[Federal Register Volume 65, Number 181 (Monday, September 18, 2000)]
[Proposed Rules]
[Pages 56268-56270]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-23855]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-124-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 757-200 and -300 Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Supplemental notice of proposed rulemaking; reopening of 
comment period.

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SUMMARY: This document revises an earlier proposed airworthiness 
directive (AD), applicable to all Boeing Model 757-200 series 
airplanes, that would have required repetitive clearing of the drain 
passage at the aft end of the main landing gear (MLG) truck beam to 
ensure moisture and contaminants within the truck beam can properly 
drain. That proposal was prompted by reports of fracture of MLG truck 
beams. This new action revises the proposed rule by expanding the 
applicability and, for certain airplanes, adding a new inspection and 
follow-on actions. The actions specified by this new proposed AD are 
intended to prevent stress corrosion cracking, leading to fracture of a 
MLG truck beam during ground operations, which could result in either 
reduced controllability of the airplane or a fire.

DATES: Comments must be received by October 13, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 99-NM-124-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. 99-NM-124-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: 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

[[Page 56269]]

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:
     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 99-NM-124-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. 99-NM-124-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    A proposal to amend part 39 of the Federal Aviation Regulations (14 
CFR part 39) to add an airworthiness directive (AD), applicable to all 
Boeing Model 757-200 series airplanes, was published as a notice of 
proposed rulemaking (NPRM) in the Federal Register on September 15, 
1999 (64 FR 50016). That NPRM would have required repetitive clearing 
of the drain passage at the aft end of the main landing gear (MLG) 
truck beam to ensure moisture and contaminants within the truck beam 
can properly drain. That NPRM was prompted by reports of fracture of 
MLG truck beams. That condition, if not corrected, could result in 
either reduced controllability of the airplane or a fire.

Actions Since Issuance of Previous Proposal

    Since the issuance of that NPRM, the FAA has reviewed and approved 
Boeing Alert Service Bulletins 757-32A0135 (for Model 757-200 series 
airplanes), and 757-32A0138 (for Model 757-300 series airplanes), both 
dated June 8, 2000. The service bulletins describe procedures for 
repetitive clearing of the drain passage at the aft end of the truck 
beam of the MLG to ensure moisture and contaminants within the truck 
beam can properly drain. For certain airplanes, Service Bulletin 757-
32A0135 also specifies an internal inspection of the truck beam 
protective finish (plating and primer) to detect discrepancies, and 
either overhaul or replacement of the truck beam if the primer is 
flaked, cracked, or missing, or if corrosion is present. The service 
bulletin references Chapter 32-11-56 of the Boeing 757 Component 
Maintenance Manual for overhaul of the truck beam, and Chapter 32-11-17 
of the Boeing 757 Airplane Maintenance Manual for replacement of the 
truck beam.
    Additionally, a note has been added to the supplemental NPRM to 
give credit to operators that may have previously accomplished the 
clearing procedure in accordance with Boeing Service Letter 757-SL-32-
060, dated March 31, 1999, which was referenced as the appropriate 
source of service information in the NPRM.

Conclusion

    Since this change expands the scope of the originally proposed 
rule, the FAA has determined that it is necessary to reopen the comment 
period to provide additional opportunity for public comment.

Differences Between Proposed Rule and Alert Service Bulletins

    Operators should note that, although the alert service bulletins 
recommend repeating the clearing procedure at planned maintenance 
intervals (such as ``C'' checks), after accomplishment of the initial 
action, the FAA has determined that repeating the procedure at every 
``C'' check thereafter would not address the identified unsafe 
condition in a timely manner. In developing an appropriate compliance 
time for this AD, the FAA considered not only the manufacturer's 
recommendation, but the degree of urgency associated with addressing 
the subject unsafe condition, the average utilization of the affected 
fleet, and the time necessary to perform the inspection (less than one 
hour). In light of all of these factors, the FAA finds a compliance 
time of 4 years since the last overhaul of the MLG or since the date of 
manufacture of the MLG (for MLG that has not been overhauled), or 
within 90 days after the effective date of this AD, whichever occurs 
latest, for initiating the initial actions to be warranted. For the 
repetitive clearing procedures, the FAA finds an interval of 6 months, 
if the drain was previously found to be clogged, or 18 months, if the 
drain was previously found to be unclogged, to be warranted. The FAA 
finds that these intervals are warranted in that they represent 
appropriate intervals of time allowable for affected airplanes to 
continue to operate without compromising safety.

Cost Impact

    There are approximately 874 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 350 Model 757-200 series 
airplanes of U.S. registry would be affected by this AD.
    It would take approximately 1 work hour per airplane to accomplish 
the proposed inspection, at that the average labor rate of $60 per work 
hour. Based on these figures, the cost impact of the proposed 
inspection on U.S. operators is estimated to be $21,000, or $60 per 
airplane, per inspection cycle.
    For Group 1 airplanes, as listed in Boeing Alert Service Bulletin 
757-32A0135: It would take approximately 28 work hours per airplane to 
accomplish the proposed internal inspection, at an average labor rate 
of $60 per work hour. Based on these figures, the cost impact of the 
proposed inspection is estimated to be $1,680 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 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.
    Currently, there are no 757-300 series airplanes on the U.S. 
Register. However, should an affected airplane be imported and placed 
on the U.S. Register in the future, it would require approximately 1 
work hour to accomplish the proposed inspection, at an average labor 
rate of $60 per work hour. Based on these figures, the cost impact of 
this

[[Page 56270]]

inspection would be $60 per airplane, per inspection cycle.

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 adding the following new 
airworthiness directive:

Boeing: Docket 99-NM-124-AD.
    Applicability: Model 757-200 series airplanes as listed in 
Boeing Alert Service Bulletin 757-32A0135, dated June 8, 2000; and 
Model 757-300 series airplanes as listed in Boeing Alert Service 
Bulletin 757-32A0138, dated June 8, 2000; 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 (c) 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 stress corrosion cracking, leading to fracture of a 
main landing gear (MLG) truck beam during ground operations, which 
could result in either reduced controllability of the airplane or a 
fire, accomplish the following:

Repetitive Clearing Procedure

    (a) Within 4 years since the last overhaul of the MLG or since 
the date of manufacture of the MLG (for MLG that have not been 
overhauled), or within 90 days after the effective date of this AD, 
whichever occurs latest: Insert a wooden probe, or similar non-
metallic object, into the aft drain hole of the MLG truck beam, to 
clear the drain passage and ensure it can properly drain, in 
accordance with Boeing Alert Service Bulletin 757-32A0135 (for Model 
757-200 series airplanes), or 757-32A0138 (for Model 757-300 series 
airplanes), both dated June 8, 2000, as applicable.
    (1) If the aft drain hole is found unclogged, repeat the 
clearing procedure thereafter at intervals not to exceed 18 months.
    (2) If the aft drain hole is found clogged, repeat the clearing 
procedure thereafter at intervals not to exceed 6 months.

    Note 2: Previous accomplishment of the clearance of the drain 
passage in accordance with Boeing Service Letter 757-SL-32-060, 
dated March 31, 1999, is considered acceptable for compliance with 
the requirements specified in paragraph (a) of this AD.

Internal Inspection

    (b) For Group 1 airplanes as listed in Boeing Alert Service 
Bulletin 757-32A0135, dated June 8, 2000: Within 8 years since the 
date of manufacture of the MLG (for MLG that have not been 
overhauled), or within 6 months after the effective date of this AD, 
whichever occurs latest, perform an internal inspection of the truck 
beam protective finish (plating and primer) to detect discrepancies 
(flaked, cracked, missing finish, or corrosion), as illustrated in 
Figure 2 of the alert service bulletin.

Corrective Action

    (1) If no discrepancy is detected, prior to further flight, 
apply corrosion preventive compound in accordance with the 
Accomplishment Instructions of the alert service bulletin.
    (2) If any discrepancy is detected, prior to further flight, 
overhaul or replace the truck beam, as applicable, in accordance 
with the Accomplishment Instructions of the alert service bulletin.

    Note 3: Overhaul of the MLG prior to the effective date of this 
AD in accordance with Boeing Alert Service Bulletin 757-32A0135, 
dated June 8, 2000, is considered acceptable for compliance with the 
requirements specified in paragraph (b) of this AD.

Alternative Methods of Compliance

    (c) 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. 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 4: 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

    (d) 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 September 12, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-23855 Filed 9-15-00; 8:45 am]
BILLING CODE 4910-13-P