AD Amdt-39-11429

[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 [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[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