Airworthiness Directives; Boeing Model 727 Series Airplanes

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 93-NM-72-AD; Amendment 39-8866; AD 94-07-08]

Airworthiness Directives; Boeing Model 727 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD),

applicable to certain Boeing Model 727 series airplanes, that requires

structural inspections of older airplanes. This amendment is prompted

by reports of incidents involving fatigue cracking and corrosion in

transport category airplanes that are approaching or have exceeded

their economic design service goal. The actions specified by this AD

are intended to prevent degradation of the structural capabilities of

the affected airplanes. This proposal relates to the recommendations of

the Airworthiness Assurance Task Force assigned to review Model 727

series airplanes, which indicate that, to assure long term continued

operational safety, various structural inspections should be

accomplished.

DATES: Effective April 28, 1994.

The incorporation by reference of Boeing Document Number D6-54860,

``Aging Airplane Service Bulletin Structural Modification and

Inspection Program - Model 727,'' Revision G, dated March 5, 1993,

listed in the regulations was approved previously by the Director of

the Federal Register as of April 21, 1994 (59 FR 13442, March 22,

1994).

ADDRESSES: The service information referenced in this AD may be

obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle,

Washington 98124-2207. This information may be examined at the Federal

Aviation Administration (FAA), Transport Airplane Directorate, Rules

Docket, 1601 Lind Avenue SW., Renton, Washington; or at the Office of

the Federal Register, 800 North Capitol Street, NW., suite 700,

Washington, DC.

FOR FURTHER INFORMATION CONTACT: Walter Sippel, Aerospace Engineer,

Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle

Aircraft Certification Office, 1601 Lind Avenue, SW., Renton,

Washington 98055-4056; telephone (206) 227-2774; fax (206) 227-1181.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal

Aviation Regulations to include an airworthiness directive (AD) that is

applicable to certain Boeing Model 727 series airplanes was published

in the Federal Register on August 31, 1993 (58 FR 45863). That action

proposed to require structural inspections of older airplanes.

Interested persons have been afforded an opportunity to participate

in the making of this amendment. Due consideration has been given to

the comments received.

One commenter supports the proposed rule.

Two commenters note errors in the Discussion section of the

proposal in the description of Boeing Document Number D6-54860, ``Aging

Airplane Service Bulletin Structural Modification and Inspection

Program - Model 727,'' Revision G, dated March 5, 1993. Although the

Discussion section does not reappear in the preamble to the final rule,

the FAA takes this opportunity to correct the number of service

bulletins referenced by the Boeing Document. There is a total of 17

service bulletins referenced by the Boeing Document: five service

bulletins that describe inspections of the wings, six service bulletins

that describe inspections of the fuselage, one service bulletin that

describes inspections of the main landing gear door support fitting,

four service bulletins that describe inspections of the empennage, and

one service bulletin that describes inspections of the attach fittings

on the center engine inlet duct housing.

One commenter requests that the FAA issue one rulemaking action

that would combine the requirements of this proposal, which proposes to

require the structural inspections listed in the Boeing Document, with

the proposal to require the structural modifications listed in that

Boeing Document. That rulemaking action was proposed in AD Docket 93-

NM-73-AD (58 FR 45861, August 31, 1993). This commenter requests that

these two rulemaking actions be combined with AD 90-06-09, Amendment

39-6488 (55 FR 8370, March 7, 1990), which references Revision C of the

Boeing Document, dated December 11, 1989. Combining all of these

actions into one AD would ease the operators' burden in tracking

compliance and recordkeeping.

The FAA does not concur. The FAA's normal policy in this regard is

that when an AD requires a substantive change, such as a change in the

existing AD's requirements, the existing AD (90-06-09) is superseded by

being removed from the system and a new AD added. However, to supersede

the existing AD and replace it with a new one having a new AD number

would serve no purpose in terms of the ability of affected operators to

track compliance with the AD and maintain accurate records of

compliance. In consideration of the consequent workload associated with

revising maintenance records to enter new AD numbers to demonstrate

compliance with requirements accomplished previously, the FAA has

determined that a less burdensome approach is to issue a separate AD.

This final rule is issued as a separate AD action since combining these

rulemaking actions would necessitate recordkeeping changes to reflect

new AD numbers. Furthermore, the FAA's intent in keeping the

requirement to accomplish the inspections listed in the Boeing Document

separated from the requirement to accomplish the modifications listed

in the Boeing Document was to minimize the recordkeeping burden to the

operators; i.e., operators will not be required to make recordkeeping

changes to their inspection entries whenever revisions are made to

modification requirements and vice versa.

One commenter requests that the proposed compliance time for the

repetitive inspections in paragraph (a) be revised to be consistent

with those recommended in the Boeing Document. The FAA does not concur

that any change is necessary. From this comment, the FAA concludes that

this commenter may have mistakenly assumed that the proposal would have

required that the repetitive inspections must be accomplished at the

times specified in the corresponding service bulletins. Consequently,

paragraph (a) of the final rule remains unchanged and states that

repetitive inspections are to be accomplished ``thereafter at intervals

not to exceed those specified in the Boeing Document for each

inspection.'' Furthermore, since the corresponding service bulletins

have been revised to be consistent with the Boeing Document, the

compliance times for the repetitive inspections are consistently

defined in the final rule, the Boeing Document, and the corresponding

service bulletins.

Several commenters request that proposed paragraphs (a) and (b) be

revised to clarify that only the structural inspections listed in

section 4 and appendices A.4 and B.4 of the Boeing Document must be

accomplished. Since the proposal stated that the inspections were

specified in ``section 4 and appendices A. and B.'' of the Boeing

Document, these commenters contend that the possibility exists for

misinterpretation. The FAA concurs. The FAA finds that these

commenters' proposal to reference the specific appendices of the Boeing

Document (rather than the generalization cited in the proposal) would

avoid any possibility for misinterpretation. Therefore, paragraphs (a)

and (b) of the final rule have been revised accordingly.

The Air Transport Association of America, on behalf of one of its

member operators, requests that the note following proposed paragraph

(b)(2) be clarified. The commenter states that the term ``phase-in

period'' was not adequately defined in the proposal and that it was not

used in the Boeing Document, which was referenced in the proposal.

Since some of the service bulletins that are referenced by the Boeing

Document specify a ``phase-in'' time, while others do not, the

commenter further requests that issuance of the final rule be delayed

until such time that the 727 Structures Working Group of the

Airworthiness Assurance Task Force has reconvened to resolve this

issue. The FAA concurs that clarification is warranted; however, the

FAA does not concur that delaying issuance of the final rule is

necessary, since the following discussion, as well as the revised final

rule, adequately defines ``phase-in period.'' The FAA's intent in using

the term ``phase-in period'' was to grant a ``grace period'' of 15

months to operators having airplanes that will soon exceed or that have

already exceeded the threshold specified in the Boeing Document.

In light of this comment, the FAA has revised paragraph (b) of the

final rule to clarify that, in those instances when a ``phase-in

period'' is specified in any of the service bulletins referenced by the

Boeing Document, the maximum initial inspection time is to be

calculated using the ``phase-in period'' specified in the service

bulletin and adding a date 15 months after the effective date of the

AD. An example of this, although not specifically referred to as a

``phase-in period'', can be found in the Accomplishment Instructions of

Boeing Service Bulletin 727-53-0041, Revision 6, dated September 5,

1991, which states, in part, that ``airplanes having accumulated more

than 16,000 flight cycles should be inspected within 3,000 flight

cycles . . .'' The ``phase-in period'' in this example is ``within

3,000 flight cycles.'' Therefore, for the purposes of this AD, the

maximum initial inspection time in this instance is 3,000 flight cycles

measured from a date 15 months after the effective date of this AD.

However, in those instances when a ``phase-in period'' is not

specified in any of the service bulletins referenced by the Boeing

Document, the FAA's intent is to allow operators 15 months for planning

purposes. In these instances, the maximum initial inspection time is 15

months after the effective date of this AD.

One commenter requests that the proposal be revised to permit

deviations to the corrective actions required by proposed paragraph

(c), and suggests that these be permitted to be accomplished in

accordance with other FAA-approved methods, e.g., Structural Repair

Manuals; Statement of Compliance with the Federal Aviation Regulations,

FAA Form 8110-3; etc. The commenter's intent for requesting this change

is to gain authorization to make minor deviations, such as oversizing

fasteners and substituting materials, without obtaining approval for an

alternative method of compliance for each deviation. The commenter

states that safety could be ensured with repetitive inspections until

such time that the corrective action specified in the corresponding

service bulletin referenced by the Boeing Document could be

accomplished during regularly scheduled maintenance, so as to minimize

the impact to operators' revenue bearing passenger service. The FAA

does not concur. The FAA has determined that the Manager, Seattle

Aircraft Certification Office, should approve any such deviations to

the AD's requirements. Given that possible new relevant issues might be

revealed during this process, it is imperative that the FAA, at this

level, have such feedback. Only by reviewing deviation approvals can

the FAA be assured of this feedback and of the adequacy of the repair

methods. However, when the FAA has obtained an adequate sampling of the

quality, type, and extent of repairs being made as a result of this AD,

the FAA anticipates that it will, at some future date, authorize

manufacturer's Designated Engineering Representatives to approve minor

deviations to the modifications required by this final rule, as it has

done in the past regarding the requirements of AD 90-06-09, and other

aging fleet AD's. Furthermore, affected operators may request approval

to use an alternative method of compliance to the corrective actions

specified in the corresponding service bulletins, under the provisions

of paragraph (e) of the final rule.

After careful review of the available data, including the comments

noted above, the FAA has determined that air safety and the public

interest require the adoption of the rule with the changes previously

described. The FAA has determined that these changes will neither

increase the economic burden on any operator nor increase the scope of

the AD.

There are approximately 1,635 Model 727 series airplanes of the

affected design in the worldwide fleet. The FAA estimates that 688

airplanes of U.S. registry will be affected by this AD, that it will

take approximately 512 work hours per airplane to accomplish the

required actions, and that the average labor rate is $55 per work hour.

Based on these figures, the total cost impact of the AD on U.S.

operators is estimated to be $19,374,080, or $28,160 per airplane.

The total cost impact figure discussed above is based on

assumptions that no operator has yet accomplished any of the

requirements of this AD action, and that no operator would accomplish

those actions in the future if this AD were not adopted.

The regulations adopted herein will not have substantial direct

effects 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. Therefore, in

accordance with Executive Order 12612, it is determined that this final

rule does not have sufficient federalism implications to warrant the

preparation of a Federalism Assessment.

For the reasons discussed above, I certify that this action (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. A final evaluation has been prepared for this action

and it is contained in the Rules Docket. A copy of it may be obtained

from the Rules Docket at the location provided under the caption

ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by

reference, Safety.

Adoption of the Amendment

Accordingly, pursuant to the authority delegated to me by the

Administrator, the Federal Aviation Administration amends 14 CFR part

39 of the Federal Aviation Regulations as follows:

PART 39--AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C.

106(g); and 14 CFR 11.89.

Sec. 39.13 [Amended]

2. Section 39.13 is amended by adding the following new

airworthiness directive:

94-07-08 Boeing: Amendment 39-8866. Docket 93-NM-72-AD.

Applicability: Model 727 series airplanes, as listed in Boeing

Document D6-54860, ``Aging Airplane Service Bulletin Structural

Modification and Inspection Program--Model 727,'' Revision G, dated

March 5, 1993; certificated in any category.

Compliance: Required as indicated, unless accomplished

previously.

To prevent degradation of the structural capability of the

airplane, accomplish the following:

(a) Accomplish the inspections specified in Section 4 and

Appendices A.4 and B.4 of Boeing Document Number D6-54860, ``Aging

Airplane Service Bulletin Structural Modification and Inspection

Program--Model 727,'' Revision G, dated March 5, 1993, within the

times specified in paragraph (b) of this AD, and thereafter at

intervals not to exceed those specified in the Boeing Document for

each inspection.

(b) The maximum initial inspection times for the inspections

contained in Section 4 and Appendices A.4 and B.4 of Boeing Document

Number D6-54860, ``Aging Airplane Service Bulletin Structural

Modification and Inspection Program--Model 727,'' Revision G, dated

March 5, 1993, shall be prior to the later of the times specified in

either paragraph (b)(1) or (b)(2) of this AD:

(1) The maximum initial inspection time for the inspection shall

be prior to the threshold for the inspection time specified in the

Boeing Document, measured as a total (flight cycles or time-in-

service, as appropriate) accumulated on the airplane; or

(2) The maximum initial inspection time shall be prior to the

time specified in either paragraph (b)(2)(i) or (b)(2)(ii) of this

AD, as applicable.

(i) If a phase-in period has been specified in the service

bulletin: The maximum initial inspection time shall be calculated by

adding the phase-in period for the inspection specified in the

Boeing Document to a date 15 months after the effective date of this

AD.

(ii) If a phase-in period has not been specified in the service

bulletin: The maximum initial inspection time shall be within 15

months after the effective date of this AD.

Note 1: For the purposes of this AD, the ``phase-in period'' is

defined as the allowable period to accomplish the initial inspection

when the required threshold specified in paragraph (b)(1) of this AD

is imminent or has elapsed.

(c) If any discrepant condition identified in the service

bulletins (that are specified in the Boeing Document) is found as a

result of the inspections required by this AD, prior to further

flight, accomplish the corresponding corrective action specified in

the service bulletins.

(d) The terminating action for each inspection required by

paragraph (a) of this AD consists of the accomplishment of the

modification specified in the corresponding service bulletin.

(e) An alternative method of compliance or adjustment of the

compliance time that provides an acceptable level of safety may be

used if approved by the Manager, Seattle Aircraft Certification

Office (ACO), FAA, Transport Airplane Directorate. Operators shall

submit their requests through an appropriate FAA Principal

Maintenance Inspector, who may add comments and then send it to the

Manager, Seattle ACO.

Note 2: Information concerning the existence of approved

alternative methods of compliance with this AD, if any, may be

obtained from the Seattle ACO.

(f) Special flight permits may be issued in accordance with

Federal Aviation Regulations (FAR) 21.197 and 21.199 to operate the

airplane to a location where the requirements of this AD can be

accomplished.

(g) The inspections shall be done in accordance with Boeing

Document Number D6-54860, ``Aging Airplane Service Bulletin

Structural Modification and Inspection Program--Model 727,''

Revision G, dated March 5, 1993. The incorporation by reference of

this document was approved previously by the Director of the Federal

Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51 as of

April 21, 1994 (59 FR 13442, April 22, 1994). Copies may be obtained

from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle,

Washington 98124-2207. Copies may be inspected at the FAA, Transport

Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or

at the Office of the Federal Register, 800 North Capitol Street,

NW., suite 700, Washington, DC.

(h) This amendment becomes effective on April 28, 1994.

Issued in Renton, Washington, on March 23, 1994.

John J. Hickey,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-7319 Filed 3-28-94; 8:45 am]

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