Airworthiness Directives; Enstrom Helicopter Corporation Model F-28A, F-28C, F-28F, TH-28, 280, 280C, 280F, 280FX, 480, and 480B Helicopters

[Federal Register Volume 72, Number 166 (Tuesday, August 28, 2007)]
[Rules and Regulations]
[Pages 49177-49180]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-16770]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2006-26771; Directorate Identifier 2005-SW-07-AD; 
Amendment 39-15059; AD 2007-11-02]
RIN 2120-AA64


Airworthiness Directives; Enstrom Helicopter Corporation Model F-
28A, F-28C, F-28F, TH-28, 280, 280C, 280F, 280FX, 480, and 480B 
Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) for 
Enstrom Helicopter Corporation (Enstrom) Model F-28A, F-28C, F-28F, TH-
28, 280, 280C, 280F, 280FX, 480, and 480B helicopters that requires 
determining the installation dates for each main rotor push-pull 
control rod (push-pull rod), inspecting the push-pull rods for 
corrosion, replacing any push-pull rod which has corrosion that is 
severe enough to cause pitting, or has visible moisture inside the rod, 
and repairing each push-pull rod that has corrosion but no pitting. 
This amendment is prompted by one reported incident in which the 
helicopter pilot encountered severe in-flight vibration due to the 
failure of a push-pull rod, requiring an emergency landing. The actions 
specified by this AD are intended to detect corrosion and prevent 
failure of a push-pull rod, and subsequent loss of control of the 
helicopter.

DATES: Effective October 2, 2007.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of October 2, 2007.

ADDRESSES: You may get the service information identified in this AD 
from The Enstrom Helicopter Corporation, Twin County Airport, P.O. Box 
490, Menominee, Michigan 49858.

[[Page 49178]]

Examining the Docket

    You may examine the docket that contains this AD, any comments, and 
other information on the Internet at http://dms.dot.gov or at the 
Docket Operations office, West Building Ground Floor, Room W12-140, 
1200 New Jersey Avenue, SE., Washington, DC.

FOR FURTHER INFORMATION CONTACT: Shawn Malekpour, Aviation Safety 
Engineer, FAA, Chicago Aircraft Certification Office, 2300 East Devon 
Ave., Des Plaines, Illinois 60018, telephone (847) 294-7837, fax (847) 
294-7834.

SUPPLEMENTARY INFORMATION: A proposal to amend 14 CFR part 39 to 
include an AD for the specified model helicopters was published in the 
Federal Register on January 8, 2007 (72 FR 669). That action proposed 
to require reviewing the helicopter maintenance records and determining 
the installation dates for the push-pull rods. If the dates cannot be 
determined from the maintenance records, using the ``Date MFD'', which 
is located on the helicopter data plate, was proposed to be used as the 
installation date for the push-pull rods. That action also proposed to 
require a visual inspection for corrosion on the exterior and interior 
of the three push-pull rods, part number (P/N) 28-16253-all dash 
numbers (for Model F-28A, F-28C, F-28F, 280, 280C, 280F, and 280FX 
helicopters) or P/N 4140532-all dash numbers (for Model TH-28, 480, and 
480B helicopters), using the compliance times stated in the following 
table. Replacing any push-pull rod that has corrosion that is severe 
enough to cause pitting or has moisture inside the rod, and repairing 
any push-pull rod that has corrosion but no pitting, was proposed to be 
required before further flight. Repairing a push-pull rod consists of 
cleaning the push-pull rod, applying a protective coating, and sealing 
the push-pull rod before remarking and reinstalling it on a helicopter.

------------------------------------------------------------------------
                                  Push-pull rod
      Helicopter models           service life        Compliance times
------------------------------------------------------------------------
Model F-28A, F-28C, F-28F,    Push-pull rod that    Inspect within 10
 280, 280C, 280F, and 280FX    has been installed    hours time-in-
 helicopters.                  for 20 or more        service (TIS) or at
                               years.                next annual
                                                     inspection,
                                                     whichever occurs
                                                     first.
Model F-28A, F-28C, F-28F,    Push-pull rod that    Inspect within 50
 280, 280C, 280F, and 280FX    has been installed    hours TIS or at the
 helicopters.                  for 10 or more        next annual
                               years, but less       inspection,
                               than 20 years.        whichever occurs
                                                     first.
Model F-28A, F-28C, F-28F,    Push-pull rod that    Inspect before the
 280, 280C, 280F, and 280FX    has been installed    service life of the
 helicopters.                  for less than 10      push-pull rod
                               years.                reaches 10 years
                                                     since initial
                                                     installation.
Model TH-28, 480, and 480B    Push-pull rod that    Inspect within 50
 helicopters.                  has been installed    hours TIS or at the
                               for 10 or more        next annual
                               years.                inspection,
                                                     whichever occurs
                                                     first.
Model TH-28, 480, and 480B    Push-pull rod that    Inspect before the
 helicopters.                  has been installed    service life of the
                               for less than 10      push-pull rod
                               years.                reaches 10 years
                                                     since initial
                                                     installation.
------------------------------------------------------------------------

    We have reviewed the following service information:
    <bullet> Enstrom Helicopter Corporation Service Directive Bulletin 
No. 0096, dated September 10, 2003, which describes visually inspecting 
the push-pull rods for corrosion and internal moisture, provides for 
repairing light corrosion, and is applicable to Model F-28A, F-28C, F-
28F, 280, 280C, 280F, and 280FX helicopters.
    <bullet> Enstrom Helicopter Corporation Service Directive Bulletin 
No. T-019, dated September 10, 2003, which describes visually 
inspecting the push-pull rods for corrosion and internal moisture, 
provides for repairing light corrosion, and is applicable to Model TH-
28, 480, and 480B helicopters.
    <bullet> Enstrom Helicopter Corporation Service Information Letter 
(SIL) No. T-019, dated December 9, 2003, applicable to Model TH-28, 
480, and 480B helicopters, which describes visually inspecting each 
push-pull rod for a crack, nick, scratch, dent, corrosion, damaged 
threads, bending, and contact wear. We are not proposing to require the 
inspections specified in the SIL.
    <bullet> Enstrom Helicopter Corporation Service Information Letter 
No. 0156, dated December 9, 2003, applicable to Model F-28A, F-28C, F-
28F, 280, 280C, 280F, and 280FX helicopters, which describes visually 
inspecting each push-pull rod for a crack, nick, scratch, dent, 
corrosion, damaged threads, bending, and contact wear. We are not 
proposing to require the inspections specified in the SIL.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. No comments were received on the 
proposal or the FAA's determination of the cost to the public. The FAA 
has determined that air safety and the public interest require the 
adoption of the rule as proposed.
    The FAA estimates that this AD will affect 378 helicopters of U.S. 
registry, and the required actions will take the following numbers of 
work hours to accomplish on each helicopter at an average labor rate of 
$80 per work hour:
    <bullet> 8 work hours to remove, disassemble, and inspect the 3 
push-pull rods;
    <bullet> 9 work hours to repair corrosion without pitting, remark 
each push-pull rod, and reassemble each push-pull rod; and
    <bullet> 3 work hours to reinstall 3 push-pull rods on the 
helicopter.

Required parts will cost approximately $900 per helicopter. Based on 
these figures, the total cost impact of the AD on U.S. operators will 
be $945,000 ($2,500 per helicopter), assuming 3 push-pull rods are 
replaced on each helicopter.

Regulatory Findings

    We have determined that this AD will not have federalism 
implications under Executive Order 13132. This AD 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.
    For the reasons discussed above, I certify that the regulation:
    1. Is not a ``significant regulatory action'' under Executive Order 
12866;
    2. Is not a ``significant rule'' under the 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.
    We prepared an economic evaluation of the estimated costs to comply 
with this AD. See the DMS to examine the economic evaluation.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue

[[Page 49179]]

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, 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

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 adding a new airworthiness directive to 
read as follows:

2007-11-02 Enstrom Helicopter Company: Amendment 39-15059. Docket 
No. FAA-2006-26771; Directorate Identifier 2005-SW-07-AD.
    Applicability: Model F-28A, F-28C, and F-28F helicopters, 
excluding serial number (S/N) 816 and subsequent; Model 280, 280C, 
280F, and 280FX helicopters, excluding S/N 2100 and subsequent; and 
Model TH-28, 480, and 480B helicopters, excluding S/N 5058 and 
subsequent, certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To detect corrosion and prevent failure of a main rotor push-
pull control rod (push-pull rod), and subsequent loss of control of 
the helicopter, accomplish the following:
    (a) Within 10 hours time-in-service (TIS) or at the next annual 
inspection, whichever occurs first, review the helicopter 
maintenance records and determine the date that each push-pull rod, 
part number (P/N) 28-16253--all dash numbers (for Model F-28A, F-
28C, F-28F, 280, 280C, 280F, and 280FX helicopters) and P/N 
4140532--all dash numbers (for Model TH-28, 480, and 480B 
helicopters), was installed. If the date cannot be determined from 
the maintenance records, use the ``Date MFD'', which is located on 
the helicopter data plate, as the installation date for the push-
pull rod.
    (b) For Model F-28A, F-28C, F-28F, 280, 280C, 280F, and 280FX 
helicopters, using the compliance times stated in Table 1 of this 
AD, visually inspect the exterior and interior of each of the three 
push-pull rods for corrosion severe enough to cause pitting or any 
moisture, paying special attention to the area of the lower fitting, 
in accordance with section 5.1., INSPECTION, in Enstrom Helicopter 
Corporation Service Directive Bulletin No. 0096, dated September 10, 
2003 (SDB 0096).

                                 Table 1
------------------------------------------------------------------------
                                  Push-pull rod
      Helicopter models           service life        Compliance times
------------------------------------------------------------------------
Model F-28A, F-28C, F-28F,    Push-pull rod that    Inspect within 10
 280, 280C, 280F, and 280FX    has been installed    hours time-in-
 helicopters.                  for 20 or more        service (TIS) or at
                               years.                next annual
                                                     inspection,
                                                     whichever occurs
                                                     first.
Model F-28A, F-28C, F-28F,    Push-pull rod that    Inspect within 50
 280, 280C, 280F, and 280FX    has been installed    hours TIS or at the
 helicopters.                  for 10 or more        next annual
                               years, but less       inspection,
                               than 20 years.        whichever occurs
                                                     first.
Model F-28A, F-28C, F-28F,    Push-pull rod that    Inspect before the
 280, 280C, 280F, and 280FX    has been installed    service life of the
 helicopters.                  for less than 10      push-pull rod
                               years.                reaches 10 years
                                                     since initial
                                                     installation.
------------------------------------------------------------------------

    (1) Before further flight, if corrosion without pitting is found 
on a push-pull rod, then repair, reassemble, remark, and reinstall 
it in accordance with section 5.2., REPAIR/REASSEMBLY, in SDB 0096.
    (2) Before further flight, if corrosion is found that is severe 
enough to cause pitting, or if any moisture is visible on the inside 
of a push-pull rod, replace it with an airworthy push-pull rod.

    Note 1: Determining continued serviceability of the push-pull 
rods by inspecting the exterior only of each push-pull rod is 
described in Enstrom Helicopter Corporation Service Information 
Letter No. 0156, dated December 9, 2003.

    (c) For Model TH-28, 480 and 480B helicopters, using the 
compliance times stated in Table 2 of this AD, visually inspect the 
exterior and interior of each of the three push-pull rods for 
corrosion severe enough to cause pitting or any moisture, paying 
special attention to the area of the lower fitting, in accordance 
with section 5.1., INSPECTION, in Enstrom Helicopter Corporation 
Service Directive Bulletin No. T-019, dated September 10, 2003 (SDB 
T-019).

                                 Table 2
------------------------------------------------------------------------
                                  Push-pull rod
      Helicopter models           service life        Compliance times
------------------------------------------------------------------------
Model TH-28, 480, and 480B    Push-pull rod that    Inspect within 50
 helicopters.                  has been installed    hours TIS or at the
                               for 10 or more        next annual
                               years.                inspection,
                                                     whichever occurs
                                                     first.
Model TH-28, 480, and 480B    Push-pull rod that    Inspect before the
 helicopters.                  has been installed    service life of the
                               for less than 10      push-pull rod
                               years.                reaches 10 years
                                                     since initial
                                                     installation.
------------------------------------------------------------------------

    (1) Before further flight, if corrosion without pitting is found 
on a push-pull rod, then repair, reassemble, remark, and reinstall 
it in accordance with section 5.2., REPAIR/REASSEMBLY, in SDB T-019.
    (2) Before further flight, if corrosion is found that is severe 
enough to cause pitting, or if any moisture is visible on the inside 
of a push-pull rod, replace it with an airworthy push-pull rod.

    Note 2: Determining continued serviceability of the push-pull 
rods by inspecting the exterior only of each push-pull rod is 
described in Enstrom Helicopter

[[Page 49180]]

Corporation Service Information Letter No. T-019, dated December 9, 
2003.

    (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 Chicago Aircraft Certification Office, Small Airplane 
Directorate, FAA, for information about previously approved 
alternative methods of compliance.
    (e) The inspection and replacement, if necessary, shall be done 
in accordance with Enstrom Helicopter Corporation Service Directive 
Bulletin No. 0096, dated September 10, 2003; Enstrom Helicopter 
Corporation Service Directive Bulletin No. T-019, dated September 
10, 2003; Enstrom Helicopter Corporation Service Information Letter 
No. T-019, dated December 9, 2003; or Enstrom Helicopter Corporation 
Service Information Letter No. 0156, dated December 9, 2003, as 
applicable. The Director of the Federal Register approved these 
incorporations by reference in accordance with 5 U.S.C. 552(a) and 1 
CFR part 51. Copies may be obtained from The Enstrom Helicopter 
Corporation, Twin County Airport, P.O. Box 490, Menominee, Michigan 
49858. 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 National Archives and Records Administration (NARA). 
For information on the availability of this material at NARA, call 
202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. 
    (f) This amendment becomes effective on October 2, 2007.

    Issued in Fort Worth, Texas, on July 5, 2007.
David A. Downey,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
 [FR Doc. E7-16770 Filed 8-27-07; 8:45 am]
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