[Federal Register Volume 63, Number 217 (Tuesday, November 10, 1998)]
[Proposed Rules]
[Pages 62970-62973]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-30052]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-202-AD]
RIN 2120-AA64


Airworthiness Directives; Fokker Model F.28 Mark 0070 and Mark 
0100 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the supersedure of an existing 
airworthiness directive (AD), applicable to certain Fokker Model F.28 
Mark 0070 and Mark 0100 series airplanes, that currently requires a 
one-time inspection for heat damage of the fuselage skin and stubwing 
structure; either repetitive tests of certain seals or repair of heat 
damage, as necessary; and eventual replacement of corrujoint seals with 
new, improved seals. This action would add a requirement for repetitive 
inspections for heat damage of the subject area, and would provide for 
a new optional terminating action for the repetitive inspections. This 
proposal is prompted by issuance of mandatory continuing airworthiness 
information by a foreign civil airworthiness authority. The actions 
specified by the proposed AD are intended to prevent leakage of hot air 
from the corrujoint seals of certain valves in the stubwings, and 
subsequent heat damage of the fuselage skin and stubwing structure, 
which could result in reduced structural integrity of the airplane.

DATES: Comments must be received by December 10, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 98-NM-202-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except 
Federal holidays.
    The service information referenced in the proposed rule 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 FAA, Transport Airplane Directorate, 1601 Lind 
Avenue, SW., Renton, Washington.

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:

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 shall 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 summarizing 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

[[Page 62971]]

Docket Number 98-NM-202-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, Transport Airplane Directorate, ANM-114, Attention: Rules 
Docket No. 98-NM-202-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On March 31, 1998, the FAA issued AD 98-08-01, amendment 39-10450 
(63 FR 17318, April 9, 1998), applicable to certain Fokker Model F.28 
Mark 0070 and Mark 0100 series airplanes. That AD requires a one-time 
visual inspection to detect heat damage of the fuselage skin and 
stubwing structure; either repetitive leak tests of the seals of the 
bleed air system or repair of any heat-damaged structure, as necessary; 
and eventual replacement of corrujoint seals with new, improved seals. 
That action was prompted by the issuance of mandatory continuing 
airworthiness information by a foreign civil airworthiness authority. 
The requirements of that 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.

Actions Since Issuance of Previous Rule

    Since the issuance of that AD, the Rijksluchtvaartdienst (RLD), 
which is the airworthiness authority for the Netherlands, has advised 
the FAA that the unsafe condition addressed in AD 98-08-01 may exist or 
develop on certain Fokker Model F.28 Mark 0070 and Mark 0100 series 
airplanes despite compliance with the requirements of that AD. Based on 
the results of the one-time visual inspection (required by AD 98-08-
01), the manufacturer has recommended, and the RLD has mandated, that a 
visual inspection be repeated at specified intervals to detect heat 
damage of the fuselage skin and stubwing connection angles in the 
stubwing area.

Explanation of Relevant Service Information

    Fokker has issued Service Bulletin SBF100-53-087, dated November 
17, 1997, which describes procedures for repetitive visual inspections 
to detect heat damage of the fuselage skin and stubwing connection 
angles in the stubwing area. This service bulletin also describes 
procedures for an additional detailed inspection of the fuselage skin 
and stubwing structure, and repair when overheat damage is detected. 
Accomplishment of the actions specified in Fokker Service Bulletin 
SBF100-53-087 is intended to adequately address the identified unsafe 
condition. The RLD classified Fokker Service Bulletin SBF100-53-087 as 
mandatory and issued Dutch airworthiness directive 1995-076/3 (A), 
dated November 28, 1997, in order to assure the continued airworthiness 
of these airplanes in the Netherlands.
    Fokker also has issued Proforma Service Bulletin SBF100-36-027, 
including Appendix I, both dated March 21, 1997, which describes 
procedures for modification of the fuselage skin and stubwing structure 
to improve heat protection. The modification involves installing new 
heat shields on the fuselage skin, relocating the aft bay overheat 
switch, and replacing insulation blankets of the bleed air ducts with 
new, improved insulation blankets. This service bulletin specifies that 
accomplishment of the modification would eliminate the need for the 
repetitive inspections described in Fokker Service Bulletin SBF100-53-
087. The RLD has approved Fokker Service Bulletin SBF100-36-027 and 
classified it as optional.

FAA's Conclusions

    These airplane models are manufactured in the Netherlands and are 
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 RLD has kept the FAA 
informed of the situation described above. The FAA has examined the 
findings of the RLD, 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 Proposed 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, the proposed AD would supersede AD 98-08-01, 
amendment 39-10450 (63 FR 17318, April 9, 1998), to continue to require 
a one-time visual inspection to detect heat damage of the fuselage skin 
and stubwing structure; 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. Additionally, this proposal would require repetitive inspections 
of the fuselage skin and stubwing connection angles to detect heat 
damage, and an additional detailed inspection of the fuselage and 
stubwing structure and repair when heat damage is detected. This 
proposal also would provide for a new optional terminating action for 
the repetitive inspections.

FAA's Determination

    Operators should note that, in consonance with the findings of the 
RLD, the FAA has determined that the repetitive inspections proposed by 
this AD can be allowed to continue in lieu of accomplishment of a 
terminating action. In making this determination, the FAA considers 
that, in this case, long-term continued operational safety will be 
adequately assured by accomplishing the repetitive inspections to 
detect heat damage to the fuselage skin and stubwing structure before 
the damage represents a hazard to the airplane.

Difference Between Proposed Rule and Relevant Service Information

    Operators should note that Fokker Service Bulletin SBF100-53-087 
specifies that heat damage of the fuselage skin should be repaired in 
accordance with Fokker Service Bulletin SBF100-53-084, dated July 6, 
1996, which describes procedures for certain repairs of heat damage, 
and recommends that the manufacturer may be contacted for disposition 
of other repairs. This proposal would require such other repairs to be 
accomplished in accordance with a method approved by either the FAA or 
the RLD (or its delegated agent). In light of the type of repair that 
would be required to address the identified unsafe condition, and in 
consonance with existing bilateral airworthiness agreements, the FAA 
has determined that, for this proposed AD, a repair approved by either 
the FAA or the RLD would be acceptable for compliance with this 
proposed AD.

Explanation of Changes Made to Applicability

    Operators should note that the applicability of the proposed AD 
differs from the applicability of AD 98-08-01 in that it excludes those 
airplanes on which Fokker Proforma Service Bulletin SBF100-36-027 has 
been accomplished. The FAA has determined that accomplishment of the 
actions described in that service bulletin would terminate the 
requirements of the new repetitive visual inspections of the

[[Page 62972]]

fuselage skin in the left- and right-hand stubwings.

Cost Impact

    The FAA estimates that 141 airplanes of U.S. registry would be 
affected by this proposed AD.
    The one-time visual inspection that was previously required by AD 
98-08-01, and retained in this AD, takes 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 one-time inspection 
requirement of this AD on U.S. operators is estimated to be $180 per 
airplane.
    The seal replacement that was previously required by AD 98-08-01, 
and retained in this AD, takes approximately 7 work hours per airplane 
to accomplish, at an average labor rate of $60 per work hour. Required 
parts cost approximately $80 per airplane. Based on these figures, the 
cost impact of the seal replacement requirement of this AD on U.S. 
operators is estimated to be $500 per airplane.
    The repetitive inspections proposed by this AD would 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 repetitive inspections proposed by this AD on U.S. 
operators is estimated to be $25,380, or $180 per airplane, per 
inspection cycle.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the current or proposed 
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 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 proposed 
regulation (1) is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the 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 is contained 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.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing amendment 39-10450 (63 FR 
17318, April 9, 1998), and by adding a new airworthiness directive 
(AD), to read as follows:

Fokker Services B.V.: Docket 98-NM-202-AD. Supersedes AD 98-08-01, 
Amendment 39-10450.

    Applicability: Model F.28 Mark 0070 and Mark 0100 series 
airplanes equipped with any corrujoint seal having part number (P/N) 
BE20061 (Rolls-Royce P/N 3405891) or on which Fokker Proforma 
Service Bulletin SBF100-36-027, including Appendix 1, both dated 
March 21, 1997, has not been accomplished; 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 (i)(1) 
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 leakage of hot air from the corrujoint seals of the 
low- and high-pressure check valves located in the stubwings, and 
subsequent heat damage of fuselage skin and stubwing structure 
adjacent to bleed air system components in the stubwings, which 
could result in reduced structural integrity of the airplane, 
accomplish the following:

Restatement of Requirements of AD 98-08-01, Amendment 39-10450

    (a) For Model F28 Mark 0070 and Mark 0100 series airplanes as 
listed in Fokker Service Bulletin SFB100-53-084, dated July 6, 1996; 
if equipped with any corrujoint seal having P/N BE20061 (Rolls-Royce 
P/N 3405891): Within 3,000 flight hours or 12 months after May 14, 
1998 (the effective date of AD 98-08-01, amendment 39-10450), 
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 SFB100-53-084, 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 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

[[Page 62973]]

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) Except as provided by paragraph (g) of this AD: 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 May 14, 1998, no person shall install a corrujoint 
seal having P/N BE20061 (Rolls-Royce P/N 3405891) on any airplane.

New Requirements for This AD

    (e) For Model F.28 Mark 0070 and Mark 0100 series airplanes on 
which Fokker Proforma Service Bulletin SBF100-36-027, including 
Appendix 1, both dated March 21, 1997, has not been accomplished: 
Perform a visual inspection of the fuselage skin in the left- and 
right-hand stubwings to detect heat damage, in accordance with the 
Accomplishment Instructions of Fokker Service Bulletin SBF100-53-
087, dated November 17, 1997, at the latest of the times specified 
in paragraphs (e)(1), (e)(2), and (e)(3) of this AD, as applicable. 
Repeat the inspection required by paragraph (e) of this AD 
thereafter at intervals not to exceed 6,000 landings.
    (1) Within 6,000 landings after the effective date of this AD.
    (2) Within 6 months after the effective date of this AD.
    (3) Within 6,000 landings after accomplishment of the inspection 
required by paragraph (a) of this AD.
    (f) If any heat damage is detected during any inspection 
required by paragraph (e) of this AD, prior to further flight, 
perform a detailed visual inspection to determine the extent of heat 
damage, in accordance with paragraph 2.B.(2) of the Accomplishment 
Instructions of Fokker Service Bulletin SBF100-53-087, dated 
November 17, 1997. Except as provided by paragraph (g) of this AD, 
prior to further flight, repair in accordance with the service 
bulletin.

    Note 2: Fokker Service Bulletin SBF100-53-087, dated November 
17, 1997, refers to Fokker Service Bulletin SBF100-53-084, dated 
July 6, 1996, as an additional source of service information for the 
detailed inspection procedures, repair limits, and repair 
procedures.

    (g) If any damage is found during accomplishment of any action 
specified by paragraph (c)(1) or (f) of this AD, and Fokker Service 
Bulletin SBF100-53-084, dated July 6, 1996, or Fokker Service 
Bulletin SBF100-53-087, dated November 17, 1997, specifies to 
contact the manufacturer for an appropriate action. Prior to further 
flight, repair in accordance with a method approved by the Manager, 
International Branch, ANM-116, FAA, Transport Airplane Directorate; 
or the RLD (or its delegated agent).
    (h) Installation of new heat shields, relocation of the aft bay 
overheat switch, and replacement of the insulation blankets of the 
bleed air ducts with new, improved insulation blankets, in 
accordance with Fokker Proforma Service Bulletin SBF100-36-027, 
including Appendix I, both dated March 21, 1997, constitutes 
terminating action for the repetitive inspection requirements of 
paragraph (e) of this AD.
    (i)(1) 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.
    (i)(2) Alternative methods of compliance, approved previously in 
accordance with AD 98-08-01, amendment 39-10450, are approved as 
alternative methods of compliance with paragraphs (a), (b), and (c) 
of this AD.
    (i)(3) Airplanes repaired in accordance with alternative methods 
of compliance, approved previously in accordance with AD 98-08-01, 
are not considered exempt from the repetitive inspection 
requirements of paragraph (e) of this AD.

    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.

    (j) 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.

    Note 4: The subject of this AD is addressed in Dutch 
airworthiness directive 1995-076/3 (A), dated November 28, 1997.

    Issued in Renton, Washington, on November 3, 1998.
Vi L. Lipski,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-30052 Filed 11-9-98; 8:45 am]
BILLING CODE 4910-13-P