[Federal Register Volume 64, Number 222 (Thursday, November 18, 1999)]
[Rules and Regulations]
[Pages 62973-62975]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-30146]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 99-SW-58-AD; Amendment 39-11429; AD 99-24-05]
RIN 2120-AA64
Airworthiness Directives; Eurocopter Deutschland GMBH (ECD) Model
BO-105CB-5 and BO-105-CBS-5 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 ECD Model BO-105CB-5
and BO-105-CBS-5 helicopters, that currently requires, before further
flight, creating a component log card or equivalent record and
determining the calendar age and number of flights on each tension-
torsion (TT) strap. This amendment requires the same actions as the
emergency priority letter AD and additionally clarifies the compliance
time requirements specified in the emergency priority letter AD. This
amendment is prompted by an accident in which a main rotor blade
(blade) separated from an ECD Model MBB-BK 117 helicopter due to
fatigue failure of a TT strap. The same part number TT strap is also
used on the ECD Model BO-105 helicopter. 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 December 3, 1999. The incorporation by reference of
certain publications listed in the regulations is approved by the
Director of the Federal Register as of December 3, 1999.
Comments for inclusion in the Rules Docket must be received on or
before January 18, 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-58-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; 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 11, 1999, the FAA issued Emergency
Priority Letter AD 99-17-15, Docket No. 99-SW-50-AD, applicable to ECD
Model BO-105CB-5, BO-105CBS, and BO 105 LS A-3 helicopters, which
required, before further flight, creating a component log card or
equivalent record and determining the calendar age and number of
flights on each TT strap. Emergency Priority Letter AD 99-17-15 also
required inspecting and removing, as necessary, certain unairworthy TT
straps. 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 investigation. The ECD Model MBB-BK-117 and certain ECD Model BO-
105 helicopters use the same part-numbered TT strap. 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.
After issuing Emergency Priority Letter AD 99-17-15, the FAA
determined that the calculations for determining the total number of
flights on a particular TT strap for the ECD Model BO-105CB-5 and the
ECD Model BO-105CBS-5 helicopters were different than the calculation
for determining the total number of flights on the part number TT strap
for the ECD Model BO-105 LS A-3 helicopters. Therefore, the FAA decided
to issue separate ADs with different calculation methods for each of
the affected models. Emergency Priority Letter AD 99-20-13, Docket No.
99-SW-56-AD, was issued on September 24, 1999 for the ECD Model BO 105
LS A-3 helicopters and Emergency Priority Letter AD 99-17-21, Docket
No. 99-SW-51-AD, applicable to ECD Model BO-105CB-5 and BO-
[[Page 62974]]
105CBS-5, was issued to supersede Emergency Priority Letter AD 99-17-
15.
Since issuing superseding Emergency Priority Letter AD 99-17-21,
the FAA has received several requests for clarification on 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 BO 105 No. ASB-BO
105-10-113, dated August 11, 1999 (ASB). The ASB describes procedures
for determining the total accumulated installation time and number of
flights on each TT strap. The ASB specifies inspecting and replacing,
as necessary, certain unairworthy TT straps and reidentifying the main
rotor head after replacing the 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 1999-289, dated
August 11, 1999, applicable to Model BO-105C (BO-105CB-5), BO-105S (BO-
105CBS-5) helicopters.
These helicopter models are manufactured in the Federal Republic of
Germany and are type certificated for operation in the United States
under the provision 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 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 these type
designs that are certificated for operations in the United States.
Since an unsafe condition has been identified that is likely to
exist or develop on other ECD Model BO-105CB-5 and BO-105-CBS-5
helicopters of the same type design, this AD supersedes Emergency
Priority Letter AD 99-17-21 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, certain 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 and determining the age and number of
flights on each TT strap and inspecting and removing, as necessary,
certain 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 85 helicopters of U.S. registry will be
affected by this AD; that it will take approximately 1 work hour 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 $965,600; $5,100 to inspect each helicopter once and
$960,500 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-58-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.
[[Page 62975]]
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding a new airworthiness directive
(AD) to read as follows:
AD 99-24-05 Eurocopter Deutschland GMBH: Amendment 39-11429. Docket
No. 99-SW-58-AD. Supersedes Emergency Priority Letter AD 99-17-21,
Docket No. 99-SW-51-AD.
Applicability: Model BO-105CB-5 and BO-105CBS-5 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 (g) 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 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. For the time-in-service (TIS) where the number of
flights is unknown, multiply the number of hours TIS by 5 to
determine the number of flights. If a TT strap has been previously
used at any time on Model BO-105 helicopters not affected by this
AD, multiply the number of flights accumulated on those other models
by a factor 0.625 and then add that result to the number of flights
accumulated on the Model BO-105CB-5 and BO-105CBS-5 helicopters.
(3) If the total hours TIS or number of flights and age cannot
be determined for a TT strap, remove it from service.
(4) Remove any TT strap from service that has either accumulated
25,000 or more flights or has an age equal to or greater than 180
months.
(b) When a TT strap age is equal to or greater than 120 months
and less than 180 months and has accumulated less than 25,000
flights, inspect the TT strap in accordance with paragraph 2.B.2. of
the ``Accomplishment Instructions,'' Eurocopter Deutschland GMBH
Alert Service Bulletin BO 105 No. ASB-BO 105-10-113, dated August
11, 1999 (ASB), 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.
(c) If a defect is found as a result of the inspection in
paragraph (b), 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 reidentified according to paragraph 2.B.1.2. of the
``Accomplishment Instructions'' of the ASB.
(f) When the TT straps are replaced because of age, usage, or
defects, reidentify the main rotor head in accordance with paragraph
2.B.1.2. of the ``Accomplishment Instructions'' of the ASB.
(g) 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.
(h) 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.
(i) The TT strap inspections and reidentification shall be done
in accordance with paragraphs 2.B.1.2. and 2.B.2. of the
``Accomplishment Instructions'' in Eurocopter Deutschland GMBH Alert
Service Bulletin No. ASB-BO 105-10-113, dated August 11, 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.
(j) This amendment becomes effective on December 3, 1999.
Note 3: The subject of this AD is addressed in Luftfahrt-
Bundesamt (LBA), Federal Republic of Germany, AD 1999-289, dated
August 11, 1999.
Issued in Fort Worth, Texas, on November 10, 1999.
Henry A. Armstrong,
Manager, Rotorcraft Directorate,
Aircraft Certification Service.
[FR Doc. 99-30146 Filed 11-17-99; 8:45 am]
BILLING CODE 4910-13-U
