[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
