[Federal Register Volume 60, Number 197 (Thursday, October 12, 1995)]
[Rules and Regulations]
[Pages 53109-53110]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-25157]



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  Federal Register / Vol. 60, No. 197 / Thursday, October 12, 1995 / 
Rules and Regulations  

[[Page 53109]]


DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95-NM-190-AD; Amendment 39-9398; AD 95-20-51]


Airworthiness Directives; Boeing Model 767-200 and -300 Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This document publishes in the Federal Register an amendment 
adopting Airworthiness Directive (AD) T95-20-51 that was sent 
previously to all known U.S. owners and operators of Boeing Model 767-
200 and -300 series airplanes by individual telegrams. This AD requires 
inspections of the lower half of the aft trunnion of the main landing 
gear (MLG) to detect damage, cracking, missing pieces, or corrosion; 
and correction of discrepancies. This amendment is prompted by a report 
indicating that the MLG collapsed on an airplane due to fracture of the 
aft trunnion outer cylinder that was caused by stress corrosion 
cracking. The actions specified by this AD are intended to prevent the 
collapse of the MLG due to the problems associated with stress 
corrosion cracking in the aft trunnion assembly; collapse of the MLG 
could lead to loss of control of the airplane during landing, taxiing, 
and takeoff.

DATES: Effective October 17, 1995, to all persons except those persons 
to whom it was made immediately effective by telegraphic AD T95-20-51, 
issued September 25, 1995, which contained the requirements of this 
amendment. -
    Comments for inclusion in the Rules Docket must be received on or 
before December 11, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 95-NM-190-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. -
    Information concerning this AD may be examined at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington.

FOR FURTHER INFORMATION CONTACT: James G. Rehrl, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle 
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (206) 227-2783; fax (206) 227-1181.

SUPPLEMENTARY INFORMATION: On September 7, 1995, the FAA issued AD 95-
19-10, amendment 39-9372 (60 FR 47689, September 14, 1995), applicable 
to all Boeing Model 767 series airplanes. That AD requires operators to 
perform visual inspections of the outer cylinder aft trunnion on the 
main landing gear (MLG) to determine if the fillet seal is cracked or 
missing, and to correct any discrepancy or to perform follow-on 
actions, if necessary. That action was prompted by reports of fractures 
of the outer cylinder aft trunnion due to stress corrosion cracking. -
    Since the issuance of that AD, the FAA has received an additional 
report indicating that the MLG collapsed on a Model 767-300 series 
airplane due to fracture of the aft trunnion outer cylinder that was 
caused by stress corrosion cracking. In this reported incident, the 
right-hand MLG separated from the aft and forward trunnion support 
structure and penetrated the wing trailing edge. The airplane rolled to 
the right and came to rest on the right engine nacelle. Extensive 
damage occurred to the right-hand MLG and its support structure, the 
wing trailing edge, and the right engine and its support structure. 
Investigation revealed that this fracture differed from those reported 
previously in that it initiated at the crossbolt hole, approximately 
five inches from the aft trunnion bushing flange. -
    Stress corrosion cracking in the outer cylinder of the aft 
trunnion, if not corrected, could result in the collapse of the MLG 
under certain loading conditions. Such a collapse could lead to the 
loss of control of the airplane during landing, taxiing, and takeoff. -
    Consequently, the FAA has determined that the problem of stress 
corrosion cracking is not limited solely to the aft trunnion bushing, 
which was addressed in AD 95-19-10. The FAA finds that additional 
inspections must be performed in an expanded area of the aft trunnion 
assembly to ensure the safety of the affected fleet. These additional 
inspections must be performed in addition to, not in lieu of, the 
inspections required by AD 95-19-10. -
    Since the unsafe condition described is likely to exist or develop 
on other airplanes of the same type design, the FAA issued Telegraphic 
AD T95-20-51 to prevent the collapse of the MLG due to the problems 
associated with stress corrosion cracking in the aft trunnion assembly. 
The AD requires operators to perform an external general visual 
inspection of the lower half of the aft trunnion of the MLG to detect 
damage, cracking, missing pieces, or corrosion emanating from the aft 
trunnion bushing fillet seal or from the aft trunnion crossbolt hole. 
(This inspection is to be performed repetitively on airplanes having 
MLG's that are 4 years old or older.) Discrepancies are to be repaired 
in accordance with a method approved by the FAA. -
    Since it was found that immediate corrective action was required, 
notice and opportunity for prior public comment thereon were 
impracticable and contrary to the public interest, and good cause 
existed to make the AD effective immediately by individual telegrams 
issued on September 25, 1995, to all known U.S. owners and operators of 
Boeing Model 767-200 and -300 series airplanes. These conditions still 
exist, and the AD is hereby published in the Federal Register as an 
amendment to section 39.13 of the Federal Aviation Regulations (14 CFR 
39.13) to make it effective to all persons.
    The FAA considers this AD to be interim action until final action 
is identified, at which time the FAA may consider further rulemaking.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons 

[[Page 53110]]
are invited to comment on this 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 under the caption ADDRESSES. All communications received on 
or before the closing date for comments will be considered, and this 
rule may be amended in light of the comments received. Factual 
information that supports the commenter's ideas and suggestions is 
extremely helpful in evaluating the effectiveness of the AD action and 
determining whether additional rulemaking action would be needed. -
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the 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 that 
summarizes each FAA-public contact concerned with the substance of this 
AD will be filed in the Rules Docket. -
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 95-NM-190-AD.'' The postcard will be date stamped and 
returned to the commenter. -
    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. -
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and that it is not a ``significant regulatory 
action'' under Executive Order 12866. It has been determined further 
that this action involves an emergency regulation under DOT Regulatory 
Policies and Procedures (44 FR 11034, February 26, 1979). If it is 
determined that this emergency regulation otherwise would be 
significant under DOT Regulatory Policies and Procedures, a final 
regulatory evaluation will be prepared and placed in the Rules Docket. 
A copy of it, if filed, 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, Safety.

Adoption of the Amendment -

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 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 USC 106(g), 40101, 40113, 44701.


Sec. 39.13  [Amended] -

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

    95-20-51  Boeing: Amendment 39-9398. Docket 95-NM-190-AD.

    -Applicability: All Model 767-200 and 767-300 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 
otherwise 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 use the authority 
provided in paragraph (d) of this AD to request approval from the 
FAA. This approval may address either no action, if the current 
configuration eliminates the unsafe condition; or different actions 
necessary to address the unsafe condition described in this AD. Such 
a request should include an assessment of the effect of the changed 
configuration on the unsafe condition addressed by this AD. In no 
case does the presence of any modification, alteration, or repair 
remove any airplane from the applicability of this AD.

     -Compliance: Required as indicated, unless accomplished 
previously. -
    To prevent the collapse of the main landing gear due to stress 
corrosion cracking in the outer cylinder of the aft trunnion, 
accomplish the following:

    -Note 2: The inspections required by this AD are in addition to, 
not in lieu of, the inspections required by AD 95-19-10, amendment 
39-9372.

    -(a) Within 48 clock hours (not flight hours) after the 
effective date of this AD, perform an external general visual 
inspection of the lower half of the aft trunnion of the main landing 
gear (MLG) to detect obvious signs of damage, cracking, missing 
pieces; or obvious visible corrosion emanating from the aft trunnion 
bushing fillet seal or from the aft trunnion crossbolt hole.

    -Note 3: For the purpose of this AD, ``external general visual 
inspection'' means that the inspection is to be conducted within one 
foot of the area to be inspected. If necessary, the area should be 
wiped clean with a rag. Finally, mirrors and additional lighting 
should be used, as needed, to increase the probability of visually 
detecting discrepancies. This inspection does not require 
disassembly of the MLG.

     -(b) Prior to four years from the date the MLG is placed in 
service or overhauled, or within 48 clock hours (not flight hours) 
after the inspection required by paragraph (a) of this AD is 
accomplished, whichever occurs later, repeat the inspection required 
by paragraph (a) of this AD. Thereafter, repeat the inspection at 
intervals not to exceed 48 clock hours. -
    (c) If any discrepancy is detected during any inspection 
required by this AD, prior to further flight, repair in accordance 
with a method approved by the Manager, Seattle Aircraft 
Certification Office (ACO), FAA, Transport Airplane Directorate. -
    (d) 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 4: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

     -(e) 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. -
    (f) This amendment becomes effective on October 17, 1995, to all 
persons except those persons to whom it was made immediately 
effective by telegraphic AD T95-20-51, issued on September 25, 1995, 
which contained the requirements of this amendment.

    Issued in Renton, Washington, on October 4, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-25157 Filed 10-11-95; 8:45 am]
BILLING CODE 4910-13-U