[Federal Register Volume 66, Number 229 (Wednesday, November 28, 2001)]
[Proposed Rules]
[Pages 59382-59384]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-29597]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NM-233-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 727 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to all Boeing Model 727 series 
airplanes. This proposal would require a review of maintenance records 
or a one-time test to determine if elevator hinge support ribs on the 
trailing edge of the horizontal stabilizer are made from a certain 
material, and follow-on repetitive inspections for corrosion or 
cracking of the elevator hinge support ribs, if necessary. For 
airplanes with the affected ribs installed, this proposal would 
eventually require replacement of all affected ribs with new, improved 
ribs. This action is necessary to prevent cracking of the elevator 
hinge support ribs, which could lead to vibration of the airframe 
during flight and consequent damage to the elevator and horizontal 
stabilizer, potentially resulting in loss of controllability of the 
airplane. This action is intended to address the identified unsafe 
condition.

DATES: Comments must be received by January 14, 2002.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2001-NM-233-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except 
Federal holidays. Comments may be submitted via fax to (425) 227-1232. 
Comments may also be sent via the Internet using the following address: 
[email protected]. Comments sent via fax or the Internet must 
contain ``Docket No. 2001-NM-233-AD'' in the subject line and need not 
be submitted in triplicate. Comments sent via the Internet as attached 
electronic files must be formatted in Microsoft Word 97 for Windows or 
ASCII text.
    The service information referenced in the proposed rule may be 
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, 
Washington 98124-2207. This information may be examined at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington.

FOR FURTHER INFORMATION CONTACT: Duong Tran, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-2773; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications shall identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this action may be changed in 
light of the comments received.
    Submit comments using the following format:
     Organize comments issue-by-issue. For example, discuss a 
request to change the compliance time and a request to change the 
service bulletin reference as two separate issues.
     For each issue, state what specific change to the proposed 
AD is being requested.
     Include justification (e.g., reasons or data) for each 
request.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2001-NM-233-AD.'' The postcard will be date-stamped 
and returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules 
Docket No. 2001-NM-233-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received numerous reports of cracking of elevator hinge 
support ribs on the trailing edge of the horizontal stabilizer on 
Boeing Model 727 series airplanes. Investigation revealed that the 
cracking is caused by stress corrosion. The affected elevator hinge 
support ribs are made from 7079-T6 material. Cracks on multiple ribs 
may continue to extend in length, until the stiffness of the elevator 
support is decreased. This condition, if not corrected, could result in 
vibration of the airframe during flight and consequent damage to the 
elevator and horizontal stabilizer, which could result in loss of 
controllability of the airplane.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
727-55A0091, dated August 16, 2001, which describes procedures for 
repetitive detailed visual inspections for corrosion or cracking of 
elevator hinge support ribs made from 7079-T6 material. The service 
bulletin specifies to contact Boeing for repair information.

Explanation of Applicability

    The service bulletin divides affected airplanes into three groups. 
Group 1 airplanes were delivered with elevator hinge support ribs made 
from 7079-T6 material installed at all 14 elevator station locations. 
Group 2 airplanes were delivered with elevator hinge support ribs made 
from 7075-T73 material (a more stress corrosion-resistant material) 
installed at 12 elevator station locations, but with ribs made from 
7079-T6 material installed at 2 elevator station locations. Group 3 
airplanes were delivered with elevator hinge support ribs made from 
7075-T73 material in all elevator station locations. However, airplanes 
in Groups 2 and 3 may have had ribs replaced after delivery with ribs 
made from 7079-T6 material. Thus we find that it is necessary for 
operators of all Boeing Model 727 series airplanes to perform an 
inspection to determine whether ribs made of 7079-T6 material are 
installed.

[[Page 59383]]

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would require a one-time review of maintenance records or a 
one-time electrical conductivity test of the elevator hinge support 
ribs, as applicable, to determine whether ribs made from 7079-T6 
material are installed on the airplane. The proposed AD also would 
require accomplishment of the actions specified in the service bulletin 
described previously, except as discussed below. Also, for airplanes 
with the affected ribs installed, the proposed AD would eventually 
require replacement of all 7079-T6 ribs with new, improved ribs.

Differences Between This Proposed AD and the Service Bulletin

    This proposed AD differs from Boeing Alert Service Bulletin 727-
55A0091 in the following ways:
     Though the effectivity summary in paragraph 1.A.1. of 
Boeing Service Bulletin 727-55A0091 identifies only Model 727-100 and -
200 series airplanes as being subject to the service bulletin, we have 
determined that the proposed actions apply to all Model 727 series 
airplanes, including Model 727, 727-100C, 727-200F, and 727C series 
airplanes.
     The service bulletin does not specify a method for 
determining whether ribs made from 7079-T6 material are installed on 
the airplane. As described previously, the proposed AD would require a 
one-time review of maintenance records or a one-time electrical 
conductivity test of the elevator hinge support ribs, as applicable, to 
determine whether ribs made from 7079-T6 material are installed on the 
airplane. The electrical conductivity test, if accomplished, would be 
required to be accomplished according to Boeing Document D6-48875, 
Boeing 727 Non-Destructive Test Manual, Part 6, Section 51-00-00, 
Figure 20; and Boeing Process Specification BAC 5946, Table I, page 12.
     The service bulletin specifies that the manufacturer may 
be contacted for disposition of certain repair conditions. However, 
this proposed AD would require the repair of those conditions to be 
accomplished per a method approved by the FAA, or per data meeting the 
type certification basis of the airplane approved by a Boeing Company 
Designated Engineering Representative who has been authorized by the 
Manager, Seattle Aircraft Certification Office, to make such findings.
     The service bulletin specifies that the next revision of 
the service bulletin will include compliance times and instructions for 
replacement of all ribs made from 7079-T6 material. However, this 
proposed AD would require accomplishment of the replacement of all ribs 
made from 7079-T6 material with new ribs within 48 months after the 
effective date of this AD, according to a method approved by the FAA. 
The decision to require such replacement is based upon our 
determination that, due to the criticality of the unsafe condition 
addressed in this proposed AD, it is not appropriate to wait until the 
airplane manufacturer revises its service bulletin to mandate the rib 
replacement. When the airplane manufacturer has prepared a revised 
service bulletin, and we have reviewed and approved it, we may consider 
further rulemaking to allow that service bulletin to be used as an 
acceptable method of compliance with this AD.

Cost Impact

    There are approximately 1,383 airplanes of the affected design in 
the worldwide fleet. The FAA estimates that 915 airplanes of U.S. 
registry would be affected by this proposed AD.
    The proposed AD offers two alternatives for compliance with the 
proposed requirement for an initial inspection to determine whether 
elevator hinge support ribs made from 7079-T6 material are installed. 
Estimates of the cost of these proposed actions are provided below.
    It would take approximately 1 work hour per airplane to accomplish 
the proposed review of maintenance records, at an average labor rate of 
$60 per work hour. Based on these figures, the cost impact of this 
proposed review is estimated to be $60 per airplane.
    In lieu of the review of maintenance records (i.e., if the review 
of maintenance records is not sufficient to make a determination), the 
proposed inspection of the ribs to determine if they are made from 
7079-T6 material would take approximately 1 work hour per airplane to 
accomplish, at an average labor rate of $60 per work hour. Based on 
these figures, the cost impact of this proposed inspection on U.S. 
operators is estimated to be $60 per airplane.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the proposed requirements 
of this AD action, and that no operator would accomplish those actions 
in the future if this proposed AD were not adopted. The cost impact 
figures discussed in AD rulemaking actions represent only the time 
necessary to perform the specific actions actually required by the AD. 
These figures typically do not include incidental costs, such as the 
time required to gain access and close up, planning time, or time 
necessitated by other administrative actions.
    Should an operator be required to accomplish the repetitive 
detailed inspections, it would take approximately 13 work hours per 
airplane to accomplish this proposed inspection, at an average labor 
rate of $60 per work hour. Based on these figures, the cost impact of 
this inspection would be $780 per airplane, per inspection cycle.
    Should an operator be required to accomplish the replacement of the 
elevator hinge support ribs, it would take approximately 722 work hours 
per airplane to accomplish the proposed replacement of all ribs (on 
both the left- and right-hand sides of the airplane, excluding the time 
for gaining access and closing up), at an average labor rate of $60 per 
work hour. Required parts would cost approximately $70,000 per 
airplane. Based on these figures, the cost impact of the proposed 
replacement would be $113,320 per airplane.

Regulatory Impact

    The regulations proposed herein 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. Therefore, it 
is determined that this proposal would not have federalism implications 
under Executive Order 13132.
    For the reasons discussed above, I certify that this proposed 
regulation (1) is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the DOT 
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 
and (3) if promulgated, 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 copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting the Rules 
Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

[[Page 59384]]

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
part 39 of the Federal Aviation Regulations (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.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

Boeing: Docket 2001-NM-233-AD.
    Applicability: All Model 727 series airplanes, certificated in 
any category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
modified, altered, or repaired in the area subject to the 
requirements of this AD. For airplanes that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must request approval for an 
alternative method of compliance in accordance with paragraph (f) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and, if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent cracking of the elevator hinge support ribs, which 
could lead to vibration of the airframe during flight and consequent 
damage to the elevators and horizontal stabilizer, potentially 
resulting in loss of controllability of the airplane, accomplish the 
following:

One-Time Inspection

    (a) Within 180 days after the effective date of this AD, review 
the airplane's maintenance records to determine whether any elevator 
hinge support rib on the trailing edge of the horizontal stabilizer 
is made from 7079-T6 material; OR, if the material cannot be 
conclusively determined from the maintenance records, do a one-time 
electrical conductivity test of the elevator hinge support ribs to 
determine whether any are made from 7079-T6 material, according to 
Boeing Document D6-48875, Boeing 727 Non-Destructive Test Manual, 
Part 6, Section 51-00-00, Figure 20; and Boeing Process 
Specification BAC 5946, Table I, page 12.
    (1) If no ribs are made from 7079-T6 material, no further action 
is required by this AD.
    (2) If any ribs are made from 7079-T6 material, do paragraph (b) 
of this AD.

Follow-on Repetitive Inspections

    (b) Within 180 days after the effective date of this AD, perform 
a detailed visual inspection for corrosion or cracking of all 
elevator hinge support ribs made from 7079-T6 material, according to 
Boeing Alert Service Bulletin 727-55A0091, including Appendix A, 
dated August 16, 2001. Thereafter, repeat this inspection every 180 
days, until paragraph (d) of this AD has been done.

    Note 2: For the purposes of this AD, a detailed visual 
inspection is defined as: ``An intensive visual examination of a 
specific structural area, system, installation, or assembly to 
detect damage, failure, or irregularity. Available lighting is 
normally supplemented with a direct source of good lighting at 
intensity deemed appropriate by the inspector. Inspection aids such 
as mirror, magnifying lenses, etc., may be used. Surface cleaning 
and elaborate access procedures may be required.''

Repair

    (c) If any corrosion or cracking is found during any inspection 
required by paragraph (b) of this AD: Before further flight, repair 
according to a method approved by the Manager, Seattle Aircraft 
Certification Office (ACO), FAA; or according to data meeting the 
type certification basis of the airplane approved by a Boeing 
Company Designated Engineering Representative (DER) who has been 
authorized by the Manager, Seattle ACO, to make such findings. For a 
repair method to be approved by the Manager, Seattle ACO, as 
required by this paragraph, the Manager's approval letter must 
specifically reference this AD.

Replacement

    (d) For airplanes on which any ribs made from 7079-T6 material 
are found: Within 48 months after the effective date of this AD, 
replace all elevator hinge support ribs made from 7079-T6 material 
with new, improved ribs, according to a method approved by the 
Manager, Seattle ACO, or according to data meeting the type 
certification basis of the airplane approved by a Boeing Company DER 
who has been authorized by the Manager, Seattle ACO, to make such 
findings. For a repair method to be approved by the Manager, Seattle 
ACO, as required by this paragraph, the Manager's approval letter 
must specifically reference this AD. Such replacement terminates the 
repetitive inspections required by paragraph (b) of this AD.

Spares

    (e) After the effective date of this AD, no one may install an 
elevator hinge support rib made from 7079-T6 material on any 
airplane.

Alternative Methods of Compliance

    (f) 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 ACO. 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 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

Special Flight Permits

    (g) Special flight permits may be issued in accordance with 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate the airplane to a location where 
the requirements of this AD can be accomplished.

    Issued in Renton, Washington, on November 21, 2001.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-29597 Filed 11-27-01; 8:45 am]
BILLING CODE 4910-13-U