Airworthiness Directives; MD Helicopters, Inc. Model 369D, 369E, 369F, and 369FF Helicopters

[Federal Register Volume 67, Number 124 (Thursday, June 27, 2002)]
[Rules and Regulations]
[Pages 43227-43229]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-16057]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-SW-40-AD; Amendment 39-12793; AD 2002-13-05]
RIN 2120-AA64


Airworthiness Directives; MD Helicopters, Inc. Model 369D, 369E, 
369F, and 369FF Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) for 
specified MD Helicopters, Inc. (MDHI) helicopters with a tailboom 
modified according to Aerometals Supplemental Type Certificate (STC) 
SH5055NM or SH4801NM. This AD requires an inspection to identify the 
part number (P/N) of the bolts that attach the tail rotor gearbox to 
the tailboom and replacing any bolt of inadequate grip length with an 
airworthy bolt. This AD also requires determining the number of bolt 
threads protruding from each nutplate and adding an additional washer 
if more than four threads protrude. This amendment is prompted by the 
discovery that bolts of inadequate grip length were specified to attach 
the tail rotor gearbox to the tailboom. The actions specified by this 
AD are intended to prevent loss of a tail rotor gearbox due to 
attaching bolts of inadequate grip length and subsequent loss of 
control of the helicopter.

DATES: Effective August 1, 2002.

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.

SUPPLEMENTARY INFORMATION: A proposal to amend 14 CFR part 39 to 
include an AD for the specified MDHI helicopters was published in the 
Federal Register on December 27, 2001 (66 FR 66821). That action 
proposed requiring the following:
    <bullet> Identifying the P/N of the bolts that attach the tail 
rotor gearbox to the tailboom;
    <bullet> Replacing any bolt that is not a NAS1304-26 part-numbered 
bolt with a NAS1304-26 bolt;
    <bullet> Replacing any bolt of inadequate grip length; and
    <bullet> Determining the number of bolt threads protruding from 
each nutplate

[[Page 43228]]

and adding an additional washer if more than four threads protrude.
    Aerometals issued Service Bulletin SB-001, dated August 3, 2000 
(SB), which describes procedures for verifying that the proper 
attaching bolts are used to install the tail rotor gearbox to the 
tailboom.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comment received.
    The one commenter states that the applicability of the AD should be 
limited to certain part-numbered tailbooms with serial number (S/N) 
5001-5032 specified in the FAA-approved Aerometals SB. The FAA 
disagrees because the specified tailbooms, S/N 5001-5032, installed 
with the affected bolts, may not have remained on the same helicopters. 
Any of the helicopters listed in the proposed AD may have had bolts 
with inadequate grip length installed per Aerometals STC SH5055NM or 
SH4801NM and must be inspected and, if required, modified.
    After careful review of the available data, including the comment 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule as proposed. However, we have 
added introductory language for Figure 1 and placed Figure 1 directly 
after the AD paragraph in which it is referenced. We have determined 
that these changes will neither increase the economic burden on any 
operator nor increase the scope of the AD.
    The FAA estimates that this AD will:
    <bullet> Affect 500 helicopters of U.S. registry;
    <bullet> Require \1/2\ work hour per helicopter to determine 
whether a helicopter has been modified by either STC; and
    <bullet> Require 1 work hour to inspect and replace the bolts for 
each of approximately 40 helicopters modified by the STC's.

    The average labor rate is $60 per work hour. Required parts will 
cost approximately $40 per helicopter. Based on these figures, we 
estimate the total cost impact of the AD on U.S. operators to be 
$19,000.
    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.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) will not have a 
significant economic impact, positive or negative, on a substantial 
number of small entities under the criteria of the Regulatory 
Flexibility Act. A final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it may be obtained 
from the FAA, Office of the Regional Counsel, Southwest Region, 2601 
Meacham Blvd., Room 663, Fort Worth, Texas.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, 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:

2002-13-05  MD Helicopters, Inc.: Amendment 39-12793. Docket No. 
2001-SW-40-AD.

    Applicability: Model 369D, 369E, 369F, and 369FF helicopters, 
modified in accordance with Aerometals Supplemental Type Certificate 
(STC) SH5055NM or SH4801NM, 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.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent loss of the tail rotor gearbox due to attaching bolts 
of inadequate grip length and subsequent loss of helicopter control, 
accomplish the following:
    (a) Within 25 hours time-in-service (TIS), conduct the following 
inspections:
    (1) For each tail rotor gearbox attaching bolt (bolt):
    (i) Determine the part number (P/N).
    (ii) If the P/N cannot be determined or if the bolt is not P/N 
NAS1304-26, before further flight, replace the bolt with bolt, P/N 
NAS1304-26.
    (iii) Torque the bolt to 100-110 in-lbs and apply a slippage 
mark.
    (2) Remove the tailboom control rod and determine the number of 
bolt threads protruding from each nutplate on the internal surface 
of the aft tailboom frame casting, P/N 369D23503, as shown in Figure 
1 of this AD. At least one thread must protrude. If more than four 
threads protrude, add an additional washer, P/N AN960D416, under the 
bolt head. Torque the bolt to 100-110 in-lbs, and reapply a slippage 
mark. See Figure 1:

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[[Page 43229]]

[GRAPHIC] [TIFF OMITTED] TR27JN02.002

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    (b) Between 2 and 10 hours TIS after accomplishing the 
requirements of paragraph (a) of this AD, inspect the torque on each 
bolt by applying 100 in-lbs. If any bolt movement occurs, retorque 
the bolt to 100-110 in-lbs and reapply a slippage mark. Reinspect 
the torque between 2 and 10 hours TIS thereafter until no bolt 
movement occurs.

    Note 2: Aerometals Service Bulletin SB-001, dated August 3, 
2000, pertains to the subject of this AD.
    (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 will not be issued.
    (e) This amendment becomes effective on August 1, 2002.

    Issued in Fort Worth, Texas, on June 18, 2002.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 02-16057 Filed 6-26-02; 8:45 am]
BILLING CODE 4910-13-P

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