[Federal Register Volume 63, Number 223 (Thursday, November 19, 1998)]
[Rules and Regulations]
[Pages 64175-64179]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-30788]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-SW-29-AD; Amendment 39-10899; AD 98-24-13]
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. That AD also requires repairing certain cracks, 
if found, and repairing and reporting those loose rivets and certain 
other cracks, if found. This amendment requires the same inspections, 
repairs, and reporting as the existing AD, but changes the reference to 
the service bulletin and

[[Page 64176]]

prohibits the use of blind rivets for the vertical fin spar repair. 
This amendment is prompted by an accident that occurred on April 15, 
1997, resulting in one fatality. 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 December 4, 1998.
    The incorporation by reference of Eurocopter Alert Service Bulletin 
MBB-BK 117-30-106, Revision 4, dated December 19, 1997, as listed in 
the regulations, is approved by the Director of the Federal Register as 
of December 4, 1998.
    The incorporation by reference of Eurocopter Alert Service Bulletin 
No. MBB-BK 117-30-106, Revision 3, dated May 5, 1997, as listed in the 
regulations, was approved previously by the Director of the Federal 
Register as of October 24, 1997 (62 FR 52655, October 9, 1997).
    Comments for inclusion in the Rules Docket must be received on or 
before January 19, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Regional Counsel, Southwest Region, 
Attention: Rules Docket No. 98-SW-29-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 the 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. That priority letter AD required that 
the inspection be performed before further flight, then repeated at 
intervals not to exceed 100 hours time-in-service (TIS). That action 
was prompted by an accident involving a Eurocopter Model MBB-BK117 
series helicopter that 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. The crack propagated across the spar cap and spar. 
A crack in the skin propagated 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.
    On September 26, 1997 the FAA issued AD 97-20-16, Amendment 39-
10153 (62 FR 52655, October 9, 1997), superseding priority letter AD 
97-09-16 to require the same initial and repetitive inspections of the 
vertical fin spar, and additionally, requiring the repair of certain 
cracks, if found, and reporting and repairing loose rivets and certain 
other cracks. That action was prompted by the issuance of Eurocopter 
Alert Service Bulletin (ASB) No. MBB-BK 117-30-106, Revision 3, dated 
May 5, 1997, which contains repair procedures for the cracks that were 
unavailable at the time of the release of priority letter AD 97-09-16. 
The requirements of both those ADs are intended to prevent failure of 
the vertical fin spar and subsequent loss of control of the helicopter.
    Since the issuance of AD 97-20-16, Eurocopter has issued Eurocopter 
ASB MBB-BK117 No. ASB-MBB-BK 117-30-106, Revision 4, dated December 19, 
1997, which replaces all previous revisions and specifies repair 
procedures for the spar cap as well as inspection requirements. It also 
deletes a reference that allows the use of blind rivets for the 
vertical fin spar repair.
    These helicopter models are manufactured in The Federal Republic of 
Germany and are 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 
Luftahrt-Bundesamt (LBA), the airworthiness authority for The Federal 
Republic of Germany, has kept the FAA informed of the situation 
described above. The LBA superseded AD No. 97-144/2, dated June 5, 
1997, with AD 1997-144/3, effective May 11, 1998. 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 A-1, A-3, A-4, B-
1, B-2, and C-1 helicopters of the same type design, this AD supersedes 
AD 97-20-16, Amendment 39-10153 (62 FR 52655, October 9, 1997) to 
require inspecting both surfaces of the vertical fin spar, 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 TIS 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 ASB MBB-
BK 117 No. ASB-MBB-BK 117-30-106, Revision 4, dated December 19, 1997, 
or in accordance with Eurocopter ASB No. MBB-BK 117-30-106, Revision 3, 
dated May 5, 1997, except use of blind rivets is not permitted. 
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 for further evaluation. 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 October 24, 1997. Thereafter, the repetitive 
visual inspections for cracks are required at intervals not to exceed 
300 hours TIS. The actions are required to be accomplished in 
accordance with the service bulletins described. The

[[Page 64177]]

short compliance time involved is required because the previously 
described critical unsafe condition can adversely affect the structural 
integrity of the helicopter. Therefore, inspections, reporting, and 
repairs, if necessary, are required prior to further flight, and this 
AD must be issued immediately.
    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.
    The FAA estimates that 132 helicopters will be affected by this AD, 
that it will take approximately 4 work hours for each inspection and 35 
hours for each repair, if necessary, per helicopter, and that the 
average labor rate is $60 per work hour. Required parts will cost 
approximately $302 per helicopter. Based on these figures, the total 
cost impact of the AD on U.S. operators is estimated to be $348,744, 
assuming one inspection and one repair per helicopter.

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. 98-SW-29-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 removing Amendment 39-10153 (62 FR 
52655, October 9, 1997), and by adding a new airworthiness directive 
(AD), Amendment 39-10899, to read as follows:

AD 98-24-13  Eurocopter Deutschland GmbH (ECD): Amendment 39-10899. 
Docket No. 98-SW-29-AD. Supersedes AD 97-20-16, Amendment 39-10153, 
Docket No. 97-SW-15-AD.

    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 
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.

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    (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 (ASB) MBB-BK 117 No. 
ASB-MBB-BK 117-30-106, Revision 4, dated December 19, 1997, or in 
accordance with Eurocopter ASB No. MBB-BK 117-30-106, Revision 3, 
dated May 5, 1997, except use of blind rivets is not permitted. 
Thereafter, perform the inspection described in paragraph (a) of 
this AD at intervals not to exceed 300 hours TIS.
    (c) 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-
30402.08, 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, until the repair is 
made in accordance with the Appendix, ``Repair of BK117 Vertical 
Fin,'' to Eurocopter ASB MBB-BK 117 No. ASB-MBB-BK 117-30-106, 
Revision 4, dated December 19, 1997, or in accordance with the 
Appendix, ``Repair of BK117 Vertical Fin,'' to Eurocopter ASB No. 
MBB-BK 117-30-106, Revision 3, dated May 5, 1997, except use of 
blind rivets is not permitted, perform the visual inspection 
required by paragraph (a) of

[[Page 64179]]

this AD at intervals not to exceed 100 hours TIS.
    (e) Within 600 hours TIS after October 24, 1997, accomplish the 
repair to the vertical fin in accordance with the Appendix, ``Repair 
of BK117 Vertical Fin,'' to Eurocopter ASB MBB-BK-117 No. ASB-MBB-BK 
117-30-106, Revision 4, dated December 19, 1997, or in accordance 
with the Appendix, ``Repair of BK117 Vertical Fin,'' to Eurocopter 
ASB No. MBB-BK 117-30-106, Revision 3, dated May 5, 1997, except use 
of blind rivets is not permitted. If blind rivets were previously 
used to accomplish the vertical fin repair, they must be removed and 
replaced with solid rivets to comply with the requirements of this 
AD. 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.

    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 repairs shall be done in accordance with 
the Appendix, ``Repair of BK117 Vertical Fin,'' to Eurocopter Alert 
Service Bulletin MBB-BK 117-30-106, Revision 4, dated December 19, 
1997, or in accordance with the Appendix, ``Repair of BK117 Vertical 
Fin,'' to Eurocopter Alert Service Bulletin No. MBB-BK 117-30-106, 
Revision 3, dated May 5, 1997, except use of blind rivets is not 
permitted. The incorporation by reference of Eurocopter Alert 
Service Bulletin No. MBB-BK 117-30-106, Revision 3, dated May 5, 
1997, was approved previously by the Director of the Federal 
Register, in accordance with 5 U.S.C. 552(a) and 1 CFR part 51, as 
of October 24, 1997 (62 FR 52655, October 9, 1997). The 
incorporation by reference of Eurocopter Alert Service Bulletin MBB-
BK 117-30-106, Revision 4, dated December 19, 1997, 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 the 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: Accomplishment of the requirements of Revision 3 of the 
referenced service bulletin, except for using solid rivets instead 
of blind rivets, or Revision 4 of the referenced service bulletin 
constitutes compliance with the requirements of this AD.

    (i) This amendment becomes effective on December 4, 1998.

    Note 4: The subject of this AD is addressed in Luftahrt-
Bundesamt (Germany) AD 1997-144/3, effective May 11, 1998.

    Issued in Fort Worth, Texas, on November 12, 1998.
Henry A. Armstrong,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 98-30788 Filed 11-18-98; 8:45 am]
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