[Federal Register Volume 63, Number 160 (Wednesday, August 19, 1998)]
[Rules and Regulations]
[Pages 44372-44374]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-22242]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-NM-194-AD; Amendment 39-10715; AD 98-17-13]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 747 and 767 Series
Airplanes Equipped with Rolls-Royce Model RB211-524G/H Engines
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
-----------------------------------------------------------------------
SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to certain Boeing Model 747 and 767 series airplanes. This
action requires modification of the engine fire detection system. This
amendment is prompted by a report of a combustor burn-through event
that damaged the engine fire detection system such that no fire warning
message was annunciated in the flight deck. The actions specified in
this AD are intended to prevent failure of the engine fire detection
system to annunciate a fire warning message to the flight crew
following a severe engine failure, which could lead to delayed or
improper flight crew response to the engine failure.
DATES: Effective September 3, 1998.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of September 3, 1998.
Comments for inclusion in the Rules Docket must be received on or
before October 19, 1998.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 98-NM-194-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: Holly Thorson, Aerospace Engineer,
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification
Office, 1601 Lind Avenue, SW., Renton, Washington; telephone (425) 227-
1357; fax (425) 227-1181.
SUPPLEMENTARY INFORMATION: The FAA has received a report of a combustor
burn-through event on the number 4 engine on a Boeing Model 747-400
series airplane equipped with Rolls-Royce Model RB211-524G engines. The
flight crew received a fault advisory message for the engine fire
detection system, but no fire warning message was annunciated. The
cabin crew and control tower observed sparks emitting from the number 4
engine and alerted the flight crew.
Subsequent investigation revealed that the flame breakout burned
through the wiring to the loop A and B fire detector elements, which
shorted both elements to ground, disabling the engine fire detection
system. At least one of the elements shorted to the grounded
[[Page 44373]]
protective shield on the wiring. The element connectors on the fire
detector are located in an area susceptible to combustor burn-through
events; damage to these connectors also could result in a short to
ground, disabling the engine fire detection system.
When both elements of an engine fire detector short to ground, a
system fault advisory message is displayed in the flight deck, but no
fire warning message is annunciated. Failure of the engine fire
detection system to annunciate a fire warning message to the flight
crew following a severe engine failure, if not corrected, could lead to
delayed or improper flight crew response to the engine failure.
The engine fire detection system on Rolls-Royce Model RB211-524H
engines is identical to the engine fire detection system installed on
Rolls-Royce Model RB211-524G engines. Both engine models can be
installed on Model 747 series airplanes; Model RB211-524H engines are
also installed on Model 767 series airplanes. Therefore, both of these
airplane and engine models may be subject to the same unsafe condition.
Explanation of Relevant Service Information
Boeing has issued Alert Service Bulletin 747-26A2250, dated June
26, 1997 (for Model 747 series airplanes), and Alert Service Bulletin
767-26A0103, dated June 26, 1997 (for Model 767 series airplanes),
which describe procedures for modification of the engine fire detection
system. This modification includes: Extension of the fire detectors to
provide 360-degree protection around the combustor, removal of the
grounded protective shield from the fire detector wiring, re-routing of
the wire bundles away from the burn-through region, and replacement of
the element connectors with terminal lug screw connections.
Accomplishment of the modification of the engine fire detection system
specified in the alert service bulletins is intended to adequately
address the identified unsafe condition.
Explanation of Requirements of the Rule
Since an unsafe condition has been identified that is likely to
exist or develop on other airplanes of the same type design, this AD is
being issued to prevent failure of the engine fire detection system
following a severe engine failure. This AD requires modification of the
engine fire detection system. The actions are required to be
accomplished in accordance with the alert service bulletins described
previously, except as discussed below.
Differences Between Rule and Alert Service Bulletin
Operators should note that, although the alert service bulletins
identify only certain Model 747 and 767 series airplanes, this AD
applies to any Model 747 and 767 series airplane equipped with Rolls-
Royce Model RB211-524G/H engines. The engines installed on the
airplanes identified in the alert service bulletins may be installed on
other Model 747 and 767 series airplanes; therefore, the FAA has
determined that this AD must apply to all Model 747 and 767 series
airplanes that are equipped with Rolls-Royce Model RB211-524G/H
engines.
Operators also should note that, although the alert service
bulletins do not recommend accomplishing the modification within
specific time period, this AD requires that the modification be
accomplished at the next shop visit of an engine or combustor module,
but no later than 5 years after the effective date of the AD. The 5-
year compliance time specified in paragraph (a) of this AD should allow
ample time for the modification to be accomplished coincidentally with
scheduled shop visits for the majority of affected engines and
represents an appropriate interval of time allowable for affected
airplanes to continue to operate without compromising safety.
Cost Impact
None of the Boeing Model 747 and 767 series airplanes affected by
this action are on the U.S. Register. All airplanes included in the
applicability of this rule currently are operated by non-U.S. operators
under foreign registry; therefore, they are not directly affected by
this AD action. However, the FAA considers that this rule is necessary
to ensure that the unsafe condition is addressed in the event that any
of these subject airplanes are imported and placed on the U.S. Register
in the future.
Should an affected Boeing Model 747 series airplane be imported and
placed on the U.S. Register in the future, it would require
approximately 64 work hours (16 hours per engine; 4 engines per
airplane) to accomplish the required modification, at an average labor
rate of $60 per work hour. Required parts would cost approximately
$56,000 per airplane ($14,000 per engine). Based on these figures, the
cost impact of this AD would be $59,840 per airplane.
Should an affected Boeing Model 767 series airplane be imported and
placed on the U.S. Register in the future, it would require
approximately 32 work hours (16 hours per engine; 2 engines per
airplane) to accomplish the required modification, at an average labor
rate of $60 per work hour. Required parts would cost approximately
$28,000 per airplane ($14,000 per engine). Based on these figures, the
cost impact of this AD would be $29,920 per airplane.
Determination of Rule's Effective Date
Since this AD action does not affect any airplane that is currently
on the U.S. register, it has no adverse economic impact and imposes no
additional burden on any person. Therefore, prior notice and public
procedures hereon are unnecessary and the amendment may be made
effective in less than 30 days after publication in the Federal
Register.
Comments Invited
Although this action is in the form of a final rule and was not
preceded by notice and 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 98-NM-194-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
[[Page 44374]]
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.
For the reasons discussed above, I certify that this action (1) is
not a ``significant regulatory action'' under Executive Order 12866;
(2) is not a ``significant rule'' under DOT Regulatory Policies and
Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action
and it is contained in the Rules Docket. A copy of it 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:
98-17-13 Boeing: Amendment 39-10715. Docket 98-NM-194-AD.
Applicability: Model 747 and 767 series airplanes, equipped with
Rolls-Royce Model RB211-524G/H engines; 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 (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 been
eliminated, the request should include specific proposed actions to
address it.
Compliance: Required as indicated, unless accomplished
previously.
To prevent failure of the engine fire detection system to
annunciate a fire warning message to the flight crew following a
severe engine failure, which could lead to delayed or improper
flight crew response to the engine failure, accomplish the
following:
(a) At the next shop visit of an engine or combustor module, but
no later than 5 years after the effective date of this AD, modify
the engine fire detection system in accordance with Boeing Alert
Service Bulletin 747-26A2250, dated June 26, 1997 (for Model 747
series airplanes) or Boeing Alert Service Bulletin 767-26A0103,
dated June 26, 1997 (for Model 767 series airplanes); as applicable.
(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 modification shall be done in accordance with Boeing
Alert Service Bulletin 747-26A2250, dated June 26, 1997; or Boeing
Alert Service Bulletin 767-26A0103, dated June 26, 1997; as
applicable. 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 September 3, 1998.
Issued in Renton, Washington, on August 12, 1998.
John J. Hickey,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 98-22242 Filed 8-18-98; 8:45 am]
BILLING CODE 4910-13-U