[Federal Register Volume 64, Number 31 (Wednesday, February 17, 1999)]
[Proposed Rules]
[Pages 7830-7833]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-3727]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-214-AD]
RIN 2120-AA64


Airworthiness Directives; British Aerospace (Jetstream) Model 
4101 Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Supplemental notice of proposed rulemaking; reopening of 
comment period.

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SUMMARY: This document revises an earlier proposed airworthiness 
directive (AD), applicable to all British Aerospace (Jetstream) Model 
4101 airplanes. That proposal would have required repetitively 
inspecting to detect damage of the structure associated with the engine 
nacelle fairing attached to the wing flaps, and repair of any damage 
found; drilling a new drain hole in each engine nacelle fairing; and 
applying a sealant to the gap between the wing flap and engine nacelle 
fairing. That proposal was prompted by reports of fatigue cracks found 
in the structure that attaches the engine nacelle fairing to the wing 
flaps. This new action revises the proposed AD by adding requirements 
to perform corrective actions for discrepancies and accomplish a 
modification that would terminate the repetitive inspections. This new 
action also would limit the applicability. The actions specified by 
this new proposed AD are intended to prevent such fatigue cracking, 
which could result in the partial or complete separation of the fairing 
from the wing flap, and consequent additional structural damage to the 
airframe and/or reduced controllability of the airplane.


[[Page 7831]]


DATES: Comments must be received by March 15, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 96-NM-214-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 AI(R) American Support, Inc., 13850 Mclearen Road, 
Herndon, Virginia 20171. 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 Docket Number 96-NM-214-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. 96-NM-214-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    A proposal to amend part 39 of the Federal Aviation Regulations (14 
CFR part 39) to add an airworthiness directive (AD), applicable to all 
British Aerospace (Jetstream) Model 4101 airplanes, was published as a 
notice of proposed rulemaking (NPRM) in the Federal Register on May 14, 
1997 (62 FR 26456). That NPRM would have required repetitive 
inspections of the structure associated with the engine nacelle fairing 
that is attached to the left and right flaps of the wings for damage, 
and repair of any damage found. That NPRM also would have required 
drilling a new drain hole in each engine nacelle fairing and applying a 
sealant to the gap between the wing flap and engine nacelle fairing. 
That NPRM was prompted by reports indicating that fatigue cracks were 
found in the structure that attaches the engine nacelle fairing to the 
wing flaps on the affected airplanes. That condition, if not corrected, 
could result in the engine nacelle fairing partially or completely 
separating from the wing flap, and consequent additional structural 
damage to the airframe and/or reduced controllability of the airplane.

Actions Since Issuance of NPRM

    Since the issuance of the original NPRM, the manufacturer has 
issued Jetstream Alert Service Bulletin J41-A57-015, Revision 1, dated 
August 23, 1996, and Revision 2, dated June 30, 1997. These revisions 
differ in several ways from the original version of the alert service 
bulletin, which was referenced in the original NPRM as the appropriate 
source of service information for accomplishment of the inspection and 
repair of certain conditions. Revision 1 of the alert service bulletin 
adds an additional procedure to the visual inspection to detect 
installation of nonstandard parts (as defined in Figure 1. of the alert 
service bulletin) in the flap structure that attaches the flap nacelle 
fairing, and describes procedures for application of a certain primer 
to be applied in conjunction with sealant on stainless steel. Revision 
2 of the alert service bulletin limits the effectivity listing to 
airplanes on which both Jetstream Modification JM41575B and 
Modification JM41575C have not been accomplished. The procedures 
described in Revision 1 and Revision 2 are otherwise identical to those 
in the original version. The Civil Aviation Authority (CAA), which is 
the airworthiness authority for the United Kingdom, classified these 
revisions of the alert service bulletin as mandatory.
    The manufacturer also has issued Jetstream Service Bulletin J41-57-
017, dated May 9, 1997, which describes procedures for modification of 
the flap structure to strengthen the attachment for the flap nacelle 
fairing. The modification includes installation of new inboard and 
outboard ribs and new land angles. Accomplishment of the modification 
would eliminate the need for the repetitive inspections specified in 
Jetstream Alert Service Bulletin J41-A57-015 (described previously). 
The CAA classified this alert service bulletin as optional.
    Accomplishment of the actions described in the service bulletins is 
intended to adequately address the identified unsafe condition.

Changes to Original NPRM

    The FAA concludes that, to positively address the identified unsafe 
condition, the original NPRM must be revised to require the 
accomplishment of certain actions in accordance with Revision 1 or 
Revision 2 of Jetstream Alert Service Bulletin J41-A57-015 because 
certain procedures for the inspection and primer application were added 
to Revision 1 and retained in Revision 2. The original NPRM also must 
be revised to limit the applicability to airplanes on which the 
terminating modification has not been accomplished in production. In 
addition, the original NPRM must be revised to require modification of 
the wing flap structure by the installation of additional flap nacelle 
fairing support structure on each wing flap. This supplemental NPRM 
would require accomplishment of the actions specified in the alert 
service bulletins described previously, except as discussed below.
    In addition, the FAA notes that the location for the inspections 
and follow-on actions was inadvertently identified as ``the engine 
nacelle fairing.'' This proposed AD correctly identifies that location 
as ``the flap nacelle fairing.''

Differences Between Proposed Rule and Relevant Service Information

    Operators should note that this supplemental NPRM proposes to 
require the modification described in Jetstream Service Bulletin J41-
57-017 as terminating action for the repetitive inspections. The FAA 
has determined that long-term continued operational safety will be 
better assured by design

[[Page 7832]]

changes to remove the source of the problem, rather than by repetitive 
inspections. Long-term inspections may not provide the degree of safety 
assurance necessary for the transport airplane fleet. This, coupled 
with a better understanding of the human factors associated with 
numerous continual inspections, has led the FAA to consider placing 
less emphasis on inspections and more emphasis on design improvements. 
The proposed modification requirement is in consonance with these 
conditions.
    Operators also should note that, although Jetstream Alert Service 
Bulletin J41-A57-015 specifies that the manufacturer may be contacted 
for disposition of certain corrective actions, this proposal would 
require those corrective actions to be accomplished in accordance with 
a method approved by either the FAA or the CAA. In light of the type of 
corrective actions 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, corrective actions approved by either the FAA or the CAA 
would be acceptable for compliance with this proposed AD.

Conclusion

    Since these changes expand the scope of the originally proposed 
rule, the FAA has determined that it is necessary to reopen the comment 
period to provide additional opportunity for public comment.

Cost Impact

    The FAA estimates that 51 airplanes of U.S. registry would be 
affected by this proposed AD.
    It would take approximately 2 work hours per airplane to perform 
the detailed visual inspection, at an average labor rate of $60 per 
work hour. Based on these figures, the cost impact of the inspection 
proposed by this AD on U.S. operators is estimated to be $6,120, or 
$120 per airplane, per inspection cycle.
    It would take approximately 1 work hour per airplane to drill a 
drain hole and apply primer and sealant, at an average labor rate of 
$60 per work hour. Based on these figures, the cost impact of these 
actions proposed by this AD on U.S. operators is estimated to be 
$3,060, or $60 per airplane.
    It would take approximately 90 work hours per airplane to 
accomplish the proposed terminating modification, at an average labor 
rate of $60 per work hour. Required parts would cost approximately 
$2,658 per airplane. Based on these figures, the cost impact of the 
modification proposed by this AD on U.S. operators is estimated to be 
$410,958, or $8,058 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:

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:

British Aerospace Regional Aircraft [Formerly Jetstream Aircraft 
Limited; British Aerospace (Commercial Aircraft) Limited]: Docket 
96-NM-214-AD.

    Applicability: Model (Jetstream) Model 4101 airplanes, excluding 
those on which Jetstream Modifications JM41575B and JM41575C have 
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 (c) 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 fatigue cracking in the structure that attaches the 
flap nacelle fairing to the wing flaps, which could result in the 
partial or complete separation of the fairing from the wing flap, 
and consequent additional structural damage to the airframe and/or 
reduced controllability of the airplane, accomplish the following:
    (a) Prior to the accumulation of 1,500 total hours time-in-
service, or within 60 days after the effective date of this AD, 
whichever occurs later, accomplish the requirements of paragraphs 
(a)(1), (a)(2), and (a)(3) of this AD.
    (1) Perform a detailed visual inspection to detect discrepancies 
[cracks, loose rivets and Jo-Bolts, chafing damage at the flap 
trailing edge, and installation of nonstandard parts (as defined in 
Figure 1. of Jetstream Alert Service Bulletin J41-A57-015, Revision 
1, dated August 23 1996, or Revision 2, dated June 30, 1997)] and 
previous repairs of the flap structure that attaches the flap 
nacelle fairing to each wing flap; in accordance with Jetstream 
Alert Service Bulletin J41-A57-015, Revision 1, dated August 23, 
1996, or Revision 2, dated June 30, 1997. Repeat the inspection 
thereafter at intervals not to exceed 1,500 hours time-in-service 
until the requirements of paragraph (b) of this AD have been 
accomplished.
    (i) Except as provided by paragraph (a)(1)(ii) of this AD, if 
any discrepancy is found, prior to further flight, perform 
corrective action in accordance with Revision 1 or Revision 2 of the 
alert service bulletin.
    (ii) If any discrepancy is found for which Revision 1 or 
Revision 2 of the alert service bulletin specifies to contact the 
manufacturer to obtain a repair scheme: Prior to further flight, 
repair in accordance with a method approved by either the Manager, 
International Branch, ANM-116, FAA,

[[Page 7833]]

Transport Airplane Directorate; or the Civil Aviation Authority (or 
its delegated agent).
    (2) Drill a drain hole in the flap nacelle fairing on each wing 
flap, in accordance with Jetstream Alert Service Bulletin J41-A57-
015, dated May 27, 1996, Revision 1, dated August 23, 1996, or 
Revision 2, dated June 30, 1997.
    (3) Apply new primer and sealant to the gap between the wing 
flap and flap nacelle fairing, in accordance with Jetstream Alert 
Service Bulletin J41-A57-015, Revision 1, dated August 23, 1996, or 
Revision 2, dated June 30, 1997.
    (b) Within 3,000 hours time-in-service after the effective date 
of this AD: Modify the wing flap structure in accordance with 
Jetstream Service Bulletin J41-57-017, dated May 9, 1997. 
Accomplishment of this modification constitutes terminating action 
for the repetitive inspection requirements of this AD.
    (c) 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.

    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.

    (d) 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 British 
airworthiness directive 006-05-96.

    Issued in Renton, Washington, on February 9, 1999.
John J. Hickey,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-3727 Filed 2-16-99; 8:45 am]
BILLING CODE 4910-13-U