05-12297. Airworthiness Directives; Boeing Model 727 Series Airplanes

AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to supersede an existing airworthiness directive (AD) for certain Boeing Model 727 series airplanes. That AD currently requires repetitive visual inspections for cracking of the forward entry doorway forward frame and repair if necessary. That AD also provides an optional modification that constitutes terminating action. This proposed AD would require adding new post-repair and post-modification inspections for previously repaired or modified airplanes, mandating the optional modification, and adding airplanes to the applicability of the AD. This proposed AD is prompted by reports of cracking of the forward entry doorway forward frame of airplanes previously modified. We are proposing this AD to prevent the loss of the structural integrity of the forward entry doorway due to cracking of the frame at BS 303.9, and consequent cracking of the fuselage skin and rapid decompression of the airplane.

DATES:

We must receive comments on this proposed AD by August 8, 2005.

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.

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

You can examine the contents of this AD docket on the Internet at http://dms.dot.gov, or at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., room PL-401, on the plaza level of the Nassif Building, Washington, DC. This docket number is FAA-2005-21593; the directorate identifier for this docket is 2002-NM-328-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 written relevant data, views, or arguments regarding this proposed AD. Send your comments to an address listed under ADDRESSES. Include “Docket No. FAA-2005-21593; Directorate Identifier 2002-NM-328-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 our docket 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 can review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you can visit http://dms.dot.gov.

Examining the Docket

You can examine the AD docket 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 DMS receives them.

Discussion

On April 11, 1991, we issued AD 91-09-07, amendment 39-6982 (56 FR 18687, April 24, 1991), applicable to certain Boeing Model 727 series airplanes. That AD requires repetitive visual inspections for cracking of the forward entry doorway forward frame and repair if necessary. That AD also provides an optional modification that constitutes terminating action. That action was prompted by reports of cracking of the forward entry doorway forward frame of airplanes previously modified. We issued that AD to prevent loss of the structural integrity of the forward entry doorway.

Actions Since Existing AD Was Issued

Since we issued AD 91-09-07, we have received several reports indicating cracking found on certain frames of certain Boeing Model 727 series airplanes. The cracks were found on airplanes that had accomplished the optional terminating action specified in AD 91-09-07. Those airplanes had between 32,000 and 35,000 total flight cycles, and ranged between 0.25 inch and 0.50 inch long. The cracks initiated from the web cut-outs at stringer S-16L at Body Station (BS) 303.9, and were typically found during routine maintenance. Additionally, cracking was also reported on certain Model 727 series airplanes that were not included in the applicability of AD 91-09-07. The cracking is primarily attributed to cyclic fatigue loading at the frame web cut-outs. Cracking of the frames, if not corrected, could result in loss of the structural integrity of the forward entry doorway forward frame, and consequent cracking of the fuselage skin and rapid decompression of the airplane.

Related AD

On January 16, 1990, we issued AD 90-06-09, amendment 39-6488 (55 FR 8370, March 7, 1990), applicable to certain Boeing Model 727 series airplanes. That AD requires incorporation of certain structural modifications. That AD was prompted by reports of incidents involving fatigue cracking and corrosion in transport category airplanes that are approaching or have exceeded their design life goal.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin (ASB), 727-53A0153, Revision 7, dated August 14, 2003. For certain airplanes, the ASB describes procedures for accomplishing repetitive high frequency eddy current (HFEC) inspections and dimensional inspections to detect anomalies (e.g., minimum geometry requirements, jagged edges, chafing, nicks, or gouges) of the web cutouts at stringers S-15L and S-16L of the forward frame of the forward entry doorway. The ASB also describes repetitive HFEC inspections to detect cracking of the frame web, web assembly, and frame outer chord of the forward frame of the forward entry doorway, and repair procedures for cracking within certain limits. The ASB also specifies certain “optional” inspection methods to detect cracking (visual detailed, eddy current, penetrant, or X-Ray inspection). Additionally, the ASB describes procedures for an optional terminating modification that eliminates the need to perform the repetitive inspections. Accomplishing the actions specified in the service information is intended to adequately address the identified unsafe condition.

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 products of this same type design. Therefore, we are proposing this AD, which would supersede AD 91-09-07. This proposed AD would continue to require repetitive visual inspections of the forward frame of the forward entry doorway for cracks. For certain airplanes, this proposed AD also would require a one-time HFEC inspection for cracks and a one-time dimensional inspection for anomalies of the web cutouts at stringers S-15L and S-16L. The proposed AD also would require repetitive HFEC inspections for cracking of the frame web and outer chord between stringer S-14L and the floor, and corrective action if necessary. Since cracking has been reported on airplanes not specified in the previous AD, we have added those airplanes to the applicability of this proposed AD. Additionally, the proposed AD would require accomplishing the modification for airplanes that have not accomplished the previous optional modification. The modification terminates the repetitive inspection requirements of the proposed AD. This proposed AD would require you to use the service information described previously to perform these actions, except as discussed under “Differences Between the Proposed AD and the Service Bulletin.”

Differences Between the Proposed AD and the Service Bulletin

Although Boeing ASB 727-53A0153, Revision 7, dated August 14, 2003, specifies accomplishing repetitive dimensional inspections of the web cutouts, this proposed AD would require those specific inspections to be accomplished only one time, as well as applicable corrective actions. We have determined that, since the purpose of the inspection is to resolve any structural interference of static structure, it need not be inspected again. Although the Boeing ASB also describes certain “optional” inspections in lieu of certain HFEC inspections, this proposed AD would require accomplishing the HFEC inspections. (Compliance times in Revision 7 are based on performing the HFEC inspections, and no compliance times were specified for the “optional” inspections.) Operators should also note that the Boeing ASB specifies a grace period for the compliance time of one year. However, this proposed AD specifies a grace period of 1,800 flight cycles because cyclic loading is the mechanism of crack propagation, rather than calendar time. Additionally, where the ASB specifies that operators may contact the manufacturer for disposition of certain repair conditions, this proposed AD would require operators to repair those conditions per a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA. The differences between the ASB and the proposed AD have been coordinated with the manufacturer.

Change to Existing AD

This proposed AD would retain certain requirements of AD 91-09-07. Since AD 91-09-07 was issued, the AD format has been revised, and certain paragraphs have been rearranged. As a result, the corresponding paragraph identifiers have changed in this proposed AD, as listed in the following table:

Revised Paragraph Identifiers

Requirement in AD 91-09-07	Corresponding requirement in this proposed AD
Paragraph (a)	Paragraph (f).
Paragraph (b)	Paragraph (g).

Costs of Compliance

There are about 1,038 Model 727 series airplanes of the affected design in the worldwide fleet. This proposed AD would affect about 616 airplanes of U.S. registry.

The actions that are required by AD 91-09-07 and retained in this proposed AD take about 58 work hours per airplane, at an average labor rate of $65 per work hour. Based on these figures, the estimated cost of the currently required actions is $3,770 per airplane, per inspection cycle.

The new inspections would take about 5 to 6 work hours per airplane, depending on the airplane configuration, at an average labor rate of $65 per work hour. Based on these figures, the estimated cost of the new actions specified in the new inspections proposed in this AD is between $325 and $390 per airplane, per inspection cycle.

The terminating action proposed by this AD would affect airplanes on which the previous optional modification has not been accomplished, and would take between 14 and 40 work hours per airplane, depending on the airplane configuration, at an average labor rate of $65 per work hour. Required parts for proposed terminating modification would cost between $877 and $6,749 per airplane, depending on the airplane configuration. Based on these figures, the estimated cost of the terminating action specified in this proposed AD is between $1,787 and $9,349 per airplane.

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. 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 FAA amends § 39.13 by removing amendment 39-6982 (56 FR 18687, April 24, 1991) and adding the following new airworthiness directive (AD):

Boeing: Docket No. FAA-2005-21593; Directorate Identifier 2002-NM-328-AD.

Comments Due Date

(a) The Federal Aviation Administration must receive comments on this airworthiness directive (AD) action by August 8, 2005.

Affected ADs

(b) This AD supersedes AD 91-09-07, amendment 39-6982 (56 FR 18687, April 24, 1991).

Applicability

(c) This AD applies to Model 727 series airplanes, certificated in any category; as identified in Boeing Alert Service Bulletin 727-53A0153, Revision 7, dated August 14, 2003.

Unsafe Condition

(d) This AD was prompted by reports of cracking of the forward frame of the forward entry doorway of airplanes previously modified. We are issuing this AD to prevent the loss of the structural integrity of the forward entry doorway due to cracking at Body Station (BS) 303.9, and consequent cracking of the fuselage skin and 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.

Restatement of Certain Requirements of AD 91-09-07

(f) For airplanes listed in Boeing Service Bulletin 727-53-0153, Revision 5, dated December 14, 1989: Visually inspect the forward entry doorway frame for cracks in accordance with Boeing Service Bulletin 727-53-0153, dated February 1, 1980, or Revisions 1 though 5, at the earlier of the times indicated in subparagraphs (a)(1) or (a)(2) of this AD. Repeat the inspection at intervals not to exceed 3,700 landings until accomplishment of the one-time high frequency eddy current (HFEC) inspection for cracking and the one-time dimensional inspection for anomalies required by paragraph (i) of this AD, or the one-time dimensional inspection for anomalies and the initial HFEC inspection for cracking of the forward frame of the forward entry doorway at BS303.9 specified in paragraph (h) of this AD, as applicable.

(1) Within the next 1,850 landings after March 11, 1983 (the effective date of AD 83-03-01, amendment 39-4561), or prior to accumulating a total of 25,000 landings, whichever occurs later; or

(2) Within the next 1,850 landings after May 16, 1986 (the effective date of AD 83-03-01 R1, amendment 39-5283), or prior to accumulating a total of 15,000 landings, whichever occurs later.

(g) For airplanes modified in accordance with Boeing Service Bulletin 727-53-0153, dated February 1, 1980; through Revision 4, dated November 8, 1985; conduct the inspections described in paragraph (f) of this AD prior to the accumulation of 10,000 landings after the modification or within the next 3,700 landings after May 28, 1991 (the effective date of AD 91-09-07), whichever occurs later. Repeat the inspection at intervals not to exceed 3,700 landings until accomplishment of the one-time HFEC inspection for cracking and the one-time dimensional inspection for anomalies required by paragraph (i) of this AD, or the one-time dimensional inspection for anomalies and the initial HFEC inspection for cracking of the forward frame of the forward entry doorway at BS303.9 specified in paragraph (h) of this AD, as applicable.

New Requirements of This AD

Repetitive Inspections for Certain Airplanes

(h) For Group l airplanes as defined by Boeing Alert Service Bulletin (ASB) 727-53A0153, Revision 7, dated August 14, 2003, with the exception of certain Group 1 airplanes specified in paragraph (i) of this AD: Perform a one-time dimensional inspection for anomalies (e.g., minimum dimension requirements, jagged edges, chaffing, nicks, or gouges) of the web cutouts at stringers S-15 and S-16, and HFEC inspections for cracking of the forward frame of the forward entry doorway at BS 303.9; in accordance with Figure 1 of the Accomplishment Instructions of Revision 7 of the ASB at the times specified in paragraph (h)(1) or (h)(2) of this AD, as applicable. With the exception of the one-time dimensional inspection (Step 1 of Figure 1) of the web cutouts at S-15L and S-16L, repeat the HFEC inspections for cracking of the forward frame of the forward entry doorway at BS 303.9 at intervals not to exceed 3,700 flight cycles until the requirements of paragraph (l) of this AD have been accomplished.

(1) For Group 1 airplanes that have not been modified or repaired in accordance with any issue of the service bulletin through Revision 7 inclusive: Perform the inspection before the accumulation of 15,000 total flight cycles, or within 1,800 flight cycles after the effective date of this AD, whichever occurs later.

(2) For Group 1 airplanes that have been modified in accordance with Repair Kit 65C20303-1 in accordance with any issue of the service bulletin through Revision 4 inclusive: Perform the inspection before the accumulation of 10,000 flight cycles after the modification, or within 1,800 flight cycles after the effective date of this AD, whichever occurs later.

One-Time Inspections and Terminating Actions for Certain Other Airplanes

(i) For Group 1 airplanes, as defined by Boeing ASB 727-53A0153, Revision 7, dated August 14, 2003, that have been modified in accordance with Revision 5 or 6 of Boeing Service Bulletin 727-53-0153, or that have been repaired in accordance with Boeing Repair Kits 65C20303-8 or -25 as specified in Revision 2 through Revision 6 inclusive of the service bulletin: Within 4,500 flight cycles after the effective date of this AD, do a one-time HFEC for cracking and a dimensional inspection for any anomaly (e.g., minimum dimension requirements, jagged edges, chaffing, nicks or gouges) of the web cutouts at stringers S-15L and S-16L of the forward frame of the forward entry doorway at BS 303.9, in accordance with Step 1 and Step 2 of Figure 1 of the Accomplishment Instructions of Revision 7 of the ASB. For these airplanes, accomplishment of the HFEC, dimensional inspections, and any applicable corrective actions, constitute terminating actions for all the repetitive inspection requirements of this AD.

Inspections for Group 2 Airplanes

(j) For Group 2 airplanes, as defined by Boeing ASB 727-53A0153, Revision 7, dated August 14, 2003, that have not been modified or repaired in accordance with Revision 7 of the service bulletin: Before the accumulation of 17,000 total flight cycles, or within 4,500 flight cycles after the effective date of this AD, whichever occurs later, perform a one-time dimensional inspection for anomalies (e.g., minimum dimension requirements, jagged edges, chafing, nicks, or gouges) of the web cutouts at stringers S-15 and S-16, and HFEC inspections for cracking of the forward frame of the forward entry doorway at BS 303.9; in accordance with Figure 2 of the Accomplishment Instructions of Revision 7 of the ASB. With the exception of the one-time dimensional inspection (Step 1 of Figure 2) of the web cutouts at S-15L and S-16L, repeat the HFEC inspections for cracking of the forward frame of the forward entry doorway at BS 303.9 at intervals not to exceed 3,700 flight cycles until the requirements of paragraph (l) of this AD have been accomplished.

Corrective Actions

(k) If any cracking is detected during any HFEC inspection, or any anomaly is detected during any dimensional inspection required by this AD: Before further flight, accomplish the actions in paragraph (k)(1) or (k)(2) of this AD, as applicable.

(1) For any cracking that is within the limits specified in the Accomplishment Instructions of Boeing ASB 727-53A0153, Revision 7, dated August 14, 2003: Repair the cracking in accordance with the Revision 7 of the ASB.

(2) For any cracking that is outside the limits specified in the Accomplishment Instructions of the ASB or for any anomaly that is detected during any dimensional inspection required by this AD: Repair in accordance with a method approved by the Manager, Seattle Aircraft Certification (ACO), FAA; or in accordance with data meeting the type certification basis of the airplane approved by an Authorized Representative for the Boeing Delegation Option Authorization Organization who has been authorized by the FAA 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 reference this AD.

Terminating Actions for Certain Airplanes

(l) For airplanes specified in paragraph (l)(1) or (l)(2) of this AD: Prior to the accumulation of 60,000 total flight cycles, or within 1,800 flight cycles after the effective date of this AD, whichever occurs later, perform the inspections specified in Figure 1 or Figure 2, as applicable, of Revision 7 of Boeing ASB 727-53A0153, dated August 14, 2003, and as specified by paragraph (h) or (j) of this AD, as applicable. Before further flight, following the inspections, modify the forward frame in accordance with the Accomplishment Instructions of Revision 7 of the ASB. Concurrent accomplishment of the inspections and modification constitutes terminating action for the repetitive inspections required by this AD.

(1) Group 1 airplanes that have not been modified or repaired in accordance with Boeing Repair Kits 65C20303-8 or -25, as specified in Boeing Service Bulletin 727-53-0153, Revision 2, dated December 3, 1982; Revision 3, dated June 17, 1983; Revision 4, dated November 8, 1985; Revision 5, dated December 14, 1989; Revision 6, dated August 27, 1992; or Revision 7 of Boeing ASB 727-53A0153, dated August 14, 2003.

(2) Group 2 airplanes that have not been repaired or modified in accordance with Revision 7 of Boeing ASB 727-53A0153, dated August 14, 2003.

Note 1:

Accomplishment of the terminating actions specified in paragraphs (i) or (l) of this AD does not relieve the operator of responsibility to comply with the inspection requirements of the operator's standard structural maintenance program.

Alternative Methods of Compliance (AMOCs)

(m)(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) 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 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.

(3) AMOCs approved previously in accordance with AD 91-09-07, amendment 39-6982, are approved as AMOCs with the corresponding requirements and provisions of this AD.

(4) Accomplishment of the actions specified in paragraph (l) of this AD constitutes an AMOC with paragraph (A) of AD 90-06-09, amendment 39-6488, only for the structural modification requirements specified in Boeing Service Bulletin 727-53-0153, Revision 4 or earlier revisions.

Issued in Renton, Washington, on June 10, 2005.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.