Airworthiness Directives; Boeing Model 747 and 767 Series Airplanes Equipped with Rolls-Royce Model RB211-524G/H Engines

[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]


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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.

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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

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