AD Amdt-39-10090

[Federal Register Volume 62, Number 144 (Monday, July 28, 1997)]
[Rules and Regulations]
[Pages 40267-40269]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 97-19599]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-137-AD; Amendment 39-10090; AD 97-16-01]
RIN 2120-AA64


Airworthiness Directives; British Aerospace (Jetstream) Model 
4101 Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to certain British Aerospace (Jetstream) Model 4101 
airplanes. This action requires repetitive detailed visual inspections 
to detect cracks of the shear cleats of the roller guide structural 
support of the passenger door, and replacement of any cracked shear 
cleat with a new shear cleat. This action also provides for an optional 
terminating modification that constitutes terminating action for the 
repetitive inspections. This amendment is prompted by a report 
indicating that fatigue cracking was found in the roller guide shear 
cleats of the passenger door. The actions specified in this AD are 
intended to detect and correct such fatigue-related cracking, which 
could result in structural failure of the passenger door, and 
consequent rapid depressurization of the airplane or loss of the 
passenger door while the airplane is in flight.

DATES: Effective August 12, 1997.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of August 12, 1997.
    Comments for inclusion in the Rules Docket must be received on or 
before September 26, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 97-NM-137-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056.
    The service information referenced in this AD 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; or at the 
Office of the Federal Register, 800 North Capitol Street, NW., suite 
700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Bud Schroeder, Aerospace Engineer, 
ANM-113, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056; telephone (425) 227-2148; fax (425) 227-
1149.

SUPPLEMENTARY INFORMATION: The Civil Aviation Authority (CAA), which is 
the airworthiness authority for the United Kingdom, recently notified 
the FAA that an unsafe condition may exist on certain British Aerospace 
(Jetstream) Model 4101 airplanes. The CAA advises that, during full-
scale fatigue tests on a Jetstream Model 4101 test article, cracking 
was found in the roller guide shear cleats of the passenger door. Such 
cracking also was found during in-service maintenance inspections. This 
cracking is attributed to fatigue-related stress. Fatigue-related 
cracking in the roller guide shear cleats of the passenger door, if not 
detected and corrected in a timely manner, could result in structural 
failure of the passenger door, and consequent rapid depressurization of 
the airplane or loss of the passenger door while the airplane is in 
flight.

Explanation of Relevant Service Information

    British Aerospace has issued Jetstream Alert Service Bulletin J41-
A52-043, Revision 2, dated May 6, 1997, which describes procedures for 
repetitive detailed visual inspections to detect cracks of the roller 
guide shear cleats of the passenger door. The service bulletin also 
describes procedures for replacement of any cracked shear cleat with a 
new shear cleat. The CAA classified the alert service bulletin as 
mandatory and issued British airworthiness directive 003-03-97 in order 
to assure the continued airworthiness of these airplanes in the United 
Kingdom.
    British Aerospace also has issued Jetstream Service Bulletin J41-
52-050, dated May 6, 1997. The service bulletin describes procedures 
for modification of the passenger door, which will eliminate the need 
for repetitive detailed visual inspections. The modification involves 
installation of a one-piece machined abutment fitting to replace the 
existing roller guide

[[Page 40268]]

intercostal and loose shear cleats of the passenger door. The 
modification will strengthen the structural support of the roller 
guides of the passenger door, which will minimize the possibility of 
fatigue cracking in the roller guide support structure.

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 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 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 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, this AD is being issued to detect and correct 
fatigue-related cracking in the shear cleats of the roller guide 
structural support of the passenger door, which could result in 
structural failure of the passenger door, and consequent rapid 
depressurization of the airplane or loss of the passenger door while 
the airplane is in flight. This AD requires repetitive detailed visual 
inspections to detect cracks of the roller guide shear cleats of the 
passenger door, and replacement of any cracked shear cleat with a new 
shear cleat. This AD also provides for an optional terminating 
modification that constitutes terminating action for the repetitive 
inspection requirements. The actions are required to be accomplished in 
accordance with the service bulletins described previously.

Differences Between the AD and the Related Foreign AD

    Operators should note that, while it is not the FAA's normal policy 
to allow flight with known cracks, this AD does permit further flight 
when one roller guide shear cleat of the passenger door is cracked 
within certain limits. The results of a review, conducted by the 
manufacturer, shows that the subject passenger door continues to comply 
with the applicable certification basis when cracking in all eight of 
roller guide shear cleats does not exceed certain limits. Therefore, 
according to the review, if certain crack size limits are strictly 
observed, and corrective action is taken to replace all cracked shear 
cleats within a certain number of landings, the cracks will not grow to 
a size that would create an unacceptable risk of structural failure. 
The CAA concurs with the findings of this review. In consideration of 
these findings and based on the FAA's criteria for flight with known 
cracking, the FAA has determined that further flight when one roller 
guide shear cleat of the passenger door is cracked within certain 
limits is permissible for an interim period. However, the FAA has 
determined that further flight with widespread (i.e., more than one 
crack) known cracking is not permitted. Therefore, for cases where more 
than one cracked shear cleat is detected within certain limits, this AD 
requires replacement of all cracked shear cleats prior to further 
flight.

Interim Action

    The FAA is considering further rulemaking action to supersede this 
AD to require the accomplishment of the optional terminating 
modification currently specified in this AD. However, the planned 
compliance time for accomplishment of that action is sufficiently long 
so that prior notice and time for public comment will be practicable.

Determination of Rule's Effective Date

    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the 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 that 
summarizes each FAA-public contact concerned with the substance of this 
AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 97-NM-137-AD.'' The postcard will be date stamped and 
returned to the commenter.

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.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and that it is not a ``significant regulatory 
action'' under Executive Order 12866. It has been determined further 
that this action involves an emergency regulation under DOT Regulatory 
Policies and Procedures (44 FR 11034, February 26, 1979). If it is 
determined that this emergency regulation otherwise would be 
significant under DOT Regulatory Policies and Procedures, a final 
regulatory evaluation will be prepared and placed in the Rules Docket. 
A copy of it, if filed, 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

[[Page 40269]]

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:

97-16-01 British Aerospace Regional Aircraft [Formerly Jetstream 
Aircraft Limited, British Aerospace (Commercial Aircraft) Limited]: 
Amendment 39-10090. Docket 97-NM-137-AD.

    Applicability: Jetstream Model 4101 airplanes, constructors 
numbers 41004 through 41099 inclusive, 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 fatigue-related cracking in the shear 
cleats of the roller guide structural support of the passenger door, 
which could result in structural failure of the passenger door, and 
consequent rapid depressurization of the airplane or loss of the 
passenger door while the airplane is in flight, accomplish the 
following:
    (a) Except as provided by paragraph (b) of this AD: Prior to the 
accumulation of 6,000 landings, or within 60 days after the 
effective date of this AD, whichever occurs later, perform a 
detailed visual inspection to detect cracks of the shear cleats of 
the roller guide structural support of the passenger door, in 
accordance with Part 1 of the Accomplishment Instructions of 
Jetstream Alert Service Bulletin J41-A52-043, Revision 2, dated May 
6, 1997. Repeat the detailed visual inspection, as specified in Part 
2 of the Accomplishment Instructions of the alert service bulletin, 
thereafter at intervals not to exceed 1,500 landings.

    Note 2: Accomplishment of the initial detailed visual inspection 
prior to the effective date of this AD in accordance with Jetstream 
Alert Service Bulletin J41-52-043, dated March 14, 1997, or Revision 
1, dated April 11, 1997, is considered acceptable for compliance 
with the initial inspection required by paragraph (a) of this AD.

    (1) If one cracked shear cleat is detected, and the crack is 
greater than 0.50 inches, prior to further flight, replace the 
cracked shear cleat with a new shear cleat in accordance with the 
alert service bulletin.
    (2) If one cracked shear cleat is detected, and the crack is 
less than or equal to 0.50 inches, within 170 landings following 
accomplishment of the inspection required by this paragraph, replace 
the cracked shear cleat with a new shear cleat in accordance with 
the alert service bulletin.
    (3) If more than one cracked shear cleat is detected, but no 
single crack is greater than 0.50 inches in length, prior to further 
flight, replace all cracked shear cleats with new shear cleats, in 
accordance with the alert service bulletin.
    (b) For airplanes on which all shear cleats have been replaced: 
Inspect as required by paragraph (a) of this AD, prior to the 
accumulation of 6,000 total landings on the highest time new shear 
cleat, or within 60 days after the effective date of this AD, 
whichever occurs later. Repeat the detailed visual inspection 
thereafter at intervals not to exceed 1,500 landings.
    (c) Modification of the passenger door (i.e. Modification No. 
JM41576) in accordance with Jetstream Service Bulletin J41-52-050, 
dated May 6, 1997, constitutes terminating action for the repetitive 
inspection requirements of paragraphs (a) and (b) of this AD.
    (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, Standardization Branch, ANM-113, 
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, 
Standardization Branch, ANM-113.

    Note 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Standardization Branch, ANM-113.

    (e) 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.
    (f) The inspections shall be done in accordance with Jetstream 
Alert Service Bulletin J41-A52-043, Revision 2, dated May 6, 1997. 
The modification shall be done in accordance with Jetstream Service 
Bulletin J41-52-050, dated May 6, 1997. 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 AI(R) American Support, Inc., 13850 Mclearen Road, 
Herndon, Virginia 20171. 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.
    (g) This amendment becomes effective on August 12, 1997.
    Issued in Renton, Washington, on July 21, 1997.
D. L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-19599 Filed 7-25-97; 8:45 am]
BILLING CODE 4910-13-U