[Federal Register Volume 64, Number 227 (Friday, November 26, 1999)]
[Proposed Rules]
[Pages 66424-66426]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-30799]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-306-AD]
RIN 2120-AA64


Airworthiness Directives; British Aerospace (Jetstream) Model 
4101 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 British Aerospace 
(Jetstream) Model 4101 airplanes, that currently requires repetitive 
detailed visual inspections to detect cracking or other damage of 
certain diaphragm support structures of the forward equipment 
compartment; and repair, if necessary. This action would continue to 
require repetitive inspections, but would also require replacement of 
cracked or damaged diaphragm support structures with improved parts, 
which would terminate the requirement for repetitive inspections. This 
action also would add airplanes to the applicability of the proposed 
AD. This proposal is prompted by the development of improved 
diaphragms. The actions specified by the proposed AD are intended to 
prevent failure of the two diaphragms that support the upper structure 
of the forward equipment compartment, which could accelerate fatigue 
damage in adjacent structure and result in reduced structural integrity 
of the airframe.

DATES: Comments must be received by December 27, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 99-NM-306-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 British Aerospace Regional Aircraft American Support, 
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 99-NM-306-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. 99-NM-306-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On November 9, 1998, the FAA issued AD 98-24-01, amendment 39-10888 
(63 FR 63975, November 18, 1998), applicable to certain British 
Aerospace (Jetstream) Model 4101 airplanes, to require repetitive 
detailed visual inspections to detect cracking or other damage of 
certain diaphragm support structures of the forward equipment 
compartment; and repair, if necessary. That action was prompted by 
issuance of mandatory continuing airworthiness information by a foreign 
civil airworthiness authority. The requirements of that AD are intended 
to detect and correct failure of the two diaphragms that support the 
upper structure of the forward equipment compartment, which could 
accelerate fatigue damage in adjacent structure and result in reduced 
structural integrity of the airframe.
    In the preamble to AD 98-24-01, the FAA indicated that the actions 
required by that AD were considered ``interim action'' and that further 
rulemaking action was being considered. The FAA now has determined that 
further rulemaking action is indeed necessary, and this proposed AD 
follows from that determination.

Actions Since Issuance of Previous Rule

    Since the issuance of that AD, the manufacturer has issued new 
service information that specifies procedures for replacement of both 
diaphragms with improved diaphragms if any cracking or damage is found. 
The replacement would eliminate the need for the repetitive 
inspections.

[[Page 66425]]

    The new service information also expands the applicability to 
include additional airplanes. This proposal would modify the 
applicability to include only those airplanes on which modification of 
the diaphragm support structure has not been accomplished. Reference to 
constructors numbers has been removed from the applicability of this 
proposed AD.

Explanation of Relevant Service Information

    British Aerospace has issued Jetstream Alert Service Bulletin J41-
A53-023, Revision 1, dated July 30, 1999, which describes procedures 
for replacement of cracked or damaged diaphragm support structures with 
improved parts, in addition to the repetitive inspections described in 
the original release of the service bulletin. This replacement would 
eliminate the need for further repetitive inspections. Accomplishment 
of the actions specified in Revision 1 of the service bulletin is 
intended to adequately address the identified unsafe condition. The 
Civil Aviation Authority (CAA), which is the airworthiness authority 
for the United Kingdom, classified this service bulletin as mandatory 
in order to assure the continued airworthiness of these airplanes in 
the United Kingdom.

FAA's Conclusions

    This airplane model is manufactured in the United Kingdom and is 
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 CAA has kept the FAA 
informed of the situation described above. The FAA has examined the 
findings of the CAA, 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 98-24-01 to 
continue to require the actions specified in that AD. This proposed AD 
would also require accomplishment of the actions specified in Revision 
1 of the service bulletin described previously, except as discussed 
below.

Differences Between Proposed Rule and Service Bulletin

    Operators should note that, unlike the procedures described in 
Jetstream Alert Service Bulletin J41-A53-023, Revision 1, dated July 
30, 1999, this proposed AD would not permit further flight if cracks 
are detected in certain diaphragms that support the upper structure of 
the forward equipment compartment. The FAA has determined that, because 
of the safety implications and consequences associated with such 
cracking, any subject diaphragm that is found to be cracked must be 
replaced with new, improved parts prior to further flight.

Cost Impact

    There are approximately 59 airplanes of U.S. registry that would be 
affected by this proposed AD.
    The inspection that is currently required by AD 98-24-01, and 
retained in this proposed AD, takes approximately 1 work hour per 
airplane to accomplish, at an average labor rate of $60 per work hour. 
Based on these figures, the cost impact of the inspection requirement 
of this proposed AD on U.S. operators is estimated to be $3,540, or $60 
per airplane, per inspection cycle.
    The cost impact figure discussed above is 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 39-10888 (63 FR 
63975, November 18, 1998), and by adding a new airworthiness directive 
(AD), to read as follows:

British Aerospace Regional Aircraft [Formerly Jetstream Aircraft 
Limited; British Aerospace (Commercial Aircraft) Limited]: Docket 
99-NM-306-AD. Supersedes AD 98-24-01, Amendment 39-10888.

    Applicability: Jetstream Model 4101 airplanes, on which British 
Aerospace Modification JM41384 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 (d) 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 detect and correct failure of the two diaphragms that support 
the upper structure of the forward equipment compartment, which 
could accelerate fatigue damage in adjacent structure and result in 
reduced structural integrity of the airframe, accomplish the 
following:

Restatement of Certain Requirements of AD 98-24-01

    (a) For airplanes having constructors numbers 41004 through 
41098 inclusive: Prior to the accumulation of 4,500 total landings, 
or within 300 landings after December 23, 1998 (the effective date 
of AD

[[Page 66426]]

98-24-01, amendment 39-10888), whichever occurs later: Perform a 
detailed visual inspection to detect cracking or other damage of the 
diaphragms installed between station 4 and station 8 of the forward 
fuselage, in accordance with Jetstream Alert Service Bulletin J41-
A53-023, dated December 2, 1996, or Revision 1, dated July 30, 1999.

    Note 2: For the purposes of this AD, a detailed visual 
inspection is defined as: ``An intensive visual examination of a 
specific structural area, system, installation, or assembly to 
detect damage, failure, or irregularity. Available lighting is 
normally supplemented with a direct source of good lighting at 
intensity deemed appropriate by the inspector. Inspection aids such 
as mirror, magnifying lenses, etc., may be used. Surface cleaning 
and elaborate access procedures may be required.''

    (1) If no cracking or other damage is detected, repeat the 
inspection thereafter at intervals not to exceed 3,000 landings.
    (2) If any cracking or other damage is detected, prior to 
further flight, accomplish the actions required by either paragraph 
(a)(2)(i) or (a)(2)(ii). After the effective date of this AD, only 
replacement of the diaphragms in accordance with paragraph 
(a)(2)(ii) of this AD is acceptable for compliance with the repair 
requirements of this paragraph.
    (i) Repair the diaphragm in accordance with a method approved by 
the Manager, International Branch, ANM-116, FAA, Transport Airplane 
Directorate. Thereafter, repeat the inspection at intervals not to 
exceed 3,000 landings.
    (ii) Replace both diaphragms with new, improved diaphragms, in 
accordance with Part 2 of the Accomplishment Instructions of 
Jetstream Alert Service Bulletin J41-A53-023, Revision 1, dated July 
30, 1999. Such replacement constitutes terminating action for the 
repetitive inspections required by this AD.

New Repetitive Inspections and Corrective Actions Required by This AD:

    (b) For airplanes other than those listed in paragraph (a) of 
this AD: Prior to the accumulation of 4,500 total landings, or 
within 300 landings after the effective date of this AD, whichever 
occurs later, perform a detailed visual inspection to detect 
cracking or other damage of the diaphragms installed between station 
4 and station 8 of the forward fuselage, in accordance with 
Jetstream Alert Service Bulletin J41-A53-023, Revision 1, dated July 
30, 1999.
    (1) If no cracking or other damage is detected, repeat the 
inspection thereafter at intervals not to exceed 3,000 landings.
    (2) If any cracking or other damage is detected, prior to 
further flight, replace both diaphragms with new, improved 
diaphragms, in accordance with Part 2 of the Accomplishment 
Instructions of Jetstream Alert Service Bulletin J41-A53-023, 
Revision 1, dated July 30, 1999. Such replacement constitutes 
terminating action for the repetitive inspections required by this 
AD.
    (c) Replacement of diaphragms with new, improved diaphragms, in 
accordance with Part 2 of the Accomplishment Instructions of 
Jetstream Alert Service Bulletin J41-A53-023, Revision 1, dated July 
30, 1999, constitutes terminating action for the requirements of 
this AD.

Alternative Methods of Compliance

    (d) 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.

Special Flight Permits

    (e) Special flight permits may be issued in accordance with 
Secs. 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.

    Issued in Renton, Washington, on November 19, 1999.
D.L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-30799 Filed 11-24-99; 8:45 am]
BILLING CODE 4910-13-P