AD 2001-24-51

[Federal Register Volume 67, Number 71 (Friday, April 12, 2002)]
[Rules and Regulations]
[Pages 17934-17936]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 02-8595]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-SW-57-AD; Amendment 39-12706; AD 2001-24-51]
RIN 2120-AA64


Airworthiness Directives; MD Helicopters, Inc. Model 600N 
Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This document publishes in the Federal Register an amendment 
adopting Airworthiness Directive (AD) 2001-24-51, which was sent 
previously to all known U.S. owners and operators of MD Helicopters, 
Inc. (MDHI) Model 600N helicopters by individual letters. This AD 
requires, within 5 hours time-in-service (TIS), inspecting both upper 
tailboom attachments, nutplates and both angles for a crack or thread 
damage and repairing or replacing any cracked or damaged part before 
further flight. Also, this AD requires replacing the upper right-hand 
(RH) tailboom attachment bolt (bolt) with a new bolt, and if the upper 
RH bolt is broken, replacing the three remaining bolts with airworthy 
bolts before further flight. Adding a washer to each bolt and modifying 
both upper access covers are also required. Thereafter, at specified 
intervals, inspecting the upper tailboom attachments and repairing or 
replacing any cracked part before further flight is required. This AD 
is prompted by the discovery of a cracked bolt on a helicopter. The 
actions specified by this AD are intended to prevent failure of a 
tailboom attachment, loss of the tailboom, and subsequent loss of 
control of the helicopter.

DATES: Effective April 29, 2002, to all persons except those persons to 
whom it was made immediately effective by Emergency AD 2001-24-51, 
issued on November 28, 2001, which contained the requirements of this 
amendment.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of April 29, 2002.
    Comments for inclusion in the Rules Docket must be received on or 
before June 11, 2002.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Regional Counsel, Southwest Region, 
Attention: Rules Docket No. 2001-SW-57-AD, 2601 Meacham Blvd., Room 
663, Fort Worth, Texas 76137. You may also send comments electronically 
to the Rules Docket at the following address: <a href="/cdn-cgi/l/email-protection#0e37236f7d79236f6a6d6163636b607a7d4e686f6f20696178"><span class="__cf_email__" data-cfemail="21180c4052560c4045424e4c4c444f5552614740400f464e57">[email&#160;protected]</span></a>.
    The applicable service information may be obtained from MD 
Helicopters Inc., Attn: Customer Support Division, 4555 E. McDowell 
Rd., Mail Stop M615-GO48, Mesa, Arizona 85215-9734, telephone 1-800-
388-3378, fax 480-891-6782, or on the web at <a href="http://www.mdhelicopters.com">www.mdhelicopters.com</a>. 
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: Fred Guerin, Aviation Safety Engineer, 
FAA, Los Angeles Aircraft Certification Office, Airframe Branch, 3960 
Paramount Blvd., Lakewood, California 90712, telephone (562) 627-5232, 
fax (562) 627-5210.

SUPPLEMENTARY INFORMATION: On November 28, 2001 the FAA issued 
Emergency AD 2001-24-51 for MDHI Model 600N helicopters which requires, 
within 5 hours TIS, inspecting both upper tailboom attachments, 
nutplates and both angles for a crack or thread damage and repairing or 
replacing any cracked or damaged part before further flight. Also 
required is replacing the upper RH bolt with a new bolt, and if the 
upper RH bolt is broken, replacing the three remaining bolts with 
airworthy bolts before further flight. Adding a washer to each bolt and 
modifying both upper access covers are also required. Thereafter, at 
intervals not to exceed 25 hours TIS, inspecting the upper tailboom 
attachments and repairing or replacing any cracked part before further 
flight is required. That action was prompted by the discovery of a 
cracked bolt on a helicopter. Further inspection revealed cracking on 
bolts and attachments on several other helicopters. This condition, if 
not corrected, could result in failure of a tailboom attachment, loss 
of the tailboom, and subsequent loss of control of the helicopter.
    The FAA has reviewed MD Helicopters, Inc. Service Bulletin SB600N-
036, dated November 2, 2001 (SB). The SB describes procedures for 
inspecting the tailboom attach fittings and repairing damaged fittings. 
In addition to those procedures, the FAA has determined that if one 
bolt is broken, all four bolts must be replaced. Also, we have 
determined that a 25-

[[Page 17935]]

hour TIS repetitive inspection of the tailboom attachments is required.
    Since the unsafe condition described is likely to exist or develop 
on other MDHI Model 600N helicopters of the same type design, the FAA 
issued Emergency AD 2001-24-51 to prevent failure of a tailboom 
attachment, loss of the tailboom, and subsequent loss of control of the 
helicopter. The AD requires the following:
    <bullet> Within 5 hours TIS:
    <bullet> Remove the tailboom fairing, tailboom, and both upper 
tailboom attachment access covers.
    <bullet> Using a light and a 10 x  or higher magnifying glass, 
inspect for a crack or damage:
    <bullet> Both upper tailboom attachments and nutplates. If a crack 
or thread damage is found, replace any cracked or damaged attachments 
or nutplates with an airworthy part before further flight.
    <bullet> Both angles. If a crack is found on the RH angle, before 
further flight, install a new clip. If a crack is found on the left-
hand angle, before further flight, replace or repair the angle.
    <bullet> Replace the upper RH tailboom attachment bolt with a new 
bolt. If the upper RH bolt is found broken, before further flight, also 
replace the three remaining bolts.
    <bullet> Add a washer to each bolt.
    <bullet> Modify both upper access covers.
    <bullet> At intervals not to exceed 25 hours TIS, using a 
borescope, through the hole in each upper access cover, inspect the 
upper tailboom attachments for a crack. Repair or replace any cracked 
part with an airworthy part before further flight.

    The actions must be accomplished in accordance with the SB 
described previously. The short compliance time involved is required 
because the previously described critical unsafe condition can 
adversely affect the structural integrity and controllability of the 
helicopter. Therefore, the previously stated actions are required 
within 5 hours TIS, and thereafter at the specified time intervals, and 
this AD must be issued immediately.

    Since it was found that immediate corrective action was required, 
notice and opportunity for prior public comment thereon were 
impracticable and contrary to the public interest, and good cause 
existed to make the AD effective immediately by individual letters 
issued on November 28, 2001 to all known U.S. owners and operators of 
MDHI Model 600N helicopters. These conditions still exist, and the AD 
is hereby published in the Federal Register as an amendment to 14 CFR 
39.13 to make it effective to all persons.
    The FAA estimates that 33 helicopters of U.S. registry will be 
affected by this AD. It will take approximately 2 work hours per 
helicopter to perform the inspections, 8 work hours per helicopter to 
replace the bolts, if necessary, and 20 work hours to repair an angle, 
if necessary. The average labor rate is $60 per work hour. Required 
parts will cost $50 for each inspection, $200 to replace the bolts on 
each helicopter, and $100 to repair an angle. Based on these figures, 
the total cost impact of the AD on U.S. operators is estimated to be 
$41,050 ($28,050 to inspect and replace the bolts on each helicopter 
and $13,000 to repair 10 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 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. 2001-SW-57-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 
to read as follows:

2001-24-51  MD Helicopters, Inc.: Amendment 39-12706. Docket No. 
2001-SW-57-AD.

    Applicability: Model 600N helicopters, serial numbers with a 
prefix ``RN'' and 003 through 063, 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 (c) 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.


[[Page 17936]]


    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent failure of a tailboom attachment, loss of the 
tailboom, and subsequent loss of control of the helicopter, 
accomplish the following:
    (a) Within 5 hours time-in-service (TIS):
    (1) Remove the tailboom fairing and tailboom. Remove both upper 
tailboom attachment access covers in accordance with the 
Accomplishment Instructions, paragraph 2.B.(2) of MD Helicopters, 
Inc. (MDHI) Service Bulletin SB600N-036, dated November 2, 2001 
(SB).

    Note 2: MDHI CSP-HMI-2, Section 53-40-30, pertains to the 
subject of this AD.

    (2) Using a light and a 10x or higher magnifying glass:
    (i) Inspect the right and left upper tailboom attachments, part 
number (P/N) 500N3422 and 500N3422-3, respectively, for a crack as 
shown in Figure 1 of the SB. If a crack is found, replace any 
cracked attachment fitting with an airworthy attachment fitting 
before further flight.
    (ii) Inspect both upper tailboom attachment nutplates for thread 
damage or a crack. Replace any damaged or cracked nutplate with an 
airworthy nutplate before further flight.
    (iii) Inspect both angles for a crack. If a crack is found on a 
right-hand angle, P/N 500N3429-6, before further flight, install a 
new clip in accordance with the Accomplishment Instructions, 
paragraph 2.B.(5)(c) of the SB. If a crack is found on the left-hand 
angle, P/N 500N3429-7, before further flight, replace the angle with 
an airworthy angle, or repair the angle in accordance with FAA-
approved procedures.
    (3) Replace the upper right-hand (pilot side) tailboom 
attachment bolt (bolt) with a new bolt.
    (4) If the removed upper pilot-side bolt is found broken, 
replace the remaining three bolts with airworthy bolts before 
further flight.
    (5) Add one washer, P/N AN960C516 (NAS1149C0563R) or AN960C616 
(NAS1149C0663R), as appropriate, to each tailboom bolt between the 
tailboom and the NAS1587 countersunk washer. A minimum of two 
threads must extend past the nutplate.
    (6) Modify both access covers in accordance with the 
Accomplishment Instructions, paragraph 2.B.(6), of the SB.
    (b) At intervals not to exceed 25 hours TIS, using a borescope, 
through the hole in each upper access cover, inspect the right and 
left upper tailboom attachments, nutplates, and angles for a crack. 
If a crack is found, replace or repair any cracked part with an 
airworthy part in accordance with the requirements of this AD before 
further flight.
    (c) 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, Los Angeles Aircraft Certification 
Office (LAACO), FAA. Operators shall submit their requests through 
an FAA Principal Maintenance Inspector, who may concur or comment 
and then send it to the Manager, LAACO.

    Note 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the LAACO.

    (d) Special flight permits may be issued in accordance with 14 
CFR 21.197 and 21.199 to operate the helicopter to a location where 
the requirements of this AD can be accomplished.
    (e) The removal of the upper tailboom attachment access covers, 
inspection of the tailboom attachments, installation of a new clip, 
and modification of the access covers shall be accomplished in 
accordance with the Accomplishment Instructions, paragraphs 2.B.(2), 
2.B.(5)(c), 2.B.(6), and Figure 1, of MD Helicopters, Inc. Service 
Bulletin SB600N-036, dated November 2, 2001. 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 MD Helicopters Inc., Attn: Customer Support Division, 
4555 E. McDowell Rd., Mail Stop M615-GO48, Mesa, Arizona 85215-9734, 
telephone 1-800-388-3378, fax 480-891-6782, or on the web at 
<a href="http://www.mdhelicopters.com">www.mdhelicopters.com</a>. 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.
    (f) This amendment becomes effective on April 29, 2002, to all 
persons except those persons to whom it was made immediately 
effective by Emergency AD 2001-24-51, issued November 28, 2001, 
which contained the requirements of this amendment.

    Issued in Fort Worth, Texas, on April 2, 2002.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 02-8595 Filed 4-11-02; 8:45 am]
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