E8-24763. Airworthiness Directives; Boeing Model 727-100 and 727-200 Series Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to adopt a new airworthiness directive (AD) for certain Boeing Model 727-100 and 727-200 series airplanes. This proposed AD would require repetitive internal and external high frequency eddy current, mid frequency eddy current, low frequency eddy current, and magneto optic imaging inspections to detect cracks, corrosion, delamination, and materials loss in the lower fastener row of the lower skin and the upper fastener row of the upper skin, and corrective actions if necessary. This proposed AD results from a report of decompression in a Boeing Model 737 airplane at flight level 290. We are proposing this AD to detect and correct scratches and excessive reduction in material thickness from excessive blend-out or corrosion, which could lead to premature cracking in the lap joint. Such cracking could adversely affect the structural integrity of the airplane.

DATES:

We must receive comments on this proposed AD by December 1, 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-2008-1103; Directorate Identifier 2008-NM-048-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 received a report of decompression in a Boeing Model 737 airplane at flight level (FL) 290. An investigation revealed that the skin flapped between stringer (S)-4R and S-5R from body station (BS) 300 to BS 328. Examination of the skin showed cracks initiating at scratches in the lower skin of a lap joint that was cold-bonded in production. The lap splice had been separated for rework. These conditions, if not corrected, may result in scratches and excessive reduction in material thickness from excessive blend out or corrosion, which could lead to premature cracking in the lap joint. Such cracking could adversely affect the structural integrity of the airplane.

The cold-bonded lap joints on certain Boeing Model 727 airplanes are similar to those on the affected Model 737 and Model 747 airplanes. Therefore, all of these models may be subject to the same unsafe condition.

Other Relevant Rulemaking

On November 7, 2003, we issued AD 2003-23-03, amendment 39-13367 (68 FR 64980, dated November 18, 2003), for certain Boeing Model 737-100, -200, and -200C series airplanes. That AD requires repetitive inspections to detect discrepancies in the upper and lower skins of the fuselage lap joint and circumferential joint, and repair if necessary. That AD requires a terminating modification for the repetitive inspections.

On June 9, 2004, we issued AD 2004-13-02, amendment 39-13682 (69 FR 35237, June 24, 2004), for certain Boeing Model 747-100, -200B, and -200F series airplanes. That AD requires initial and repetitive inspections to find discrepancies in the upper and lower skins of the fuselage lap joints, and repair if necessary.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin 727-53A0223, dated March 28, 2002. The service bulletin describes procedures for repetitive internal and external high frequency eddy current (HFEC), mid frequency eddy current (MFEC), low frequency eddy current (LFEC), and magneto optic imaging (MOI) inspections to detect cracks, corrosion, delamination, and materials loss in the lower fastener row of the lower skin and the upper fastener row of the upper skin, and corrective actions if necessary. The corrective actions include repairing all cracks; repairing skin material loss that is greater than 10%; separating, cleaning, and refastening corroded areas where skin loss is less than 10%; and replacing remaining fasteners with serviceable fasteners, if necessary.

The service bulletin also specifies compliance times for initial HFEC, MFEC, LFEC, and MOI inspections ranging between 9 months or 1,500 flight cycles, whichever is earlier, and 60 months or 7,500 flight cycles, whichever is earlier, depending on number of flight cycles on the airplane. The service bulletin also specifies repetitive intervals for HFEC, MFEC, LFEC, and MOI inspections every 2,000 or 7,000 flight cycles, or every 4 years, depending on inspection area and type.

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, except as discussed under “Differences Between the Proposed Rule and Referenced Service Bulletin.”

Differences Between the Proposed Rule and Referenced Service Bulletin

Operators should note that, although the Accomplishment Instructions of Boeing Alert Service Bulletin 727-53A0223, dated March 28, 2002, describes procedures for reporting all cracks and evidence of corrosion to Boeing, this proposed AD would not require that action.

Costs of Compliance

We estimate that this proposed AD would affect 73 airplanes of U.S. registry. We also estimate that it would take about 56 work hours 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 $327,040, or $4,480 per product, 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
• 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-2008-1103; Directorate Identifier 2008-NM-048-AD.

Comments Due Date

(a) We must receive comments by December 1, 2008.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Boeing Model 727-100 and 727-200 series airplanes, certificated in any category; as identified in Boeing Alert Service Bulletin 727-53A0223, dated March 28, 2002.

Unsafe Condition

(d) This proposed AD results from a report of decompression in a Boeing Model 737 airplane at flight level 290. We are proposing this AD to detect and correct scratches and excessive reduction in material thickness from excessive blend-out or corrosion, which could lead to premature cracking in the lap joint. Such cracking could adversely affect the structural integrity of the airplane.

Compliance

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

Inspections and Corrective Actions

(f) Except as provided by paragraphs (f)(1), (f)(2), and (f)(3)of this AD, at the applicable compliance times and repeat intervals listed in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 727-53A0223, dated March 28, 2002: Do repetitive internal and external high frequency eddy current, mid frequency eddy current, low frequency eddy current, and magneto optic imaging inspections to detect cracks, corrosion, delamination, and materials loss in the lower fastener row of the lower skin and the upper fastener row of the upper skin, and corrective actions by accomplishing all the applicable actions specified in the Accomplishment Instructions of the service bulletin. The applicable corrective actions must be done before further flight.

(1) Where paragraph 1.E., “Compliance,” of the service bulletin identifies airplanes, “Airplane Fight Cycles (f/c) at time of SB Release,” this AD affects those airplanes with the specified flight cycles as of the effective date of this AD.

(2) Where paragraph 1.E., “Compliance,” of the service bulletin specifies “Initial Inspection Threshold From SB Rel Upper and Lower Skin,” the AD requires compliance within the specified compliance times after the effective date of this AD.

(3) Where paragraph 1.E., “Compliance,” of the service bulletin specifies “Repeat every * * *,” this AD requires compliance at intervals not to exceed the specified flight cycles or years.

No Reporting

(g) Although Boeing Alert Service Bulletin 727-53A0223, dated March 28, 2002, specifies to submit information to the manufacturer, this AD does not include that requirement.

Alternative Methods of Compliance (AMOCs)

(h)(1) The Manager, Seattle Aircraft Certification Office, FAA, ATTN: 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]; 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 September 29, 2008.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.