[Federal Register Volume 67, Number 64 (Wednesday, April 3, 2002)]
[Proposed Rules]
[Pages 15755-15758]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-7993]


=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NM-22-AD]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: This document proposes the supersedure of an existing 
airworthiness directive (AD), applicable to certain Boeing Model 747-
200B, -300, -400, -400D, and -400F series airplanes, that currently 
requires repetitive inspections to detect cracking of fire extinguisher 
discharge tubes in certain engine struts, and corrective action, if 
necessary. For certain airplanes, that AD also provides for an optional 
modification of the fire extinguisher discharge tubes, which 
constitutes terminating action for the repetitive inspections. This 
action would make the previously optional modification of the fire 
extinguisher discharge tubes mandatory for all affected airplanes and 
would add one airplane to the applicability. This proposal is prompted 
by a report that the check tee valve at the top of an engine strut can 
be damaged such that no extinguishing agent can get to the engine. The 
actions specified by the proposed AD are intended to prevent blockage 
of the check tee valve and cracks in the fire extinguisher discharge 
tubes in the engine struts, which could prevent the fire extinguishing 
agent from being delivered to the engine or reduce the amount delivered 
to the engine, which could permit a fire to spread from the engine to 
the wing of the airplane.

DATES: Comments must be received by May 20, 2002.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2001-NM-22-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except 
Federal holidays. Comments may be submitted via fax to (425) 227-1232. 
Comments may also be sent via the Internet using the following address: 
[email protected]. Comments sent via fax or the Internet must 
contain ``Docket No. 2001-NM-22-AD'' in the subject line and need not 
be submitted in triplicate. Comments sent via the Internet as attached 
electronic files must be formatted in Microsoft Word 97 for Windows or 
ASCII text.
    The service information referenced in the proposed rule may be 
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, 
Washington 98124-2207. This information may be examined at the FAA, 
1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Sulmo Mariano, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone 
(425) 227-2686; fax (425) 227-1181.

[[Page 15756]]


SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed 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 above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this action may be changed in 
light of the comments received. Submit comments using the following 
format:
     Organize comments issue-by-issue. For example, discuss a 
request to change the compliance time and a request to change the 
service bulletin reference as two separate issues.
     For each issue, state what specific change to the proposed 
AD is being requested.
     Include justification (e.g., reasons or data) for each 
request.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2001-NM-22-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules 
Docket No. 2001-NM-22-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On March 30, 2000, the FAA issued AD 2000-07-10, amendment 39-11664 
(65 FR 18881, April 10, 2000), applicable to certain Boeing Model 747-
200B, -300, -400, -400D, and -400F series airplanes, to require 
repetitive inspections to detect cracking of fire extinguisher 
discharge tubes in certain engine struts, and corrective action, if 
necessary. For certain airplanes, that action also provides for a 
modification of the fire extinguisher discharge tubes, which 
constitutes terminating action for the repetitive inspections. That 
action was prompted by reports that cracked fire extinguisher discharge 
tubes have been found in the engine struts on certain airplanes. The 
requirements of that 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 prevent the fire extinguishing agent 
from being delivered to the engine or reduce the amount that could be 
delivered to the engine, and could permit a fire to spread from the 
engine to the wing of the airplane.

Actions Since Issuance of Previous Rule

    Since the issuance of that AD, there has been a report that the 
check tee valve at the top of the engine strut can be damaged such that 
no extinguishing agent can reach the engine. The check tee valve 
contains a ball that directs the extinguishing agent to the engine. It 
was determined that the ball of the check tee valve could cause a 
blockage of the downstream part of the check tee valve. Wear between 
the ball and the housing and the position of the valve would allow the 
ball to block the outlet port of the check tee valve. The blockage at 
the check tee valve, if not corrected, could also prevent the fire 
extinguishing agent from being delivered to the engine or reduce the 
amount delivered to the engine, and could permit a fire to spread from 
the engine to the wing of the airplane.

Explanation of Relevant Service Information

    Since the issuance of that AD, the FAA has reviewed and approved 
two service bulletins which describe procedures for modifying the route 
of the fire extinguisher discharge tubes between the inboard fire 
bottles and the inboard engines. Boeing Alert Service Bulletin 747-
26A2233, Revision 1, dated November 16, 2000, applies to Model 747-400 
and 747-400F series airplanes equipped with Pratt & Whitney PW4000 
engines. Boeing Alert Service Bulletin 747-26A2267, dated December 20, 
2000, applies to Model 747-200B, -300, -400, -400D, and -400F series 
airplanes equipped with General Electric CF6-80C2 series engines. The 
modification moves the check tee valve from the top of the strut to a 
position adjacent to the front spar, and precludes the ball from 
obstructing the outlet port of the valve. The modification constitutes 
terminating action for the repetitive inspections required by AD 2000-
07-10. Accomplishment of the actions specified in the service bulletins 
is intended to adequately address the identified unsafe condition.

Explanation of Requirements of Proposed Rule

    The FAA has determined that the repetitive inspections of the fire 
extinguisher discharge tubes, required by AD 2000-07-10, are 
insufficient to address the unsafe condition which has been identified. 
The proposed AD would supersede AD 2000-07-10 to continue to require 
the repetitive inspections but would mandate modification of the 
routing of the fire extinguisher discharge tubes, terminating the need 
for repetitive inspections. (That modification was included in AD 2000-
07-10 as an optional terminating action for certain airplanes.) In 
addition, the proposed AD would add an airplane to the applicability to 
parallel the effectivity specified in Boeing Alert Service Bulletin 
747-26A2233, Revision 1, dated November 16, 2000. The proposed AD would 
require the actions to be accomplished in accordance with the service 
bulletins described previously, except as discussed below.

Differences Between Service Bulletins and Proposed AD

    Operators should note that, although the service bulletins do not 
provide a compliance time for accomplishing the modification, the 
proposed AD would require that the modification be accomplished within 
24 months after the effective date of this AD. In developing an 
appropriate compliance time for this AD, the FAA considered not only 
the manufacturer's recommendation, but also the degree of urgency 
associated with addressing the unsafe condition, the average 
utilization of the affected fleet, and the time necessary to perform 
the modification. In light of all of these factors, the FAA finds a 24-
month compliance time for completing the required modification to be 
warranted, in that it represents an appropriate interval of time 
allowable for affected airplanes to continue to operate without 
compromising safety.

Cost Impact

    There are approximately 268 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 47 airplanes of U.S. registry 
would be affected by this proposed AD.
    The inspections that are currently required by AD 2000-07-10, and 
retained in this AD, take approximately 1 work hour per airplane to 
accomplish, at an average labor rate of $60 per work hour. Based on 
these figures, the cost

[[Page 15757]]

impact of the currently required inspections on U.S. operators is 
estimated to be $2,820, or $60 per airplane, per inspection cycle.
    The modification that is proposed in this AD action would take 
approximately 32 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. Required parts would cost 
approximately $5,488 per airplane. Based on these figures, the cost 
impact of the proposed requirements of this AD on U.S. operators is 
estimated to be $348,176, or $7,408 per airplane.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the proposed requirements 
of this AD action, and that no operator would accomplish those actions 
in the future if this proposed AD were not adopted. The cost impact 
figures discussed in AD rulemaking actions represent only the time 
necessary to perform the specific actions actually required by the AD. 
These figures typically do not include incidental costs, such as the 
time required to gain access and close up, planning time, or time 
necessitated by other administrative actions.

Regulatory Impact

    The regulations proposed herein would 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 proposal would not have federalism implications 
under Executive Order 13132.
    For the reasons discussed above, I certify that this proposed 
regulation (1) is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the DOT 
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 
and (3) if promulgated, 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 copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting the Rules 
Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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 removing amendment 39-11664 (65 FR 
18881, April 10, 2000), and by adding a new airworthiness directive 
(AD), to read as follows:

Boeing: Docket 2001-NM-22-AD. Supersedes AD 2000-07-10, Amendment 
39-11664.

    Applicability: Model 747-200B, -300, -400, -400D, and -400F 
series airplanes equipped with General Electric CF6-80C2 series 
engines, line number 679 through 1060 inclusive; and Model 747-400 
and 747-400F series airplanes equipped with Pratt & Whitney PW4000 
engines, line numbers 696 through 1062 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 (d) 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 blockage of the check tee valve and cracks in the 
fire extinguisher discharge tubes in the engine struts, which could 
prevent the fire extinguishing agent from being delivered to the 
engine or reduce the amount delivered to the engine, which could 
permit a fire to spread from the engine to the wing of the airplane, 
accomplish the following:

Restatement of Requirements of AD 2000-07-10

Repetitive Inspections and Corrective Actions

    (a) For Model 747-200B, -300, -400, -400D, and -400F series 
airplanes equipped with General Electric CF6-80C2 series engines, 
line number 679 through 1060 inclusive; and Model 747-400 and 747-
400F series airplanes equipped with Pratt & Whitney PW4000 engines, 
line numbers 696 through 1061 inclusive: Within 30 days after April 
25, 2000 (the effective date of AD 2000-07-10, amendment 39-11664), 
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.

New Requirements of This AD

Modification

    (b) For Model 747-400 and 747-400F series airplanes equipped 
with Pratt & Whitney PW4000 engines: Within 24 months after the 
effective date of this AD, modify the routing of the fire 
extinguishing tubes between the inboard fire bottles and the inboard 
engines in accordance with Boeing Alert Service Bulletin 747-
26A2233, Revision 1, dated November 16, 2000. Accomplishment of the 
requirements of this paragraph constitutes terminating action for 
the repetitive inspections required by paragraph (a) of this AD for 
Model 747-400 and 747-400F airplanes equipped with Pratt & Whitney 
PW4000 engines.
    (c) For 747-200B, -300, -400, -400D, and -400F series airplanes 
equipped with General Electric CF6-80C2 series engines: Within 24 
months after the effective date of this AD, modify the routing of 
the fire extinguishing tubes between the inboard fire bottles and 
the inboard engines in accordance with Boeing Alert Service Bulletin 
747-26A2267, dated December 20, 2000. Accomplishment of the 
requirements of this paragraph constitutes terminating action for 
the repetitive inspections required by paragraph (a) of this AD for 
Model 747-200B, -300, -400, -400D, and -400F series airplanes 
equipped with General Electric CF6-80C2 engines.

Alternative Methods of Compliance

    (d) 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. 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

[[Page 15758]]

compliance with this AD, if any, may be obtained from the Seattle 
ACO.

Special Flight Permits

    (e) 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.


    Issued in Renton, Washington, on March 27, 2002.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 02-7993 Filed 4-2-02; 8:45 am]
BILLING CODE 4910-13-U