[Federal Register Volume 64, Number 202 (Wednesday, October 20, 1999)]
[Rules and Regulations]
[Pages 56426-56428]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-26935]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-244-AD; Amendment 39-11377; AD 99-21-31]
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 removing the control quadrant, securing the 
power lever cam screws with Loctite, and reinstalling the control 
quadrant. This amendment is prompted by issuance of mandatory 
continuing airworthiness information by a foreign civil airworthiness 
authority. The actions specified by this AD are intended to prevent the 
cam screws of the engine power levers from backing out and interfering 
with the movement of the engine power levers, which could result in 
limited engine power, and consequent reduced controllability of the 
airplane.

DATES: Effective November 24, 1999.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of November 24, 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

[[Page 56427]]

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 in the Federal Register on 
October 27, 1998 (63 FR 57260). That action proposed to require 
removing the control quadrant, securing the power lever cam screws with 
Loctite, and reinstalling the control quadrant.

Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Request To Withdraw Proposed AD

    One commenter states that the proposed action (i.e., removal of all 
control quadrants to put Loctite on the screws) is not warranted for 
the following reasons:
    1. The proposed rule is based on two events that occurred at a 
single operator. Investigation of these events showed that the migrated 
screw was an incorrect part number from the flight idle stop assembly. 
The commenter notes that no other operators have reported this problem, 
which indicates that the installation was an error in the field, and 
not a problem introduced during the modification of the control 
quadrant by its vendor (Adams-Rite). The commenter also states that an 
audit of related inventory, kits, and items in stock at the control 
quadrant vendor found no screws with incorrect part numbers, which 
further indicates that the problem was caused by a field installation 
error of the flight idle stop modification kit.
    2. The commenter states that a check of it's spare throttle 
quadrants shows that the correct screws have been installed within the 
flight idle stop assembly and are installed tightly. There is no 
indication that these screws can migrate, or ``back out'' of place.
    3. Given the amount of time and hours accrued since installation of 
the flight idle stop, the commenter states that any screws susceptible 
to such migration should already have shown signs of movement. The 
commenter further notes that a much simpler inspection would be to use 
a strong light and look through the power lever slot in the control 
quadrant to examine the screws, and only remove the quadrant if the 
screws show signs of looseness. An inspection interval of 200 flight 
hours would be sufficient until the quadrant was removed for other 
causes, which would allow accomplishment of the service bulletin (i.e., 
Saab Service Bulletin 340-76-042, dated May 28, 1998, including 
Attachments 1, 2, and 3, all dated May 1, 1998, was cited as the 
appropriate source of service information in this NPRM) at that time.
    4. A test conducted at the control quadrant vendor showed that, in 
the worst-case, interference with the power levers caused by any 
migration of loose screws could be overcome by the flight crew using an 
additional 8 lbs of force. Therefore, the crew would not lose control 
of engine power.
    The FAA does not concur with the commenter's statement that the 
proposed AD is not warranted. The FAA has determined that the actions 
required by this AD are appropriate for the reasons described below.
    Although the commenter states that a single operator incorrectly 
installed the migrated screws, installation of any screws in the area 
affected by this AD would not have been accomplished by any operator, 
only by the vendor of the control quadrant.
    Additionally, the FAA has been advised that the two control 
quadrants that have had the problem were manufactured in different 
batches with a long period of time in between.
    The results of the audit at the control quadrant vendor do not 
adequately explain why incorrect screws were installed during 
manufacture of these two quadrants. Therefore, the FAA has determined 
that it is necessary to accomplish an inspection and modification of 
all quadrants.
    The FAA also disagrees with the commenter's statement that it has 
determined that correct screws are installed inside its spare 
quadrants. Further discussions with Luftfartsverket (LFV), which is the 
airworthiness authority for Sweden, and Saab have revealed that it is 
not possible for operators to adequately check the installation of the 
correct screw length without disassembling the control quadrant. 
Further, such disassembly is only to be accomplished by the quadrant 
vendor.
    The FAA also disagrees that the screws should already have 
migrated, or that they can be checked periodically for looseness. It 
may be possible for the screws to remain in place for some time due to 
friction below the head of the screw, and then suddenly become loose 
due to vibration. It is not possible to predict how quickly or when 
such an event would occur. A periodic inspection such as the commenter 
suggests would not adequately prevent the possibility of a sudden 
restriction of power lever movement.
    Although the FAA does not disagree with the results of the test 
showing that 8 lbs. of force would overcome restriction of the power 
levers, the FAA does not concur that such action on the part of the 
flight crew is appropriate. Since the flight crew would not be aware of 
the cause of the sudden binding in the power levers, they would not 
reasonably be expected to know what action to take, how much force to 
apply, and when to stop applying the extra force.

Request for Revision of Cost Impact Information

    One commenter requests that the FAA remove the sentence that reads 
``required parts would be supplied by the manufacturer at no cost to 
the operators'' from the Cost Impact section of the proposed AD. The 
commenter notes that no parts are necessary to accomplish the 
modification, only consumables (i.e., Loctite and Loctite primer).
    The FAA concurs with the commenter's request. The cost impact 
information, below, has been revised accordingly.

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 283 airplanes of U.S. registry will be 
affected by this AD, that it will take approximately 9 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 AD on U.S. operators is estimated to be $152,820, or $540 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.

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

[[Page 56428]]

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:

99-21-31 SAAB AIRCRAFT AB: Amendment 39-11377. Docket 98-NM-244-AD.

    Applicability: Model SAAB SF340A and SAAB 340B series airplanes, 
as listed in Saab Service Bulletin 340-76-042, dated May 28, 1998, 
certificated in any category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
otherwise 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 (c) 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 the cam screws of the engine power levers from 
backing out and interfering with the movement of the engine power 
levers, which could result in limited engine power, and consequent 
reduced controllability of the airplane, accomplish the following:
    (a) Within 1,200 flight hours or 6 months after the effective 
date of this AD, whichever occurs first, remove the control 
quadrant, secure the power lever cam screws with Loctite, and 
reinstall the control quadrant, in accordance with Saab Service 
Bulletin 340-76-042, dated May 28, 1998, including Attachments 1, 2, 
and 3, all dated May 1, 1998.
    (b) As of the effective date of this AD, no person shall install 
on any airplane any control quadrant unit having part number (P/N) 
53082, 53162, or 53170, unless the control quadrant unit has been 
modified in accordance with this AD.

Alternative Methods of Compliance

    (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, International Branch, ANM-116, 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, International 
Branch, ANM-116.
    Note 2: 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

    (d) Special flight permits may be issued in accordance with 
Secs. 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

    (e) The actions shall be done in accordance with Saab Service 
Bulletin 340-76-042, dated May 28, 1998, including Attachment 1, 
dated May 1, 1998, Attachment 2, dated May 1, 1998, and Attachment 
3, dated May 1, 1998, which contains the following list of effective 
pages:

------------------------------------------------------------------------
                      Revision level shown on
      Page Nos.                 page               Date shown on page
------------------------------------------------------------------------
1-4.................  Original...............  May 28, 1998.
------------------------------------------------------------------------
                              Attachment 1
1-4.................  Original...............  May 1, 1998.
------------------------------------------------------------------------
                              Attachment 2
1-4.................  Original...............  May 1, 1998.
------------------------------------------------------------------------
                              Attachment 3
1-4.................  Original...............  May 1, 1998.
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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 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 3: The subject of this AD is addressed in Swedish 
airworthiness directive 1-128, dated May 29, 1998.

    (f) This amendment becomes effective on November 24, 1999.

    Issued in Renton, Washington, on October 8, 1999.
D.L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-26935 Filed 10-19-99; 8:45 am]
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