[Federal Register Volume 65, Number 196 (Tuesday, October 10, 2000)]
[Proposed Rules]
[Pages 60129-60132]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-25969]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-184-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 757-200 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the supersedure of an existing 
airworthiness directive (AD), applicable to certain Boeing Model 757-
200 series airplanes, that currently requires inspections to detect 
cracking on the free edge of the tang, if necessary, and of the 
fastener holes in the lower spar chord; and various follow-on actions. 
That AD also provides for an optional terminating action for the 
repetitive inspections. This action would add inspections to detect 
additional cracking of the fastener holes in the lower spar chord. This 
action also adds an optional terminating modification. This proposal is 
prompted by the issuance of new service information. The actions 
specified by the proposed AD are intended to detect and correct fatigue 
cracking in the lower spar chord, which could result in reduced 
structural integrity of the engine strut.

DATES: Comments must be received by November 24, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2000-NM-184-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: 
<a href="/cdn-cgi/l/email-protection#4d74602c232060233d3f202e2220202823390d2b2c2c632a223b"><span class="__cf_email__" data-cfemail="3f06125e515212514f4d525c5052525a514b7f595e5e11585049">[email protected]</span></a>. Comments sent via fax or the Internet must 
contain ``Docket No. 2000-NM-184-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

[[Page 60130]]

98124-2207. This information may be examined at the FAA, Transport 
Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Dennis Stremick, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-2776; 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 notice may be changed in 
light of the comments received.
    Submit comments using the following format:
    <bullet>  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.
    <bullet>  For each issue, state what specific change to the 
proposed AD is being requested.
    <bullet> 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 2000-NM-184-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. 2000-NM-184-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On March 5, 1997, the FAA issued AD 97-06-04, amendment 39-9961 (62 
FR 11760, March 13, 1997), applicable to certain Boeing Model 757-200 
series airplanes, to require inspections to detect cracking on the free 
edge of the tang, if necessary, and of the fastener holes in the lower 
spar chord; and various follow-on actions. That AD also provides for 
optional terminating action for the repetitive inspections. That action 
was prompted by a report of fatigue cracking in the lower spar chord of 
two Model 757 series airplanes. The requirements of that AD are 
intended to detect and correct such fatigue cracking, which could 
result in reduced structural integrity of the engine strut.

Related Rulemaking

    This proposed AD is related to AD 99-24-07, amendment 39-11431 (64 
FR 66370, November 26, 1999), applicable to certain Boeing Model 757 
series airplanes equipped with Rolls Royce RB211 engines, that requires 
modification of the nacelle strut and wing structure. In the preamble 
to AD 97-06-04, the FAA specified that the actions required by that AD 
were considered ``interim action'' and that the manufacturer was 
developing a modification to positively address the unsafe condition. 
The FAA indicated that it may consider further rulemaking action once 
the modification was developed, approved, and available. The 
manufacturer now has developed such a modification, and the FAA issued 
AD 99-24-07 to require accomplishment of that modification.

Actions Since Issuance of Previous Rule

    Since the issuance of AD 97-06-04, the FAA has reviewed and 
approved Boeing Service Bulletin 757-54-0031, Revision 4, dated 
November 11, 1999, which describes procedures for additional bolt hole 
inspections to detect further cracking of the fastener holes that 
promulgated in a different direction in the lower spar chord than the 
area described in that AD. This inspection was added due to a report of 
a crack in the lower spar chord on a Model 757 series airplane with 
fewer flight cycles than the number of flight cycles stated in the 
threshold table of Boeing Service Bulletin 757-54-0031, Revision 2, 
dated December 19, 1996. Revision 2 was referenced as the appropriate 
source of service information for accomplishment of the actions 
required by AD 97-06-04, but did not include the lower spar chord area 
specified in Revision 4.

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 supersede AD 97-06-04 to continue to require 
inspections to detect cracking on the free edge of the tang, if 
necessary, and of the fastener holes in the lower spar chord; and 
various follow-on actions. This proposed AD also would continue to 
provide an optional terminating action for the repetitive inspections. 
This new action would add inspections to detect additional cracking of 
the fastener holes in the lower spar chord. This action also adds an 
optional terminating modification. The actions would be required to be 
accomplished in accordance with the service bulletin described 
previously, except as discussed below.

Difference Between Service Bulletin and This AD

    Operators should note that, although the service bulletin 
referenced in this AD recommends accomplishment of the second eddy 
current inspection within 6,000 flight cycles after accomplishment of 
the first inspection, this AD adds a ``grace period'' of 60 days due to 
the length of time that has passed since the issuance of that AD. The 
FAA has been advised that a significant number of the affected Model 
757 series airplanes have already accomplished the first inspection. In 
developing an appropriate compliance time for this action, the FAA 
considered not only the degree of urgency associated with addressing 
the subject unsafe condition, but the manufacturer's recommendation as 
to an appropriate compliance time, parts availability, and the 
practical aspect of accomplishing the required inspection within an 
interval of time that parallels the normal scheduled maintenance for 
the majority of affected operators.
    In light of this, the FAA has determined that, for operators that 
have already accomplished the first inspection, a ``grace period'' of 
60 days is necessary to ensure that the affected airplanes are 
inspected in a timely manner and that an acceptable level of safety is 
maintained.

Cost Impact

    There are approximately 418 Model 757-200 series airplanes of the 
affected design in the worldwide fleet. The FAA estimates that 151 
airplanes of U.S. registry would be affected by this proposed AD.
    The inspections that are currently required by AD 97-06-04 take

[[Page 60131]]

approximately 52 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. Based on these figures, the cost 
impact of the currently required actions on U.S. operators is estimated 
to be $471,120, or $3,120 per airplane.
    The new inspections that are proposed in this AD action would take 
approximately 4 work hours per inspection, per airplane to accomplish, 
at an average labor rate of $60 per work hour. Based on these figures, 
the cost impact of the proposed requirements of this AD on U.S. 
operators is estimated to be $36,240, or $240 per airplane.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the current or proposed 
requirements of this AD action, and that no operator would accomplish 
those actions in the future if this 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.

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.

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 removing amendment 39-9961 (62 FR 
11760, March 13, 1997), and by adding a new airworthiness directive 
(AD), to read as follows:

Boeing: Docket 2000-NM-184-AD. Supersedes AD 97-06-04, Amendment 39-
9961.

    Applicability: Model 757-200 series airplanes having line 
numbers 1 through 736 inclusive, powered by Rolls Royce engines, 
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 (n) 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 detect and correct fatigue cracking of the lower spar chord, 
which could result in reduced structural integrity of the engine 
strut, accomplish the following:

Restatement of Requirements of AD 97-06-04

Repetitive Inspections

    (a) Prior to the accumulation of 15,000 total flight cycles, or 
within 60 days after March 28, 1997 (the effective date of AD 97-06-
04, amendment 39-9961), whichever occurs later: Perform an eddy 
current inspection to detect cracking on the free edge of the tang, 
in accordance with the Accomplishment Instructions of Boeing Service 
Bulletin 757-54-0031, Revision 2, dated December 19, 1996, or 
Revision 4, dated November 11, 1999. Repeat this inspection 
thereafter at intervals not to exceed 3,000 flight cycles until the 
inspection required by paragraph (d) of this AD is accomplished.

    Note 2: The inspection required by paragraph (a) of this AD need 
not be performed on airplanes on which the inspection required by 
paragraph (d) of this AD is performed prior to the compliance time 
specified in paragraph (a) of this AD.

Follow-On Actions

    (b) If any cracking is found during the inspection required by 
paragraph (a) of this AD, and the cracking is within the limits 
specified in Boeing Service Bulletin 757-54-0031, Revision 2, dated 
December 19, 1996, or Revision 4, dated November 11, 1999: Prior to 
further flight, remove the midchord channels, stop-drill the 
cracking, and install a repair in accordance with the service 
bulletin. No further action is required by paragraph (a) of this AD.
    (c) If any cracking is found, and the cracking is outside the 
limits specified in Boeing Service Bulletin 757-54-0031, Revision 2, 
dated December 19, 1996, or Revision 4, dated November 11, 1999: 
Prior to further flight, replace the lower spar chord with a new or 
serviceable chord in accordance with a method approved by the 
Manager, Seattle Aircraft Certification Office (ACO), FAA.

Bolt Hole Inspection

    (d) Perform an eddy current inspection (bolt hole inspection) to 
detect cracking of the two fastener holes in the lower spar chord, 
in accordance with the Accomplishment Instructions of Boeing Service 
Bulletin 757-54-0031, Revision 2, dated December 19, 1996, or 
Revision 4, dated November 11, 1999, at the time specified in 
paragraph (d)(1) and (d)(2) of this AD, as applicable. 
Accomplishment of this inspection terminates the inspections 
required by paragraph (a) of this AD.
    (1) For airplanes on which the stiffening straps have been 
removed from the midchord in accordance with Boeing Service Bulletin 
757-54-0028 prior to the effective date of this AD: Accomplish the 
inspection at the time specified in Paragraph 1.D. (``Description'') 
of Boeing Service Bulletin 757-54-0031, Revision 2, dated December 
19, 1996, or Revision 4, dated November 11, 1999.
    (2) For airplanes other than those identified in paragraph 
(d)(1) of this AD: Accomplish the inspection prior to the 
accumulation of 18,000 total flight cycles, or within 60 days after 
March 28, 1997, whichever occurs later.
    (e) Accomplish either paragraph (e)(1) or (e)(2) of this AD, as 
applicable, in accordance with Boeing Service Bulletin 757-54-0031, 
Revision 2, dated December 19, 1996, or Revision 4, dated November 
11, 1999.
    (1) If any fastener installed as a result of an inspection 
required by paragraph (d) of this AD has a diameter of \5/8\-inch or 
greater: Install the repair prior to the accumulation of the number 
of flight cycles specified in the ``Subsequent Inspection Interval'' 
column of the Threshold Table included in Paragraph 1.E. 
(``Compliance'') of Boeing Service Bulletin 757-54-0031, Revision 2, 
dated December 19, 1996, or Revision 4, dated November 11, 1999.
    (2) If any fastener installed as a result of an inspection 
required by paragraph (d) of this AD has a diameter of less than \5/
8\-inch: Repeat the bolt hole inspection required by

[[Page 60132]]

paragraph (d) of this AD prior to the accumulation of the number of 
flight cycles specified in the ``Subsequent Inspection Interval'' 
column of the Threshold Table included in Paragraph 1.E. 
(``Compliance'') of the service bulletin until the repair specified 
in paragraph (h) of this AD is installed.

Optional Terminating Action

    (f) Installation of the repair in accordance with the 
Accomplishment Instructions of Boeing Service Bulletin 757-54-0031, 
Revision 2, dated December 19, 1996, or Revision 4, dated November 
11, 1999, constitutes terminating action for the requirements in 
paragraphs (a) and (d) of this AD.

New Requirements of This AD

Revised Service Information

    (g) Except as provided by paragraphs (c) and (l)(3) of this AD: 
As of the effective date of this new AD, Boeing Service Bulletin 
757-54-0031, Revision 4, dated November 11, 1999, must be used for 
accomplishment of the actions required by this AD.

Second Bolt Hole Inspection

    (h) Within 6,000 flight cycles after accomplishment of paragraph 
(d) of this AD, or within 60 days after the effective date of this 
AD, whichever occurs later: Perform a second eddy current inspection 
(bolt hole inspection) to detect cracking of the two fastener holes 
in the lower spar chord, in accordance with Part IV of the 
Accomplishment Instructions of Boeing Service Bulletin 757-54-0031, 
Revision 4, dated November 11, 1999. If no cracking is found during 
the inspection required by this paragraph, no further action is 
required by this paragraph.

Third Bolt Hole Inspection

    (i) After accomplishment of the inspection required by paragraph 
(h) of this AD, when the airplane has reached the flight cycle 
threshold as defined by the flight cycle threshold formula on page 
9, Paragraph 1.E. (``Compliance'') of Boeing Service Bulletin 757-
54-0031, Revision 4, dated November 11, 1999: Perform a third eddy 
current inspection (bolt hole inspection) to detect cracking of the 
two fastener holes in the lower spar chord, in accordance with Part 
II of the Accomplishment Instructions of the service bulletin.

Fourth Bolt Hole Inspection

    (j) If, after accomplishment of the inspection required by 
paragraph (i) of this AD, paragraph (m) of this AD has not yet been 
accomplished: When the airplane has reached the flight cycle 
threshold as defined by the flight cycle threshold formula on page 
9, Paragraph 1.E. (``Compliance'') of Boeing Service Bulletin 757-
54-0031, Revision 4, dated November 11, 1999; perform a fourth eddy 
current inspection (bolt hole inspection) to detect cracking of the 
two fastener holes in the lower spar chord, in accordance with Part 
II of the Accomplishment Instructions of the service bulletin.

Follow-On Actions

    (k) If no cracking is found during any inspection required by 
paragraph (d), (i), or (j) of this AD, prior to further flight, 
increase the diameter of the holes by the dimensions specified in 
the Accomplishment Instructions of Boeing Service Bulletin 757-54-
0031, Revision 2, dated December 19, 1996, or Revision 4, dated 
November 11, 1999, and install new fasteners in accordance with the 
service bulletin.
    (l) If any cracking is found during any inspection required by 
paragraph (d), (h), (i), or (j) of this AD, prior to further flight, 
accomplish paragraph (l)(1), (l)(2), or (l)(3) of this AD, as 
applicable, in accordance with the Accomplishment Instructions of 
Boeing Service Bulletin 757-54-0031, Revision 2, dated December 19, 
1996, or Revision 4, dated November 11, 1999.
    (1) If the cracking can be removed by increasing the diameter of 
the hole in accordance with the service bulletin: Increase the 
diameter of the hole by the dimensions specified in the 
Accomplishment Instructions of the service bulletin, and install new 
fasteners in accordance with the service bulletin.
    (2) If the cracking cannot be removed by increasing the diameter 
of the hole in accordance with the Accomplishment Instructions of 
the service bulletin, but the cracking is within the limits 
specified in the service bulletin: Install the repair in accordance 
with the service bulletin. No further action is required by 
paragraph (d) of this AD.
    (3) If the cracking is outside the limits specified in the 
service bulletin: Replace the lower spar chord with a new or 
serviceable chord in accordance with a method approved by the 
Manager, Seattle ACO.

Optional Terminating Modification

    (m) Accomplishment of the modification of the nacelle strut and 
wing structure as required by AD 99-24-07, amendment 39-11431, 
constitutes terminating action for the requirements of this AD.

Alternative Methods of Compliance

    (n) 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

    (o) 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 October 3, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-25969 Filed 10-6-00; 8:45 am]
BILLING CODE 4910-13-U


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