[Federal Register Volume 62, Number 196 (Thursday, October 9, 1997)]
[Rules and Regulations]
[Pages 52655-52659]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-26792]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 97-SW-15-AD; Amendment 39-10153; AD 97-20-16]
RIN 2120-AA64
Airworthiness Directives; Eurocopter Deutschland GmbH (ECD)
(Eurocopter) Model MBB-BK117 A-1, A-3, A-4, B-1, B-2, and C-1
Helicopters
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
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SUMMARY: This amendment supersedes an existing airworthiness directive
(AD), applicable to Eurocopter Model MBB-BK117 A-1, A-3, A-4, B-1, B-2,
and C-1 helicopters, that currently requires initial and repetitive
inspections of both surfaces of the tail boom vertical fin (vertical
fin) spar, the skin, and the left-hand and right-hand frame sheets for
cracks or loose rivets. This amendment requires the same initial and
repetitive inspections of the vertical fin spar that are required by
the existing AD, and also requires repairing certain cracks, if found,
and repairing and reporting loose rivets and certain other cracks, if
found. This amendment is prompted by an accident which occurred on
April 15, 1997, resulting in one fatality. A subsequent investigation
revealed that the vertical fin had failed as a result of a fatigue
crack that initiated on the left side of the vertical fin spar cap. The
actions specified by this AD are intended to prevent failure of the
vertical fin and subsequent loss of control of the helicopter.
DATES: Effective October 24, 1997. The incorporation by reference of
certain publications listed in the regulations is approved by the
Director of the Federal Register as of October 24, 1997.
Comments for inclusion in the Rules Docket must be received on or
before December 8, 1997.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Office of Regional Counsel, Southwest Region,
Attention: Rules Docket No. 97-SW-15-AD, 2601 Meacham Blvd., Room 663,
Fort Worth, Texas 76137.
The service information referenced in this AD may be obtained from
American Eurocopter Corporation, 2701 Forum Drive, Grand Prairie, Texas
75053-4005, telephone (972) 641-3460, fax (972) 641-3527. This
information may be examined at the FAA, Office of Regional Counsel,
Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas
76137; or at the Office of the Federal Register, 800 North Capitol
Street, NW., suite 700, Washington, DC.
FOR FURTHER INFORMATION CONTACT: Mr. Richard Monschke, Aerospace
Engineer, Rotorcraft Standards Staff, 2601 Meacham Blvd., Fort Worth,
Texas 76137, telephone (817) 222-5116, fax (817) 222-5961.
SUPPLEMENTARY INFORMATION: On April 25, 1997, the FAA issued priority
letter AD 97-09-16, to require inspecting both surfaces of the vertical
fin spar, part number (P/N) 105-304061.03, P/N 1120-30406.03, or P/N
117-30423-03, paying particular attention to the area extending from
the top edge of the second lightening hole from the top of the vertical
fin spar to the bottom edge of the fourth lightening hole, the outer
skin (skin), and the left-hand and right-hand frame plates for cracks,
loose rivets, or other anomalies. This inspection must be performed
before further flight, then repeated at intervals not to exceed 100
hours time-in-service. That action was prompted by an accident
involving a Eurocopter Model MBB-BK117 series helicopter, which
occurred on April 15, 1997, resulting in one fatality. A subsequent
investigation revealed that the vertical fin had failed as a result of
a fatigue crack that initiated on the left side of the vertical fin
spar cap. The crack propagated across the spar cap and spar web until
only the skin was carrying the flight load. The skin then started
cracking, with the crack propagating horizontally toward the vertical
fin leading edge until catastrophic overstress occurred. Inspections of
other helicopters of the same type design revealed cracks in the
vertical fin spars of three additional helicopters. That condition, if
not corrected, could result in failure of the vertical fin and
subsequent loss of control of the helicopter.
Since the issuance of that AD, the manufacturer has developed
repair procedures for the cracks, which were unavailable at the time of
the release of the priority letter AD, and has issued Eurocopter Alert
Service Bulletin MBB-BK117 No. ASB-MBB-BK117-30-106, Revision 3, dated
May 5, 1997, which specifies repair procedures for the spar cap, as
well as subsequent inspection requirements.
This helicopter model is manufactured in The Federal Republic of
Germany 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
[[Page 52656]]
airworthiness agreement. Pursuant to this bilateral airworthiness
agreement, the Luftahrt-Bundesamt (LBA) has kept the FAA informed of
the situation described above. The FAA has examined the findings of the
LBA, 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.
Since an unsafe condition has been identified that is likely to
exist or develop on other Eurocopter Model MBB-BK117 series helicopters
of the same type design, this AD supersedes AD 97-09-16 to require
inspecting both surfaces of the vertical fin spar, part number (P/N)
105-304061.03, P/N 1120-30406.03, or P/N 117-30423-03, paying
particular attention to the area extending from the top edge of the
third lightening hole from the top of the vertical fin spar to halfway
between the fourth and fifth lightening hole (see Figure 1 for
description of area to be inspected), the skin, and the left-hand and
right-hand frame sheets for cracks or loose rivets. This inspection
must be repeated at intervals not to exceed 100 hours time-in-service
until the repair is accomplished. If a crack is found in the area of
the fourth lightening hole of the vertical fin spar, including a crack
in the cap or ``c'' channel area of the spar, or in the left-hand frame
sheet, P/N 105-304161 or P/N 1120-30416, or in the right-hand frame
sheet, P/N 105-304211 or P/N 1120-30421, before further flight, the
crack must be repaired in accordance with the repair instructions that
are an Appendix titled ``Repair of BK117 Vertical Fin'' to Eurocopter
Alert Service Bulletin MBB-BK117 No. ASB-MBB-BK117-30-106, Revision 3,
dated May 5, 1997. Thereafter, this AD requires that a visual
inspection for cracks be performed at intervals not to exceed 300 hours
TIS. If a crack or loose rivet is found in the area other than that
described in paragraph (a) of this AD, including any crack that is
found to extend into the skin, P/N 105-304011.18 or P/N 1120-30402.0,
contact the Rotorcraft Standards Staff before further flight. Further
evaluation is required before further flight. If no crack is found, the
repetitive visual inspection for cracks is required at intervals not to
exceed 100 hours TIS until the repair specified in the repair
instruction is accomplished. The repair must be accomplished within 600
hours TIS after the accomplishment of the initial inspection.
Thereafter, the repetitive visual inspections for cracks at intervals
not to exceed 300 hours TIS are required. The actions are required to
be accomplished in accordance with the service bulletin described
previously.
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 should 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 No. 97-SW-15-AD.'' The postcard will be date stamped and
returned to the commenter.
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 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 a new airworthiness directive
(AD), Amendment 39-10153, to read as follows:
97-20-16 Eurocopter Deutschland GmbH (ECD): Amendment 39-10153.
Docket No. 97-SW-15-AD. Supersedes priority letter AD 97-09-16.
Applicability: Model MBB-BK117 A-1, A-3, A-4, B-1, B-2, and C-1
helicopters, certificated in any category.
Note 1: This AD applies to each helicopter identified in the
preceding applicability provision, regardless of whether it has been
modified, altered, or repaired in the area subject to the
requirements of this AD. For helicopters that have been modified,
altered, or repaired so that the performance of the requirements of
this AD is affected, the owner/operator must use the authority
provided in paragraph (f) to request approval from the FAA. This
approval may address either no action, if the current configuration
eliminates the unsafe condition, or different actions necessary to
address the unsafe condition described in this AD. Such a request
should include an assessment of the effect of the changed
configuration on the unsafe condition addressed by this AD. In no
[[Page 52657]]
case does the presence of any modification, alteration, or repair
remove any helicopter from the applicability of this AD.
Compliance: Required as indicated, unless accomplished
previously.
To prevent failure of the tail boom vertical fin (vertical fin)
and subsequent loss of control of the helicopter, accomplish the
following:
(a) Before further flight, remove the tail rotor drive shaft
between the intermediate and tail rotor gearboxes and the yaw servo
(if installed). Thoroughly clean the vertical fin spar and adjacent
areas and visually inspect the following for cracks or loose rivets:
(1) Both surfaces of the vertical fin spar, part number (P/N)
105-304061.03, P/N 1120-30406.03, or P/N 117-30423-03, paying
particular attention to the area extending from the top edge of the
third lightening hole from the top of the vertical fin spar to
halfway between the fourth and fifth lightening hole (see Figure 1).
(2) The skin and left-hand and right-hand frame sheets.
(b) If a crack or loose rivet is found in the area described in
paragraph (a) of this AD (see Figure 1), before further flight,
repair in accordance with the Appendix, ``Repair of BK117 Vertical
Fin'', to Eurocopter Alert Service Bulletin MBB-BK117 No. ASB-MBB-
BK117-30-106, Revision 3, dated May 5, 1997. Thereafter, perform the
inspection described in paragraph (a) of this AD at intervals not to
exceed 300 hours TIS.
(c) If a crack or lose rivet is found in the area other than
that described in paragraph (a) of this AD, including any crack that
is found to extend into the skin, P/N 105-304011.18 or P/N 1120-
30402.08, before further flight, contact the Rotorcraft Standards
Staff. Reporting requirements have been approved by the Office of
Management and Budget and assigned OMB control number 2120-0056.
(d) If no crack or loose rivet is found as a result of the
inspection required by paragraph (a) of this AD, thereafter, until
the repair is made in accordance with the Appendix, ``Repair of
BK117 Vertical Fin'', to
Eurocopter Alert Service Bulletin MBB-BK117 No. ASB-MBB-BK117-30-
106, Revision 3, dated May 5, 1997, conduct the visual inspection
required by paragraph (a) of this AD at intervals not to exceed 100
hours TIS.
(e) Within 600 hours TIS after the effective date of this AD,
accomplish the repair to the vertical fin in accordance with the
Appendix, ``Repair of BK117 Vertical Fin'', to Eurocopter Alert
Service Bulletin MBB-BK117 No. ASB-MBB-BK117-30-106, Revision 3,
dated May 5, 1997. Thereafter, perform the visual inspection
required by paragraph (a) of this AD at intervals not to exceed 300
hours TIS.
(f) 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, FAA, Rotorcraft Directorate,
Rotorcraft Standards Staff. Operators shall submit their requests
through an FAA Principal Maintenance Inspector, who may concur or
comment and then send it to the Manager, Rotorcraft Standards Staff.
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Note 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Rotorcraft Standards Staff.
(g) Special flight permits will not be issued.
(h) The inspections and repair shall be done in accordance with
Eurocopter Deutschland GmbH (ECD) Alert Service Bulletin ASB-MBB-
BK117-30-106, Revision 3, dated May 5, 1997, including Appendix.
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 American Eurocopter Corporation,
2701 Forum Drive, Grand Prairie, Texas 75053-4005, telephone (972)
641-3460, fax (972) 641-3527. Copies may be inspected at the FAA,
Office of Regional Counsel, Southwest Region, 2601 Meacham Blvd.,
Room 663, Fort Worth, Texas; or at the Office of the Federal
Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
Note 3: The subject of this AD is addressed in Luftfahrt-
Bundesamt (Germany) AD 97-144/2, dated June 5, 1997.
(i) This amendment becomes effective on October 24, 1997.
Issued in Fort Worth, Texas, on September 26, 1997.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 97-26792 Filed 10-8-97; 8:45 am]
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