[Federal Register Volume 61, Number 79 (Tuesday, April 23, 1996)]
[Rules and Regulations]
[Pages 17825-17826]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-9339]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 95-NM-121-AD; Amendment 39-9572; AD 96-08-06]
Airworthiness Directives; Saab Model SAAB SF340A and SAAB 340B
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 Saab Model SAAB SF340A and SAAB 340B series
airplanes, that requires visual and dye penetrant inspection(s) to
detect cracks of the nose rib of the rudder, and stop drilling and
blending of minor cracks. This amendment also requires replacement of
the nose rib with a new nose rib and reinforcement of the nose rib, if
extensive cracking is detected or if an operator elects to terminate
the repetitive inspections. This amendment is prompted by the result of
an inspection that revealed a cracked nose rib on the front spar of the
rudder due to vibration-related stress. The actions specified by this
AD are intended to prevent such stress and cracking, which could result
in the deformation of the nose rib; this condition may lead to friction
and jamming between the fin and the rudder and subsequent reduced
controllability of the airplane.
DATES: Effective May 23, 1996.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of May 23, 1996.
ADDRESSES: The service information referenced in this AD may be
obtained from SAAB Aircraft AB, SAAB Aircraft Product Support, S-
581.88, Linkoping, Sweden. 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: Ruth Harder, Aerospace Engineer,
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate,
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206)
227-1721; fax (206) 227-1149.
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 Saab Model SAAB SF340A and
SAAB 340B series airplanes was published in the Federal Register on
January 9, 1996 (61 FR 640). That action proposed to require visual and
dye penetrant inspection(s) to detect cracks of the nose rib of the
rudder, and stop drilling and blending of minor cracks. That action
also proposed to require replacement of the nose rib with a new nose
rib and reinforcement of the nose rib, if any extensive crack is
detected or if an
[[Page 17826]]
operator elects to terminate the repetitive inspections.
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 supports the proposed rule.
After careful review of the available data, including the comment
noted above, the FAA has determined that air safety and the public
interest require the adoption of the rule as proposed.
The FAA estimates that 221 Saab Model SAAB SF340A and SAAB 340B
series airplanes of U.S. registry will be affected by this AD, that it
will take approximately 4 work hours per airplane to accomplish the
required actions, and that the average labor rate is $60 per work hour.
Based on these figures, the cost impact of the inspection requirement
of this AD on U.S. operators is estimated to be $53,040, or $240 per
airplane.
The 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 USC 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
96-08-06 Saab Aircraft AB: Amendment 39-9572. Docket 95-NM-121-AD.
Applicability: Model SAAB. SF340A series airplanes having serial
numbers (S/N) 004 through 159 inclusive, and Model SAAB 340B having
S/N's 160 through 369 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 (b) 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 vibration-related stress and cracking and consequent
deformation of the nose rib, which could result in friction and
jamming between the fin and the rudder and subsequent reduced
controllability of the airplane, accomplish the following:
(a) Prior to the accumulation of 2,400 total flight hours, or
within 800 flight hours after the effective date of this AD,
whichever occurs later, perform a visual and dye penetrant
inspection to detect cracks of the nose rib of the rudder, in
accordance with Saab Service Bulletin 340-55-032, dated May 22,
1995.
(1) If no cracks are detected, repeat the inspection thereafter
at intervals not to exceed 800 flight hours, or replace the nose rib
with a new nose rib and reinforce it, in accordance with the service
bulletin. Accomplishment of the replacement and reinforcement
constitutes terminating action for this AD.
(2) If any minor crack [less than 25.4 mm (1.0 inch) long] is
detected, prior to further flight, stop drill and blend the crack in
accordance with the service bulletin. Repeat the inspection
thereafter at intervals not to exceed 800 flight hours, or replace
the nose rib with a new nose rib and reinforce it, in accordance
with the service bulletin. Accomplishment of the replacement and
reinforcement constitutes terminating action for this AD.
(3) If any extensive crack [greater than or equal to 25.4 mm
(1.0 inch) long] is detected, prior to further flight, replace the
nose rib with a new nose rib and reinforce it, in accordance with
the service bulletin. Accomplishment of this replacement and
reinforcement constitutes terminating action for this AD.
(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, 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.
(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 actions shall be done in accordance with Saab Service
Bulletin 340-55-032, dated May 22, 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 SAAB Aircraft AB, SAAB Aircraft Product Support, S-
581.88, Linkoping, Sweden. 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 May 23, 1996.
Issued in Renton, Washington, on April 10, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 96-9339 Filed 4-22-96; 8:45 am]
BILLING CODE 4910-13-U
