E8-19137. Airworthiness Directives; Boeing Model 727 Airplanes

AGENCY:

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

ACTION:

Final rule.

SUMMARY:

The FAA is superseding an existing airworthiness directive (AD), which applies to certain Boeing Model 727 series airplanes. That AD currently requires repetitive inspections to detect cracks and loose brackets of the elevator rear spar, and corrective actions if necessary. The existing AD also provides for an optional terminating action for the repetitive inspections. This new AD reduces the repetitive intervals of the inspections, mandates the previously optional terminating action for the repetitive inspections, and no longer allows stop-drilling. This AD results from new reports of cracks, elongated fastener holes, and loose fittings of the elevator rear spar. We are issuing this AD to prevent cracking of the elevator rear spar at the tab hinge locations, which could cause excessive freeplay of the elevator control tab and possible tab flutter, and consequent loss of control of the airplane.

DATES:

This AD becomes effective October 2, 2008.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in the AD as of October 2, 2008.

On April 22, 1996 (61 FR 11529, March 21, 1996), the Director of the Federal Register approved the incorporation by reference of Boeing Service Bulletin 727-55-0089, dated June 29, 1995.

ADDRESSES:

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 AD, the regulatory evaluation, any comments received, and other information. The address for the Docket Office (telephone [phone]) is the Document Management Facility, U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.

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:

Discussion

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that supersedes AD 96-06-05, amendment 39-9542 (61 FR 11529, March 21, 1996). The existing AD applies to certain Boeing Model 727 series airplanes. That NPRM was published in the Federal Register on November 23, 2007 (72 FR 65678). That NPRM proposed to require repetitive inspections to detect cracks and loose brackets of the elevator rear spar, and corrective actions if necessary. The NPRM also proposed to reduce the repetitive intervals of the inspections, mandate the previously optional terminating action for the repetitive inspection, and no longer allow stop-drilling.

Comments

We provided the public the opportunity to participate in the development of this AD. We have considered the comments that have been received on the NPRM.

Request To Extend Compliance Time for Terminating Action (Spar Replacement)

Several commenters (Boeing, Champion Air, DHL, FedEx, and ReadyJetGo) request that we extend the compliance time (18 months) for the terminating action specified in the NPRM. Boeing, Champion Air, and ReadyJetGo request an extension from 18 months to 24 months; DHL requests 36 months; and FedEx requests 36 months or 3,600 flight hours, whichever occurs later. The commenters request the extension for the following reasons:

• The parts supply is limited. Champion Air and FedEx note that Boeing does not have any complete kits available. Boeing estimates it will not have any complete kits available until October 1, 2008.
• An extension of the compliance time would permit the spar replacement to be done during most operators' scheduled C-check maintenance intervals, and at a maintenance facility (FedEx), which is preferred due to the work-hours and skills involved with the modification.
• The number of cracks found during accomplishment of inspections required by AD 96-06-05 is low. Champion Air notes it has had zero findings from 89 inspections. DHL reports 3 findings. FedEx has documented 7 findings from 991 inspections.
• The repair of stop-drilled cracks in combination with the current inspections will maintain fleet safety during this extended time period.

We partially agree with the commenters' request to extend the compliance time for the terminating replacement. We have determined that 24 months for the spar replacement will not adversely affect safety. However, in considering the other factors to extend the compliance time (data submitted, maintenance schedule differences, stop-drilling as a suggested repair method), we found that those factors were not sufficient to extend the compliance time further.

In developing an appropriate compliance time for this action, we considered the urgency associated with the subject unsafe condition, the availability of required parts, and the practical aspect of accomplishing the required action within a period of time that corresponds to the normal scheduled maintenance for most affected operators. We have confirmed with Boeing that there is a parts supply problem. We have determined that we will extend the compliance time for the spar replacement from 18 to 24 months as recommended by the manufacturer due to the parts supply problem. We have revised paragraph (q) of this AD accordingly.

Request To Change From Calendar-Based to Use-Based Compliance Time for Terminating Replacement

Champion Air notes that in the “Differences Between the Proposed AD and Service Information” section in the NPRM, we stated that a calendar time is not appropriate for addressing problems associated with fatigue. However, for the terminating replacement, the NPRM specifies a compliance time in terms of months instead of hours or cycles.

We understand the comment and while Champion Air does not request a specific change, we consider that clarification is appropriate. While most initial and all repeat inspection times specified in this AD are given in flight hours because the inspections are intended to find problems associated with fatigue issues, the terminating action (replacement) is intended to ensure that there is not an undue reliance on inspections to maintain the safety of the fleet and to ensure that the terminating action is accomplished within an appropriate time period. We have not changed the AD in this regard.

Request To Lengthen Inspection Intervals

DHL requests that we lengthen the repetitive inspection interval from 1,600 flight hours to 2,400 flight hours so that the intervals match the heavy maintenance intervals in their approved maintenance program.

We do not agree with the commenter's request to lengthen the inspection interval. In light of the inspection results, and the analysis and recommendation of the airplane manufacturer, we have determined that 1,600 flight hours is an appropriate repetitive inspection interval. However, according to the provisions of paragraph (s) of this AD, we might approve requests to adjust the compliance time if the request includes data that prove the new compliance time would provide an acceptable level of safety. We have not changed the AD in this regard.

Request for Further Clarification on Effect of Human Factors on Repetitive Inspections

FedEx requests further clarification of why the repetitive inspections required by AD 96-06-05 are no longer considered adequate. Such information could be used to better evaluate FedEx's current maintenance program. FedEx notes that the NPRM states “human factors associated with numerous continual inspections” have led to an emphasis on design change.

As discussed in the “Actions Since Existing AD Was Issued” section of the NPRM, which is not repeated in this final rule, we determined that the existing long-term repetitive inspections do not provide an acceptable level of safety. This determination, in part, is based on a better understanding of the human factors element that errors do occur when associated with numerous continual inspections. This has led us to consider placing less emphasis on inspections and more emphasis on design improvements. Therefore, for consistency with our policy, we have determined that it is necessary to require modifications to adequately address the identified unsafe condition of this AD rather than continued reliance on inspections.

In regard to FedEx's request for further information to assist the evaluation of their maintenance program, we have determined that this request would be best posed to their FAA Principal Maintenance Inspector. We have not changed the AD in this regard.

Conclusion

We have carefully reviewed the available data, including the comments that have been received, and determined that air safety and the public interest require adopting the AD with the change described previously. We have determined that this change will neither increase the economic burden on any operator nor increase the scope of the AD.

Costs of Compliance

There are about 815 airplanes of the affected design in the worldwide fleet. The following table provides the estimated costs for U.S. operators to comply with this AD.

Estimated Costs

Action	Work hours	Average labor rate per hour	Parts	Cost per airplane	Number of U.S.-registered airplanes	Fleet cost
Detailed Inspection (required by AD 96-06-05)	17	$80	None	$1,360, per inspection cycle	448	$609,280, per inspection cycle.
Terminating action (new action)	416	$80	$14,975	$48,255	448	$21,618,240

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 AD will not have federalism implications under Executive Order 13132. This AD will 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 this AD:

(1) Is not a “significant regulatory action” under Executive Order 12866;

(2) Is not a “significant rule” under 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 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
• Incorporation by reference
• Safety

Adoption of the Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 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 removing amendment 39-9542 ( 61 FR 11529, March 21, 1996) and by adding the following new airworthiness directive (AD):

2008-17-14 Boeing: Amendment 39-15652. Docket No. FAA-2007-0223; Directorate Identifier 2007-NM-156-AD.

Effective Date

(a) This AD becomes effective October 2, 2008.

Affected ADs

(b) This AD supersedes AD 96-06-05.

Applicability

(c) This AD applies to Boeing Model 727, 727C, 727-100, 727-100C, 727-200, and 727-200F series airplanes, certificated in any category, as identified in Boeing Service Bulletin 727-55-0089, Revision 1, dated March 2, 2000.

Unsafe Condition

(d) This AD results from new reports of cracks, elongated fastener holes, and loose fittings of the elevator rear spar. We are issuing this AD to prevent cracking of the elevator rear spar at the tab hinge locations, which could cause excessive freeplay of the elevator control tab and possible tab flutter, and consequent loss of control 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.

Requirements of AD 96-06-05

Repetitive Inspections and Follow-On Actions

(f) For airplanes on which the modification or repair described in Boeing Service Bulletin 727-55-0085, dated August 31, 1984 (specified as terminating action in AD 84-22-02, amendment 39-4951), has not been accomplished and the repetitive inspections required by AD 84-22-02 have not been initiated: Prior to the accumulation of 8,000 total flight hours since date of manufacture, or within 300 flight hours after April 22, 1996 (the effective date of AD 96-06-05), whichever occurs later, perform a detailed inspection to detect cracks and loose hinge brackets of the elevator rear spar in the area along the upper and lower edges at the shear plate, in accordance with Boeing Service Bulletin 727-55-0089, dated June 29, 1995. Then accomplish the follow-on actions (i.e., repetitive inspections, stop-drilling, modification) in accordance with that service bulletin, at the times specified as follows:

Note 1:

For the purposes of this AD, a detailed inspection is: “An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirror, magnifying lenses, etc., may be necessary. Surface cleaning and elaborate procedures may be required.”

Note 2:

AD 84-22-02 pertains to the one-piece elevator rear spar.

(1) Repeat the detailed inspection thereafter at intervals not to exceed 1,600 flight hours.

(2) If any crack is detected and stop-drilled as a result of any inspection required by this paragraph, accomplish the requirements of paragraph (l) of this AD, except as provided by paragraph (o) of this AD, at the times specified in paragraph (l) of this AD.

Repetitive Inspections and Follow-On Actions

(g) For airplanes on which the modification or repair described in Boeing Service Bulletin 727-55-0085, dated August 31, 1984 (specified as terminating action in AD 84-22-02), has not been accomplished and the repetitive inspections required by AD 84-22-02 have been initiated: Accomplish either paragraph (g)(1) or (g)(2) of this AD, as applicable.

(1) If no crack has been detected as a result of inspections required by AD 84-22-02: Within 1,600 flight hours after the last inspection required by that AD, perform a detailed inspection to detect cracks and loose brackets of the elevator rear spar in the area along the upper and lower edges at the shear plate, in accordance with the Boeing Service Bulletin 727-55-0089, dated June 29, 1995. Accomplish follow-on actions (i.e., repetitive inspection, stop-drilling, modification) in accordance with that service bulletin, except as provided by paragraph (o) of this AD, at the times specified as follows:

(i) Repeat the detailed inspection thereafter at intervals not to exceed 1,600 flight hours.

(ii) If any crack is detected and stop-drilled as a result of any inspection required by this paragraph, accomplish the requirements of paragraph (l) of this AD, except as provided by paragraph (o) of this AD, at the times specified in paragraph (l) of this AD.

(2) If any crack has been stop-drilled in accordance with AD 84-22-02, accomplish the requirements of paragraph (l) of this AD, except as provided by paragraph (o) of this AD, at the times specified in paragraph (l) of this AD.

(h) For airplanes on which the modification or repair described in Boeing Service Bulletin 727-55-0085, dated August 31, 1984 (specified as terminating action in AD 84-22-02, amendment 39-4951), has been accomplished: Within 4,000 flight hours after April 22, 1996, perform a detailed inspection to detect cracks and loose hinge brackets of the elevator rear spar in the area along the upper and lower edges at the shear plate, in accordance with Boeing Service Bulletin 727-55-0089, dated June 29, 1995. Accomplish follow-on actions (i.e., repetitive inspections, stop-drilling, modification) in accordance with that service bulletin, except as provided by paragraph (o) of this AD, at the times specified as follows:

(1) Repeat the detailed inspection thereafter at intervals not to exceed 4,000 flight hours, except as provided by paragraph (n) of this AD.

(2) If any crack is detected and stop-drilled as a result of any inspection required by this paragraph, accomplish the requirements of paragraph (l) of this AD, except as provided by paragraph (o) of this AD, at the times specified in paragraph (l) of this AD.

(i) For airplanes on which the modification or repair described in Boeing Service Bulletin 727-55-087, dated June 20, 1986 (specified as terminating action in AD 87-24-03, amendment 39-5769), has not been accomplished and the repetitive inspections required by AD 87-24-03 have not been initiated: Accomplish the requirements of paragraph (i)(1) of this AD at the earliest of the times specified in paragraph (i)(2) of this AD.

Note 3:

AD 87-24-03 pertains to the two-piece elevator rear spar.

(1) Perform a detailed inspection to detect cracks and loose hinge brackets of the elevator rear spar in the area along the upper and lower edges at the shear plate, at the earliest of the times specified in paragraph (i)(2) of this AD, and in accordance with Boeing Service Bulletin 727-55-0089, dated June 29, 1995. Accomplish follow-on actions (i.e., repetitive inspection, stop-drilling, modification) in accordance with that service bulletin, at the times specified as follows:

(i) Repeat the detailed inspection thereafter at intervals not to exceed 4,000 flight hours, except as provided by paragraph (n) of this AD.

(ii) If any crack is detected and stop-drilled as a result of any inspection required by this paragraph, accomplish the requirements of paragraph (l) of this AD, except as provided by paragraph (o) of this AD, at the times specified in paragraph (l) of this AD.

(2) Accomplish the initial detailed inspection required by paragraph (i)(1) of this AD at the earliest of the following times:

(i) Prior to the accumulation of 27,000 total flight hours since date of manufacture, or within 4,000 flight hours after December 24, 1987 (the effective date of AD 87-24-03), whichever occurs later; or

(ii) Prior to the accumulation of 12,000 total flight hours since date of manufacture, or within 4,000 flight hours after April 22, 1996, whichever occurs later; or

(iii) Prior to the accumulation of 27,300 total flight hours since date of manufacture, or within 300 flight hours after April 22, 1996, whichever occurs later.

(j) For airplanes on which the modification or repair described in Boeing Service Bulletin 727-55-087, dated June 20, 1986 (specified as terminating action in AD 87-24-03), has not been accomplished and the repetitive inspections required by AD 87-24-03 have been initiated: Accomplish either paragraph (j)(1) or (j)(2) of this AD, as applicable.

(1) If no crack has been detected as a result of inspections required by AD 87-24-03: Within 4,000 flight hours after the last inspection required by that AD, perform a detailed inspection to detect cracks and loose brackets of the elevator rear spar in the area along the upper and lower edges at the shear plate, in accordance with Boeing Service Bulletin 727-55-0089, dated June 29, 1995, except as provided by paragraph (m) of this AD. Accomplish follow-on actions (i.e., repetitive inspection, stop-drilling, modification) in accordance with that service bulletin, except as provided by paragraph (o) of this AD, at the times specified as follows:

(i) Repeat the detailed inspection thereafter at intervals not to exceed 4,000 flight hours, except as provided by paragraph (n) of this AD.

(ii) If any crack is detected and stop-drilled as a result of any inspection required by paragraph (j)(1) of this AD, accomplish the requirements of paragraph (l) of this AD, except as provided by paragraph (o) of this AD, at the times specified in paragraph (l) of this AD.

(2) If any crack has been detected and stop-drilled in accordance with AD 87-24-03, accomplish the requirements of paragraph (l) of this AD, except as provided by paragraph (o) of this AD, at the times specified in paragraph (l) of this AD.

(k) For airplanes on which the modification or repair described in Boeing Service Bulletin 727-55-087, dated June 20, 1986 (specified as terminating action in AD 87-24-03), has been accomplished: Within 4,000 flight hours after April 22, 1996, perform a detailed inspection to detect cracks and loose hinge brackets of the elevator rear spar in the area along the upper and lower edges at the shear plate, in accordance with Boeing Service Bulletin 727-55-0089, dated June 29, 1995. Accomplish follow-on actions (i.e., repetitive inspection, stop-drilling, modification) in accordance with the service bulletin, except as provided by paragraph (o) of this AD, at the times specified as follows:

(1) Repeat the detailed inspection thereafter at intervals not to exceed 4,000 flight hours, except as provided by paragraph (n) of this AD.

(2) If any crack is detected and stop-drilled as a result of any inspection required by this paragraph, accomplish the requirements of paragraph (l) of this AD, except as provided by paragraph (o) of this AD, at the times specified in that paragraph.

(l) If any crack is detected and stop-drilled in accordance with paragraph (f)(2), (g)(1)(ii), (g)(2), (h)(2), (i)(1)(ii), (j)(1)(ii), (j)(2), or (k)(2) of this AD, accomplish the following, except as provided by paragraphs (o) and (p) of this AD:

(1) Within 1,600 flight hours after stop-drilling, perform a detailed inspection to detect cracks and loose hinge brackets of the elevator rear spar in the area along the upper and lower edges at the shear plate, and accomplish follow-on actions (i.e., stop-drilling, modification) in accordance with the service bulletin. If any crack growth is detected after stop-drilling, prior to further flight, modify the elevator rear spar in accordance with Part II of the Accomplishment Instructions of Boeing Service Bulletin 727-55-0089, dated June 29, 1995. Accomplishment of this modification constitutes terminating action for the repetitive inspection requirements of this AD.

(2) Within 3,200 flight hours after stop-drilling, modify the elevator rear spar in accordance with Part II of the Accomplishment Instructions of Boeing Service Bulletin 727-55-0089, dated June 29, 1995. Accomplishment of this modification constitutes terminating action for the repetitive inspection requirements of this AD.

New Actions Required by This AD

New Service Information

(m) As of the effective date of this AD, use only the Accomplishment Instructions of Boeing Service Bulletin 727-55-0089, Revision 1, dated March 2, 2000, to do the repetitive detailed inspections required by this AD.

Certain Repetitive Inspections at Reduced Intervals

(n) For airplanes being inspected at intervals not to exceed 4,000 flight hours in accordance with paragraphs (h)(1), (i)(1)(i), (j)(1)(i), and (k)(1) of this AD: As of the effective date of this AD, do those inspections within 1,600 flight hours since the last detailed inspection or 6 months after the effective date of this AD, whichever occurs later, and thereafter at intervals not to exceed 1,600 flight hours.

Stop-Drilling Prohibited

(o) As of the effective date of this AD, stop-drilling required by paragraphs (f) through (l) inclusive of this AD is prohibited.

Replacement of Cracked Rear Spars/Loose Brackets

(p) As of the effective date of this AD, if any cracked rear spar or loose bracket is detected during any inspection required by this AD, before further flight, do the replacement specified in paragraph (q) of this AD.

Terminating Replacement

(q) Within 24 months after the effective date of this AD, replace the elevator rear spar with a new elevator rear spar and support fittings, in accordance with Part II of the Accomplishment Instructions of Boeing Service Bulletin 727-55-0089, Revision 1, dated March 2, 2000. Accomplishing the replacement constitutes terminating action for the requirements of this AD.

(r) Accomplishing the replacement before the effective date of this AD in accordance with Boeing Service Bulletin 727-55-0089, dated June 29, 1995, is considered acceptable for compliance with the corresponding action specified in paragraph (q) of this AD.

Alternative Methods of Compliance (AMOCs)

(s)(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, ATTN: Berhane Alazar, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle ACO, 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.

(4) AMOCs approved previously in accordance with AD 96-06-05 are approved as AMOCs for the corresponding provisions of this AD.

Material Incorporated by Reference

(t) You must use Boeing Service Bulletin 727-55-0089, dated June 29, 1995; or Boeing Service Bulletin 727-55-0089, Revision 1, dated March 2, 2000; as applicable; to perform the actions that are required by this AD, unless the AD specifies otherwise.

(1) The Director of the Federal Register approved the incorporation by reference of Boeing Service Bulletin 727-55-0089, Revision 1, dated March 2, 2000, in accordance with 5 U.S.C. 552(a) and 1 CFR part 51.

(2) On April 22, 1996 (61 FR 11529, March 21, 1996), the Director of the Federal Register approved the incorporation by reference of Boeing Service Bulletin 727-55-0089, dated June 29, 1995.

(3) Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207, for a copy of this service information. You may review copies at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/​federal-register/​cfr/​ibr-locations.html.

Issued in Renton, Washington, on August 7, 2008.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.