[Federal Register Volume 59, Number 29 (Friday, February 11, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-3105]


[[Page Unknown]]

[Federal Register: February 11, 1994]


-----------------------------------------------------------------------


DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 94-NM-02-AD; Amendment 39-8822; AD 94-04-04]

 

Airworthiness Directives; Boeing Model 757 Series Airplanes 
Equipped With Rolls Royce Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

-----------------------------------------------------------------------

SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to certain Boeing Model 757 series airplanes. This action 
requires inspections to detect fatigue-related cracking or breakage of 
the hydraulic tubing support brackets located on the upper spar web in 
the engine struts; further inspection to detect related damage of the 
upper spar web, the fuel lines, and the hydraulic lines, as necessary; 
and repair or replacement of cracked or damaged parts. This action also 
provides for an optional terminating action which, if accomplished, 
would eliminate the need for the required inspections. This amendment 
is prompted by reports of fatigue-related cracks in the hydraulic 
tubing support brackets located on the upper spar web in the engine 
struts. The actions specified in this AD are intended to prevent fire 
or explosion in the interior of the engine struts.

DATES: Effective February 28, 1994.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of February 28, 1994.
    Comments for inclusion in the Rules Docket must be received on or 
before April 12, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 94-NM-02-AD, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056.
    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 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.

FOR FURTHER INFORMATION CONTACT: Sheila Mariano, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130S, FAA, Transport Airplane 
Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue, 
SW., Renton, Washington 98055-4056; telephone (206) 227-2675; fax (206) 
227-1182.

SUPPLEMENTARY INFORMATION: The FAA has recently received reports from 
Boeing that operators have reported fatigue-related cracks in the 
hydraulic tubing support brackets located on the upper spar web of the 
engine struts in several Model 757 series airplanes. The cracked 
support brackets were manufactured from 2219 aluminum alloy. On one 
airplane, a support bracket cracked completely and the clamp assembly 
wore a hole in the upper spar web. (A bracket that is completely 
cracked can permit the clamp assembly to loosen and rotate on the 
hydraulic line.) On another airplane, a support bracket cracked 
completely and the clamp assembly wore a hole in the fuel feed line 
located next to the hydraulic pressure line.
    The interior part of the strut contains ignition sources. The upper 
spar web acts as a seal to keep fluids and vapors from hydraulic lines 
and fuel lines out of the interior part of the strut, where the 
pneumatic bleed air ducts are located. If fluids leak from the fuel 
line or the hydraulic lines that are on top of the upper spar web, 
those fluids will drain from the strut through the strut drain system. 
If the upper spar web has a hole in it and fuel or hydraulic fluid 
leaks occur, then those fluids could drain into the interior of the 
strut. The surface temperatures of the bleed air ducts are hot enough 
to be an ignition source. Fatigue-related cracking in the hydraulic 
tubing support brackets, if not detected and corrected in a timely 
manner, could result in fuel or hydraulic fluid leaking and draining 
into the interior of the strut, which could result in fire or 
explosion.
    The FAA has reviewed and approved Boeing Alert Service Bulletin 
757-54A-0030, Revision 1, dated December 20, 1993, that describes 
procedures for performing a one-time inspection on Group Two airplanes 
using a magnet to determine whether the forward support bracket for the 
hydraulic tubing in the upper spar web of each strut is manufactured 
from 17-7PH steel. (No further inspection is recommended for support 
brackets manufactured from 17-7PH steel, since it is not subject to the 
identified fatigue cracking problems.) For Group Two airplanes, the 
forward bracket is manufactured from either 17-7PH steel or 2219 
aluminum alloy; the remainder of the support brackets (two to four 
brackets) are manufactured from 17-7PH steel. Group One airplanes are 
not equipped with 17-PH steel brackets. The alert service bulletin also 
describes procedures for performing an initial visual inspection to 
detect fatigue-related cracking or breakage of all non-17-7PH steel 
support brackets. If any completely broken or cracked support bracket 
is found as a result of the initial inspection, this alert service 
bulletin describes procedures for performing a further visual 
inspection to detect related damage of the upper spar web, the fuel 
lines, and the hydraulic lines, as necessary; repair or replacement of 
damaged parts with new or serviceable parts; and removal of any broken 
or cracked support brackets. This alert service bulletin also describes 
procedures for replacing the existing support brackets with new nickel 
alloy support brackets. Finally, this alert service bulletin recommends 
that a limited number of flights be permitted prior to replacement of 
any removed support bracket with a new nickel alloy support bracket.-
    Since an unsafe condition has been identified that is likely to 
exist or develop on other Boeing Model 757 series airplanes of the same 
type design, this AD is being issued to prevent fire or explosion in 
the interior of the engine struts. This AD requires the following 
actions: -
    1. A one-time inspection using a magnet to determine whether the 
forward support bracket for the hydraulic tubing in the upper spar web 
of each engine strut is manufactured from 17-7PH steel. No further 
action is necessary for support brackets manufactured from 17-7PH 
steel. -
    2. An initial visual inspection to detect fatigue-related cracking 
or breakage of all support brackets that are not manufactured from 17-
7PH steel. -
    3. If any completely broken or cracked support bracket is found as 
a result of the initial inspection, a further visual inspection to 
detect related damage of the upper spar web, the fuel lines, and the 
hydraulic lines, as necessary.
    4. Repair or replacement of damaged parts with new or serviceable 
parts.
    5. Removal and replacement of any broken or cracked support 
brackets.
    The actions are required to be accomplished in accordance with the 
alert service bulletin described previously.
    This AD also requires repetitive inspections for airplanes having 
one or more support brackets that are manufactured from 2219 aluminum, 
2024-T42 aluminum alloy, or 301 stainless steel. The repetitive 
inspections would be required to be performed in accordance with the 
procedures described in the alert service bulletin.
    This AD also provides for replacement of the existing support 
brackets on the upper spar web of each engine strut with new nickel 
alloy support brackets. If accomplished at all locations, this 
replacement would terminate the need for all of the required 
inspections. If accomplished, this replacement is required to be 
performed in accordance with the alert service bulletin described 
previously.
    This AD specifies that if certain brackets are found cracked or 
broken, a certain number of further flights are allowed prior to 
replacement of the bracket, provided that:
    (1) Cracked or broken brackets are removed completely;
    (2) Damaged spar webs are repaired, and
    (3) Damaged fuel lines and hydraulic lines are repaired or 
replaced.
    This is considered to be interim action. The FAA is currently 
considering requiring the replacement of all existing support brackets 
manufactured from 2219 aluminum, 2024-T42 aluminum alloy, or 301 
stainless steel with new nickel alloy support brackets, which will 
constitute terminating action for the inspections required by this AD 
action. However, the proposed compliance time for the installation of 
the modification is sufficiently long so that notice and public comment 
would not be impracticable. -
    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.
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 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 notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 94-NM-02-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 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, 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:

94-04-04 Boeing: Amendment 39-8822. Docket 94-NM-02-AD.

     -Applicability: Model 757 series airplanes equipped with Rolls 
Royce engines; as listed in Boeing Alert Service Bulletin 747-
54A0030, Revision 1, dated December 20, 1993; certificated in any 
category. -
    Compliance: Required as indicated, unless accomplished 
previously. -
    To prevent fire or explosion in the interior of the engine 
struts, accomplish the following:
    (a) For Group 2 Airplanes: Within 60 days after the effective 
date of this AD, perform an inspection using a magnet to determine 
whether the forward support bracket for the hydraulic tubing on the 
upper spar web of each engine strut is manufactured from 17-7PH 
steel, in accordance with Boeing Alert Service Bulletin 757-54A0030, 
Revision 1, dated December 20, 1993. If any forward support bracket 
is manufactured from 17-7PH steel, no further action is required by 
this AD for that forward bracket.

    Note 1: The brackets positioned after the forward bracket should 
be manufactured from 17-7PH steel, as shown below: 

------------------------------------------------------------------------
                                                            (Power plant
                   Bracket-part number-                       station   
                                                              number)   
------------------------------------------------------------------------
-First Bracket-312N5817-13 (or equivalent)-..............  PPS 102      
Second Bracket-312N5817-19 (or equivalent)-..............  PPS 120      
Third Bracket-312N5817-23 (or equivalent)-...............  PPS 129      
Fourth Bracket-312N5817-25 (or equivalent)-..............  PPS 145      
------------------------------------------------------------------------

    (b) For Groups 1 and 2 Airplanes: Within 60 days after the 
effective date of this AD (for Group 1 airplanes), and prior to further 
flight following the inspection required by paragraph (a) of this AD 
(for Group 2 airplanes), perform an initial visual inspection to detect 
fatigue-related cracks or breakage on the hydraulic tubing support 
brackets not manufactured of 17-7PH steel on the upper spar web of each 
engine strut, in accordance with Boeing Alert Service Bulletin 757-
54A0030 , Revision 1, dated December 20, 1993. If any discrepancy is 
detected, prior to further flight, accomplish the following in 
accordance with the alert service bulletin:
    (1) For any support bracket that is completely broken: Perform a 
further visual inspection to detect worn areas or other damage of the 
upper spar web, the fuel lines, and the hydraulic lines; and prior to 
further flight, accomplish paragraphs (b)(1)(i), (b)(1)(ii), 
(b)(1)(iii) and (b)(1)(iv) of this AD in accordance with the alert 
service bulletin:
    (i) Repair any damaged upper spar web.
    (ii) Repair or replace any damaged fuel line with new or 
serviceable parts, as necessary.
    (iii) Replace any damaged hydraulic line with new or serviceable 
parts.
    (iv) Remove any broken support bracket; and, except as provided by 
paragraph (c) of this AD, replace it with a new nickel alloy bracket.
    (2) For any support bracket that is cracked, but not completely 
broken: Perform a further visual inspection to detect damage of the 
hydraulic pressure line only; and prior to further flight, accomplish 
paragraphs (b)(2)(i) and (b)(2)(ii) of this AD in accordance with the 
alert service bulletin:
    (i) Replace any damaged hydraulic pressure line with new or 
serviceable parts, as necessary.
    (ii) Remove any cracked support bracket; and, except as provided by 
paragraph (c) of this AD, replace it with a new nickel alloy bracket.
    (c) For any airplane having a support bracket that is removed 
during accomplishment of paragraph (b)(1)(iv) or (b)(2)(ii) of this AD: 
The following number of flights are permitted prior to replacement of 
any removed support bracket with a new nickel alloy bracket (in 
accordance with Boeing Alert Service Bulletin 757-54A0030, Revision 1, 
dated December 20, 1993), provided that, prior to further flight, the 
cracked or broken brackets are removed completely, damaged spar webs 
are repaired, and fuel lines and hydraulic lines are repaired or 
replaced, in accordance with paragraph (b) of this AD: 

------------------------------------------------------------------------
  Bracket-part number-(power plant                                      
          station number)                     Flights permitted         
------------------------------------------------------------------------
First Bracket Removed P/N 312N5817-   No Flights.                       
 55 (PPS 102)-.                                                         
Second Bracket Removed P/N 312N5817- Ten Flights.                       
 69 (PPS 120)-.                                                         
Third Bracket Removed P/N 312N5817-  Ten Flights.                       
 73 (PPS 129)-.                                                         
Fourth Bracket Removed P/N 312N5817- Three Flights.                     
 75 (PPS 145)-.                                                         
Second and Third Brackets Removed-.  One Flight.                        
Multiple Brackets, other than        No Flights.                        
 Second and Third-.                                                     
------------------------------------------------------------------------

    (d) For any airplane having a support bracket that is manufactured 
from 2024-T42 aluminum alloy or 301 stainless steel: Repeat the initial 
inspection required by paragraph (b) of this AD thereafter at intervals 
not to exceed 2,000 flight hours in accordance with the procedures 
described in Boeing Alert Service Bulletin 757-54A0030, Revision 1, 
dated December 20, 1993.
    (e) For any airplane having a support bracket that is manufactured 
from 2219 aluminum: Repeat the initial inspection required by paragraph 
(b) of this AD thereafter at intervals not to exceed 1,000 flight hours 
in accordance with the procedures described in Boeing Alert Service 
Bulletin 757-54A0030, Revision 1, dated December 20, 1993.
    (f) Installation of new nickel alloy hydraulic tubing support 
brackets for the hydraulic tubing on the upper spar web of the engine 
struts at all locations in accordance with the requirements of Boeing 
Alert Service Bulletin 757-54A0030, Revision 1, dated December 20, 
1993, constitutes terminating action for the requirements of this AD.
    (g) As of the effective date of this AD, no person shall install 
any hydraulic tubing support bracket on the upper spar web of the 
engine struts that is manufactured from 2219 aluminum, 2024-T42 
aluminum alloy, or 301 stainless steel on any airplane.
    (h) 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.

    (i) Special flight permits may be issued in accordance with FAR 2nd 
21.199 to operate the airplane to a location where the requirements of 
this AD can be accomplished.
    (j) The inspections, repairs and replacement shall be done in 
accordance with Boeing Alert Service Bulletin 757-54A0030, Revision 1, 
dated December 20, 1993. This incorporation by reference was approved 
by the Director of the Federal Register in accordance with 5 U.S.C. 
552(a) and 1 CFR part 51. 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.
    (k) This amendment becomes effective on February 28, 1994.

    Issued in Renton, Washington, on February 4, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-3105 Filed 2-10-94; 8:45 am]
BILLING CODE 4910-13-U