Airworthiness Directives; Saab Model SAAB SF340A and SAAB 340B Series Airplanes

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-220-AD; Amendment 39-11310; AD 99-19-21]

RIN 2120-AA64

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 repetitive inspections to detect cracking

around certain fastener holes and adjacent areas of the front spar of

the horizontal stabilizers; and corrective actions, if necessary. This

amendment also requires repetitive x-ray inspections, cold working of

certain fastener holes of the front spar of the horizontal stabilizers,

and follow-on actions; and installation of new fasteners, which

constitutes terminating action for the repetitive inspections required

by this AD. This amendment is prompted by the issuance of mandatory

continuing airworthiness information by a foreign civil airworthiness

authority. The actions specified by this AD are intended to prevent

failure of the front spar due to fatigue cracking around certain

fastener holes of the front spar of the horizontal stabilizers, which

could result in reduced structural integrity of the airplane.

DATES: Effective October 20, 1999.

The incorporation by reference of certain publications listed in

the regulations is approved by the Director of the Federal Register as

of October 20, 1999.

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: Norman B. Martenson, Manager,

International Branch, ANM-116, FAA, Transport Airplane Directorate,

1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425)

227-2110; fax (425) 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 as a supplemental notice of

proposed rulemaking (NPRM) in the Federal Register on July 15, 1999 (64

FR 38150). That action proposed to require repetitive inspections to

detect cracking around certain fastener holes and adjacent areas of the

front spar of the horizontal stabilizers; and corrective actions, if

necessary. That action also proposed to require cold working of certain

fastener holes of the front spar of the horizontal stabilizers, and

follow-on actions; and installation of new fasteners, which would

constitute terminating action for the repetitive inspections. That

action also proposed to add repetitive x-ray inspections.

Comments

Interested persons have been afforded an opportunity to participate

in the making of this amendment. No comments were submitted in response

to the proposal or the FAA's determination of the cost to the public.

Explanation of Change Made to Final Rule

The FAA has added a note to the final rule to clarify the

definition of a detailed visual inspection.

Conclusion

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 described

previously. The FAA has determined that this change will neither

increase the economic burden on any operator nor increase the scope of

the AD.

Cost Impact

The FAA estimates that 279 airplanes of U.S. registry will be

affected by this AD.

[[Page 49965]]

It will take approximately 4 work hours per airplane to perform the

required detailed visual inspection, at an average labor rate of $60

per work hour. Based on these figures, the cost impact of the

inspection required by this AD on U.S. operators is estimated to be

$66,960, or $240 per airplane, per inspection cycle.

It will take approximately 6 work hours per airplane to accomplish

the required eddy current and x-ray inspections, at an average labor

rate of $60 per work hour. Based on these figures, the cost impact of

the inspections required by this AD on U.S. operators is estimated to

be $100,440, or $360 per airplane, per inspection cycle.

It will take approximately 42 work hours to accomplish the cold

working of the fastener holes, at an average labor rate of $60 per work

hour. Required parts will cost approximately $400 per airplane. Based

on these figures, the cost impact of the cold work required by this AD

on U.S. operators is estimated to be $814,680, or $2,920 per airplane.

The cost impact figures discussed above are 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.

Regulatory Impact

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. 106(g), 40113, 44701.

Sec. 39.13 [Amended]

2. Section 39.13 is amended by adding the following new

airworthiness directive:

99-19-21 SAAB Aircraft AB: Amendment 39-11310. Docket 98-NM-220-

AD.

Applicability: Model SAAB SF340A series airplanes,

manufacturer's serial numbers -004 through -159 inclusive; and SAAB

340B series airplanes, manufacturer's serial numbers -160 through -

439 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 (f) 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 failure of the front spar due to fatigue cracking

around certain fastener holes of the front spar of the horizontal

stabilizers, which could result in reduced structural integrity of

the airplane, accomplish the following:

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.''

Initial and Repetitive Inspections

(a) For Model SAAB SF340A series airplanes with manufacturer's

serial numbers -004 through -159 inclusive: Perform the inspections

(detailed visual, eddy current, and x-ray) specified in paragraph

2.D. of the Accomplishment Instructions of Saab Service Bulletin

340-55-033, Revision 04, dated December 1, 1998, to detect cracking

around certain fastener holes and adjacent areas of the front spar

of the horizontal stabilizer, in accordance with the service

bulletin, at the time specified in paragraph (a)(1), (a)(2), or

(a)(3) of this AD, as applicable. Thereafter, repeat only the eddy

current and x-ray inspections at intervals not to exceed 12,000

flight cycles until the requirements of paragraph (d) of this AD are

accomplished.

(1) For airplanes that have accumulated less than 22,000 total

flight cycles as of the effective date of this AD: Perform an eddy

current and an x-ray inspection prior to the accumulation of 22,000

total flight cycles, or within 2,000 flight cycles after the

effective date of this AD, whichever occurs later.

(2) For airplanes that have accumulated 22,000 or more total

flight cycles and less than 30,000 total flight cycles as of the

effective date of this AD: Accomplish the requirements of paragraphs

(a)(2)(i) and (a)(2)(ii) of this AD.

(i) Perform a detailed visual inspection within 800 flight

cycles after the effective date of this AD; and

(ii) Perform an eddy current and an x-ray inspection within

2,000 flight cycles after the effective date of this AD.

(3) For airplanes that have accumulated 30,000 or more total

flight cycles as of the effective date of this AD: Accomplish the

requirements of paragraphs (a)(3)(i) and (a)(3)(ii) of this AD.

(i) Perform a detailed visual inspection within 400 flight

cycles after the effective date of this AD; and

(ii) Perform an eddy current and an x-ray inspection within

1,200 flight cycles after the effective date of this AD.

Initial and Repetitive Inspections

(b) For Model SAAB 340B series airplanes with manufacturer's

serial numbers -160 through -439 inclusive: Perform the inspections

(detailed visual, eddy current, and x-ray) specified in paragraph

2.D. of the Accomplishment Instructions of Saab Service Bulletin

340-55-033, Revision 04, dated December 1, 1998, to detect cracking

around certain fastener holes and adjacent areas of the front spar

of the horizontal stabilizer, in accordance with the service

bulletin, at the time specified in paragraph (b)(1), (b)(2), or

(b)(3) of this AD, as applicable. Thereafter, repeat only the eddy

current and x-ray inspections at intervals not to exceed 6,000

flight cycles until the requirements of paragraph (d) of this AD are

accomplished.

(1) For airplanes that have accumulated less than 12,000 total

flight cycles as of the effective date of this AD: Perform an eddy

current and an x-ray inspection prior to the accumulation of 12,000

total flight cycles, or within 2,000 flight cycles after the

effective date of this AD, whichever occurs later.

(2) For airplanes that have accumulated 12,000 or more total

flight cycles and less than 16,000 total flight cycles as of the

effective date of this AD: Accomplish the requirements of paragraphs

(b)(2)(i) and (b)(2)(ii) of this AD.

[[Page 49966]]

(i) Perform a detailed visual inspection within 800 flight

cycles after the effective date of this AD; and

(ii) Perform an eddy current and an x-ray inspection within

2,000 flight cycles after the effective date of this AD.

(3) For airplanes that have accumulated 16,000 or more total

flight cycles as of the effective date of this AD: Accomplish the

requirements of paragraphs (b)(3)(i) and (b)(3)(ii) of this AD.

(i) Perform a detailed visual inspection within 400 flight

cycles after the effective date of this AD; and

(i) Perform a detailed visual inspection within 400 flight

cycles after the effective date of this AD; and (ii) Perform an eddy

current and an x-ray inspection within 1,200 flight cycles after the

effective date of this AD.

Corrective Actions

(c) If any cracking is detected during any inspection required

by paragraph (a) or (b) of this AD, prior to further flight, either

repair in accordance with a method approved by the Manager,

International Branch, ANM-116, FAA, Transport Airplane Directorate,

or the Luftfartsverket (LFV) (or its delegated agent); or accomplish

the requirements of paragraph (d) of this AD.

Note 3: Inspections to detect cracking around certain fastener

holes and adjacent areas of the front spar of the horizontal

stabilizers that have been accomplished prior to the effective date

of this AD in accordance with Saab Service Bulletin 340-55-033,

Revision 03, dated January 22, 1998, are considered acceptable for

compliance with the applicable action specified by this AD.

Terminating Action

(d) For all airplanes: Except as provided by paragraph (e) of

this AD, accomplish cold working of certain fastener holes of the

front spar of the horizontal stabilizers, and follow-on actions; and

install new fasteners; in accordance with Saab Service Bulletin 340-

55-034, dated October 16, 1998; at the time specified in paragraph

(d)(1), (d)(2), or (d)(3) of this AD, as applicable. Accomplishment

of this action constitutes terminating action for this AD.

(1) For all airplanes that have accumulated less than 26,000

total flight cycles as of the effective date of this AD: Within

10,000 flight cycles after the effective date of this AD.

(2) For all airplanes that have accumulated 26,000 or more total

flight cycles and less than 30,000 total flight cycles as of the

effective date of this AD: Within 6,000 flight cycles after the

effective date of this AD.

(3) For all airplanes that have accumulated 30,000 or more total

flight cycles as of the effective date of this AD: Within 3,000

flight cycles after the effective date of this AD.

(e) If any crack is detected during the accomplishment of

paragraph (d) of this AD, and if the service bulletin listed in

paragraph (d) of this AD specifies to contact the manufacturer for

an appropriate corrective action: Prior to further flight, repair in

accordance with a method approved by the Manager, International

Branch, ANM-116, or the LFV (or its delegated agent).

Alternative Method of Compliance

(f) 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, International Branch, ANM-116.

Operators shall submit their requests through an appropriate FAA

Principal Maintenance Inspector, who may add comments and then send

it to the Manager, International Branch, ANM-116.

Note 4: Information concerning the existence of approved

alternative methods of compliance with this AD, if any, may be

obtained from the International Branch, ANM-116.

Special Flight Permits

(g) 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.

Incorporation by Reference

(h) Except as provided by paragraphs (c) and (e) of this AD, the

actions shall be done in accordance with Saab Service Bulletin 340-

55-033, Revision 04, dated December 1, 1998; and Saab Service

Bulletin 340-55-034, dated October 16, 1998; as applicable. 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.

Note 5: The subject of this AD is addressed in Swedish

airworthiness directives 1-110R2, dated December 7, 1998, and 1-133,

dated October 20, 1998.

(i) This amendment becomes effective on October 20, 1999.

Issued in Renton, Washington, on September 1, 1999.

Dorenda D. Baker,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 99-23352 Filed 9-14-99; 8:45 am]

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