[Federal Register Volume 59, Number 234 (Wednesday, December 7, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-29437]
[[Page Unknown]]
[Federal Register: December 7, 1994]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 94-NM-23-AD; Amendment 39-9083; AD 94-24-10]
Airworthiness Directives; Saab Model SAAB SF340A and SAAB 340B
Airplanes Equipped With Flight Equipment and Engineering Limited Model
121 Series Seats
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to certain Saab Model SAAB SF340A and SAAB 340B airplanes,
that requires repetitive inspections to detect cracking of the tray
stop spindle and backrest spindle bosses on the inboard sections of
certain seats; and replacement of the inboard sections, if necessary.
This amendment also requires repair and identification of the
modification plate, which would terminate the requirement to inspect
repetitively. This amendment is prompted by reports of fatigue cracking
in the vicinity of the tray stop spindle and backrest spindle bosses,
which could lead to excessive movement and eventual failure of the
backrest on these seats during aft loading. The actions specified by
this AD are intended to prevent failure of the backrest on these seats,
which could inhibit emergency egress.
DATES: Effective January 6, 1995.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of January 6, 1995.
ADDRESSES: The service information referenced in this AD may be
obtained from Flight Equipment and Engineering Limited, Technical
Manager, Nissen House, Grovebury Road, Leighton Buzzard, Bedfordshire
LU7 8TB, United Kingdom. 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: Mark Quam, Aerospace Engineer,
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate,
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206)
227-2145; fax (206) 227-1320.
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 Saab Model SAAB SF340A and SAAB
340B airplanes, equipped with Flight Equipment and Engineering Limited
Model 121 series seats, was published in the Federal Register on May 3,
1994 (59 FR 22771). That action proposed to require repetitive
inspections to detect cracking of the tray stop spindle and backrest
spindle bosses on the inboard sections of certain seats; and
replacement of the inboard sections, if necessary. It also proposed to
require repair and identification of the modification plate, which
would terminate the requirement to inspect repetitively.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the single comment received.
The commenter has no objections to the proposal, but questions the
accuracy of the description of the point of failure, as described in
the preamble to the notice. The preamble stated, ``Cracking in this
area may weaken the machined component that attaches the backrest of
the seats to the main spars of the airplane and may lead to excessive
movement and eventual failure of the backrest on these seats during aft
loading'' (emphasis added). The commenter implies that it is not
accurate to state that the failure point is where the seat backrests
attach to the main spar of the airplane. The FAA has reconsidered its
previous description and concurs that clarification is warranted. The
FAA finds that the following wording comprises a more accurate
description:
Cracking in this area may eventually weaken the seat section
such that the spindles attaching the table and seat back to the seat
section may break free during crash loads or normal loads. This
condition, if not corrected, could result in failure of the backrest
of these seats, which could inhibit emergency egress.
This clarification of the description of the failure scenario in no
way alters the basis for issuance of this AD or the unsafe condition
addressed by it.
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. Under
these circumstances, at least one operator appears to have incorrectly
assumed that its airplane was not subject to an AD. On the contrary,
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
added to this final rule to clarify this requirement.
The FAA has recently reviewed the figures it has used over the past
several years in calculating the economic impact of AD activity. In
order to account for various inflationary costs in the airline
industry, the FAA has determined that it is necessary to increase the
labor rate used in these calculations from $55 per workhour to $60 per
workhour. The economic impact information below has been revised to
reflect this increase in the specified hourly labor rate.
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 changes previously
described. The FAA has determined that these changes will neither
increase the economic burden on any operator nor increase the scope of
the AD.
The FAA estimates that 73 airplanes of U.S. registry will be
affected by this AD, that it will take approximately 2 work hours per
seat to accomplish the required actions, and that the average labor
rate is $60 per work hour. There are usually 34 seats per airplane.
Required parts will be provided by the manufacturer at no cost to the
operator. Based on these figures, the total cost impact of the AD on
U.S. operators is estimated to be $297,840, or $4,080 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.
39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
94-24-10 SAAB Aircraft AB: Amendment 39-9083. Docket 94-NM-23-AD.
Applicability: Model SAAB SF340A airplanes having serial numbers
004 through 159 inclusive, and Model SAAB 340B airplanes having
serial numbers 160 through 330 inclusive; equipped with Flight
Equipment and Engineering Limited (FEEL) Model 121 series seats
listed in FEEL Service Bulletin 25-20-1294, Revision 1, dated May
1993, and FEEL Service Bulletin 25-20-1287, Revision 3, dated March
1993; 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) 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 failure of the backrest on these seats, which could
inhibit emergency egress, accomplish the following:
(a) Within 28 days after the effective date of this AD, perform
a detailed visual inspection to detect cracking of the tray stop
spindle and backrest spindle bosses of the inboard section of the
seat, in accordance with FEEL Service Bulletin 25-20-1287, Revision
3, dated March 1993.
(1) If no cracking is found, or if cracking is found that does
not penetrate the shear web, repeat the inspection of that seat
thereafter at intervals not to exceed 150 hours time-in-service
until the requirements or paragraph (b) of this AD are accomplished.
(2) If any cracking is found that penetrates the shear web,
prior to further flight, replace the inboard section (up to issue
12), and identify the modification plate with ``25-20-1287A,'' in
accordance with the service bulletin. Thereafter, repeat the
inspection at intervals not to exceed 150 hours time-in-service
until the requirements of paragraph (b) of the AD are accomplished.
(b) Within 6 months after the effective date of this AD, repair
and identify the modification plate with ``25-20-1294,'' in
accordance with FEEL Service Bulletin 25-20-1294, Revision 1, dated
May 1993. Accomplishment of the actions required by this paragraph
constitutes terminating action for the requirements of this AD.
(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, Standardization Branch, ANM-113,
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,
Standardization Branch, ANM-113.
Note 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Standardization Branch, ANM-113.
(d) 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.
(e) The inspection shall be done in accordance with FEEL Service
Bulletin 25-20-1287, Revision 3, dated March 1993. The repair and
identification shall be done in accordance with FEEL Service
Bulletin 25-20-1294, Revision 1, dated May 1993, which contains the
following list of effective pages:
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Revision
Page No. level shown Date shown on
on page page
------------------------------------------------------------------------
1-3, 19................................. 1........... May 1993.
4-18.................................... Basic....... Mar. 1993.
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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 Flight Equipment and Engineering
Limited, Technical Manager, Nissen House, Grovebury Road, Leighton
Buzzard, Bedfordshire LU7 8TB, United Kingdom. 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.
(f) This amendment becomes effective on January 6, 1995.
Issued in Renton, Washington, on November 23, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 94-29437 Filed 12-6-94; 8:45 am]
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