[Federal Register Volume 63, Number 103 (Friday, May 29, 1998)]
[Proposed Rules]
[Pages 29360-29362]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-14192]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-CE-30-AD]
RIN 2120-AA64


Airworthiness Directives; Pilatus Aircraft Ltd. Model PC-7 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes to adopt a new airworthiness directive 
(AD) that would apply to certain Pilatus Aircraft Ltd. Model PC-7 
airplanes. The proposed AD would require replacing the seal unit on 
both main landing gear (MLG) legs and the nose landing gear (NLG) leg. 
The proposed AD is the result of mandatory continuing airworthiness 
information (MCAI) issued by the airworthiness authority for 
Switzerland. The actions specified by the proposed AD are intended to 
prevent MLG or NLG failure caused by deterioration of a MLG or NLG leg 
seal unit, which could result in damage to the airplane or airplane 
controllability problems during takeoff, landing, or taxi operations.

DATES: Comments must be received on or before July 3, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

[[Page 29361]]

Administration (FAA), Central Region, Office of the Regional Counsel, 
Attention: Rules Docket No. 98-CE-30-AD, Room 1558, 601 E. 12th Street, 
Kansas City, Missouri 64106. Comments may be inspected at this location 
between 8 a.m. and 4 p.m., Monday through Friday, holidays excepted.
    Service information that applies to the proposed AD may be obtained 
from Pilatus Aircraft Ltd., Customer Liaison Manager, CH-6371 Stans, 
Switzerland; telephone: +41 41 619 6509; facsimile: +41 41 610 3351. 
This information also may be examined at the Rules Docket at the 
address above.

FOR FURTHER INFORMATION CONTACT: Mr. Roman T. Gabrys, Aerospace 
Engineer, Small Airplane Directorate, Airplane Certification Service, 
FAA, 1201 Walnut, suite 900, Kansas City, Missouri 64106; telephone: 
(816) 426-6932; facsimile: (816) 426-2169.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications should identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this notice may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed 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 proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket No. 98-CE-30-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Central Region, Office of the Regional Counsel, Attention: 
Rules Docket No. 98-CE-30-AD, Room 1558, 601 E. 12th Street, Kansas 
City, Missouri 64106.

Discussion

    The Federal Office for Civil Aviation (FOCA), which is the 
airworthiness authority for Switzerland, recently notified the FAA that 
an unsafe condition may exist on certain Pilatus Model PC-7 airplanes. 
The FOCA of Switzerland reports two cases of improper landing gear 
extension after take-off. These incidents are attributed to 
deterioration of the MLG or NLG seal unit.
    These conditions, if not corrected in a timely manner, could result 
in MLG or NLG failure and cause airplane damage or airplane 
controllability problems during takeoff, landing, or taxi operations.

Relevant Service Information

    Pilatus has issued Service Bulletin No. 32-018, dated March 6, 
1998, which specifies procedures for replacing the seal unit, on both 
MLG legs and the NLG leg, with improved design seal units.
    The FOCA of Switzerland classified this service bulletin as 
mandatory and issued Swiss AD HB 98-069, dated March 23, 1998, in order 
to assure the continued airworthiness of these airplanes in 
Switzerland.

The FAA's Determination

    This airplane model is manufactured in Switzerland and is type 
certificated for operation in the United States under the provisions of 
section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and 
the applicable bilateral airworthiness agreement. Pursuant to this 
bilateral airworthiness agreement, the FOCA has kept the FAA informed 
of the situation described above.
    The FAA has examined the findings of the FOCA; reviewed all 
available information, including the service information referenced 
above; and determined that AD action is necessary for products of this 
type design that are certificated for operation in the United States.

Explanation of the Provisions of the Proposed AD

    Since an unsafe condition has been identified that is likely to 
exist or develop in other Pilatus PC-7 airplanes of the same type 
design registered in the United States, the FAA is proposing AD action. 
The proposed AD would require replacing the seal unit on both MLG legs 
and the NLG leg. Accomplishment of the proposed installation would be 
in accordance with Pilatus Service Bulletin No. 32-018, dated March 6, 
1998.

Cost Impact

    The FAA estimates that 5 airplanes in the U.S. registry would be 
affected by the proposed AD, that it would take approximately 8 
workhours per airplane to accomplish the proposed action, and that the 
average labor rate is approximately $60 an hour. Parts cost 
approximately $932 per airplane. Based on these figures, the total cost 
impact of the proposed AD on U.S. operators is estimated to be $7,060, 
or $1,412 per airplane.

Regulatory Impact

    The regulations proposed herein would 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 
proposal would 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) if promulgated, 
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 copy of the draft regulatory evaluation 
prepared for this action has been placed in the Rules Docket. A copy of 
it may be obtained by contacting the Rules Docket at the location 
provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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.

[[Page 29362]]

Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding a new airworthiness directive 
(AD) to read as follows:

Pilatus Aircraft LTD.: Docket No. 98-CE-30-AD.

    Applicability: Model PC-7 airplanes, serial numbers MSN 001 
through MSN 609, 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 in the body of this AD, unless 
already accomplished.
    To prevent main landing gear (MLG) or nose landing gear (NLG) 
failure caused by deterioration of a MLG or NLG leg seal unit, which 
could result in damage to the airplane or airplane controllability 
problems during takeoff, landing, or taxi operations, accomplish the 
following:
    (a) Within the next 100 hours time-in-service after the 
effective date of this AD, replace the seal unit on both MLG legs 
and the NLG leg in accordance with the ACCOMPLISHMENT INSTRUCTIONS 
section of Pilatus Service Bulletin No. 32-018, dated March 6, 1998.
    (b) As of the effective date of this AD, no person may install a 
MLG leg or NLG leg that does not have an improved seal unit 
installed in accordance with the ACCOMPLISHMENT INSTRUCTIONS section 
of Pilatus Service Bulletin No. 32-018, dated March 6, 1998.
    (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) An alternative method of compliance or adjustment of the 
compliance time that provides an equivalent level of safety may be 
approved by the Manager, Small Airplane Directorate, 1201 Walnut, 
suite 900, Kansas City, Missouri 64106. The request shall be 
forwarded through an appropriate FAA Maintenance Inspector, who may 
add comments and then send it to the Manager, Small Airplane 
Directorate.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Small Airplane Directorate.

    (e) Questions or technical information related to Pilatus 
Service Bulletin No. 32-018, dated March 6, 1998, should be directed 
to Pilatus Aircraft Ltd., Customer Liaison Manager, CH-6371 Stans, 
Switzerland; telephone: +41 41 619 6509; facsimile: +41 41 610 3351. 
This service information may be examined at the FAA, Central Region, 
Office of the Regional Counsel, Room 1558, 601 E. 12th Street, 
Kansas City, Missouri 64106.

    Note 3: The subject of this AD is addressed in Swiss AD HB 98-
069, dated March 23, 1998.

    Issued in Kansas City, Missouri, on May 21, 1998.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 98-14192 Filed 5-28-98; 8:45 am]
BILLING CODE 4910-13-P