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Proposed Rule

Airworthiness Directives; The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 Series Airplanes

Document Details

Information about this document as published in the Federal Register.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

Start Preamble

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to adopt a new airworthiness directive (AD) for certain Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. This proposed AD would require installing two warning level indicator lights on the P2-2 center instrument panel in the flight compartment for certain airplanes. For a certain other airplane, this proposed AD would require activating the cabin altitude warning and takeoff configuration warning lights. For all airplanes, this proposed AD also would require revising the airplane flight manual to remove certain requirements included by previous AD actions, to require new pressure altitude limitations for certain airplanes, and to advise the flightcrew of the following changes: revised emergency procedures to use when a cabin altitude warning or rapid depressurization occurs, and revised cabin pressurization procedures for normal operations. This proposed AD results from a design change in the cabin altitude warning system that would address the identified unsafe condition. We are proposing this AD to prevent failure of the flightcrew to recognize and react to a valid cabin altitude warning horn, which could result in incapacitation of the flightcrew due to hypoxia (lack of oxygen in body), and consequent loss of control of the airplane.

DATES:

We must receive comments on this proposed AD by September 27, 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: 202-493-2251.
  • 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 206-544-5000, extension 1; fax 206-766-5680; e-mail me.boecom@boeing.com; 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.

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 800-647-5527) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

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FOR FURTHER INFORMATION CONTACT:

Jeffrey W. Palmer, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 917-6472; fax (425) 917-6590.

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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-2010-0761; Directorate Identifier 2010-NM-069-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

The Model 737 cabin altitude warning is an intermittent horn that sounds when cabin altitude exceeds 10,000 feet. The same intermittent warning horn sound is utilized by the takeoff configuration warning system (TCWS) to warn of unsafe airplane configuration for takeoff. The TCWS warning functionality is inhibited by air/ground logic when the airplane is in flight. However, the Model 737 cabin altitude warning system design does not currently incorporate a dedicated means of positively identifying the warning horn as a cabin altitude warning or a takeoff configuration warning. There are approximately 25 known instances where flightcrews have misinterpreted a valid cabin altitude warning as a takeoff configuration warning.

Failure of the flightcrew to recognize and react to a valid cabin altitude warning horn could result in incapacitation of the flightcrew due to hypoxia (lack of oxygen in body), and consequent loss of control of the airplane. To address this unsafe condition, we issued the following ADs.

On November 7, 2003, we issued related AD 2003-03-15 R1, Amendment 39-13366 (68 FR 64802, November 17, 2003), for various The Boeing Company and McDonnell Douglas Corporation transport category airplanes. That AD requires revising the airplane flight manual (AFM) to advise the flightcrew to don oxygen masks as a first and immediate step when the cabin altitude warning occurs. We issued that AD to prevent incapacitation of the flightcrew due to lack of oxygen, which could result in loss of control of the airplane.

On June 15, 2006, we issued related AD 2006-13-13, Amendment 39-14666 (71 FR 35781, June 22, 2006). (A correction of that AD was published in the Federal Register on July 3, 2006 (71 FR 37980).) That AD applies to all Model 737 airplanes. That AD requires revising the AFM to advise the flightcrew of improved procedures for pre-flight setup of the cabin pressurization system, as well as improved procedures for interpreting and responding to the cabin altitude/configuration warning horn. That AD resulted from reports that airplanes had failed to pressurize, and that the flightcrews failed to react properly to the cabin altitude warning horn. We issued that AD to prevent failure of the airplane to pressurize and subsequent failure of the flightcrew to recognize and react to a valid cabin altitude warning horn, which could result in incapacitation of the flightcrew due to hypoxia (lack of oxygen in body) and consequent loss of airplane control.

On October 24, 2008, we issued related AD 2008-23-07, Amendment 39-15728 (73 FR 66512, November 10, 2008), for all Model 737 airplanes. That AD requires revising the AFM to include a new flightcrew briefing that must be done before the first flight of the day and following any change in flightcrew members, and to advise the flightcrew of this additional briefing. That AD resulted from continuing reports that flightcrews have failed to recognize and react properly to the cabin altitude warning horn. We issued that AD to prevent failure of the flightcrew to recognize and react properly to a valid cabin altitude warning horn, which could result in incapacitation of the flightcrew due to hypoxia (lack of oxygen in body) and consequent loss of airplane control.

The preambles to AD 2006-13-13 and AD 2008-23-07 explain that the revisions to the AFM required by those ADs are considered to be interim action. The manufacturer had advised us that it was developing a design change in the cabin altitude warning system that would address the identified unsafe condition(s), and that once this design change was developed, approved, and available, the FAA might consider additional rulemaking. The manufacturer now has developed such a modification, and we have determined that further rulemaking is necessary; this proposed AD follows from that determination. We can better ensure long-term continued operational safety by modifications or design changes to remove the source of the problem, rather than by AFM revisions alone.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin 737-31A1325, dated January 11, 2010 (for Model 737-100, -200, -200C, -300, -400, and -500 series airplanes). This service bulletin describes procedures for installing two warning level indicator lights on the P2-2 center instrument panel in the flight compartment. This installation includes changing three wire bundles.

We have also reviewed Boeing Alert Service Bulletin 737-31A1398, dated January 7, 2010 (for Model 737-400 series airplane, variable number PW234). This service bulletin describes procedures for activating the cabin altitude warning and takeoff configuration warning lights. The activation includes changing the wiring in the W066 wire bundle and removing the INOP markers from the cabin altitude warning and takeoff configuration warning lights.

FAA's Determination and Requirements of This Proposed AD

We are proposing this AD because we evaluated all relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of the same type design. This proposed AD would require accomplishing the actions specified in the service information described previously. The proposed AD would also require revising the AFM to remove certain requirements included by previous AD actions, to require new pressure altitude limitations for certain airplanes, and to advise the flightcrew of the following changes: revised emergency procedures to use when a cabin altitude warning or rapid depressurization occurs, and revised cabin pressurization procedures for normal operations.

Costs of Compliance

We estimate that this proposed AD would affect 741 airplanes of U.S. registry. The following table provides the estimated costs for U.S. operators to comply with this proposed AD.Start Printed Page 48622

Table—Estimated Costs

ActionWork hoursAverage labor rate per hourPartsCost per productNumber of U.S.- registered airplanesFleet cost
Installation of warning indicator lights20$85$2,738$4,438740$3,284,120
Activation of the cabin altitude warning system/takeoff configuration warning lights185085185
AFM revision18508574162,985

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), 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.

You can find our regulatory evaluation and the estimated costs of compliance in the AD Docket.

Start List of Subjects

List of Subjects in 14 CFR Part 39

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The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

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PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Start Authority

Authority: 49 U.S.C. 106(g), 40113, 44701.

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[Amended]

2. The FAA amends § 39.13 by adding the following new AD:

The Boeing Company: Docket No. FAA-2010-0761; Directorate Identifier 2010-NM-069-AD.

Comments Due Date

(a) We must receive comments by September 27, 2010.

Affected ADs

(b) This AD affects the ADs identified in paragraphs (b)(1), (b)(2), and (b)(3) of this AD. This AD does not supersede the requirements of these ADs.

(1) AD 2008-23-07, Amendment 39-15728.

(2) AD 2006-13-13, Amendment 39-14666.

(3) AD 2003-03-15 R1, Amendment 39-13366.

Applicability

(c) This AD applies to the airplanes, certificated in any category, identified in paragraphs (c)(1) and (c)(2) of this AD.

(1) The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes identified in Boeing Alert Service Bulletin 737-31A1325, dated January 11, 2010.

(2) The Boeing Company Model 737-400 series airplanes identified in Boeing Alert Service Bulletin 737-31A1398, dated January 7, 2010.

Subject

(d) Air Transport Association (ATA) of America Code 31: Instruments.

Unsafe Condition

(e) This AD results from a design change in the cabin altitude warning system that would address the identified unsafe condition. The Federal Aviation Administration is issuing this AD to prevent failure of the flightcrew to recognize and react properly to a valid cabin altitude warning horn, which could result in incapacitation of the flightcrew due to hypoxia (lack of oxygen in body) and consequent loss of airplane control.

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.

Installation of Warning Indicator Lights

(g) For airplanes identified in Boeing Alert Service Bulletin 737-31A1325, dated January 11, 2010: Within 36 months after the effective date of this AD, install two warning level indicator lights on the P2-2 center instrument panel in the flight compartment, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-31A1325, dated January 11, 2010.

Activation of Warning Indicator Lights

(h) For airplanes identified in Boeing Alert Service Bulletin 737-31A1398, dated January 7, 2010: Within 36 months after the effective date of this AD, activate the cabin altitude warning and takeoff configuration warning lights, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-31A1398, dated January 7, 2010.

Airplane Flight Manual (AFM) Revisions

(i) Before further flight after doing the installation or activation of the warning lights required by paragraph (g) or (h) of this AD, do the actions specified in paragraphs (i)(1), (i)(2), and (i)(3) of this AD.

(1) Revise the Limitations Section of the applicable Boeing 737 AFM by doing the actions specified in paragraphs (i)(1)(i) and (i)(1)(ii) of this AD.

(i) Delete the “CABIN ALTITUDE WARNING TAKEOFF BRIEFING” added by AD 2008-23-07.

(ii) Add the following statement. This may be done by inserting a copy of this AD into the applicable AFM.

“For airplanes approved for maximum takeoff and landing altitudes above 8,400 feet pressure altitude, change the limitation for Maximum Takeoff and Landing pressure altitude as follows: With the CABIN ALTITUDE and TAKEOFF CONFIG lights installed and operative on those airplanes without the High Altitude Landing switch installed, maximum takeoff and landing altitude is limited to 9,000 feet pressure altitude.”Start Printed Page 48623

(2) Revise the Emergency Procedures Section of the applicable Boeing 737 AFM by doing the actions specified in paragraphs (i)(2)(i), (i)(2)(ii), (i)(2)(iii), and (i)(2)(iv) of this AD.

(i) Delete the procedure “WARNING HORN—CABIN ALTITUDE OR CONFIGURATION” added by AD 2006-13-13.

(ii) Delete the procedure entitled “CABIN ALTITUDE WARNING OR RAPID DEPRESSURIZATION” added by AD 2006-13-13.

(iii) If the procedure entitled “CABIN ALTITUDE (Airplanes with the CABIN ALTITUDE lights installed)” is currently contained in the applicable Boeing 737 AFM, delete the procedure entitled “CABIN ALTITUDE (Airplanes with the CABIN ALTITUDE lights installed).”

(iv) Add the following statement. This may be done by inserting a copy of this AD into the applicable AFM.

“CABIN ALTITUDE WARNING OR RAPID DEPRESSURIZATION (required by this ad)

Condition: The CABIN ALTITUDE warning light illuminates or the intermittent warning horn sounds in flight above 10,000 ft MSL.

RECALL:
Oxygen Masks and RegulatorsOn, 100%
Crew CommunicationsEstablish
REFERENCE:
Pressurization Mode SelectorManual
Outflow Valve SwitchClose
Passenger Oxygen (If Required)On
Descent (If Required)Initiate

(3) Revise the Normal Procedures Section of the applicable Boeing 737 AFM by doing the actions specified in paragraphs (i)(3)(i) and (i)(3)(ii) of this AD.

(i) Delete the “CABIN ALTITUDE WARNING TAKEOFF BRIEFING” procedure added by AD 2008-23-07.

(ii) Add the following statement. This may be done by inserting a copy of this AD into the applicable AFM.

“For normal operations, the pressurization mode selector should be in AUTO prior to takeoff. (Required by this AD)”

Note 1:

When statements identical to those specified in paragraphs (i)(1)(ii), (i)(2)(iv), and (i)(3)(ii) of this AD have been included in the general revisions of the AFM, the general revisions may be inserted into the AFM, and the copies of this AD may be removed from the AFM.

Terminating Action for Affected ADs

(j) Accomplishment of the requirements of this AD terminates the specified requirements of the ADs identified in paragraphs (j)(1), (j)(2), and (j)(3) of this AD, for only the airplanes identified in paragraphs (c)(1) and (c)(2) of this AD.

(1) AD 2008-23-07: All requirements of that AD.

(2) AD 2006-13-13: All requirements of that AD.

(3) AD 2003-03-15 R1: The requirements specified in paragraph (a), Table 2, and Figures 2 and 3 of that AD.

Special Flight Permit

(k) Special flight permits, as described in Section 21.197 and Section 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199), are not allowed.

Alternative Methods of Compliance (AMOCs)

(l)(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: Jeffrey W. Palmer, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 917-6472; fax (425) 917-6590. Information may be e-mailed to: 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov.

(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.

Start Signature

Issued in Renton, Washington, on July 28, 2010.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.

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[FR Doc. 2010-19834 Filed 8-10-10; 8:45 am]

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