05-6250. Airworthiness Directives; Boeing Model 757-200, -200CB, and -200PF 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 757-200, -200CB, and -200PF series airplanes. This proposed AD would require an inspection of each trailing edge flap transmission assembly to determine the part number and serial number, and related investigative and corrective actions and part marking if necessary. This proposed AD is prompted by a report indicating that cracked flap transmission output gears have been discovered during routine overhaul of the trailing edge flap transmission assemblies. We are proposing this AD to prevent an undetected flap skew, which could result in a flap loss, damage to adjacent airplane systems, and consequent reduced controllability of the airplane.

DATES:

We must receive comments on this proposed AD by May 16, 2005.

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.
• 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. This docket number is FAA-2005-20726; the directorate identifier for this docket is 2004-NM-265-AD.

FOR FURTHER INFORMATION CONTACT:

Douglas Tsuji, 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].

SUPPLEMENTARY INFORMATION:

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-2005-20726; Directorate Identifier 2004-NM-265-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.

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 cracked flap transmission output gears have been discovered during routine overhaul of the trailing edge flap transmission assemblies on certain Boeing Model 757-200, -200CB, and -200 PF series airplanes. Investigation revealed that the cracks are the result of a manufacturing error in the production of transmission assemblies having certain part numbers and serial numbers. A damaged output gear could result in a disconnect within the flap transmission and cause an undetected flap skew. An undetected flap skew, if not corrected, could result in a flap loss, damage to adjacent airplane systems, and consequent reduced controllability of the airplane.

Relevant Service Information

We have reviewed Boeing Special Attention Service Bulletin 757-27-0150, dated December 9, 2004. The service bulletin describes procedures for inspecting each trailing edge flap transmission assembly to determine the part number and serial number, and related investigative and corrective actions if necessary. The related investigative and corrective actions include removing the transmission output gear from the affected transmission assembly, performing a magnetic particle inspection of the output gear, and replacing the output gear with a new output gear if any cracks or defects are found. The service bulletin also includes procedures for marking the nameplate of a trailing edge flap transmission assembly with the service bulletin number to indicate that the inspection of the output gear has been completed. 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 accomplishing the actions specified in the service information described previously.

Costs of Compliance

There are about 979 airplanes of the affected design in the worldwide fleet. This proposed AD would affect about 644 airplanes of U.S. registry.

It will take approximately 1 work hour per airplane to accomplish the proposed inspection at an average labor rate of $65 per work hour. Based on this figure, the cost impact of the proposed AD on U.S. operators is estimated to be $41,860, or $65 per airplane.

Removal of a transmission assembly; removal, inspection, and reassembly of the transmission output gear; and reinstallation of the transmission assembly; if required; will take about 20 work hours per transmission assembly, at an average labor rate of $65 per work hour. Required parts will cost about $325 per transmission output gear. Based on these figures, we estimate the cost of replacement to be $1,625 per transmission output assembly (there are 8 transmission output assemblies per airplane and 325 suspect assemblies).

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. 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-2005-20726; Directorate Identifier 2004-NM-265-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this AD action by May 16, 2005.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Boeing Model 757-200, -200CB, and -200PF series airplanes, certificated in any category, as identified in Boeing Special Attention Service Bulletin 757-27-0150, dated December 9, 2004.

Unsafe Condition

(d) This AD was prompted by a report indicating that cracked flap transmission output gears have been discovered during routine overhaul of the trailing edge flap transmission assemblies. We are issuing this AD to prevent an undetected flap skew, which could result in a flap loss, damage to adjacent airplane systems, and consequent reduced controllability 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.

Inspection To Determine Part Number and Serial Number

(f) Within 60 months after the effective date of this AD: Do an inspection of each trailing edge flap transmission assembly to determine the part number and serial number, and any applicable related investigative and corrective actions and part marking, by accomplishing all of the applicable actions specified in the Accomplishment Instructions of Boeing Special Attention Service Bulletin 757-27-0150, dated December 9, 2004. If, during any related investigative action, any transmission output gear is found with a defect or crack, replace that transmission output gear before further flight.

Parts Installation

(g) As of the effective date of this AD, no person may install a trailing edge flap transmission assembly, part number (P/N) 251N4050-37, -38, -39, or -40, having any serial number (S/N) 001 through 325 inclusive; or P/N 251N4022-28, -29, -30, or -31, having any S/N 001 through 325 inclusive; on any airplane; unless the transmission assembly has been inspected, and any applicable related investigative and corrective actions and part marking has been accomplished, in accordance with the Accomplishment Instructions of Boeing Special Attention Service Bulletin 757-27-0150, dated December 9, 2004.

Alternative Methods of Compliance (AMOCs)

(h) 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 March 21, 2005.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.