[Federal Register Volume 60, Number 154 (Thursday, August 10, 1995)]
[Rules and Regulations]
[Pages 40748-40750]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-19653]
=======================================================================
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 95-NM-130-AD; Amendment 39-9335; AD 95-15-52]
Airworthiness Directives; Boeing Model 747-100 and -200 Series
Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
-----------------------------------------------------------------------
SUMMARY: This document publishes in the Federal Register an amendment
adopting Airworthiness Directive (AD) T95-15-52 that was sent
previously to all known U.S. owners and operators of certain Boeing
Model 747-100 and -200 series airplanes by individual telegrams. This
AD requires a revision of the Airplane Flight Manual (AFM) and Airplane
Weight and Balance Supplement to restrict cargo loading to a certain
level. This AD also provides for the removal of the restrictions
following accomplishment of a modification of the longitudinal floor
beams. This amendment is prompted by a determination that inadequate
strength in the floor beams exists on certain airplanes that have been
modified for cargo configurations. The actions specified by this AD are
intended to prevent failure of the longitudinal floor beams, which may
cause the keel beam to fail and result in rupture of the fuselage.
DATES: Effective August 25, 1995, to all persons except those persons
to whom it was made immediately effective by telegraphic AD T95-15-52,
issued July 14, 1995, which contained the requirements of this
amendment.
Comments for inclusion in the Rules Docket must be received on or
before October 10, 1995.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
[[Page 40749]]
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 95-NM-130-AD, 1601 Lind Avenue, SW.,
Renton, Washington 98055-4056.
Information pertaining to this AD may be examined at the FAA,
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton,
Washington.
FOR FURTHER INFORMATION CONTACT: Steven C. Fox, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton,
Washington 98055-4056; telephone (206) 227-2777; fax (206) 227-1181.
SUPPLEMENTARY INFORMATION: On July 14, 1995, the FAA issued telegraphic
AD T95-15-52, which is applicable to Model 747-100 series airplanes
modified in accordance with Supplemental Type Certificate (STC)
SA2322SO, SA2323SO, or SA5199NM; and Model 747-200 series airplanes
modified in accordance with STC SA4227NM-D or SA5759NM.
Certain Model 747-100 and -200 series airplanes have been converted
from a passenger configuration to a freighter configuration in
accordance with STC's SA2322SO and SA2323SO (for Model 747-100 series
airplanes) and SA4227NM-D (for Model 747-200 series airplanes). These
STC's include, as part of their data packages, new Weight and Balance
Supplements that specify the maximum allowable linear load per inch
(commonly referred to as ``running load'') along the length of the
fuselage. The Supplements increased this limit from 66.7 pounds per
inch to 240 pounds per inch between Body Stations (BS) 1000 and 1480.
The Supplements also define the maximum area load (expressed in pounds
per square foot). The Supplement increased this limit from 100 pounds
per square foot to 320 pounds per square foot between BS 1000 and BS
1480.
On January 16, 1990, the FAA issued AD 90-06-06, amendment 39-6490
(55 FR 8374, March 7, 1990), applicable to certain Boeing Model 747
series airplanes, to require structural modifications of older
airplanes, including a requirement to modify the longitudinal floor
beams. Recently, an operator of Model 747 airplanes applied for
approval of an alternative method of compliance (AMOC) to AD 90-06-06.
In reviewing the data to approve this AMOC, the FAA has found that the
longitudinal floor beams between BS 1265 and BS 1480 had not been
upgraded to withstand the increased running loads that would result
from an airplane's conversion to freighter service. These Body Stations
comprise a 215 inch-long linear portion of the fuselage over the wheel
well section of the airplane.
Furthermore, the FAA finds that this same problem of inadequate
strength in the floor beams exists on Model 747-100 and -200 series
airplanes for which the type design has been changed to allow operation
in accordance with STC's SA5199NM (for Model 747-100 series airplanes)
and SA5759NM (for Model 747-200 series airplanes). These two STC's
modify the weight and balance limitations of STC's SA2322SO, SA2323SO,
and SA4227NM-D. However, these two STC's continue to define the maximum
running load at 240 pounds per inch and the maximum area load at 320
pounds per square foot without strengthening the floor beam structure
between BS 1000 and BS 1480.
The FAA has determined that a running load of 240 pounds per inch,
for the freighter configuration, is above the capability of floor beam
structure between BS 1265 and BS 1480. Additionally, the FAA finds that
this structure, when loaded to the STC's-allowed limits is not
sufficiently strong to sustain limit loads under all of the airspeed
and load factor conditions, including those defined by section 25.333,
``Flight envelope,'' and section 25.341, ``Gust loads,'' of the Federal
Aviation Regulations (14 CFR 25.333 and 14 CFR 25.341). Failure of the
longitudinal floor beams may cause the keel beam to fail, and result in
the rupture of the fuselage.
Since the unsafe condition described is likely to exist or develop
on other airplanes having these STC's as part of their type design, the
FAA issued Telegraphic AD T95-15-52 to require a revision to the
Limitations section of the FAA-approved Airplane Flight Manual (AFM)
and the Limitations section of the Airplane Weight and Balance
Supplement to restrict cargo loading to a suitable level. The level
established by this AD is based upon an FAA evaluation of the
unmodified floor beam structure. The AD also provides for the removal
of the restrictions following accomplishment of a modification of the
longitudinal floor beams in accordance with a method approved by the
FAA.
As a result of recent communications with the Air Transport
Association (ATA) of America, the FAA has learned that, in general,
some operators may misunderstand the legal effect of AD's on airplanes
that are identified in the applicability provision of the AD, but that
have been altered or repaired in the area addressed by the AD. The FAA
points out that all airplanes identified in the applicability provision
of an AD are legally subject to the AD. If an airplane has been altered
or repaired in the affected area in such a way as to affect compliance
with the AD, the owner or operator is required to obtain FAA approval
for an alternative method of compliance with the AD, in accordance with
the paragraph of each AD that provides for such approvals. A Note has
been included in this rule to clarify this long-standing requirement.
Since it was found that immediate corrective action was required,
notice and opportunity for prior public comment thereon were
impracticable and contrary to the public interest, and good cause
existed to make the AD effective immediately by individual telegrams
issued on July 14, 1995 to all known U.S. owners and operators of the
affected Boeing Model 747-100 and -200 series airplanes. These
conditions still exist, and the AD is hereby published in the Federal
Register as an amendment to section 39.13 of the Federal Aviation
Regulations (14 CFR 39.13) to make it effective to all persons.
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
[[Page 40750]]
postcard on which the following statement is made: ``Comments to Docket
Number 95-NM-130-AD.'' The postcard will be date stamped and returned
to the commenter.
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.
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 in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, 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 USC 106(g), 40101, 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
95-15-52 Boeing: Amendment 39-9335. Docket 95-NM-130-AD.
Applicability: Model 747-100 series airplanes modified in
accordance with Supplemental Type Certificates (STC) SA2322SO,
SA2323SO, or SA5199NM; and Model 747-200 series airplanes modified
in accordance with STC's SA4227NM-D or SA5759NM; 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 use the authority
provided in paragraph (c) of this AD to request approval from the
FAA. This approval may address either no action, if the current
configuration eliminates the unsafe condition; or different actions
necessary to address the unsafe condition described in this AD. Such
a request should include an assessment of the effect of the changed
configuration on the unsafe condition addressed by this AD. In no
case does the presence of any modification, alteration, or repair
remove any airplane from the applicability of this AD.
Compliance: Required as indicated, unless accomplished
previously.
To prevent structural failure of the longitudinal floor beams
and keel beam and the subsequent rupture of the fuselage, accomplish
the following:
(a) Within 24 clock hours (not flight hours) after the effective
date of this AD, revise the Limitations section of the FAA-approved
Airplane Flight Manual (AFM) and the Limitations section of the
Airplane Weight and Balance Supplement (Model 747-100 or -200 series
airplanes) to include the following information. This may be
accomplished by inserting a copy of this AD in the AFM.
``1.1 MAIN CARGO DECK LIMITS (ADDITION):
Each of the following payload limits for pallet cargo apply to
the main cargo deck floor between Body Stations 1265 and 1480.
Note: These limits take precedence over any other payload limits
that may appear elsewhere in this or in any other document.
1. Do not exceed a linear load of 96.0 pounds per inch between
Body Stations 1265 and 1480.
2. The maximum local floor loading in any area located between
Body Stations 1265 and 1480 shall not exceed 150 pounds per square
foot.
3. The cargo pallets that are located entirely or partially
between Body Stations 1265 and 1480 are restricted as follows:
A. Pallets that are 96.0 inches in width and 125.0 inches in
length shall not exceed a 1.0 g loading of 6,000 pounds.
B. Pallets that are 88.0 inches in width and 125.0 inches in
length shall not exceed a 1.0 g loading of 5,500 pounds.
C. Pallets that are 88.0 inches in width and 108.0 inches in
length shall not exceed a 1.0 g loading of 4,800 pounds.'' -
(b) Accomplishment of a modification of the longitudinal floor
beams in accordance with a method approved by the Manager, Seattle
Aircraft Certification Office (ACO), FAA, Transport Airplane
Directorate, constitutes terminating action for the limitation
requirements of paragraph (a) of this AD. The AFM limitation and
Weight and Balance Supplement limitation may be removed following
accomplishment of such a modification. -
(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 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.
-(d) This amendment becomes effective on August 25, 1995, to
all persons except those persons to whom it was made immediately
effective by telegraphic AD T95-15-52, issued on July 14, 1995,
which contained the requirements of this amendment.
Issued in Renton, Washington, on August 3, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 95-19653 Filed 8-9-95; 8:45 am]
BILLING CODE 4910-13-U
