[Federal Register Volume 59, Number 131 (Monday, July 11, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-16535]
[[Page Unknown]]
[Federal Register: July 11, 1994]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 94-NM-61-AD; Amendment 39-8970; AD 94-14-21]
Airworthiness Directives; Boeing Model 747-400 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to certain Boeing Model 747-400 series airplanes, that
requires a revision to the Flap Control Unit input wiring. This
amendment is prompted by reports of disconnection of the Landing Gear
Module electrical connectors, which can result in the loss of the
primary, secondary, and alternate control of the flaps. The actions
specified by this AD are intended to prevent the possibility of an all-
flaps-up landing due to the loss of control of all flap operations.
DATES: Effective August 10, 1994. The incorporation by reference of
certain publications listed in the regulations is approved by the
Director of the Federal Register as of August 10, 1994.
ADDRESSES: 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 Federal
Aviation Administration (FAA), Transport Airplane Directorate, Rules
Docket, 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: Kathi Ishimaru, Aerospace Engineer,
Systems & Equipment Branch, ANM-130S, Seattle Aircraft Certification
Office, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW.,
Renton, Washington 98055-4056; telephone (206) 227-2674; fax (206) 227-
1181.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations (14 CFR part 39) to include an airworthiness
directive (AD) that is applicable to certain Boeing Model 747-400
series airplanes was published in the Federal Register on May 12, 1994
(59 FR 24671). That action proposed to require a revision to the Flap
Control Unit (FCU) input wiring.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
One commenter, Boeing, requests that the discussion of the
addressed unsafe condition that appeared in the preamble to the notice
be clarified. In that preamble, the FAA stated that, if the landing
gear module connectors become disconnected, all FCU modes of flap
operation (primary, secondary, and alternate control of flaps) could be
lost. The commenter suggests that the discussion would have been more
precise if it had contained information to indicate that the landing
gear module includes the ALTN ARM FLAPS switch and the ALTN FLAPS
position selector used to control the leading and trailing edge flaps
in the alternate mode. The FAA acknowledges this information.
This same commenter requests that the proposal be revised to cite
the latest revision of Boeing Service Bulletin 747-27A2346 as the
source for modification procedures. The FAA concurs. Since issuance of
the notice, the FAA has reviewed and approved Revision 1 of Boeing
Service Bulletin 747-27A2346, dated May 19, 1994. This revision
contains a correction to a type of wire that had been called out in the
original version of the service bulletin; this correction ensures that
the wire and its associated solder sleeve are metalurgically
compatible. In order to ensure that the correct wiring modification
assembly is installed on the affected airplanes, the FAA has determined
that the revised service bulletin should be cited as the appropriate
source of service information for complying with the requirements of
this rule. The final rule has been revised accordingly. The FAA has
confirmed that no U.S. operators have yet modified any affected
airplane in accordance with the original service bulletin; therefore,
by citing the revised service bulletin, the final rule will impose no
additional economic burden on any U.S. operator.
One commenter requests that the compliance time be extended from
the proposed 30 days to 90 days, due to a possible parts availability
problem. This commenter states that it does not normally stock the
required parts and materials to accomplish the proposed requirements of
the rule. This commenter has ordered these parts from a supplier and is
currently waiting to obtain them. Additionally, this commenter points
out that the manufacturer's service bulletin, referenced in the
proposal, recommends 60 days for modification. The FAA does not concur
with the commenter's request. In developing an appropriate compliance
time for this action, the FAA considered not only the degree of urgency
associated with addressing the subject unsafe condition, but the
manufacturer's recommendation as to an appropriate compliance time, the
availability of required parts, and the practical aspect of installing
the required modification within a maximum interval of time allowable
for all affected airplanes to continue to operate without compromising
safety. The FAA points out that the parts required for the wiring
modification are readily available; therefore, obtaining them within
the proposed compliance time should not pose a problem for any affected
operator. Further, the FAA took into account the 60-day compliance time
recommended by the manufacturer, as well as the number of days required
for the rulemaking process; in consideration of these factors, the FAA
finds that 30 days after the effective date of this final rule will
fall approximately at the same time for compliance as recommended by
the manufacturer. However, under the provisions of paragraph (b) of the
final rule, the FAA may approve requests for adjustments to the
compliance time if data are submitted to substantiate that such an
adjustment would provide an acceptable level of safety.
After careful review of the available data, including the comments
noted above, the FAA has determined that air safety and the public
interest require the adoption of the rule with the change previously
described. The FAA has determined that this change will neither
increase the economic burden on any operator nor increase the scope of
the AD.
There are approximately 300 Model 747-400 series airplanes of the
affected design in the worldwide fleet. The FAA estimates that 34
airplanes of U.S. registry will be affected by this AD, that it will
take approximately 10 work hours per airplane to accomplish the
required actions, and that the average labor rate is $55 per work hour.
Required parts will cost approximately $200 per airplane. Based on
these figures, the total cost impact of the AD on U.S. operators is
estimated to be $25,500, or $750 per airplane.
The total cost impact figure discussed above is based on
assumptions that no operator has yet accomplished any of the
requirements of this AD action, and that no operator would accomplish
those actions in the future if this AD were not adopted.
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.
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. App. 1354(a), 1421 and 1423; 49 U.S.C.
106(g); and 14 CFR 11.89.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
94-14-21 Boeing: Amendment 39-8970. Docket 94-NM-61-AD.
Applicability: Model 747-400 airplanes having line numbers 696
through 1019, inclusive, and 1021 through 1026, inclusive;
certificated in any category.
Compliance: Required as indicated, unless accomplished
previously.
To prevent the possibility of an all-flaps-up landing due to the
loss of control of flap operations, accomplish the following:
(a) Within 30 days after the effective date of this AD, revise
the Flap Control Unit (FCU) input wiring in accordance with Boeing
Alert Service Bulletin 747-27A2346, Revision 1, dated May 19, 1994.
(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: 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 wiring revision shall be done in accordance with Boeing
Alert Service Bulletin 747-27A2346, Revision 1, dated May 19, 1994.
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 August 10, 1994.
Issued in Renton, Washington, on July 1, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 94-16535 Filed 7-8-94; 8:45 am]
BILLING CODE 4910-13-U