E8-25758. Airworthiness Directives; Boeing Model 727 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 727 airplanes. This proposed AD would require inspections for cracking of the left- and right-side shear ties and web posts of the kickload beam and the adjacent structure in the vertical stabilizer, and corrective actions if necessary. This proposed AD results from a report of cracking of the left- and right-side web posts and shear ties of the kickload beam. We are proposing this AD to detect and correct cracking of the left- and right-side web posts and shear ties of the kickload beam, which, when coupled with failures in the adjacent structure, could result in structural failure of the vertical stabilizer, and loss of control of the airplane.

DATES:

We must receive comments on this proposed AD by December 15, 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:

Berhane Alazar, 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-2008-1117; Directorate Identifier 2008-NM-106-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 a report of cracking of the left- and right-side web posts and shear ties of the kickload beam. The cracking was discovered during a scheduled maintenance visit of an airplane with 65,000 total flight hours and 42,000 total flight cycles. The reported cracking of the left- and right-side web posts, which attach to the kickload beam and the left- and right-side stringer 11 in the vertical stabilizer, was due to stress corrosion caused by elevated fit up stress. Cracking in the left- and right-side shear ties, which attach to the kickload beam, was a result of fatigue caused by compensation for cracking in the web posts. Cracking of the shear ties and web posts can diminish the effectiveness of both left- and right-side stringer 11. When coupled with failures in the rear spar chord or stringer 10, the critical crack length at which limit load can be sustained is reduced, rendering the existing inspection intervals for stringer 10 and the rear spar chord insufficient. This condition, if not corrected, could result in structural failure of the vertical stabilizer, which could lead to loss of control of the airplane.

Relevant Service Information

We have reviewed Boeing Special Attention Service Bulletin 727-55-0093, dated March 12, 2008. The service bulletin describes procedures for doing repetitive high frequency eddy current (HFEC) and low frequency eddy current (LFEC) inspections for cracking of the left- and right-side shear ties, left- and right-side web posts, left- and right-side stringers 10 and 11, rear spar chord, associated critical fasteners, and adjacent surfaces in the vertical stabilizer. For airplanes on which any cracking is found in the shear ties or web posts, the service bulletin describes replacing the cracked parts with new parts and inspecting all open fastener holes in the kickload beam web and chords for cracking. For airplanes on which cracking is found in stringer 10 or 11, rear spar chord and skin, associated critical fasteners, adjacent surfaces of the vertical stabilizer, or areas other than the shear ties and web posts, the service bulletin specifies contacting Boeing for repair instructions. The service bulletin specifies the following compliance times:

Compliance Times

Airplanes/condition	Compliance time		Repetitive interval
	(whichever occurs first)
Less than 52,000 total flight hours or 39,000 total flight cycles	Before 56,000 total flight hours	Before 42,000 total flight cycles	10,000 flight hours or 7,500 flight cycles, whichever occurs first.
More than 52,000 total flight hours or 39,000 total flight cycles	Within 4,000 flight hours after the date of the service bulletin	Within 3,000 flight cycles after the date of the service bulletin	10,000 flight hours or 7,500 flight cycles, whichever occurs first.
Any cracking found	Before further flight		(None).

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(se) same type design(s). This proposed AD would require accomplishing the actions specified in the service information described previously, except as discussed under “Differences Between the Proposed AD and the Service Bulletin.”

Differences Between the Proposed AD and the Service Bulletin

Boeing Special Attention Service Bulletin 727-55-0093, dated March 12, 2008, specifies to contact the manufacturer for instructions on how to repair certain conditions, but this proposed AD would require repairing those conditions in one of the following ways:

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

The service bulletin does not specify a compliance time for airplanes with exactly 52,000 total flight hours or 39,000 total flight cycles. We have grouped those airplanes with airplanes having “less than” 52,000 total flight hours or 39,000 total flight cycles, as specified in paragraph (g) of this proposed AD.

Interim Action

We consider this proposed AD interim action. If final action is later identified, we might consider further rulemaking then.

Costs of Compliance

We estimate that this proposed AD would affect 364 airplanes of U.S. registry. The following table provides the estimated costs for U.S. operators to comply with this proposed AD.

Estimated Costs

Action	Work hours	Average labor rate per hour	Parts	Cost per product	Number of U.S.-registered airplanes	Fleet cost
Inspection	10	$80	$0	$800, per inspection cycle	364	$291,200, 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 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
• Incorporation by reference
• 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-2008-1117; Directorate Identifier 2008-NM-106-AD.

Comments Due Date

(a) We must receive comments by December 15, 2008.

Affected ADs

(b) None.

Applicability

(c) This AD applies to all Boeing Model 727, 727C, 727-100, 727 -100C, 727-200, and 727-200F series airplanes, certificated in any category.

Unsafe Condition

(d) This AD results from a report of cracking of the left- and right-side web posts and shear ties of the kickload beam. We are issuing this AD to detect and correct cracking of the left- and right-side web posts and shear ties of the kickload beam, which, when coupled with failures in the adjacent structure, could result in structural failure of the vertical stabilizer, and loss of control of the airplane.

Compliance

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

Inspections and Corrective Actions

(f) At the times specified in paragraph 1.E., “Compliance,” of Boeing Special Attention Service Bulletin 727-55-0093, dated March 12, 2008 (“the service bulletin”), except as provided by paragraphs (g) and (h) of this AD: Do the inspections to detect cracking of the left- and right-side web posts and shear ties of the kickload beam, by doing all of the actions specified in Part 2 and the applicable corrective actions specified in Part 3 of the Accomplishment Instructions of the service bulletin, except as provided by paragraph (i) of this AD. Do all applicable corrective actions before further flight. Repeat the inspections thereafter at the intervals specified in paragraph 1.E. of the service bulletin.

Clarification and Exception to the Specified Compliance Times

(g) To determine the compliance times for airplanes having exactly 52,000 total flight hours or 39,000 total flight cycles, for the purposes of this AD, these airplanes are grouped with airplanes having “less than” 52,000 total flight hours or 39,000 total flight cycles, as specified in paragraph 1.E., “Compliance,” of Boeing Special Attention Service Bulletin 727-55-0093, dated March 12, 2008.

(h) Where Boeing Special Attention Service Bulletin 727-55-0093, dated March 12, 2008, 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.

Exception to the Specified Corrective Actions

(i) If any cracking is found during any inspection required by this AD, and Boeing Special Attention Service Bulletin 727-55-0093, dated March 12, 2008, specifies contacting Boeing for appropriate action: Before further flight, repair the cracking or damage using a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA. For a repair method to be approved by the Manager, Seattle ACO, as required by this paragraph, the Manager's approval letter must specifically refer to this AD.

Alternative Methods of Compliance (AMOCs)

(j)(1) The Manager, Seattle ACO, FAA, ATTN: Berhane Alazar, Aerospace Engineer, Airframe Branch, ANM-120S, 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 October 10, 2008.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.