[Federal Register Volume 63, Number 68 (Thursday, April 9, 1998)]
[Rules and Regulations]
[Pages 17318-17320]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-9123]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-249-AD; Amendment 39-10450; AD 98-08-01]
RIN 2120-AA64


Airworthiness Directives; Fokker Model F28 Mark 0070 and Mark 
0100 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 Fokker Model F28 Mark 0070 and Mark 0100 series 
airplanes, that requires a one-time visual inspection to detect heat 
damage of the fuselage skin and stubwing structure. This proposal also 
would require either repetitive leak tests of the seals of the bleed 
air system, or repair of any heat-damaged structure, as necessary; and 
replacement of corrujoint seals with new improved seals. 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 the leakage of hot air 
from the corrujoint seals of the low- and high-pressure check valves 
located in the stubwings, which could result in heat damage to the 
fuselage skin and stubwing structure, and consequent reduced structural 
integrity of the airplane.

DATES: Effective May 14, 1998.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of May 14, 1998.

ADDRESSES: The service information referenced in this AD may be 
obtained from Fokker Services B.V., Technical Support Department, P. O. 
Box 75047, 1117 ZN Schiphol Airport, the Netherlands. 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 Fokker Model F28 Mark 0070 
and Mark 0100 series airplanes was published in the Federal Register on 
November 28, 1997 (62 FR 63292). That action proposed to require a one-
time visual inspection to detect heat damage of the fuselage skin and 
stubwing structure. That action also proposed to require either 
repetitive leak tests of the seals of the bleed air system, or repair 
of any heat-damaged structure, as necessary; and replacement of 
corrujoint seals with new improved seals.

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.
    One commenter, the Air Transport Association (ATA) of America, on 
behalf of one of its members, requests that the AD include a statement 
excluding aircraft previously inspected and modified in accordance with 
the referenced Fokker service information. The ATA member indicates 
that it has already completed the inspection and modifications 
described in the service bulletins cited in the proposed AD. The FAA 
concurs that previously accomplished inspections and modifications need 
not be repeated; however, the commenters' concern in that regard was 
already addressed in the proposed AD by the statement, ``Compliance: 
Required as indicated, unless accomplished previously.'' That language 
reappears in this final rule. Therefore, no change to the final rule is 
necessary.
    Similarly, the ATA requests that a provision be added to exclude 
airplanes on which the intent of the proposed AD has already been 
accomplished, including repairs that were generated to repair damaged 
structure, in accordance with Fokker Service Bulletin SBF100-53-081, 
which is not referenced in the proposed rule.
    The FAA concurs that replacements and repairs accomplished prior to 
the effective date of this AD in accordance with the service bulletin 
referenced by the commenter are acceptable provided that no seal has 
been subsequently replaced with a seal having part number BE20061 
(Rolls-Royce part number 3405891). This final rule, therefore, includes 
a note stating that inspections for heat damage, leak tests, seal 
replacements, and repairs accomplished prior to the effective date of 
this AD, in accordance with Fokker Service Bulletin SBF100-53-081, 
dated July 7, 1995, are considered acceptable for compliance with the 
requirements of this AD, provided that no seal has been subsequently 
replaced with a seal having part number BE20061 (Rolls-Royce part 
number 3405891).
    The ATA, on behalf of another commenter, requests that a provision 
be added to allow the leak tests to be omitted if the inspection 
reveals no heat damage and if, prior to further flight, the corrujoint 
seals at the seventh stage low pressure check valve and twelfth stage 
high pressure check valves are replaced with the improved corrujoint 
seals. The commenter states that accomplishment of these actions is 
similar to the optional method of complying with Fokker Service 
Bulletin SBF100-53-084.
    The FAA concurs with the commenter's request. The FAA agrees that, 
if the inspection required by paragraph (a) of this AD reveals no heat 
damage, and if, prior to further flight, all affected corrujoint seals 
are replaced with the improved corrujoint seals, then accomplishment of 
the leak tests is not necessary. The FAA has revised and

[[Page 17319]]

reformatted paragraph (b) of this final rule to include this provision.
    The ATA also requests that the compliance time be extended from 12 
to 18 months. The commenter states that 18 months is the accepted 
industry standard and further notes that, because of the areas to which 
access is needed, the work must be accomplished while an airplane is 
out of service for maintenance.
    The FAA does not concur. In developing an appropriate compliance 
time for this action, the FAA considered not only the degree of urgency 
associated with addressing the subject unsafe condition, but a number 
of other factors as well. Those included the recommendations of the 
manufacturer and foreign airworthiness authority, the availability of 
required parts, and the practical aspect of accomplishing the required 
actions within an interval of time coinciding with normal scheduled 
maintenance for the majority of the affected operators. Considering all 
of those factors, the FAA determined that the proposed compliance time 
represents the maximum interval in which the affected airplanes could 
continue to operate without compromising safety. In that regard, the 
commenter did not provide any data to substantiate that an extension of 
the compliance time would not compromise safety. In view of those 
factors, and the amount of time that has already elapsed since issued 
of the original notice of proposed rulemaking, the FAA has determined 
that further delay of these actions is, in general, not appropriate. 
The FAA may, however, approve a request for an adjustment of the 
compliance time under the provisions of this final rule if data are 
submitted to substantiate that such an adjustment would provide an 
equivalent level of safety.

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 changes previously 
described. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.

Cost Impact

    The FAA estimates that 131 Fokker Model F28 Mark 0070 and Mark 0100 
series airplanes of U.S. registry will be affected by this AD.
    The inspection will take approximately 3 work hours per airplane to 
accomplish, 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 $23,580, or $180 per airplane.
    The replacement of the corrujoint seals will take approximately 7 
work hours per airplane to accomplish, at an average labor rate of $60 
per work hour. Required parts will cost approximately $80 per airplane. 
Based on these figures, the cost impact of the replacement required by 
this AD on U.S. operators is estimated to be $65,500, or $500 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:

98-08-01  Fokker: Amendment 39-10450. Docket 97-NM-249-AD.

    Applicability: Model F28 Mark 0070 and Mark 0100 airplanes; as 
listed in Fokker Service Bulletin SBF100-53-084, dated July 6, 1996; 
if equipped with any corrujoint seal having part number (P/N) 
BE20061 (Rolls-Royce P/N 3405891); 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 (e) 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 leakage of hot air from the corrujoint seals of 
low- and high-pressure check valves located in the stubwings, which 
could result in heat damage to the fuselage skin and stubwing 
structure and consequent reduced structural integrity, accomplish 
the following:

    Note 2: Inspections for heat damage, leak tests, seal 
replacements, and repairs accomplished prior to the effective date 
of this AD in accordance with Fokker Service Bulletin SBF100-53-081, 
dated July 7, 1995, are considered acceptable for compliance with 
the requirements of this AD, provided that no seal has been 
subsequently replaced with a seal having part number BE20061 (Rolls-
Royce part number 3405891).

    (a) Within 3,000 flight hours or 12 months after the effective 
date of this AD, whichever occurs first, perform a one-time visual 
inspection of the fuselage skin in the left- and right-hand 
stubwings to detect heat damage; in accordance with Part 2 of the 
Accomplishment Instructions of Fokker Service Bulletin SBF100-53-
084, dated July 6, 1996.
    (b) If no heat damage is found during the inspection required by 
paragraph (a) of this AD, prior to further flight, accomplish either 
paragraph (b)(1) or (b)(2) of this AD.
    (1) Replace all corrujoint seals having P/N BE20061 (Rolls-Royce 
P/N 3405891) at the 7th stage low-pressure and 12th stage high-
pressure check valves of the left- and right-hand bleed air systems 
with new improved

[[Page 17320]]

corrujoint seals having P/N EU15969, in accordance with the 
Accomplishment Instructions of Fokker Service Bulletin SBF100-36-
026, Revision 1, dated July 6, 1996.
    (2) Perform a leak test of each corrujoint seal at the 7th stage 
low-pressure and 12th stage high-pressure check valves of the left-
and right-hand bleed air systems, in accordance with Part 3 of the 
Accomplishment Instructions of Fokker Service Bulletin SBF100-53-
084, dated July 6, 1996.
    (i) If any leakage is found at a seal, prior to further flight, 
replace that seal with a new improved seal having part number 
EU15969, in accordance with the Accomplishment Instructions of 
Fokker Service Bulletin SBF100-36-026, Revision 1, dated July 6, 
1996.
    (ii) If no leakage is found at a seal, perform an additional 
leak test of that seal within 250 flight hours after the initial 
test.
    (A) If no leakage is found during the additional test of the 
seal, within 3,000 flight hours after the additional test, replace 
the seal with an improved seal having P/N EU15969, in accordance 
with the Accomplishment Instructions of Fokker Service Bulletin 
SBF100-36-026, Revision 1, dated July 6, 1996.
    (B) If any leakage is found during the additional test of the 
seal, prior to further flight, replace the seal with a new improved 
seal having P/N EU15969, in accordance with the Accomplishment 
Instructions of Fokker Service Bulletin SBF100-36-026, Revision 1, 
dated July 6, 1996; and inspect the fuselage skin in the applicable 
left- or right-hand stubwing to detect heat damage, in accordance 
with Part 2 of the Accomplishment Instructions of Fokker Service 
Bulletin SBF100-53-084, dated July 6, 1996.
    (c) If any heat damage is found during the inspection required 
by paragraph (a) or paragraph (b)(2)(ii)(B) of this AD, prior to 
further flight, perform a detailed inspection of the fuselage skin 
and stubwing structure to detect the extent of heat damage, in 
accordance with Parts 4 and 5 of the Accomplishment Instructions of 
Fokker Service Bulletin SBF100-53-084, dated July 6, 1996; and 
accomplish paragraphs (c)(1) and (c)(2) of this AD.
    (1) Repair the affected structure, in accordance with Part 6 of 
the Accomplishment Instructions of Fokker Service Bulletin SBF100-
53-084, dated July 6, 1996. And
    (2) Replace all corrujoint seals having P/N BE20061 (Rolls-Royce 
P/N 3405891) at the 7th stage low-pressure and 12th stage high-
pressure check valves of the left- and right-hand bleed air systems 
with new improved corrujoint seals having P/N EU15969, in accordance 
with the Accomplishment Instructions of Fokker Service Bulletin 
SBF100-36-026, Revision 1, dated July 6, 1996.
    (d) As of the effective date of this AD, no person shall install 
a corrujoint seal having P/N BE20061 (Rolls-Royce P/N 3405891) on 
any airplane.
    (e) 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 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.

    (f) 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.
    (g) The actions shall be done in accordance with Fokker Service 
Bulletin SBF100-53-084, dated July 6, 1996, and Fokker Service 
Bulletin SBF100-36-026, Revision 1, dated July 6, 1996. 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 Fokker Services B.V., Technical 
Support Department, P.O. Box 75047, 1117 ZN Schiphol Airport, the 
Netherlands. 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 Dutch 
airworthiness directive BLA 1995-076/2 (A), dated August 30, 1996.

    (h) This amendment becomes effective on May 14, 1998.

    Issued in Renton, Washington, on March 31, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-9123 Filed 4-8-98; 8:45 am]
BILLING CODE 4910-13-U