Airworthiness Directives; Boeing Model 737-300, -400, -500, -600, -700, -700C, -800, and -900 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, -500, -600, -700, -700C, -800, and -900 series airplanes. This proposed AD would require installing a new circuit breaker, relays, and wiring to allow the flightcrew to turn off electrical power to the in-flight entertainment (IFE) systems and other non-essential electrical systems through a switch in the flight compartment, and doing other specified actions. This proposed AD results from an IFE systems review. We are proposing this AD to ensure that the flightcrew is able to turn off electrical power to IFE systems and other non-essential electrical systems through a switch in the flight compartment. The flightcrew's inability to turn off power to IFE systems and other non-essential electrical systems during a non-normal or emergency situation could result in the inability to control smoke or fumes in the airplane flight deck or cabin.

DATES:

We must receive comments on this proposed AD by December 24, 2007.

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 AD, contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207.

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.

FOR FURTHER INFORMATION CONTACT:

Shohreh Safarian, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 917-6418; fax (425) 917-6590.

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-2007-0163; Directorate Identifier 2007-NM-046-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 Federal Aviation Administration (FAA) completed a review of in-flight entertainment (IFE) systems installed on transport category airplanes. The review focused on the interface between the IFE system and airplane electrical system, with the objective of determining if any unsafe conditions exist with regard to the interface.

The type of IFE systems considered for review were those that contain video monitors (cathode ray tubes or liquid crystal displays, either hanging above the aisle or mounted on individual seat backs or seat trays), or complex circuitry (i.e., power supplies, electronic distribution boxes, extensive wire routing, relatively high power consumption, multiple layers of circuit protection, etc.). In addition, in-seat power supply systems that provide power to more than 20 percent of the total passenger seats were also considered for the review. The types of IFE systems not considered for review include systems that provide only audio signals to each passenger seat, ordinary in-flight telephone systems (e.g., one telephone handset per group of seats or bulkhead-mounted telephones), systems that have only a video monitor on the forward bulkhead(s) (or a projection system) to provide passengers with basic airplane and flight information, and in-seat power supply systems that provide power to less than 20 percent of the total passenger seats.

Items considered during the review include the following:

• Can the electrical bus(es) supplying power to the IFE system be de-energized when necessary without removing power from systems that might be required for continued safe flight and landing?
• Can IFE system power be removed when required without pulling IFE system circuit breakers (i.e., is there a switch (dedicated to the IFE system or a combination of loads) located in the flight deck or cabin that can be used to remove IFE power?)?
• If the IFE system requires changes to flightcrew procedures, has the airplane flight manual (AFM) been properly amended?
• If the IFE system requires changes to cabin crew procedures, have they been properly amended?
• Does the IFE system require periodic or special maintenance?

In all, we reviewed approximately 180 IFE systems. The review results indicate that unsafe conditions exist on some IFE systems installed on various transport category airplanes. These conditions can be summarized as:

• Electrical bus(es) supplying power to the IFE system cannot be de-energized when necessary without removing power from systems that might be required for continued safe flight and landing.
• Power cannot be removed from the IFE system when required without pulling IFE system circuit breakers (i.e., there is no switch dedicated to the IFE system or combination of systems for the purpose of removing power).
• Installation of the IFE system has affected crew (flightcrew and/or cabin crew) procedures, but the procedures have not been properly revised.

Currently, certain Boeing Model 737-300, -400, -500, -600, -700, -700C, -800, and -900 series airplanes do not have a switch in the flight compartment allowing the flightcrew to turn off power to IFE systems and other non-essential electrical systems, in the event of smoke or fumes. The flightcrew's inability to turn off electrical power to IFE systems and other non-essential electrical systems, if not corrected, could result in the inability to control smoke or fumes in the airplane flight deck or passenger cabin during a non-normal or emergency situation.

Relevant Service Information

We have reviewed Boeing Service Bulletin 737-24-1145, dated March 4, 2004, for Model 737-300, -400, and -500 series airplanes. Boeing Service Bulletin 737-24-1145 describes procedures for installing a new circuit breaker, relays, and wiring to allow the flightcrew to turn off electrical power to IFE systems through the IFE/galley switch and for doing other specified actions. The other specified actions include rerouting the wiring between the IFE relays, disconnect panels, and circuit breakers; replacing the lightplate assembly at the P5-13 module assembly with a new lightplate assembly; and testing the IFE control systems.

We have also reviewed Boeing Service Bulletin 737-24-1147, Revision 1, dated March 1, 2007, for Model 737-600, -700, -700C, -800, and -900 series airplanes. Boeing Service Bulletin 737-24-1147 describes procedures for installing a new circuit breaker, relays, and wiring to allow the flightcrew to turn off electrical power to the IFE systems and other non-essential electrical systems through a utility switch in the flight compartment. Part 1 of the Work Instructions, which is applicable to Groups 1 and 2 airplanes, describes procedures for changing the wiring on the E4-2 shelf assembly and testing the changed electrical control system to ensure it operates correctly. For Group 2 airplanes, Part 1 also describes procedures for installing new wiring and changing certain wiring between a terminal bus and circuit breaker.

Part 2 of the Work Instructions, which is applicable to Groups 3 through 139 airplanes, describes the following procedures:

• Installing a circuit breaker on the P6-11 panel door, a new terminal board and two new relays on the aft wall of the P6 electrical panel, a new relay adapter plate on the relay panel assembly, new wires W40 between the relays, terminal board, and the P6 disconnect panel assemblies, and a new relay on the relay plate assembly; and installing new wires W40/W44 and changing the wiring between the relays, circuit breakers, and disconnect panel assemblies.
• Replacing the P5-13 module assembly with a new improved or modified P5-13 module assembly and installing new wires W2510 between the P5 overhead panel and the P6 electrical panel.
• Changing the wiring W422 on the E4-2 shelf assembly and installing new wires W44 between the E4-2 shelf assembly and P6 electrical panel.
• Testing the electrical supply and IFE control systems to ensure that they operate correctly.

Part 3 of the Work Instructions, which is applicable to Groups 140 through 169 airplanes, describes procedures for making a wiring change to a certain wire bundle for the printer and testing the printer and changed systems to ensure they operate correctly.

Boeing Service Bulletin 737-24-1145 specifies concurrent accomplishment of Boeing Component Service Bulletin 69-37321-31-03, dated August 21, 2003, for Model 737-300 series airplanes equipped with P5-13 module assembly, part number (P/N) 69-37321-81. Boeing Component Service Bulletin 69-37321-31-03 describes procedures for replacing the lightplate assembly at the P5-13 module assembly with a new lightplate assembly and reidentifying and testing the modified P5-13 module assembly.

Boeing Service Bulletin 737-24-1147 specifies concurrent accomplishment of Boeing Component Service Bulletin 285A1840-24-02, dated August 28, 2003, for Model 737-600, -700, -700C, -800, and -900 series airplanes equipped with P5-13 module assembly, P/N 285A1840-3 or -4. Boeing Component Service Bulletin 285A1840-24-02 describes procedures for modifying the P5-13 module assembly. The modification includes installing new analog and interface printed wire assemblies (PWAs) on the processor PWA, new toggle switches on the new front panel assembly, a new PWA cable between the analog and interface PWAs, new standoff posts on the interface and processor PWAs, the new front panel assembly on the new standoff posts, and a new light plate on the modified module assembly.

Boeing Service Bulletin 737-24-1147 specifies prior or concurrent accomplishment of Boeing Service Bulletin 737-23-1189, dated June 27, 2002, for two Model 737-800 series airplanes. Boeing Service Bulletin 737-23-1189 describes procedures for installing wiring for the No. 4 video display unit (VDU) cluster, an INOP marker, and stow clip at the P6-1 circuit breaker panel; rerouting certain wiring for the No. 4 VDU cluster between stations 685 and 767; and doing a continuity test of the newly installed and rerouted wire bundles.

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 1,617 airplanes of the affected design in the worldwide fleet. The following table provides the estimated costs, at an average labor rate of $80 per hour, for U.S. operators to comply with this proposed AD.

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.