[Federal Register Volume 63, Number 147 (Friday, July 31, 1998)]
[Rules and Regulations]
[Pages 40807-40809]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-20439]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-CE-40-AD; Amendment 39-10681; AD 98-11-01 R2]
RIN 2120-AA64


Airworthiness Directives; Pilatus Aircraft Ltd. Models PC-12 and 
PC-12/45 Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; correction.

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SUMMARY: This amendment clarifies information contained in 
Airworthiness Directive (AD) 98-11-01 R1, which currently requires 
replacing the fuel tank vent valves and drilling a 4.8 millimeter 
(0.1875 inch) hole in each fuel filler cap on certain Pilatus Aircraft 
Ltd. (Pilatus) Models PC-12 and PC-12/45 airplanes. AD 98-11-01 R1 also 
requires inserting a temporary revision in the Pilot's Operating 
Handbook (POH) that specifies checking to assure that the fuel filler 
cap hole is clear of ice and foreign objects. The intent of AD 98-11-01 
R1 was to provide the option of incorporating new modified fuel tank 
vent valves instead of the replacement, drilling, and POH insertion 
requirements. The new modified vent valves cannot be incorporated 
without removing the fuel tank vent valves installed as originally 
required by AD 97-23-04 and carried over in the current AD. This 
provision of removing those vent valves is currently not provided for. 
This document clarifies and corrects this procedure. The actions 
specified in this AD are intended to continue to prevent moisture from 
entering the fuel tank inward vent valve and then freezing after a cold 
soak at altitude, which could result in wing airfoil distortion and 
structural damage with consequent degradation of the airplane's 
handling qualities.

DATES: Effective September 22, 1998.
    The incorporation by reference of Pilatus Service Bulletin No. 28-
003, Revision 1, dated September 30, 1997, as listed in the 
regulations, was previously approved by the Director of the Federal 
Register as of December 1, 1997 (62 FR 59993, November 6, 1997).
    The incorporation by reference of Pilatus Service Bulletin No. 28-
004, dated March 27, 1998, as listed in the regulations, was previously 
approved by the Director of the Federal Register as of June 7, 1998 (63 
FR 27195, May 18, 1998).
    The incorporation by reference of Pilatus Service Bulletin No. 28-
005, dated May 4, 1998, was previously approved by the Director of the 
Federal Register as of September 22, 1998 (63 FR 34565, June 25, 1998).

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Central Region, Office of the Regional Counsel, 
Attention: Rules Docket No. 98-CE-40-AD, Room 1558, 601 E. 12th Street, 
Kansas City, Missouri 64106.
    Service information that applies to this AD may be obtained from 
Pilatus Aircraft Ltd., CH-6370 Stans, Switzerland. This information may 
also be examined at the Federal Aviation Administration (FAA), Central 
Region, Office of the Regional Counsel, Attention: Rules Docket No. 98-
CE-40-AD, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106; 
or at the Office of the Federal Register, 800 North Capitol Street, NW, 
suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Mr. Roman T. Gabrys, Aerospace 
Engineer, FAA, Small Airplane Directorate, 1201 Walnut, suite 900, 
Kansas City, Missouri 64106; telephone: (816) 426-6934; facsimile: 
(816) 426-2169.

SUPPLEMENTARY INFORMATION:

Discussion

    On October 29, 1997, the FAA issued AD 97-23-04, Amendment 39-10192 
(62 FR 5993, November 6, 1997), which applies to certain Pilatus Models 
PC-12 and PC-12/45 airplanes. AD 97-23-04 was the result of a report 
from the Federal Office for Civil Aviation (FOCA), which is the 
airworthiness authority for Switzerland, of an instance of abnormal 
automatic engagement of the fuel booster pumps during normal operation 
of a Pilatus Model PC-12 airplane. The FOCA's investigation

[[Page 40808]]

revealed that the fuel tank inward vent valves may fail in the closed 
position under certain conditions. Moisture ingestion, followed by cold 
soak, can lead to the fuel tank inward vent valve freezing.
    AD 97-23-04 required replacing the fuel tank vent valves with 
modified fuel tank vent valves before the FAA superseded it with AD 98-
11-01, Amendment 39-10528 (63 FR 27195, May 18, 1998). AD 98-11-01 
currently requires the fuel tank vent valves replacement required by AD 
97-23-04, and requires drilling a 4.8 millimeter (0.1875 inch) hole in 
each fuel filler cap. This AD also requires inserting the following 
temporary revision to the POH that specifies checking to assure that 
the fuel filler cap hole is clear of ice and foreign objects:

    PC-12 Pilot's Operating Handbook, Pilatus Report No. 01973-001, 
Temporary Revision, Fuel Filler Cap, dated March 27, 1998.

Accomplishment of the replacement is required in accordance with 
Pilatus Service Bulletin No. 28-003, Revision 1, dated September 30, 
1997. Accomplishment of the drilling and POH insertion is required in 
accordance with Pilatus Service Bulletin No. 28-004, dated March 27, 
1998.
    AD 98-11-01 was the result of a report of an incident where the 
inward vent valve of the fuel tank froze closed on one of the affected 
airplanes that was in compliance with the fuel tank vent valves 
replacement requirement of AD 97-23-04. This resulted in permanent 
structural damage to the wing skins and ribs.
    Pilatus then issued Service Bulletin No. 28-005, dated May 4, 1998, 
which specifies procedures for modifying the fuel tank vent valves. 
This modification, when incorporated, would eliminate the need for the 
drilling and POH requirements of AD 98-11-01.
    The FAA followed by issuing AD 98-11-01 R1, mendment 39-10608 (63 
FR 34565, June 25, 1998), to incorporate Pilatus Service Bulletin No. 
28-005, dated May 4, 1998, as an alternative method of compliance to AD 
98-11-01 R1.

Need for the Correction

    The way AD 98-11-01 R1 is currently written makes it impossible for 
the new modified fuel vent valves to be incorporated because it does 
not provide the option of removing the previous replacement fuel tank 
vent valves as originally required by AD 97-23-04 and carried over in 
the current AD. In particular, paragraph (d) reads:

    (d) As an alternative method of compliance to the actions 
required in paragraph (b)(1) and (b)(2) of this AD, modify the fuel 
tank vent valve system in accordance with the Accomplishment 
Instructions section of Pilatus Service Bulletin No. 28-005, dated 
May 4, 1998.

Paragraph (b)(1) requires the 4.8 millimeter hole to be drilled in each 
filler cap and paragraph (b)(2) requires the insertion of the temporary 
POH revision. Paragraph (a) requires replacement of the fuel tank vent 
valves.
    The new modified vent valves cannot be incorporated without 
removing the vent valves required by paragraph (a) of the current AD. 
AD 98-11-01 R1 currently does not provide for this.
    Consequently, the FAA sees a need to clarify AD 98-11-01 R1 to 
assure that the modification can be fully carried out as an alternative 
method of compliance for all the actions of the AD.

Correction of Publication

    This document clarifies the intent of the fuel tank vent valve 
modification specified in Pilatus Service Bulletin No. 28-005, dated 
May 4, 1998, as an alternative method of compliance to all of the 
actions of AD 98-11-01 R1. This document also adds the amendment to 
section 39.13 of the Federal Aviation Regulations (14 CFR 39.13).
    Since this action only clarifies the intent of the fuel tank vent 
valve modication, it has no adverse economic impact and imposes no 
additional burden on any person than would have been necessary to 
comply with paragraph (d) of AD 98-11-01 R1. Therefore, the FAA has 
determined that prior notice and opportunity for public comment are 
unnecessary.

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 removing Airworthiness Directive 
(AD) 98-11-01 R1, Amendment 39-10608 (63 FR 34565, June 25, 1998), and 
by adding a new AD to read as follows:

98-11-01 R1 Pilatus Aircraft, Ltd.: Amendment 39-10681; Docket No. 
98-CE-40-AD; Revises AD 98-11-01 R1, Amendment 39-10608; which 
revised AD 98-11-01, Amendment 39-10528; which superseded AD 97-23-
04, Amendment 39-34565.

    Applicability: Models PC-12 and PC-12/45 airplanes; serial 
numbers 101 through 230, 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 in the body of this AD, unless 
already accomplished.
    To prevent moisture from entering the fuel tank inward vent 
valve and then freezing after a cold soak at altitude, which could 
result in wing airfoil distortion and structural damage with 
consequent degradation of the airplane's handling qualities, 
accomplish the following:
    (a) Within the next 10 hours time-in-service (TIS) after 
December 1, 1997 (the effective date of AD 97-23-04), replace the 
fuel tank vent valves with modified fuel tank vent valves in 
accordance with the Accomplishment Instructions section of Pilatus 
Service Bulletin No. 28-003, Revision 1, dated September 30, 1997.
    (b) Within the next 10 hours TIS after June 7, 1998 (the 
effective date of AD 98-11-01), accomplish the following:
    (1) Drill a 4.8 millimeter (0.1875 inch) hole in each fuel 
filler cap in accordance with the Accomplishment Instructions 
section of Pilatus Service Bulletin No. 28-004, dated March 27, 
1998.
    (2) Insert a temporary revision (as referenced in Pilatus 
Service Bulletin 28-004, dated March 27, 1998) into the Pilot's 
Operating Handbook (POH) that specifies checking to assure that the 
fuel filler cap hole is clear of ice and foreign objects. This 
document is entitled ``PC-12 Pilot's Operating Handbook, Pilatus 
Report No. 01973-001, Temporary Revision, Fuel Filler Cap, dated 
March 27, 1998.''
    (c) Inserting the POH revision, as required by paragraph (b)(2) 
of this AD, may be performed by the owner/operator holding at least 
a private pilot certificate as authorized by section 43.7 of the 
Federal Aviation Regulations (14 CFR 43.7), and must be entered into 
the aircraft records showing compliance with this AD in accordance 
with section 43.9 of the Federal Aviation Regulations (14 CFR 43.9).

[[Page 40809]]

    (d) As an alternative method of compliance to the actions 
required by this AD, including the actions in paragraphs (a), 
(b)(1), and (b)(2), modify the fuel tank vent valve system in 
accordance with the Accomplishment Instructions section of Pilatus 
Service Bulletin No. 28-005, dated May 4, 1998.
    (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.
    (f) 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, FAA, 1201 
Walnut, suite 900, Kansas City, Missouri 64106.
    (1) 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.
    (2) Alternative methods of compliance approved in accordance 
with AD 98-11-01 R1 (revised by this action), AD 98-11-01 (revised 
by AD 98-11-01 R1), and AD 97-23-04 (superseded by AD 98-11-01) are 
considered approved as alternative methods of compliance for this 
AD.

    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.

    (g) Questions or technical information to the service 
information referenced in this document should be directed to 
Pilatus Aircraft Ltd., CH-6370 Stans, Switzerland. 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.
    (h) The replacement required by this AD shall be done in 
accordance with Pilatus Service Bulletin No. 28-003, Revision 1, 
dated September 30, 1997. The drilling required by this AD shall be 
done in accordance with Pilatus Service Bulletin No. 28-004, dated 
March 27, 1998. The modification required by this AD shall be done 
in accordance with Pilatus Service Bulletin No. 28-005, dated May 4, 
1998.
    (1) The incorporation by reference of Pilatus Service Bulletin 
No. 28-003, dated September 30, 1997, was previously approved by the 
Director of the Federal Register as of December 1, 1997 (62 FR 
59993, November 6, 1997).
    (2) The incorporation by reference of Pilatus Service Bulletin 
No. 28-004, dated March 27, 1998, was previously approved by the 
Director of the Federal Register as of June 7, 1998 (63 FR 27195, 
May 18, 1998).
    (3) The incorporation by reference of Pilatus Service Bulletin 
No. 28-005, dated May 4, 1998, was previously approved by the 
Director of the Federal Register as of September 22, 1998 (63 FR 
34565, June 25, 1998).
    (4) Copies of these service bulletins may be obtained from 
Pilatus Aircraft Ltd., CH-6370 Stans, Switzerland. Copies may be 
inspected at the FAA, Central Region, Office of the Regional 
Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri, 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 Swiss AD HB 97-
432A, dated October 3, 1997; Swiss AD HB 98-086, dated March 31, 
1998; and Swiss AD HB 98-126, dated May 15, 1998.

    (i) This amendment revises AD 98-11-01 R1, amendment 39-10608; 
which revised AD 98-11-01, Amendment 39-10528; which superseded AD 
97-23-04, Amendment No. 39-10192.
    (j) This amendment becomes effective on September 22, 1998.

    Issued in Kansas City, Missouri, on July 23, 1998.
Michael Gallagher,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-20439 Filed 7-30-98; 8:45 am]
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