Standards District Office. The AMOC approval letter must specifically reference this AD.

(3) An AMOC that provides an acceptable level of safety may be used for any repair required by this AD, if it is approved by an Authorized Representative for the Boeing Commercial Airplanes Delegation Option Authorization Organization who has been authorized by the Manager, Seattle ACO, to make those findings. For a repair method to be approved, the repair must meet the certification basis of the airplane.

Issued in Renton, Washington, on December 21, 2009.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.