E8-5014. Airworthiness Directives; Boeing Model 757 Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to adopt a new airworthiness directive (AD) for all Boeing Model 757-200, -200PF, -200CB, and -300 series airplanes. This proposed AD would require an inspection of the two spring arms in the spin brake assemblies in the nose wheel well to determine if the spring arms are made of aluminum or composite material, and repetitive related investigative/corrective actions if necessary. This proposed AD results from reports of cracked and broken aluminum spring arms. We are proposing this AD to detect and correct cracked or broken spring arms. A cracked or broken spring arm could separate from the airplane and result in potential hazard to persons or property on the ground, or ingestion into the engine with engine damage and potential shutdown, or damage to the airplane.

DATES:

We must receive comments on this proposed AD by April 28, 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, FAA, Seattle Aircraft Certification Office, 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-2008-0295; Directorate Identifier 2007-NM-298-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

Two spin brake assemblies are installed in the nose wheel well and include the spin brake spring arms. Wear bars or brake pads installed on the spin brake spring arms bring the nose wheel to a stop after the gear is retracted. We have received reports of cracked and broken aluminum spring arms. In some cases, the aluminum spin brake spring arm separated from the airplane. Cracked or broken spring arms, if not detected and corrected, could separate from the airplane and result in potential hazard to persons or property on the ground, or ingestion into the engine with engine damage and potential shutdown, or damage to the airplane.

Relevant Service Information

We have reviewed Boeing Special Attention Service Bulletin 757-32-0176, dated September 10, 2007. The service bulletin describes procedures for an inspection of the two spring arms in the spin brake assemblies in the nose wheel well to determine if the spring arms are made of aluminum or composite material. The compliance time for determining the material of the spring arm is before the accumulation of 6,000 total flight cycles on the spring arm, or within 300 flight cycles, whichever occurs later.

For any aluminum spin arm, the service bulletin describes procedures for related investigative/corrective actions. The related investigative actions include repetitive detailed and high frequency eddy current inspections for cracking of the aluminum spring arm. The compliance time for doing the first detailed inspection is before the accumulation of 6,000 total flight cycles on the spin arm; or within 300 flight cycles, whichever occurs later. The repetitive interval for the detailed inspection is 300 flight cycles. The compliance time for doing the first high frequency eddy current inspection is before the accumulation of 6,000 total flight cycles on the spin arm; or within 1,500 flight cycles, whichever occurs later. The repetitive interval for the high frequency eddy current inspection is 1,500 flight cycles.

The corrective action if any crack is found on an aluminum spring arm is replacing the spring arm with a new spring arm made of either aluminum or composite material. The service bulletin states that the replacement is to be done before further flight, except that the airplane can be operated for 10 calendar days with the spin brake spring arms removed provided the airplane is operated within the restrictions given in the Boeing Model 757 Master Minimum Equipment List (MMEL).

The service bulletin also specifies that replacing an aluminum spring arm with a spring arm made of composite material ends the need for the repetitive inspections.

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.

Interim Action

The service bulletin indicates that the design for the spring arm was changed from composite to aluminum due to reports of excessive noise related to the spring arm made of composite material. Boeing is currently developing a kit to replace the aluminum spring arm with a new part made from corrosion resistant steel (CRES). Once the CRES spring arm is developed, approved, and available, the FAA might consider additional rulemaking. However, the spring arm made of composite material is adequate to ensure continued operational safety of the airplane.

Costs of Compliance

We estimate that this proposed AD would affect 668 airplanes of U.S. registry. We also estimate that it would take about 1 work-hour per product to comply with this proposed AD. The average labor rate is $80 per work-hour. Based on these figures, we estimate the cost of this proposed AD to the U.S. operators to be $53,440, or $80 per product.

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.

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 AD:

Boeing: Docket No. FAA-2008-0295; Directorate Identifier 2007-NM-298-AD.

Comments Due Date

(a) We must receive comments by April 28, 2008.

Affected ADs

(b) None.

Applicability

(c) This AD applies to all Boeing Model 757-200, -200PF, -200CB, and -300 series airplanes, certificated in any category.

Unsafe Condition

(d) This AD results from reports of cracked and broken aluminum spring arms. We are issuing this AD to detect and correct cracked or broken spring arms. A cracked or broken spring arm could separate from the airplane and result in potential hazard to persons or property on the ground, or ingestion into the engine with engine damage and potential shut down, or damage to the airplane.

Compliance

(e) Comply with this AD within the compliance times specified, unless already done.

Inspections and Corrective Actions

(f) At the applicable time specified in paragraph 1.E., “Compliance,” of Boeing Special Attention Service Bulletin 757-32-0176, dated September 10, 2007, do a general visual inspection to determine the material (aluminum or composite) of the two spring arms in the spin brake assemblies in the nose wheel well. A review of airplane maintenance records is acceptable in lieu of this inspection if the material can be conclusively determined from that review. Do all applicable related investigative and corrective actions, and all repetitive inspections thereafter, at the applicable time specified in paragraph 1.E., “Compliance,” of the service bulletin. Do all actions in accordance with the Accomplishment Instructions of Boeing Special Attention Service Bulletin 757-32-0176, dated September 10, 2007, except, where the service bulletin specifies a compliance time after the date on the service bulletin, this AD requires compliance within the specified compliance time after the effective date of this AD.

Optional Terminating Action

(g) Replacing an aluminum spring arm with a spring arm made of composite material in accordance with Figure 5 of Boeing Special Attention Service Bulletin 757-32-0176, dated September 10, 2007, ends the repetitive inspections required by paragraph (f) of this AD for that spring arm.

Alternative Methods of Compliance (AMOCs)

(h)(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, ATTN: Jason Deutschman, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone [phone]; fax [phone]; has the authority to approve AMOCs for this AD, if requested using 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, and the approval must specifically refer to this AD.

Issued in Renton, Washington, on March 3, 2008.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.