Airworthiness Directives; Saab Model SAAB 2000 Series Airplanes

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-350-AD; Amendment 39-11232; AD 99-15-12]

RIN 2120-AA64

Airworthiness Directives; Saab Model SAAB 2000 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD),

applicable to certain Saab Model SAAB 2000 series airplanes. This

action requires repetitive detailed inspections to detect looseness or

gap of the press fit bushing installation of the actuator fittings of

the aileron trim tabs, and eventual replacement of the bushings with

new, staked bushings. Accomplishment of such replacement terminates the

repetitive inspections. This action also provides for an optional

temporary preventive action, which, if accomplished, would terminate

the repetitive inspections until the terminating action is

accomplished. This amendment is prompted by issuance of mandatory

continuing airworthiness information by a foreign civil airworthiness

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

looseness or gap of the bushings. In the event of failure of the

redundant trim tab actuator, such looseness or gap of the bushings

could lead to trim tab flutter and consequent structural failure of the

trim tab and reduced controllability of the airplane.

DATES: Effective August 6, 1999.

The incorporation by reference of certain publications listed in

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

of August 6, 1999.

Comments for inclusion in the Rules Docket must be received on or

before August 23, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

Administration (FAA), Transport Airplane Directorate, ANM-114,

Attention: Rules Docket No. 98-NM-350-AD, 1601 Lind Avenue, SW.,

Renton, Washington 98055-4056.

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 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.

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:

Discussion

The Luftfartsverket (LFV), which is the airworthiness authority for

Sweden, notified the FAA that an unsafe condition may exist on certain

Saab Model SAAB 2000 series airplanes. The LFV advises that a failure

of a bushing of the flap support fitting occurred during a fatigue

test. The bushing installation of the flap support fitting is similar

to the bushing installation of the actuator fittings of the aileron

trim tabs. In the event of failure of the redundant trim tab actuator,

such a failure of the bushing could lead to trim tab flutter and

consequent structural failure of the trim tab and reduced

controllability of the airplane.

Explanation of Relevant Service Information

Saab has issued Service Bulletin 2000-57-011, dated October 1,

1998, which describes procedures for repetitive visual inspections to

detect looseness or gap of the press fit bushing installation of the

actuation fittings of the aileron trim tabs. In addition, the service

bulletin describes procedures for eventual replacement of existing

bushings with new, staked bushings in the fittings. Such replacement

when accomplished, eliminates the need for the repetitive inspections.

The service bulletin also describes procedures for an optional

temporary preventive action that involves the installation of washers

on the bushings of the actuator fittings of the aileron trim tabs.

Accomplishment of the actions specified in the service bulletin is

intended to adequately address the identified unsafe condition.

The LFV classified this service bulletin as mandatory and issued

Swedish airworthiness directive (SAD) No. 1-132, dated October 8, 1998,

in order to assure the continued airworthiness of these airplanes in

Sweden.

FAA's Conclusions

This airplane model is manufactured in Sweden and is type

certificated for operation in the United States under the provisions of

section 21.29 of the Federal Aviation Regulations (14 CFR 21.19) and

the applicable bilateral airworthiness agreement. Pursuant to this

bilateral airworthiness agreement, the LFV has kept the FAA informed of

the situation described above. The FAA has examined the findings of the

LFV, reviewed all available information, and determined that AD action

is necessary for products of this type design that are certificated for

operation in the United States.

Explanation of Requirements of the Rule

Since an unsafe condition has been identified that is likely to

exist or develop on other airplanes of the same type design registered

in the United States, this AD is being issued to prevent looseness or

gap of the press fit bushing installation of the actuator fittings of

the aileron trim tabs. This AD requires accomplishment of the actions

specified in the service bulletin described previously, except as

discussed below.

Differences Between this AD and Service Bulletin

Operators should note that, although the service bulletin specifies

that the manufacturer may be contacted for disposition of a certain

repair condition, this AD requires the repair of that condition to be

accomplished in accordance with a method approved by the FAA, or the

LFV (or its delegated agent).

Cost Impact

None of the airplanes affected by this action are on the U.S.

Register. All airplanes included in the applicability of this rule

currently are operated by non-U.S. operators under foreign registry;

therefore, they are not directly affected by this AD action. However,

the FAA considers that this rule is necessary to ensure that the unsafe

condition is addressed in the event that any of these subject airplanes

are imported and placed on the U.S. Register in the future.

[[Page 39397]]

Should an affected airplane be imported and placed on the U.S.

Register in the future, it would require approximately 3 work hours to

accomplish the required inspection, at an average labor rate of $60 per

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

would be $180 per airplane, per inspection cycle.

It would require approximately 12 work hours for the bushing

replacement, at an average labor rate of $60 per work hour. Required

parts would be provided by the manufacturer at no cost to the operator.

Based on these figures, the cost impact of the installation would be

$720 per airplane.

Should an operator elect to accomplish the optional temporary

preventive action, it would take approximately 8 work hours to

accomplish it, at an average labor rate of $60 per work hour. Required

parts would be provided by the manufacturer at no cost to the operator.

Based on these figures, the cost impact of the optional temporary

preventive action would be $480 per airplane.

Determination of Rule's Effective Date

Since this AD action does not affect any airplane that is currently

on the U.S. register, it has no adverse economic impact and imposes no

additional burden on any person. Therefore, prior notice and public

procedures hereon are unnecessary and the amendment may be made

effective in less than 30 days after publication in the Federal

Register.

Comments Invited

Although this action is in the form of a final rule and was not

preceded by notice and 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 postcard on which the following statement is made: ``Comments

to Docket Number 98-NM-350-AD.'' The postcard will be date stamped and

returned to the commenter.

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:

99-15-12 Saab Aircraft AB: Amendment 39-11232. Docket 98-NM-350-AD.

Applicability: Model SAAB 2000 series airplanes having serial

numbers -004 through -011 inclusive and -013 through -016 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 (d) 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 detect looseness or gap of the press fit bushing installation

of the actuation fittings of the aileron trim tabs, which, in the

event of failure of the redundant trim tab actuator, could lead to

trim tab flutter and consequent structural failure of the trim tab,

accomplish the following:

Inspection

(a) Within 400 flight hours after the effective date of this AD,

perform a detailed inspection of the bushing installation of the

actuator fittings of the aileron trim tabs to detect looseness or

gap, in accordance with Saab Service Bulletin 2000-57-011, dated

October 1, 1998.

(1) If no looseness or gap is found, repeat the inspection

thereafter at intervals not to exceed 800 flight hours until the

requirements of paragraph (b) of this AD have been accomplished.

Accomplishment of the temporary preventive action specified in

paragraph 2.C. of the Accomplishment Instructions of the service

bulletin terminates the repetitive inspections until the

requirements of paragraph (b) of this AD have been accomplished.

(2) Except as specified in paragraph (c) of this AD, if any

looseness or gap is found, prior to further flight, accomplish the

corrective actions specified in paragraph 2.G. of the Accomplishment

Instructions of the service bulletin. Repeat the inspection

thereafter at intervals not to exceed 800 flight hours until the

requirements of paragraph (b) of this AD have been accomplished.

Accomplishment of the temporary preventive action specified in

paragraph 2.C. of the Accomplishment Instructions of the service

bulletin terminates the repetitive inspections of paragraph (a) of

this AD.

Note 2: For the purposes of this AD, a detailed inspection is

defined as: ``An intensive visual examination of a specific

structural area, system, installation, or

[[Page 39398]]

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.''

Terminating Action

(b) Except as specified in paragraph (c) of this AD, within

6,000 flight hours after the effective date of this AD, replace the

existing bushings with new, staked bushings in the actuator fittings

of the aileron trim tabs in accordance with Saab Service Bulletin

2000-57-011, dated October 1, 1998. Accomplishment of this

replacement terminates the requirements of this AD.

Conditional Corrective Action

(c) If, during the accomplishment of the bushing installation

inspection required by paragraph (a)(2) or the bushing replacement

required by paragraph (b) of this AD, any radial play is detected

between the small diameter flanged bushing and the fitting lug hole,

and the radial play is 0.006 inch or less, prior to further flight,

repair it 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).

Alternative Methods of Compliance

(d) 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 3: 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

(e) 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

(f) Except as provided in paragraph (c) of this AD, the actions

shall be done in accordance with Saab Service Bulletin 2000-57-011,

dated October 1, 1998. 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 4: The subject of this AD is addressed in Swedish

airworthiness directive (SAD) 1-132, dated October 8, 1998.

(g) This amendment becomes effective on August 6, 1999.

Issued in Renton, Washington, on July 14, 1999.

D.L. Riggin,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 99-18409 Filed 7-21-99; 8:45 am]

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