[Federal Register Volume 70, Number 199 (Monday, October 17, 2005)]
[Rules and Regulations]
[Pages 60206-60211]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-20678]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2004-SW-13-AD; Amendment 39-14340; AD 2005-21-02]
RIN 2120-AA64


Airworthiness Directives; MD Helicopters, Inc. Model 369D, 369E, 
369F, 369FF, 500N, and 600N 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) for the MD Helicopters, Inc. (MDHI) Model 369A, H, HE, HM, HS, D, 
and E helicopters with a certain part-numbered main rotor blade (blade) 
and modified with a Helicopter Technology Company, LLC (HTC), 
Supplemental Type Certificate (STC) No. SR09172RC, SR09074RC, or 
SR09184RC. That AD currently requires recording on the component 
history card or equivalent record (record) each torque event (TE) on 
each blade, inspecting both surfaces of the blade, and replacing any 
cracked blade with an airworthy blade. Also, that AD establishes life 
limits for certain part-numbered blades. This amendment revises the 
model applicability, adds MDHI part-numbered blades, removes any 
reference to the life limits of the blades, changes the requirements 
for inspecting the blades, and revises the STC applicability. This 
amendment also provides that compliance with portions of certain 
documents constitutes alternative methods of compliance with portions 
of this AD, contains editorial changes for clarification, and makes 
some corrections. This amendment is prompted by additional reports of 
cracked blades and by the comments received in response to AD 2003-24-
01. The actions specified in this AD are intended to detect fatigue 
cracking of the blade to prevent blade failure and subsequent loss of 
control of the helicopter.

DATES: Effective November 1, 2005. Comments for inclusion in the Rules 
Docket must be received on or before December 16, 2005.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Regional Counsel, Southwest Region, 
Attention: Rules Docket No. 2004-SW-13-AD, 2601 Meacham Blvd., Room 
663, Fort Worth, Texas 76137. You may also send comments electronically 
to the Rules Docket at the following address: [email protected].
    The service information referenced in this AD may be obtained from 
the following addresses: MD Helicopters Inc., Attn: Customer Support 
Division, 4555 E. McDowell Rd., Mail Stop M615, Mesa, Arizona 85215-
9734, telephone 1-800-388-3378, fax 480-346-6813, or on the Web at 
http://www.mdhelicopters.com and Helicopter Technology Company, LLC, 
12902 South Broadway, Los Angeles, CA 90061, telephone 310-523-2750, 
fax 310-523-2745.

FOR FURTHER INFORMATION CONTACT: John Cecil, Aviation Safety Engineer, 
FAA, Los Angeles Aircraft Certification Office, Airframe Branch, 3960 
Paramount Blvd., Lakewood, California 90712-4137, telephone (562) 627-
5228, fax (562) 627-5210.

[[Page 60207]]


SUPPLEMENTARY INFORMATION: On November 17, 2003, the FAA issued AD 
2003-24-01, Amendment 39-13370 (68 FR 66004, November 25, 2003), to 
require recording TE and inspecting certain blades with 13,720 TEs and 
750 hours TIS. The AD also requires replacing any cracked blade with an 
airworthy blade. Also, the AD revises the Limitations and Conditions of 
HTC, LLC, STC Nos. SR09172RC, SR09074RC, and SR09184RC by establishing 
life limits for certain part-numbered blades. The AD was prompted by 
reports of certain blades cracking due to a higher number of TEs per 
hour than originally calculated. This condition, if not corrected, 
could result in fatigue cracking of the blade, blade failure, and 
subsequent loss of control of the helicopter.
    Interested persons were afforded an opportunity to participate in 
the making of AD 2003-24-01. The FAA received several comments from 10 
commenters. We have given due consideration to the comments received.
    One commenter, the manufacturer (MDHI), states the scope of the AD 
should be expanded to add the OH-6A designation immediately after the 
model to read ``Model 369A (OH-6A), H, etc.''
    The FAA disagrees that we should add the Model OH-6A. We included 
STC No. SR09184RC and the Model 369A (OH-6A), H, HE, HM, and HS 
helicopters to AD 2003-24-01 in error. We have reviewed reports, 
summaries about rates of use, incident reports, certification data, 
weight limits, and other information from the manufacturer. These 
models may have the affected part-numbered blades installed. However, 
the data shows that even with a higher than expected number of TEs, 
these models have approved operating limitations that assume operations 
at maximum gross weight and are conservative enough to compensate for 
the higher TEs. We have received no reports of these blades cracking in 
the areas affected by this AD. These blades should reach their 
retirement lives based on hours TIS before the number of TEs results in 
cracks in the affected area. Also, we have determined that we should 
have included STC No. SR01050LA and the Model 369F, FF, 500N, and 600N 
helicopters in the AD applicability. Our data shows the unsafe 
condition addressed by this AD correlates to a flight profile with a 
higher number of TEs than expected during certification (six TEs per 
hour). The Model 369D, E, F, FF, 500N and 600N helicopters, with a 
higher gross weight limit, fit that profile. Therefore, we have 
determined that this AD should apply only to the Model 369D, E, F, FF, 
500N and 600N helicopters.
    Five commenters state the new definition of a TE in AD 2003-24-01 
is inconsistent with the definition given in other ADs and in a service 
letter. One commenter, MDHI, states the new definition is likely to 
cause confusion.
    The FAA agrees. The definition introduced in AD 2003-24-01 is 
inconsistent with previously issued ADs and could unnecessarily burden 
and confuse the operators. Therefore, we have changed the definition to 
make it consistent with the definition of a TE as that term is defined 
in AD 98-15-26, Amendment 39-10675, Docket 98-SW-22-AD. The TE 
definition in AD 98-15-26 is also consistent with the definition in 
MDHI Service Letter SL369H-132R1, SL369D-111R1, SL369E-063R1, SL369F-
056R1, SL500N-008R1, and SL600N-005R1, dated May 15, 2001.
    One commenter asks that the word ``reliably'' be added to the AD 
paragraph requiring operators to determine the number of TEs. The 
commenter states that FAA approved service information reads, 
``operators who cannot reliably determine the actual number of TEs for 
a blade * * *.''
    The FAA does not agree. The word ``reliably'' is subjective and 
does not assist operators in determining accumulated TEs. The 
requirement is that operators determine actual TEs or assume 13,720 
accumulated TEs.
    One commenter, MDHI, states the actions in the AD do not prevent 
cracks but mandate a 35-hour repetitive inspection to detect cracks 
before blade failure.
    The FAA agrees. The AD wording is revised to read: ``The actions 
specified in this AD are intended to detect fatigue cracking to prevent 
* * *''
    Four commenters do not agree with the blade inspection 
requirements. One commenter states the inspection is unnecessary. The 
four commenters state the use of a 10X or higher magnifying glass is 
unnecessary and that cracks have been found without the use of a 
magnifying glass. Three commenters ask if pilots can do the inspections 
instead of a mechanic.
    The FAA disagrees and has determined the inspection is necessary 
because the affected blades on these model helicopters continue to 
crack. The manufacturer has not identified a permanent modification but 
has identified TE counting or replacing the blade as a corrective 
measure. The FAA has also determined that a 10X or higher magnifying 
glass is necessary to detect a chord-wise crack protruding from under 
the root fitting and doubler on the bottom-side of the blade to prevent 
blade failure because these cracks may not be detectable without a 10X 
magnifying glass until they are near failure. Current FAA policy does 
not allow pilots to do these inspections. Pilots may only perform 
simple visual checks authorized by the AD. Pilots may perform checks 
that do not require the use of tools, precision measuring equipment, 
training, pilot logbook endorsements, or the use of or reference to 
technical data not contained in the body of the AD. The inspection in 
the AD requires the use of a 10X or higher magnifying glass, which is 
not considered a simple visual check.
    One commenter states that an eddy current inspection is effective 
in detecting cracks in the ``C'' channel of certain blades. The 
commenter states the FAA may want to consider having the manufacturer 
incorporate an eddy current inspection into the maintenance 
instructions for all blades.
    The FAA does not agree that an eddy current inspection is necessary 
to detect a crack in the blade in the areas specified in this AD. We 
have determined the cracks can be detected in the specified areas by 
inspecting the blades using a 10X or higher magnifying glass.
    Two commenters suggest the service bulletins and their amendments, 
created by MDHI and HTC, are adequate to address the unsafe condition. 
One of those commenters states that normally an AD is coordinated with 
the manufacturer who produces a service bulletin (SB) and the FAA backs 
it up with an AD stating the operators must comply. That commenter 
further states that the idea of an AD should be to address an issue the 
manufacturer is either unaware of or has not addressed.
    The FAA is responsible for determining which portions, if any, of 
an SB to incorporate in an AD and any additional requirements necessary 
to correct the unsafe condition. Even though an SB may address an 
unsafe condition, an AD mandates compliance with the actions specified 
in the SB by all affected operators. While we generally seek technical 
information from the manufacturer, we neither solicit the 
manufacturer's assistance in drafting an AD nor its consent before 
issuing an AD. However, we do note in this AD that complying with 
certain portions of certain documents constitutes an approved 
alternative method of compliance for certain parts of this AD.
    One commenter states that only a few companies consistently have 
cracked blades. That commenter suggests that we should look at those 
companies. The same commenter states an AD is not

[[Page 60208]]

needed because the maintenance manual criteria are sufficient to detect 
a cracked blade.
    The FAA partially concurs with the commenter. The commenter is 
correct in that most cracked blades do appear to occur as a result of 
the operations of a relatively few operators. However, the affected 
blades from these relatively few operators may be placed on any of the 
affected model helicopters regardless of their previous use. Thus, the 
AD must include all affected model helicopters. Although we agree that 
the maintenance manual criteria are sufficient to detect a cracked 
blade, we do not agree that the AD is not needed. The AD requires 
determining and recording the number of TEs accumulated on each blade 
and provides the required time intervals to perform the inspections. We 
have determined the affected blades must be inspected to determine if a 
crack exists at the required TEs or hours TIS.
    One commenter, MDHI, states that it disagrees that specific blade 
station inspections are any more meaningful than the area described as 
``* * * around the root fitting, doubler and skin * * *.''
    The FAA, upon reconsideration, agrees and no longer refers to the 
six blade stations because the reference is not necessary to identify 
the required inspection area.
    One commenter, the blade manufacturer, HTC, states the instructions 
in paragraph (b)(2) of AD 2003-24-01 ``(parallel to the blade) from the 
center of the root fitting and lead lag attach bolt-holes closest to 
the trailing edge,'' are confusing. The commenter asks if the direction 
is perhaps ``span wise'' and states that the trailing edge of the blade 
is not relevant. The commenter also states the instructions will cause 
many operators to perform the inspection in the wrong areas.
    The FAA included the specific measurements, reference points, and 
directions in paragraph (b)(2) of AD 2003-24-01 to provide the mechanic 
the location of the specific blade stations stated in HTC SB No. 2100-
3R2. To simplify these instructions, we have decided to remove the 
specific locations from the AD and include a figure that depicts the 
blade inspection area.
    Six commenters commented on the cost analysis stating the AD poses 
an economic burden on operators. One commenter states it will cause a 
hardship on the industry. Another commenter states it will not be 
economically feasible. Another commenter states the AD will put 
operators out of work and force them to switch to other aircraft types. 
Another commenter states the AD will cause an increase in paperwork. 
Another commenter asks what is the basis for the cost of the blades and 
the number of additional inspections. Another commenter states the 
economic impact should be redone using realistic blade rejections due 
to fatigue cracks.
    While the FAA must consider the economic burdens caused by issuing 
an AD, the primary purpose of an AD is to correct an unsafe condition. 
We did, however, reassess the cost analysis as a result of the 
comments. Therefore, we are assuming a total of 9000 TE inspections and 
blade replacements will be required for 10 percent of the fleet. Also, 
we have determined the paperwork costs will be negligible.
    A commenter, HTC, states the AD establishes life limits for certain 
blades that already have published service lives, the action is FAA 
approved, and the life limits are contained in Maintenance Manual HTCM-
001.
    The FAA agrees with the commenters statements. When the life limits 
were originally issued, they were inadvertently omitted from the 
Limitations and Conditions of HTC, LLC, STC Nos. SR09172RC, SR01050LA, 
and SR09184RC. The STCs were amended and now include the life limits. 
However, the life limits can only be established in an AD because a 
change to a life limit appearing only in a manual or on type 
certificate data sheets, even if FAA-approved, does not require 
compliance by the pilot or operator. To be legally required, the change 
must be made through an AD. We are addressing the issue of establishing 
life limits in another AD. Therefore, the paragraph establishing life 
limits is excluded from this AD.
    A commenter, HTC, notes the AD states that this proposal is 
prompted by several reports. The commenter states there are two known 
reports, both from the same Canadian operator, and they received only 
one of those two reports.
    The FAA agrees there were two reports when AD 2003-24-01 was 
issued, and we also note that we inadvertently called the ``action'' 
required by the AD a ``proposal''. However, since the AD was issued, we 
have received additional reports. We have reviewed a total of five 
reports in making our decision to issue this AD.
    Three commenters question the statement in AD 2003-24-01, paragraph 
(a)(2), about recording the total number of TEs. One commenter asks 
whether the AD intent is to require that the pilots land or record the 
100 TEs by taking their hands off the controls. Another commenter wants 
to know the basis for the 100 external lifts. Another commenter states 
that requiring the operator to record TEs after 100 external lifts will 
add a burden and a penalty to the operator in having to land and record 
the TEs. That same commenter suggests that they be allowed to record TE 
at the end of daily operations.
    The FAA partially agrees with the comments. The AD does not dictate 
the flight profile of the helicopter when recording TEs. It's up to the 
operator to record the TEs. The time required to record the number of 
TEs is a negligible burden. The basis for our initial assessment was 
that in any given day there would be 100 external lift operations. We 
have since determined the use of 100 external lift operations is not 
realistic given that some operators often exceed that number before a 
single day of operation. Therefore, after additional analysis, we have 
determined that recording the TEs at the end of each day's operation or 
on or before accumulating an additional 200 TEs, whichever occurs 
first, is sufficient.
    One commenter states that AD 98-15-26 requires recording unknown 
TEs using a formula to determine TE against TIS. In AD 2003-24-01, the 
operator must assume a penalty of 13,720 TEs for blades with unknown 
TEs. The commenter expresses concern that at some future date, the FAA 
will decide that these HTC blades must be retired at a similar TE as 
the MD blades now have. The commenter further states that this could 
cost operators about $44,000,000.
    The FAA has determined that because of the critical nature of the 
unsafe condition, the formula for TEs as required in AD 98-15-26 would 
not adequately address the unsafe condition. While we cannot rule out 
further AD action related to this unsafe condition, any such action 
would require justification and consideration of the financial impact 
of that action.
    One commenter states the paragraph in the preamble of the AD that 
begins with the statement, ``This unsafe condition is likely to exist 
or develop on other helicopters * * *'' seems to indicate that only 
HTC-built blades could cause the condition.
    The FAA issues an AD when it believes there is an unsafe condition 
in a product and that an unsafe condition is likely to exist or develop 
in other products of the same type design. In AD 2003-24-01, the unsafe 
condition was identified as fatigue cracking of the part-numbered 
blades listed in the ``applicability'' section and installed as part of 
the three listed STCs. These helicopter models, listed in the 
``applicability section'' with the affected blades installed, are 
susceptible to fatigue cracking of the blades. These

[[Page 60209]]

blades include both MDHI and HTC blades. Therefore, this AD retains 
similar wording for the revised model helicopters and STCs for 
helicopters with blades installed, which are susceptible to fatigue 
cracking.
    One commenter, HTC, states the comment period for an NPRM is 1 
year. The commenter asks why is this AD so urgent when the FAA was so 
unconcerned before. The same commenter also states that they requested 
an NPRM more than 16 months ago.
    The FAA comment period for an NPRM is usually 60 days. We issued AD 
2003-24-01 as a final rule; request for comments with a typical 60-day 
comment period. Since the original incident, we have been evaluating 
the reports and data as it becomes available to determine the necessary 
corrective action. In addition to the reports of cracked blades that 
prompted the AD, we have received additional reports of cracked blades. 
We have determined that this critical unsafe condition and the short 
compliance time to correct it require an immediate AD.
    Two commenters suggest the January 26, 2003, date for receipt of 
comments for inclusion in the rules docket may be a typographical 
error.
    The FAA agrees the date was a typographical error and should have 
been January 26, 2004.
    Finally, two commenters state the FAA should include and cross-
reference the blades specified in the HTC and MDHI SBs so that 
operators understand that the new AD affects both HTC and MDHI part 
number (P/N) blades.
    The FAA agrees. In this AD, we include both MDHI and HTC part-
numbered blades and cross-reference the part numbers and the STCs to 
clearly show the affected helicopters, blades, and STC's.
    Since issuing AD 2003-24-01, the FAA has reviewed MDHI SB369H-
245R2, SB369E-095R2, SB500N-023R2, SB369D-201R2, SB369F-079R2, SB600N-
031R2, dated February 4, 2004. The SB contains information about the 
blade TEs and determining an inspection interval. Also, the SB lists 
certain MDHI helicopter models and HTC and MDHI blade part numbers.
    HTC superseded Mandatory Notice No. 2100-3R2, dated December 20, 
2002, with Notice No. 2100-3R3, dated January 5, 2004. Notice No. 2100-
3R3 contains information about blade TE inspections and determining an 
inspection interval. The notice references the information contained in 
MDHI CSP-HMI-2, Section 62-10-00, Main Rotor Blade Torque Event 
Inspection. Also, Notice No. 2100-3R3 ``revises the model effectivity 
and the scope of the additional inspection with a 10X glass.''
    Also since issuing AD 2003-24-01, the FAA determined that STC 
SR09184RC approves the installation of blades, P/N 500P2100-301 and -
303, only, on the MDHI 369A, H, HE, HM, and HS model helicopters. Based 
on our determination, this AD will not apply to these five model 
helicopters. Likewise, the AD will not apply to STC SR09184RC and 
blades, P/N 500P2100-301 and -303. However, we will establish life 
limits for these blades in a subsequent AD.
    Also, after further review of the service information, the FAA has 
determined that helicopters modified under STC SR01050LA, STC 
SR09172RC, and STC SR09074RC may have the affected blades installed. 
Therefore, they are included in the applicability of this AD.
    In addition, since issuing AD 2003-24-01, the FAA has received 
three additional reports of incidents of cracked blades in 2004 and 
2005. A preliminary evaluation of the cracked blades continues to 
indicate that the cracking is related to a high number of TEs 
accumulated by the blades. None of the blades identified in incident 
reports that caused the FAA to publish AD 2003-24-01 or this final rule 
involved helicopters modified with STC SR09184RC. Therefore, exclusion 
of STC SR09184RC is appropriate because none of the blades used in that 
modification, based on a review of technical data and accident records, 
should be affected by this AD.
    An unsafe condition is likely to exist or develop on other Model 
369D, 369E, 369F, 369FF, 500N, and 600N helicopters of these same type 
designs modified with an HTC STC No. SR09172RC, SR09074RC, or 
SR01050LA. Therefore, this AD supersedes AD 2003-24-01 to require:
     On or before the next 50-hours time-in-service (TIS), 
unless accomplished previously, determine and record the number of TEs 
accumulated on each blade. A TE is the transition to a hover from 
forward flight or any external lift operation. Each transition to a 
hover from forward flight is recorded as a TE, and any external lift 
operation is recorded as two TEs. Forward flight is considered to be 
flight at any airspeed (or direction) after attaining translational 
lift. If you cannot determine the number of TEs, assume 13,720. 
Continue to record the number of TEs accumulated (actual usage) 
throughout the life of the blades and the hours TIS. On or before 
accumulating an additional 200 TEs or at the end of each day's 
operation, whichever occurs first, record and update the accumulated 
TEs total.
     For each blade that has accumulated 13,720 or more TEs and 
750 or more hours TIS, before further flight, unless accomplished 
previously, and thereafter at intervals not to exceed 200 TEs or 35 
hours TIS, whichever occurs first, perform a main rotor blade torque 
event inspection.
     If a crack is found, replace the blade with an airworthy 
blade before further flight.
    The short compliance time involved is required because the 
previously described critical unsafe condition can adversely affect the 
controllability and structural integrity of the helicopter. Some 
operators not affected by AD 2003-24-01 may have already exceeded the 
13,720 TEs and 750 hours TIS. Therefore, based on the high usage rate 
of some of these model helicopters, the 35-hour TIS or 200 TE 
inspections may occur in a short time span, 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 this AD will:
     Affect 886 helicopters of U.S. registry;
     Take about 1 work hour per helicopter for inspecting 
blades, assuming 9000 TE inspections for 10 percent of the fleet, at an 
average labor rate of $65 per work hour;
     Cost about $50,000 for one set of blades (on condition), 
assuming 10 percent of the fleet has blades that are replaced; and
     Have paperwork costs that are negligible.
    Based on these figures, we estimate the total cost impact of the AD 
on U.S. operators is $56,261,000, assuming 10 percent of the fleet is 
affected.

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 FAA, Office of the Regional Counsel, Southwest 
Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas. All 
communications

[[Page 60210]]

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 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 mailed 
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. 2004-SW-13-AD.'' The postcard will be date 
stamped and returned to the commenter.

Regulatory Findings

    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.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, section 106, describes the 
authority of the FAA Administrator. Subtitle VII, Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
subtitle VII, part A, subpart III, section 44701, ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

Adoption of the Amendment

0
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

0
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]

0
2. Section 39.13 is amended by removing Amendment 39-13370 (68 FR 
66004, November 25, 2003), and by adding a new airworthiness directive 
(AD), Amendment 39-14340, to read as follows:

2005-21-02 MD Helicopters, Inc.: Amendment 39-14340. Docket No. 
2004-SW-13-AD. Supersedes AD 2003-24-01, Amendment 39-13770, Docket 
No. 2003-SW-16-AD.

    Applicability: Models 369D, 369E, 369F, 369FF, 500N, or 600N 
with either an MD Helicopter, Inc. (MDHI) main rotor blade (blade) 
installed or modified with Helicopter Technology Company, LLC (HTC), 
Supplemental Type Certificate (STC) No. SR09172RC, SR09074RC, or 
SR01050LA with an HTC blade installed as listed in the following 
table, certificated in any category:

--------------------------------------------------------------------------------------------------------------------------------------------------------
                          Helicopter model                                MDHI blade part No. (P/N)              HTC blade P/N            HTC STC Nos.
--------------------------------------------------------------------------------------------------------------------------------------------------------
369D...............................................................   369D21100 Basic, -516, -517, -523          500P2100-BSC, -BSC-1          SR09172RC
369E...............................................................                 369D21120-501, -503            500P2100-101, -103          SR09074RC
369F, FF...........................................................   369D21102 Basic, -503, -517, -523            500P2300-501, -503          SR01050LA
                                                                                    369D21121-501, -503  ............................  .................
500N...............................................................           369D21102-503, -517, -523            500P2300-501, -503          SR01050LA
                                                                                    369D21121-501, -503  ............................  .................
600N...............................................................                 369D21102-517, -523            500P2300-501, -503          SR01050LA
                                                                                    369D21121-501, -503
--------------------------------------------------------------------------------------------------------------------------------------------------------


    Note 1: The terms ``BSC'' and ``Basic'' are interchangeable when 
identifying blades produced by MDHI and HTC.

    Compliance: Required as indicated.
    To detect fatigue cracking of the blade to prevent blade failure 
and subsequent loss of control of the helicopter, accomplish the 
following:
    (a) On or before the next 50 hours time-in-service (TIS), unless 
accomplished previously:
    (1) Determine and record the number of torque events accumulated 
on each blade. A torque event (TE) is the transition to a hover from 
forward flight or any external lift operation. Each transition to a 
hover from forward flight is recorded as a TE, and any external lift 
operation is recorded as two TEs. Forward flight is considered to be 
flight at any airspeed (or direction) after attaining translational 
lift. If you cannot determine the number of TEs, use 13,720 TEs.
    (2) Continue to record the number of TEs accumulated (actual 
usage) throughout the life of the blades along with hours TIS. On or 
before accumulating an additional 200 TEs or at the end of each 
day's operations, whichever occurs first, record and update the 
accumulated TEs total.
    (b) For each blade that has accumulated 13,720 or more TEs and 
750 or more hours TIS, before further flight, unless accomplished 
previously, and thereafter at intervals not to exceed 200 TEs or 35 
hours TIS, whichever occurs first, perform a main rotor blade torque 
event inspection.

    Note 2: MD Helicopters, Inc. Maintenance Manual CSP-HMI-2, 
Revision 36, section 62-10-00, paragraph 8, Main Rotor Blade Torque 
Event Inspection, pertains to the subject of this AD.

    (c) If a crack is found, replace the blade with an airworthy 
blade before further flight.


[[Page 60211]]


    Note 3: MDHI Maintenance Manual CSP-HMI-2, Section 20-30-00 Main 
Rotor Blade Painting pertains to the subject of this AD. This 
section of the maintenance manual recommends painting the inboard 24 
inches (not to be exceeded) of the blade gloss white to aid in 
detecting a crack; and if this is done, painting all blades alike 
and rebalancing them.


    Note 4: TEs are used only to establish an additional inspection 
interval and not to establish an alternative retirement life.

    (d) To request a different method of compliance or a different 
compliance time for this AD, follow the procedures in 14 CFR 39.19. 
Contact the Los Angeles Aircraft Certification Office, Transport 
Airplane Directorate, for information about previously approved 
alternative methods of compliance.

    Note 5: Complying with the inspection procedures in the 
Accomplishment Instructions, paragraphs 2.B.(2). and 2.B.(3)., of MD 
Helicopter Inc. Service Bulletin (SB) SB369H-245R2, SB369E-095R2, 
SB500N-023R2, SB369D-201R2, SB369F-079R2, SB600N-031R2, dated 
February 4, 2004, constitutes an approved alternative method of 
conducting the inspection required by paragraph (b) of this AD.


    Note 6: Complying with the Inspection Instructions procedures in 
paragraphs 2 and 3 of HTC Mandatory SB, Notice No. 2100-3R3, dated 
January 5, 2004, constitutes an approved alternative method of 
conducting the inspection required by paragraph (b) of this AD.

    (e) This amendment becomes effective on November 1, 2005.

    Issued in Fort Worth, Texas, on October 7, 2005.
David A. Downey,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 05-20678 Filed 10-14-05; 8:45 am]
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