[Federal Register Volume 62, Number 229 (Friday, November 28, 1997)]
[Proposed Rules]
[Pages 63292-63294]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-31159]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-249-AD]
RIN 2120-AA64


Airworthiness Directives; Fokker Model F28 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 adoption of a new airworthiness 
directive (AD) that is applicable to certain Fokker Model F28 Mark 0070 
and Mark 0100 series airplanes. This proposal would require 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 proposal is prompted by the issuance of 
mandatory continuing airworthiness information by a foreign civil 
airworthiness authority. The actions specified by the proposed 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: Comments must be received by December 29, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 97-NM-249-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: 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

[[Page 63293]]

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 Docket Number 97-NM-249-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-103, Attention: Rules 
Docket No. 97-NM-249-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The Rijksluchtvaartdienst (RLD), which is the airworthiness 
authority for the Netherlands, notified the FAA that an unsafe 
condition may exist on certain Fokker Model F28 Mark 0070 and Mark 0100 
series airplanes. The RLD advises that several operators of Fokker 
Model F28 Mark 0100 series airplanes have reported bleed air leakage at 
corrujoint seals at the 7th stage low-pressure and 12th stage high-
pressure check valves, which are located in the stubwings (engine 
pylons). On a few airplanes, leakage of hot air from these joints has 
resulted in heat damage to the fuselage skin and stubwing structure, 
which required internal and external repairs to ensure structural 
integrity. Such heat damage, if not corrected, could result in reduced 
structural integrity of the airplane.

Explanation of Relevant Service Information

    Fokker has issued Service Bulletin SBF100-53-084, dated July 6, 
1996, which describes the following procedures:
     An inspection of aircraft maintenance records to determine 
whether maintenance was accomplished on certain components for the 
bleed air system.
     A one-time visual inspection to detect heat damage of the 
fuselage skin and stubwing structure.
     Repetitive leak tests of the seals of the bleed air 
system, or repair of any heat-damaged structure, as necessary.
     Replacement of corrujoint seals with new improved seals.
    Fokker has also issued Service Bulletin SBF100-36-026, Revision 1, 
dated July 6, 1996, which describes procedures for the replacement of 
certain corrujoint seals 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 seals.
    Accomplishment of the actions specified in the service bulletins is 
intended to adequately address the identified unsafe condition. The RLD 
classified these service bulletins as mandatory and issued Dutch 
airworthiness directive BLA 1995-076/2 (A), dated August 30, 1996, in 
order to assure the continued airworthiness of these airplanes in the 
Netherlands.

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 Sec. 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 require accomplishment of 
the actions specified in the service bulletins described previously, 
except as discussed below.

Differences Between Proposed Rule and Service Bulletin

    Operators should note that, unlike the procedures described in 
Fokker Service Bulletin SBF100-53-084, this proposed AD does not 
require an inspection of the maintenance records to determine whether 
maintenance was accomplished on certain components (check valves and 
corrujoint seals) of the bleed air system. The FAA has determined that 
such a records inspection is unnecessary; instead, this AD specifies 
applicability to those airplanes equipped with any corrujoint seal 
having P/N BE20061 (Rolls-Royce P/N 3405891).

Cost Impact

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

[[Page 63294]]

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:

Fokker: Docket 97-NM-249-AD.

    Applicability: Model F28 Mark 0070 and Mark 0100 series 
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 
otherwise modified, altered, or repaired in the area subject to the 
requirements of this AD. For airplanes that have been otherwise 
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:
    (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, 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.
    (1) 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.
    (2) If no leakage is found at a seal, perform an additional leak 
test of that seal within 250 flight hours after the initial test.
    (i) 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.
    (ii) If any leakage is found during the additional test of the 
seal, prior to further flight, accomplish paragraphs (b)(2)(ii)(A) 
and (b)(2)(ii)(B) of this AD.
    (A) 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.
    (B) 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 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.

    (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.

    Note 3: The subject of this AD is addressed in Dutch 
airworthiness directive BLA 1995-076/2 (A), dated August 30, 1996.

    Issued in Renton, Washington, on November 20, 1997.
Stewart R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-31159 Filed 11-26-97; 8:45 am]
BILLING CODE 4910-13-U