E7-22924. Airworthiness Directives; Boeing Model 757 Airplanes Equipped with Rolls Royce RB211-535E Engines

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 airplanes equipped with Rolls Royce RB211-535E engines. This proposed AD would require repetitive inspections for signs of damage of the aft hinge fittings and attachment bolts of the thrust reversers, and related investigative and corrective actions if necessary. This proposed AD results from reports of several incidents of bolt failure at the aft hinge fittings of the thrust reversers due to, among other things, high operational loads. We are proposing this AD to prevent failure of the attachment bolts and consequent separation of a thrust reverser from the airplane during flight, which could result in structural damage to the airplane.

DATES:

We must receive comments on this proposed AD by January 10, 2008.

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 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 [phone]) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

Jason Deutschman, Aerospace Engineer, Airframe Branch, ANM-120S, Seattle Aircraft Certification Office, FAA, 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-2007-0225; Directorate Identifier 2007-NM-210-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

We have received reports indicating that several incidents of bolt failure at the aft hinge fittings of the thrust reversers have occurred on certain Boeing Model 757 airplanes equipped with Rolls Royce RB211-535E engines. Of these incidents, there were nine hinges with failure of one out of four bolts, two hinges with failure of two out of four bolts, and three hinges with failure of three out of four bolts. The possible causes of the bolt failures can be high operational loads, contact loads caused by possible interference between the thrust reverser hinge and the hinge beam, or installation of the four attachment bolts with washers that could rub against the radius of the hinge fitting spotface. The hinge has integral fail safe features, but loss of the entire four-bolt pattern constitutes complete loss of the load path. Failure of the attachment bolts could result in separation of a thrust reverser from the airplane during flight and consequent structural damage to the airplane.

Relevant Service Information

We have reviewed Boeing Special Attention Service Bulletins 757-54-0049 and 757-54-0050, both dated July 16, 2007. The service information describes procedures for doing a detailed inspection of the aft hinge fittings and the eight attachment bolts of the thrust reversers for signs of damage (includes, but is not limited to, cracked or broken hinge fittings or contact damage to the base metal), and related investigative and corrective actions if necessary. The compliance time for the initial inspection is within 3,000 flight cycles after the date on the service bulletin.

The related investigative and corrective actions for the number 1 and number 2 engines include the following:

• For airplanes on which any aft hinge fitting is cracked or broken: Accomplish the preventive modification specified in Part III of the Accomplishment Instructions and install a new fitting.
• For airplanes on which any contact damage to the base metal is found that is less than .005 inch deep: Accomplish the preventive modification specified in Part III of the Accomplishment Instructions before further flight; or reapply the surface finish as specified in Part II of the Accomplishment Instructions (standard operating procedures manual 20-60-02), and accomplish the preventive modification within 3,000 flight cycles after the surface finish is applied.
• For airplanes on which any contact damage to the base metal is found that is equal to or more than .005 inches deep: Accomplish the preventive modification as specified in Part III of the Accomplishment Instructions.
• For airplanes on which any damage is found that is outside the limits specified in the service information, the service bulletins recommend contacting Boeing for repair instructions.
• For airplanes on which any attachment bolt is damaged: Accomplish the preventive modification specified in Part III of the Accomplishment Instructions, or remove the damaged bolt and accomplish a high frequency eddy current inspection of the bolt hole for cracking. If no crack is found in the bolt hole, replace the bolt with a new or serviceable bolt before further flight and accomplish the preventive modification within 3,000 flight cycles after the bolt is replaced. If any crack is found, accomplish the preventive modification.

For airplanes on which no attachment bolt is found damaged, repeat the detailed inspection at intervals not to exceed 3,000 flight cycles. Accomplishing the preventive modification at any time would eliminate the need for the repetitive inspections.

Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition.

Concurrent Service Information

Service Bulletin 757-54-0049 recommends prior or concurrent accomplishment of Boeing Service Bulletin 757-54-0015, Revision 3, dated September 19, 1996. Service Bulletin 757-54-0015 describes procedures for replacing a certain older hinge fitting and attachment on airplanes after line number 241.

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, except as discussed under “Difference Between the AD and the Service Information.”

Difference Between the AD and the Service Information

Although Boeing Special Attention Service Bulletins 757-54-0049 and 757-54-0050 specify that you may contact the manufacturer for repair instructions, this proposed AD requires you to repair in one of the following ways:

• Using a method that we approve; or
• Using data that meet the certification basis of the airplane that have been approved by an Authorized Representative for the Boeing Delegation Option Authorization Organization who has been authorized by the FAA to make those findings.

Costs of Compliance

There are about 606 airplanes of the affected design in the worldwide fleet. This proposed AD would affect about 295 airplanes of U.S. registry. The proposed inspections would take about 2 work hours per airplane, at an average labor rate of $80 per work hour. Based on these figures, the estimated cost of the proposed AD for U.S. operators is $47,200, or $160 per airplane, per inspection cycle.

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.

§ 39.13

[Amended]

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

Boeing: Docket No. FAA-2007-0225; Directorate Identifier 2007-NM-210-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by January 10, 2008.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Boeing Model 757-200, -200CB, -200PF, and -300 series airplanes, certificated in any category; equipped with Rolls Royce RB211-535E engines.

Unsafe Condition

(d) This AD results from reports of several incidents of bolt failure at the aft hinge fittings of the thrust reversers due to, among other things, high operational loads. We are issuing this AD to prevent failure of the attachment bolts and consequent separation of a thrust reverser from the airplane during flight, which could result in structural damage to 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.

Repetitive Inspections/Investigative and Corrective Actions

(f) At the time specified in paragraph 1.E. “Compliance” of Boeing Special Attention Service Bulletins 757-54-0049 or 757-54-0050, both dated July 16, 2007, as applicable, except as provided by paragraph (g) of this AD: Do a detailed inspection for signs of damage of the aft hinge fittings and attachment bolts of the thrust reversers by doing all the actions, including all applicable related investigative and corrective actions, as specified in the Accomplishment Instructions of the applicable service bulletin. Do all applicable related investigative and corrective actions at the time specified in paragraph 1.E., “Compliance” of the applicable service bulletin. If any damage is found and the service bulletins specify to contact Boeing for appropriate action: Before further flight, repair using a method approved in accordance with the procedures specified in paragraph (j) of this AD.

(g) Where Boeing Special Attention Service Bulletins 757-54-0049 and 757-54-0050, both dated July 16, 2007, specify compliance times relative to the date on the service bulletin, this AD requires compliance within the specified compliance time after the effective date of this AD.

Concurrent Service Information

(h) Prior to or concurrently with accomplishing the actions specified in Boeing Special Attention Service Bulletin 757-54-0049, dated July 16, 2007, accomplish the replacement specified in Boeing Service Bulletin 757-54-0015, Revision 3, dated September 19, 1996.

(i) Actions accomplished before the effective date of this AD in accordance with Boeing Service Bulletin 757-54-0015, dated February 16, 1989; Revision 1, dated December 20, 1990; or Revision 2, dated April 21, 1994; are considered acceptable for compliance with the corresponding actions specified in paragraph (h) of this AD.

Alternative Methods of Compliance (AMOCs)

(j)(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.

(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 appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO.

(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 November 13, 2007.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.