[Federal Register Volume 65, Number 9 (Thursday, January 13, 2000)]
[Rules and Regulations]
[Pages 2017-2019]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-721]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-SW-60-AD; Amendment 39-11509; AD 2000-01-11]
RIN 2120-AA64


Airworthiness Directives; Eurocopter Deutschland GMBH Model MBB-
BK 117 Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment supersedes an existing emergency priority 
letter airworthiness directive (AD), applicable to Eurocopter 
Deutschland GMBH (ECD) Model MBB-BK 117 helicopters, that currently 
requires, before further flight, creating a component log card or 
equivalent record and determining the age and number of flights on the 
tension-torsion (TT) strap. The AD also requires inspecting and 
removing, as necessary, certain unairworthy TT straps. This amendment 
requires the same actions as the emergency priority letter AD but 
clarifies the compliance requirements specified in the emergency 
priority letter AD. This amendment is prompted by an accident in which 
a main rotor blade (blade) separated from a helicopter due to fatigue 
failure of a TT strap. The actions specified by this AD are intended to 
prevent failure of a TT strap, loss of a blade, and subsequent loss of 
control of the helicopter.

DATES: Effective January 28, 2000. The incorporation by reference of 
certain publications listed in the regulations is approved by the 
Director of the Federal Register as of January 28, 2000.
    Comments for inclusion in the Rules Docket must be received on or 
before March 13, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Regional Counsel, Southwest Region, 
Attention: Rules Docket No. 99-SW-60-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: Charles Harrison, Aerospace Engineer, 
FAA, Rotorcraft Directorate, Rotorcraft Standards Staff, 2601 Meacham 
Blvd., Fort Worth, Texas 76137, telephone (817) 222-5128, fax (817) 
222-5961.

SUPPLEMENTARY INFORMATION: On August 6, 1999, the FAA issued Emergency 
Priority Letter AD 99-17-07, applicable to ECD Model MBB-BK 117 
helicopters, which requires, before further flight, creating a 
component log card or equivalent record and determining the calendar 
age and number of flights on the TT strap. The AD also requires 
inspecting and removing, as necessary, certain unairworthy TT straps. 
Certain TT straps are not eligible for installation until they are re-
identified. That action was prompted by an accident in which a blade 
separated from an ECD Model MBB-BK-117 helicopter resulting in three 
fatalities. The cause of the blade separation was a TT strap rupture 
within the main rotor head. The cause of the TT strap rupture remains 
under

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investigation. That condition, if not corrected, could result in 
failure of a TT strap, loss of a blade, and subsequent loss of control 
of the helicopter.
    Since the issuance of that emergency priority letter AD, the FAA 
has received several requests for clarification of the terms ``calendar 
year'' and ``calendar age.'' To clarify the required compliance times, 
the FAA has converted years to months and has removed the terms 
``calendar year'' and ``calendar age'' from the AD.
    The FAA has reviewed ECD Alert Service Bulletin MBB-BK 117 No. ASB-
MBB-BK 117-10-120, Revision 1, dated August 31, 1999 (ASB). The ASB 
describes procedures for determining the total accumulated installation 
time and number of flights on the TT strap. The ASB specifies 
inspecting each TT strap and replacing any unairworthy TT strap with an 
airworthy TT strap. The Luftfahrt-Bundesamt (LBA), which is the 
airworthiness authority for the Federal Republic of Germany, classified 
that ASB as mandatory and issued AD 1999-284, dated August 6, 1999, 
applicable to all ECD Model MBB-BK 117 helicopters.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other ECD Model MBB-BK 117 helicopters of the same 
type design, this AD supersedes Emergency Priority Letter AD 99-17-07 
to require, before further flight, creating a component log card or 
equivalent record and determining the age and number of flights on each 
TT strap. The AD also requires inspecting and removing, as necessary, 
any unairworthy TT straps. Certain TT straps are not eligible for 
installation until they are reidentified. The actions must be 
accomplished in accordance with the ASB described previously. The short 
compliance time involved is required because the previously described 
critical unsafe condition can adversely affect the structural integrity 
of the helicopter. Therefore, creating a component log card or 
equivalent record, determining the age and number of flights on each TT 
strap, and inspecting and removing, as necessary, any unairworthy TT 
straps 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 127 helicopters of U.S. registry will be 
affected by this AD, that it will take approximately 1 work hour per 
helicopter to inspect the 4 TT straps on each helicopter, 15 work hours 
per helicopter to remove and replace the 4 TT straps, if necessary, and 
the average labor rate is $60 per work hour. Required parts will cost 
approximately $2,600 per TT strap ($10,400 per helicopter). Based on 
these figures, the total cost impact of the AD on U.S. operators is 
estimated to be $1,442,720; $7,620 to inspect each helicopter once and 
$1,435,100 to remove and replace the 4 TT straps on all helicopters.

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. 99-SW-60-AD.'' The postcard will be date stamped and 
returned to the commenter.
    The regulations adopted herein will not have a substantial direct 
effect 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, it 
is determined that this final rule does not have federalism 
implications under Executive Order 13132.
    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) to read as follows:

AD 2000-01-11  Eurocopter Deutschland GMBH: Amendment 39-11509. 
Docket No. 99-SW-60-AD. Supersedes Emergency Priority Letter AD 99-
17-07, Docket No. 99-SW-49-AD.

    Applicability: Model MBB-BK 117 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 
otherwise 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 request approval for an 
alternative method of compliance in accordance with paragraph (f) 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

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eliminated, the request should include specific proposed actions to 
address it.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent main rotor blade (blade) separation due to failure of 
a tension-torsion (TT) strap, accomplish the following:
    (a) Before further flight,
    (1) Create a component log card or equivalent record for each TT 
strap.
    (2) Review the history of the helicopter and each TT strap. 
Determine the age since initial installation on any helicopter (age) 
and the number of flights on each TT strap. Enter both the age and 
the number of flights for each TT strap on the component log card or 
equivalent record. Where the number of flights is unknown, multiply 
the number of hours time-in-service (TIS) by 5 to determine the 
number of flights.
    (3) If the number of flights and age cannot be determined, 
remove the TT strap from service.
    (4) Remove any TT strap from service that has either accumulated 
25,000 or more flights or is equal to or greater than 180 months of 
age.
    (b) When a TT strap age is equal to or greater than 120 months 
and less than 180 months and the number of flights on the TT straps 
are less than 25,000, inspect the TT strap in accordance with 
paragraph 2.B.2 of the ``Accomplishment Instructions,'' Eurocopter 
Deutschland GMBH Alert Service Bulletin MBB-BK 117 No. ASB-MBB-BK 
117-10-120 (ASB), Revision 1, dated August 31, 1999, according to 
the following:
    (1) If the age is greater than or equal to 120 months but less 
than 132 months and has less than 22,000 flights, inspect the TT 
strap within the next 6 weeks. If the number of flights equals or 
exceeds 22,000, inspect the TT strap before further flight.
    (2) If the age is greater than or equal to 132 months but less 
than 144 months and has less than 19,000 flights, inspect the TT 
strap within the next 5 weeks. If the number of flights equals or 
exceeds 19,000, inspect the TT strap before further flight.
    (3) If the age is greater than or equal to 144 months but less 
than 156 months and has less than 16,000 flights, inspect the TT 
strap within the next 4 weeks. If the number of flights equals or 
exceeds 16,000, inspect the TT strap before further flight.
    (4) If the age is greater than or equal to 156 months but less 
than 168 months and has less than 13,000 flights, inspect the TT 
strap within the next 3 weeks. If the number of flights equals or 
exceeds 13,000, inspect the TT strap before further flight.
    (5) If the age is greater than or equal to 168 months but less 
than 180 months and has less than 10,000 flights, inspect the TT 
strap within the next 2 weeks. If the number of flights equals or 
exceeds 10,000, inspect the TT strap before further flight.
    Remove any TT strap from service before exceeding the allowable 
number of flights or 180 months, whichever occurs first.
    (c) If a defect is found as a result of the inspection, remove 
the TT strap from service prior to further flight.
    (d) If no defect is found as a result of the inspection in 
paragraph (b), a maximum of 500 flights is permitted on a one-time 
basis before the TT strap must be replaced, provided the limits of 
paragraphs (a)(4) and (b) are not exceeded.
    (e) TT straps, part number (P/N) 2604067 or J17322-1, are not 
eligible for installation. Prior to installation, P/N 2604067 or 
J17322-1 must be re-identified according to paragraph 2.B.1 of the 
``Accomplishment Instructions'' of the ASB, Revision 1, dated August 
31, 1999.
    (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, Regulations Group, FAA. Operators 
shall submit their requests through an FAA Principal Maintenance 
Inspector, who may concur or comment and then send it to the 
Manager, Regulations Group.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Regulations Group.

    (g) Special flight permits may be issued for up to five flights 
in accordance with sections 21.197 and 21.199 of the Federal 
Aviation Regulations (14 CFR 21.197 and 21.199) to operate the 
helicopter to a location where the requirements of this AD can be 
accomplished.
    (h) The inspections and re-identification of TT straps shall be 
done in accordance with the ``Accomplishment Instructions,'' 
paragraph 2.B.1 and 2.B.2, of Eurocopter Deutschland GMBH Alert 
Service Bulletin MBB-BK 117 No. ASB-MBB-BK 117-10-120, Revision 1, 
dated August 31, 1999. 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 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.
    (i) This amendment becomes effective on January 28, 2000.

    Note 3: The subject of this AD is addressed in Luftfahrt-
Bundesamt (LBA), Federal Republic of Germany, AD 1999-284, dated 
August 6, 1999.

    Issued in Fort Worth, Texas, on January 5, 2000.
Henry A. Armstrong,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 00-721 Filed 1-12-00; 8:45 am]
BILLING CODE 4910-13-P