05-24052. Airworthiness Directives; Boeing Model 727, 727C, 727-100, and 727-100C 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 all Boeing Model 727, 727C, 727-100, and 727-100C series airplanes. This proposed AD would require repetitive inspections for cracks in the body skin and bear strap at the upper and lower hinge cutouts of the mid-cabin galley doorway, along the upper fastener row of the stringer 14R lap splice, and in the doorstop fitting adjacent to the upper hinge cutout; and corrective action if necessary. This proposed AD also provides for optional terminating action for certain inspections. This proposed AD results from reports of skin and bear strap cracking at the upper and lower hinge cutout and along the upper fastener row of the stringer 14R lap splice, and cracking in the doorstop fitting adjacent to the upper hinge cutout. There are also reports of cracking on airplanes previously modified to prevent such cracking. We are proposing this AD to find and fix fatigue cracking of the fuselage, which could result in reduced structural integrity and consequent rapid decompression of the airplane.

DATES:

We must receive comments on this proposed AD by January 30, 2006.

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.
• 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.

Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207 for the service information identified in this proposed AD.

FOR FURTHER INFORMATION CONTACT:

Daniel F. Kutz, Aerospace Engineer, Airframe Branch, ANM-120S, 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. Include the docket number “FAA-2005-23313; Directorate Identifier 2005-NM-111-AD” at the beginning 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 received 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 Web site, 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 may review DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you may visit http://dms.dot.gov.

Examining the Docket

You may 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 Docket Management System receives them.

Discussion

We have received a report indicating that a 0.73 inch long skin crack was found at the upper corner of the upper hinge cutout of the mid-cabin galley doorway on a Model 727 series airplane. The crack was similar to cracking found and fixed previously on other Model 727 series airplanes. Further inspections revealed a 1 inch crack in the bear strap, and cracks in the doorstop fitting adjacent to the upper hinge cutout. Investigation of the Model 727 airplane history revealed reports of 15 skin cracks having lengths up to 2 inches on 12 airplanes with between 23,400 and 54,600 flight cycles. Of the reported skin cracks, there were three reports of associated bear strap crack indications on three airplanes. One of the airplanes also had a cracked door stop fitting adjacent to the upper hinge cutout. Five cracks on five of the airplanes were located near the lower hinge cutout in the upper row of fasteners of the skin lap joint at stringer 14R. Some of the cracks were found on airplanes that were modified in service by increasing the radius of the corners of the body skin at the hinge cutouts, and installing doublers at the high cutouts; and airplanes on which the equivalent modification was done in production. These modifications did not prevent the cracking. This cracking, if not corrected, could result in reduced structural integrity and consequent rapid decompression of the airplane.

Other Relevant Rulemaking

On January 16, 1990, the FAA issued AD 90-06-09, amendment 39-6488 (55 FR 8370, March 7, 1990), applicable to certain Boeing Model 727 series airplanes, which requires the incorporation of certain structural modifications specified by Boeing Document No. D6-54860, Revision C, dated December 11, 1989, “Aging Airplane Service Bulletin Structural Modification Program—Model 727.” That Boeing document references numerous Boeing service bulletins that specify various modification actions that are mandated by AD 90-06-09. The actions required by that AD are intended to prevent a degradation in the structural capabilities of the affected airplanes, which could result in structural failure. That action also reflects the FAA's decision that long-term continued operational safety would be ensured by actual modification of the airframe rather than repetitive inspection. One of the structural modifications in that AD is of the body skin of the mid-galley door hinge cutouts done in accordance with Boeing Service Bulletin 727-53-0054, Revision 1, dated November 16, 1989. Service Bulletin 727-53-0054 describes procedures for inspection of the forward upper and lower corners at the hinge cutouts of the mid-cabin galley doorway for cracks in the body skin, a modification to the corners of the hinge cutouts, and installation of doublers at the hinge cutouts of the mid-cabin galley doorway. (Service Bulletin 727-53-0054 is referenced in Boeing Document No. D6-54860, Revision C, as one source of service information for accomplishing the actions.)

On May 12, 1998, we issued AD 98-11-03, amendment 39-10530 (63 FR 27455, May 19, 1998), applicable to all Boeing Model 727 series airplanes. (A correction of that AD was published in the Federal Register as AD 98-11-03 R1, amendment 39-10983, on December 30, 1998 (64 FR 989, January 7, 1999).) That AD requires that the FAA-approved maintenance inspection program be revised to include inspections of Structurally Significant Items (SSI) based on damage tolerance analysis. That AD also allows operators not to change their programs if they determine that the existing inspections are effective for the new or affected SSI.

On April 19, 2000, we issued AD 2000-08-19, amendment 39-11705 (65 FR 25278, May 1, 2000), applicable to certain Boeing Model 727 and 727C series airplanes. That AD requires one-time inspections of the exterior body skin located at the forward corners of the mid-galley door hinge cutouts to detect cracking, and corrective actions if necessary. That AD also requires modification of the body skin of the mid-galley door hinge cutouts. Boeing Service Bulletin 727-53-0054, Revision 1, dated November 16, 1989, was referenced in that AD as the appropriate source of service information for accomplishing the required actions. The service bulletin describes procedures for inspection of the forward upper and lower corners at the hinge cutouts of the mid-cabin galley doorway for cracks in the body skin, a modification to the corners of the hinge cutouts, and installation of doublers at the hinge cutouts of the mid-cabin galley doorway.

Since issuance of AD 90-06-09 and AD 2000-08-19, we have determined that the actions required by those ADs pertaining to the mid-galley door hinge cutouts are not adequate to prevent cracking in this area. The subject cracking of the bear strap, door stop fitting, and skin lap joint area is bigger than the area specified in the actions required by AD 90-06-09 and AD 2000-08-19; therefore, the cracks may have been undetected at the time a modification or repair was done. We have determined that additional work is necessary for airplanes on which a modification or repair required by AD 90-06-09 or AD 2000-08-19 was done without additional inspections recommended in the service bulletin referenced in this proposed AD.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin 727-53A0228, dated March 24, 2005. The service bulletin describes procedures for repetitive inspections for any cracks, including stop-drilled, trimmed-out, or repaired cracks, in the body skin and bear strap at the upper and lower hinge cutouts of the mid-cabin galley doorway; along the upper fastener row of the stringer 14R lap splice; and in the doorstop fitting adjacent to the upper hinge cutout; and corrective action if necessary. The types of inspections are detailed and special detailed inspections'which include surface high frequency eddy current (HFEC), open-hole HFEC, and fluorescent dye penetrant inspections. If a modification or repair required by AD 90-06-09 or AD 2000-08-19 was done, the service bulletin describes procedures for removing the doublers before accomplishing the inspections. Corrective action includes replacing any cracked doorstop fitting with a new fitting, and repairing cracks in the skin or bear strap per repair instructions from Boeing. The service bulletin also specifies that replacement of a door stop fitting with a new door stop fitting made of 7075 material eliminates the need to repeat the inspection of that stop fitting. Door stop fittings having part number 65-23674-7 are made of 7075 material and do not need to be inspected. The service bulletin also recommends providing the details of any crack findings to Boeing for repair instructions.

The compliance times for the inspections specified in Table 1 of paragraph 1.E. “Compliance” of the service bulletin are to be accomplished before the accumulation of 20,000 total flight cycles or within 2,000 flight cycles after the effective date of the AD, whichever is later; the repetitive interval is every 6,000 flight cycles.

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 Proposed AD and the Service Bulletin.”

Difference Between the Proposed AD and the Service Bulletin

Paragraph 1.F. of the service bulletin specifies, “Any cracks found must be repaired, before further flight, in accordance with a method approved by the Manager, Seattle ACO, FAA, Transport Airplane Directorate; or in accordance with data meeting the type certification basis of the airplane, approved by a Boeing Company Authorized Representative who has been authorized by the Manager, Seattle ACO, to make such findings.” However, the Accomplishment Instructions of the alert service bulletin specify to contact the manufacturer for instructions on how to repair certain conditions. Therefore, we provide the following clarification: Where the Accomplishment Instructions of the alert service bulletin specify to provide the details of any crack findings to Boeing for repair instructions, this proposed AD would require repairing those conditions in one of the following ways:

• Using a method we approve; or
• Using data 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.

Interim Action

We consider this proposed AD interim action. The manufacturer is currently developing a modification that will address the unsafe condition identified in this proposed AD. Once this modification is developed, approved, and available, we may consider additional rulemaking.

Costs of Compliance

There are about 232 airplanes of the affected design in the worldwide fleet. This proposed AD would affect about 123 airplanes of U.S. registry. The following table provides the estimated costs for U.S. operators to comply with this proposed AD.

Estimated Costs

Airplane group	Work hours	Average hourly labor rate	Cost per airplane
Group 1, Configuration 1	10	$65	$650
Group 1, Configuration 2	10	65	650
Group 1, Configuration 3	9	65	585
Group 2	9	65	585

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-2005-23313; Directorate Identifier 2005-NM-111-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by January 30, 2006.

Affected ADs

(b) This AD is related to AD 98-11-03, amendment 39-10530, as corrected by AD 98-11-03 R1, amendment 39-10983.

Applicability

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

Unsafe Condition

(d) This AD results from reports of skin and bear strap cracking at the upper and lower hinge cutout and along the upper fastener row of the stringer 14R lap splice, and cracking in the doorstop fitting adjacent to the upper hinge cutout. There are also reports of cracking on airplanes previously modified to prevent such cracking. We are issuing this AD to find and fix fatigue cracking of the fuselage, which could result in reduced structural integrity and consequent rapid decompression 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.

Service Bulletin Reference

(f) The term “alert service bulletin,” as used in this AD, means Boeing Alert Service Bulletin 727-53A0228, dated March 24, 2005.

Repetitive Inspections

(g) Accomplish the applicable inspections for any cracks (including stop-drilled, trimmed-out, or repaired cracks) in the body skin and bear strap at the upper and lower hinge cutouts of the mid-cabin galley doorway, along the upper fastener row of the stringer 14R lap splice, and in the doorstop fitting adjacent to the upper hinge cutout, as specified in Table 1 of paragraph 1.E. “Compliance” of the alert service bulletin. Accomplish the inspections at the applicable compliance time specified in Table 1 of paragraph 1.E.; except, where Table 1 specifies a compliance time relative to the date of the release of the alert service bulletin, this AD requires compliance relative to the effective date of this AD. Accomplish the inspections by doing all the applicable actions specified in the Accomplishment Instructions of the alert service bulletin. Inspections of door stop fittings made of 7075 material having part number (P/N) 65-23674-7 are not required. Repeat the applicable inspection at the applicable repeat interval specified in Table 1 of paragraph 1.E. of the alert service bulletin.

Corrective Action

(h) If any cracking is found during any inspection required by paragraph (g) of this AD, repair the cracking and repeat the inspection at the applicable compliance time specified in Table 1 of paragraph 1.E. “Compliance” of the alert service bulletin. Do the repair by doing all the applicable actions specified in the Accomplishment Instructions of the alert service bulletin. Where the alert service bulletin specifies to report cracking to Boeing for repair instructions: Before further flight, repair any cracking according to a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA; or using a method approved in accordance with paragraph (j)(3) of this AD.

Optional Terminating Action

(i) Replacement of the doorstop fitting with a fitting made of 7075 material having P/N 65-23674-7, in accordance with the Accomplishment Instructions of the alert service bulletin, terminates the repetitive inspections of that fitting, as required by paragraph (g) of this AD.

Alternative Methods of Compliance (AMOCs)

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

(2) The inspection methods specified in Figures 9 through 12 of the alert service bulletin, as required by paragraph (g) of this AD, at the thresholds and intervals specified in paragraph (g), are approved as a method of compliance (MOC) to paragraph (b) of AD 98-11-03 and 98-11-03 R1, for the inspections of Structurally Significant Item F-16A, Supplemental Structural Inspection Document D6-48040-1, affected by the repair or modification. The MOC applies only to the areas inspected in accordance with Boeing Alert Service Bulletin 727-53A0228, dated March 24, 2005. All provisions of AD 98-11-03 R1 that are not specifically referenced in this paragraph remain fully applicable and must be complied with.

(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.

(4) Before using any AMOC approved in accordance with 14 CFR 39.19 on any airplane to which the AMOC applies, notify the appropriate principal inspector in the FAA Flight Standards Certificate Holding District Office.

Issued in Renton, Washington, on December 8, 2005.

Michael Zielinski,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.