04-22355. Airworthiness Directives; Boeing Model 737-300, -400, -500, -600, -700, -700C, -800 and -900 Series Airplanes

AGENCY:

Federal Aviation Administration (FAA), 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 modifying the wiring for the master dim and test system. For certain airplanes, this proposed AD would also require related concurrent actions as necessary. This proposed AD is prompted by a report that the master dim and test system circuit does not have wiring separation of the test ground signal for redundant equipment in the flight compartment. We are proposing this AD to prevent a single fault failure inflight from simulating a test condition and showing test patterns instead of the selected radio frequencies on the communications panels, which could inhibit communication between the flightcrew and the control tower, affecting the continued safe flight of the airplane.

DATES:

We must receive comments on this proposed AD by November 19, 2004.

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: Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., Nassif Building, room PL-401, Washington, DC 20590.

sbull By fax: [phone].

• Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street SW., Washington, DC, 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, P.O. Box 3707, Seattle, Washington 98124-2207.

You can examine the contents of this AD docket on the Internet at http://dms.dot.gov,, or in person at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., room PL-401, on the plaza level of the Nassif Building, Washington, DC.

FOR FURTHER INFORMATION CONTACT:

Technical information: Binh Tran, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone [phone]; fax [phone].

Plain language information: Marcia Walters, [e-mail].

SUPPLEMENTARY INFORMATION:

Docket Management System (DMS)

The FAA has implemented new procedures for maintaining AD dockets electronically. As of May 17, 2004, new AD actions are posted on DMS and assigned a docket number. We track each action and assign a corresponding directorate identifier. The DMS AD docket number is in the form “Docket No. FAA-2004-99999.” The Transport Airplane Directorate identifier is in the form “Directorate Identifier 2004-NM-999-AD.” Each DMS AD docket also lists the directorate identifier (“Old Docket Number”) as a cross-reference for searching purposes.

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 under ADDRESSES. Include “Docket No. FAA-2004-19245; Directorate Identifier 2004-NM-108-AD” in the subject line 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 submitted 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 website, 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 can review DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you can visit http://dms.dot.gov.

We are reviewing the writing style we currently use in regulatory documents. We are interested in your comments on whether the style of this document is clear, and your suggestions to improve the clarity of our communications that affect you. You can get more information about plain language at http://www.faa.gov/​language and http://www.plainlanguage.gov.

Examining the Docket

You can examine the AD docket on the Internet at http://dms.dot.gov,, or in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone [phone]) is located on the plaza level of the Nassif Building at the DOT street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the DMS receives them.

Discussion

We have received a report indicating that the master dim and test system circuit does not have wiring separation of the test ground signal for redundant equipment in the flight compartment on certain Boeing Model 737-300, -400, -500, -600, -700, -700C, -800 and -900 series airplanes. This condition could allow a single fault to simulate a test condition in the annunciators, switches, and displays in the flight compartment. A single fault failure could also simulate a test condition on the communications panels and show test patterns instead of the selected radio frequencies. The flightcrew needs to know the selected radio frequencies so they can communicate with the control tower. In flight, if test patterns appear instead of the selected radio frequencies on the communications panels, communication between the flightcrew and the control tower could be inhibited, and the continued safe flight of the airplane could be affected.

Relevant Service Information

We have reviewed Boeing Special Attention Service Bulletin 737-33-1132, Revision 1, dated March 4, 2004 (for Model 737-300, -400, and-500 series airplanes). We have also reviewed Boeing Service Bulletin 737-33-1133, Revision 2, dated December 4, 2003 (for Model 737-600, -700, -700C, -800, and -900 series airplanes). These service bulletins describe procedures for modifying the wiring for the master dim and test system. The modification includes re-routing existing wiring, creating splices, and performing operational testing.

For certain airplanes, Service Bulletin 737-33-1132 specifies prior or concurrent accomplishment of Boeing Service Bulletin 737-77-1022, currently at Revision 1, dated October 26, 1989. Service Bulletin 737-77-1022 describes procedures for installing an engine instrument system (EIS), and specifies prior or concurrent accomplishment of Boeing Service Bulletin 737-77-1023, currently at Revision1, dated November 9, 1989. Service Bulletin 737-77-1023 describes procedures for modifying the advisory system for the EIS. Boeing Service Bulletin 737-77-1023 references Smiths Industries Service Bulletin 311EDP-77-348 as an additional source of service information for modifying the existing EIS unit.

For certain other airplanes, Service Bulletin 737-33-1133 specifies prior or concurrent accomplishment of Boeing Service Bulletin 737-26A1083, currently at Revision 1, dated November 15, 2001; and Boeing Service Bulletin 737-33-1121, currently at Revision 1, December 19, 2002. Service Bulletin 737-26A1083 describes procedures for installing a smoke detection and fire extinguishing system in the cargo compartment. Service Bulletin 737-33-1121 describes procedures for installing wiring for the test system for the audio control panel lamp.

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. Therefore, we are proposing this AD, which would require modifying the wiring for the master dim and test system. The proposed AD would require you to use the service information described previously to perform these actions.

Costs of Compliance

This proposed AD would affect about 2,868 airplanes worldwide, and 1,181 airplanes of U.S. registry. The following table provides the estimated costs for U.S. operators to comply with this proposed AD.

Estimated Costs

Boeing service bulletin	Work hours	Average labor rate per hour	Parts	Cost per airplane
737-33-1132, Revision 1	14	$65	Nominal	$910
737-33-1133, Revision 2	3	65	Nominal	195

Estimated Concurrent Service Bulletin Costs

Boeing service bulletin	Work hours	Average labor rate per hour	Parts	Cost per airplane
737-26A1083, Revision 1 (Only one airplane affected)	185	$65	Between $30,000 and $36,400	Between $42,025 and $48,425.
737-33-1121, Revision 1	Between 5 and 6	65	Between $200 and $340	Between $525 and $730.
737-77-1022, Revision 1 (Only four airplanes affected)	72	65	No charge	$4,680.
737-77-1023, Revision 1	Between 1 and 3	65	Nominal	Between $65 and $195.

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. 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.

§ 39.13

[Amended]

2. The FAA amends § 39.13 by adding the following new airworthiness directive (AD):

Boeing: Docket No. FAA-2004-19245; Directorate Identifier 2004-NM-108-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this AD action by November 19, 2004.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Boeing Model 737-300, -400, and -500 series airplanes listed in Boeing Special Attention Service Bulletin 737-33-1132, Revision 1, dated March 4, 2004; and Model 737-600, -700, -700C, -800, and -900 series airplanes listed in Boeing Service Bulletin 737-33-1133, Revision 2, dated December 4, 2003; certificated in any category.

Unsafe Condition

(d) This AD was prompted by a report that the master dim and test system circuit does not have wiring separation of the test ground signal for redundant equipment in the flight compartment. We are issuing this AD to prevent a single fault failure inflight from simulating a test condition and showing test patterns instead of the selected radio frequencies on the communications panels, which could inhibit communication between the flightcrew and the control tower, affecting the continued safe flight of the airplane.

Compliance

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

Modification

(f) Within 30 months after the effective date of this AD: Modify the wiring for the master dim test system in accordance with the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-33-1132, Revision 1, dated March 4, 2004 (for Model 737-300, -400, -500 series airplanes); and Boeing Service Bulletin 737-33-1133, Revision 2, dated December 4, 2003 (for Model 737-600, -700, -700C, -800, and -900 series airplanes); as applicable.

Actions Required To Be Accomplished Prior to or Concurrently With Paragraph (f) of This AD

(g) Prior to or concurrently with accomplishment of paragraph (f) of this AD, do the actions specified in Table 1 of this AD, as applicable.

Table 1—Prior/Concurrent Actions

For—	Accomplish all actions associated with—	According to the Accomplishment Instructions of—
Group 57 airplanes identified in Boeing Service Bulletin 737-33-1132, Revision 1, dated March 4, 2004	Installing an engine instrument system (EIS) and	Boeing Service Bulletin 737-77-1022, Revision 1, dated October 26, 1989.
	Modifying the advisory system for the EIS	Boeing Service Bulletin 737-77-1023, Revision 1, dated November 9, 1989.
Group 4, 5, 7, 15, 16, 20, 24, 25, 29, 30, 33, 37, 39, 40, 41, and 46 airplanes identified in Boeing Service Bulletin 737-33-1133, Revision 2, dated December 4, 2003	Installing wiring for the test system for the audio control panel lamp	Boeing Service Bulletin 737-33-1121, Revision 1, dated December 19, 2002.
Group 2 airplanes identified in Boeing Service Bulletin 737-33-1121, Revision 1, dated December 19, 2002	Installing splice SP896	Boeing Service Bulletin 737-26A1083, Revision 1, dated November 15, 2001.
Group 39 airplanes identified in Boeing Service Bulletin 737-33-1133, Revision 2, dated December 4, 2003	Installing a smoke detection and fire extinguishing system in the cargo compartment	Boeing Service Bulletin 737-26A1083, Revision 1, dated November 15, 2001.

Actions Accomplished per Previous Issue of Service Bulletins

(h) Actions accomplished before the effective date of this AD in accordance with Boeing Special Attention Service Bulletin 737-33-1132, dated March 20, 2003; Boeing Service Bulletin 737-33-1133, dated December 19, 2002; or Boeing Service Bulletin 737-33-1133, Revision 1, dated April 17, 2003, as applicable, are considered acceptable for compliance with the corresponding actions specified in this AD.

Alternative Methods of Compliance (AMOCs)

(i) The Manager, Seattle Aircraft Certification Office, FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.

Issued in Renton, Washington, on September 27, 2004.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.