[Federal Register Volume 62, Number 80 (Friday, April 25, 1997)]
[Rules and Regulations]
[Pages 20098-20100]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-10661]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 97-NM-73-AD; Amendment 39-10002; AD 97-09-06]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 757 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
-----------------------------------------------------------------------
SUMMARY: This amendment adopts a new airworthiness directive (AD) that
is applicable to all Boeing Model 757 series airplanes. This action
requires repetitive inspections to detect damage of the tubes of the
fire extinguishing and smoke detection systems, and duct support
brackets of the auxiliary power unit (APU); and corrective actions, if
necessary. This amendment is prompted by reports of incidents in which
the tubes of the fire extinguishing and smoke detection systems chafed
against the stiffener rings and support brackets of the pneumatic duct
of the APU. The actions specified in this AD are intended to detect and
correct such chafing, which could result in a hole in the tube of the
fire extinguishing system and consequently, could prevent the proper
distribution of the fire extinguishing agent within the aft cargo
compartment in the event of a fire. Such chafing also could result in a
hole in the smoke detection system, which could result in the delay of
detection of a fire in the aft cargo compartment.
DATES: Effective May 15, 1997.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of May 12, 1997.
Comments for inclusion in the Rules Docket must be received on or
before June 24, 1997.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 97-NM-73-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: Clayton R. Morris, Jr., Aerospace
Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft
Certification Office, 1601 Lind Avenue, SW., Renton, Washington;
telephone (206) 227-2794; fax (206) 227-1181.
SUPPLEMENTARY INFORMATION: The FAA has received several reports of
incidents in which the tubes of the fire extinguishing and smoke
detection systems of the aft cargo compartment chafed against the
stiffener rings and support brackets of the pneumatic duct of the
auxiliary power unit (APU). These incidents occurred on Boeing Model
757 series airplanes. Investigation revealed that thermal growth of the
pneumatic duct of the APU caused the stiffener rings to contact the
tubes. Such thermal growth also can cause a stiffener ring to contact a
support bracket of the pneumatic duct of the APU, which could
eventually break the support bracket. A broken support bracket could
chafe the tubes of the fire extinguishing and smoke detection systems
of the aft cargo compartment. Chafing of the subject tubes could
eventually create a hole in the tubes.
[[Page 20099]]
Unsafe Conditions
A hole in the tubes of the fire extinguishing system, if not
detected and corrected, could prevent the proper distribution of the
fire extinguishing agent within the aft cargo compartment in the event
of a fire. In addition, such a hole could release the fire
extinguishing agent outside of the aft cargo compartment, which could
migrate through the return air grilles in the passenger cabin.
Localized hazardous concentrations of a fire extinguishing agent could
cause deleterious physiological effects on the passengers and crew.
Additionally, a hole in the tubes of the smoke detection system, if
not detected and corrected, could result in the delay of detection of a
fire in the aft cargo compartment.
Explanation of Relevant Service Information
The FAA has reviewed and approved Boeing Alert Service Bulletin
757-26A0040, dated March 27, 1997. The alert service bulletin describes
procedures for repetitive detailed visual inspections to detect damage
of the tubes of the fire extinguishing and smoke detection systems, and
support brackets of the pneumatic duct of the APU. The alert service
bulletin also describes procedures for replacing, repairing, or
splicing (as applicable) any damaged part.
Explanation of the Requirements of the Rule
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 detect and correct chafing of
the tubes of the fire extinguishing and smoke detection systems. Such
chafing could result in a hole in a tube of the fire extinguishing
system, and consequently prevent the proper distribution of the fire
extinguishing agent within the aft cargo compartment in the event of a
fire. Such chafing also could result in a hole in a tube of the smoke
detection system, which could result in the delay of detection of a
fire in the aft cargo compartment. This AD requires repetitive detailed
visual inspections to detect damage of the tubes of the fire
extinguishing and smoke detection systems, and support brackets of the
pneumatic duct of the APU; and corrective actions, if necessary. The
actions are required to be accomplished in accordance with the alert
service bulletin described previously.
Interim Action
This is considered to be interim action until final action is
identified, at which time the FAA may consider further rulemaking.
Determination of Rule's Effective Date
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 rule must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 97-NM-73-AD.'' The postcard will be date stamped and
returned to the commenter.
Regulatory Impact
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, Incorporation by
reference, 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 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
97-09-06 Boeing: Amendment 39-10002. Docket 97-NM-73-AD.
Applicability: All Model 757 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 request approval for an
alternative method of compliance in accordance with paragraph (b) 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
[[Page 20100]]
been eliminated, the request should include specific proposed
actions to address it.
Compliance: Required as indicated, unless accomplished
previously.
To detect and correct chafing of the tubes of the fire
extinguishing and smoke detection systems, which could prevent the
proper distribution of the fire extinguishing agent within the aft
cargo compartment in the event of a fire, or could result in the
delay of detection of a fire in the aft cargo compartment,
accomplish the following:
(a) Prior to the accumulation of 10,000 flight hours, or within
60 days after the effective date of this AD, whichever occurs later,
accomplish paragraphs (a)(1), (a)(2), and (a)(3) of this AD, in
accordance with Boeing Alert Service Bulletin 757-26A0040, dated
March 27, 1997. Repeat all inspections thereafter at intervals not
to exceed 10,000 flight hours.
(1) Perform a detailed visual inspection to detect damage of the
tubes of the fire extinguishing system between stations 1300 and
1580, as applicable, in accordance with the alert service bulletin.
If any damaged tube is detected, prior to further flight, repair or
replace it with a new tube, in accordance with the alert service
bulletin.
(2) Perform a detailed visual inspection to detect damage of the
tubes of the smoke detection system between stations 1300 and 1580,
in accordance with the alert service bulletin.
(i) If any damage is detected, and the damage is within the
limits specified in the alert service bulletin, prior to further
flight, repair it in accordance with the alert service bulletin.
(ii) If any damage is detected, and the damage is outside the
limits specified in the alert service bulletin, prior to further
flight, splice any damaged tube or replace it with a new tube, in
accordance with the alert service bulletin.
(3) Perform a detailed visual inspection to detect damage of the
support brackets of the pneumatic duct of the auxiliary power unit
(APU) at stations 1380, 1460, and 1540, in accordance with the alert
service bulletin. If any damage is detected, prior to further
flight, repair any damaged duct support bracket, or replace it with
a new duct support bracket, in accordance with the alert service
bulletin.
(b) 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.
(c) 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.
(d) The actions shall be done in accordance with Boeing Alert
Service Bulletin 757-26A0040, dated March 27, 1997. 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.
(e) This amendment becomes effective on May 12, 1997.
Issued in Renton, Washington, on April 18, 1997.
James V. Devany,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 97-10661 Filed 4-24-97; 8:45 am]
BILLING CODE 4910-13-U