Airworthiness Directives; Boeing Model 747-200B, -300, -400, -400D, and -400F Series Airplanes

[Federal Register Volume 65, Number 69 (Monday, April 10, 2000)]
[Rules and Regulations]
[Pages 18881-18883]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-8393]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-87-AD; Amendment 39-11664; AD 2000-07-10]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-200B, -300, -400, -
400D, and -400F Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to certain Boeing Model 747-200B, -300, -400, -400D, and 
-400F series airplanes. This action requires repetitive inspections to 
detect cracking of fire extinguisher discharge tubes in certain engine 
struts, and corrective action, if necessary. For certain airplanes, 
this action also provides for a modification of the fire extinguisher 
discharge tubes, which constitutes terminating action for the 
repetitive inspections. This amendment is prompted by reports that 
cracked fire extinguisher discharge tubes have been found in the engine 
struts on certain airplanes. The actions specified in this AD are 
intended to detect and correct cracked fire extinguishing tubes in the 
engine struts. In the event of an engine fire, such cracked tubes could 
reduce the amount of fire extinguishing agent that can be delivered to 
the engine, and could result in a fire spreading from the engine to the 
wing of the airplane.

DATES: Effective April 25, 2000.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of April 25, 2000.
    Comments for inclusion in the Rules Docket must be received on or 
before June 9, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2000-NM-87-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: Sulmo Mariano, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Transport Airplane Directorate, 
Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (425) 227-2686; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION: The FAA has recently received reports 
indicating that several operators have found cracked fire extinguisher 
discharge tubes in the number 2 and number 3 struts on several Boeing 
Model 747-400 series airplanes that are equipped with General Electric 
(GE) CF6-80C2 series engines. Further investigation revealed similarly 
cracked fire extinguisher discharge tubes on Boeing Model 747-400 
series airplanes equipped with Pratt & Whitney PW4000 series engines, 
which incorporate a similar tube installation. The cause of the 
cracking has been attributed to installation preload and flexing of the 
tube due to motion between the wing and the strut.
    The subject fire extinguisher discharge tubes extend from the fire 
extinguisher bottles to the number 2 and number 3 engine struts, and 
are intended to deliver fire extinguishing agent to the engine in the 
event of an engine fire. Similar designs exist in Boeing Model 747-200B 
and -300 series airplanes equipped with GE CF6-80C2 series engines. A 
cracked tube could reduce the amount of fire extinguishing agent that 
can be delivered to the engine. In the worst case (a broken tube), no 
fire-extinguishing agent would be delivered to the engine. This 
condition, if not corrected, could result in a fire spreading from the 
engine to the wing of the airplane.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
747-26A2266, dated March 3, 2000. That alert service bulletin describes 
procedures for repetitive detailed visual inspections to detect 
cracking of fire extinguisher discharge tubes in the number 2 and 
number 3 engine struts. The alert service bulletin also describes 
procedures for replacement of any cracked tube with a new or 
serviceable tube.
    The FAA also has reviewed and approved Boeing Service Bulletin 747-
26-2233, dated May 11, 1995. That service bulletin applies to Model 
747-400 series airplanes equipped with Pratt & Whitney PW4000 series 
engines and describes procedures for a modification

[[Page 18882]]

of the fire extinguisher discharge tubes in the number 2 and number 3 
engine struts, and a post-modification test of the fire extinguishing 
system to ensure that it functions properly. The modification is 
intended to prevent cracked fire extinguishing tubes by rerouting the 
fire extinguisher discharge tubes along the front spar and changing the 
orientation of two wire bundle clamps in the number 2 engine strut. 
Accomplishment of the modification eliminates the need for the 
repetitive inspections described previously on the subject airplanes.

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 747-200B, -300, -400, -400D, and 
-400F series airplanes of the same type design, this AD is being issued 
to detect and correct cracked fire extinguishing tubes in the engine 
struts. In the event of an engine fire, such cracked tubes could reduce 
the amount of fire extinguishing agent that can be delivered to the 
engine, and could result in a fire spreading from the engine to the 
wing of the airplane. This AD requires repetitive detailed visual 
inspections to detect cracking of fire extinguisher discharge tubes in 
certain engine struts, and replacement of any cracked tube with a new 
or serviceable tube. These actions are required to be accomplished in 
accordance with Boeing Alert Service Bulletin 747-26A2266. For Boeing 
Model 747-400 series airplanes equipped with Pratt & Whitney PW4000 
series engines, this AD also provides for a modification of the fire 
extinguisher discharge tubes, which constitutes terminating action for 
the repetitive inspections. If accomplished, that modification is 
required to be accomplished in accordance with Boeing Service Bulletin 
747-26-2233.

Explanation of Applicability

    Though Boeing Alert Service Bulletin 747-26A2266 specifies that it 
applies to airplanes having line numbers 679 through 1062 inclusive, 
this AD applies to airplanes having line numbers 679 through 1061 
inclusive. The alert service bulletin states that the intent of Boeing 
Service Bulletin 747-26-2233 was accomplished (by service bulletin 
validation) prior to delivery on the airplane having line number 1062. 
As stated previously, accomplishment of Boeing Service Bulletin 747-26-
2233 constitutes terminating action for the requirements of this AD for 
Boeing Model 747-400 series airplanes equipped with Pratt & Whitney 
PW4000 series engines. Therefore, the airplane with line number 1062 is 
not included in the applicability statement of this AD.

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 2000-NM-87-AD.'' The postcard will be date stamped and 
returned to the commenter.

Regulatory Impact

    The regulations adopted herein will not have a substantial direct 
effect 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, it 
is determined that this final rule does not have federalism 
implications under Executive Order 13132.
    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 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:

2000-07-10  Boeing: Amendment 39-11664. Docket 2000-NM-87-AD.

    Applicability: Model 747-200B, -300 series airplanes equipped 
with General Electric (GE) CF6-80C2 series engines, and Model 747-
400, 747-400D, and 747-400F series airplanes equipped with General 
Electric (GE) CF6-80C2 series engines or Pratt & Whitney PW4000 
series engines; line numbers (L/N) 679 through 1061 inclusive; 
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 (c) of 
this AD. The request should include an assessment of

[[Page 18883]]

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 detect and correct cracked fire extinguishing tubes in the 
engine struts, which, in the event of an engine fire, could reduce 
the amount of fire extinguishing agent that can be delivered to the 
engine, and result in a fire spreading from the engine to the wing 
of the airplane, accomplish the following:

Repetitive Inspections and Corrective Actions

    (a) Within 30 days after the effective date of this AD, perform 
a detailed visual inspection to detect cracking of the fire 
extinguisher discharge tubes in the number 2 and number 3 engine 
struts, in accordance with Boeing Alert Service Bulletin 747-
26A2266, dated March 3, 2000.

    Note 2: For the purposes of this AD, a detailed visual 
inspection is defined as: ``An intensive visual examination of a 
specific structural area, system, installation, or assembly to 
detect damage, failure, or irregularity. Available lighting is 
normally supplemented with a direct source of good lighting at 
intensity deemed appropriate by the inspector. Inspection aids such 
as mirror, magnifying lenses, etc., may be used. Surface cleaning 
and elaborate access procedures may be required.''

    (1) If no cracking is detected, repeat the inspection thereafter 
at intervals not to exceed 18 months.
    (2) If any cracking is detected, prior to further flight, 
replace the cracked tube with a new or serviceable part, in 
accordance with Boeing Alert Service Bulletin 747-26A2266, dated 
March 3, 2000. Repeat the inspection required by paragraph (a) of 
this AD within 18 months after the replacement and thereafter at 
intervals not to exceed 18 months.

Optional Terminating Action

    (b) For Model 747-400 series airplanes, L/N 696 through 1061 
inclusive, equipped with Pratt & Whitney PW4000 series engines: 
Modification of the fire extinguisher discharge tubes in the number 
2 and number 3 struts, in accordance with Boeing Service Bulletin 
747-26-2233, dated May 11, 1995, constitutes terminating action for 
the repetitive inspection requirements of this AD.

Alternative Methods of Compliance

    (c) 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 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

Special Flight Permits

    (d) Special flight permits may be issued in accordance with 
Secs. 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.

Incorporation by Reference

    (e) The inspections and replacement shall be done in accordance 
with Boeing Alert Service Bulletin 747-26A2266, dated March 3, 2000. 
If accomplished, the optional terminating action shall be 
accomplished in accordance with Boeing Service Bulletin 747-26-2233, 
dated May 11, 1995. 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.

Effective Date

    (f) This amendment becomes effective on April 25, 2000.

    Issued in Renton, Washington, on March 30, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-8393 Filed 4-7-00; 8:45 am]
BILLING CODE 4910-13-P

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