[Federal Register Volume 69, Number 107 (Thursday, June 3, 2004)]
[Rules and Regulations]
[Pages 31287-31291]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-12442]



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  Federal Register / Vol. 69, No. 107 / Thursday, June 3, 2004 / Rules 
and Regulations  

[[Page 31287]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2004-SW-09-AD; Amendment 39-13651; AD 2004-06-51]
RIN 2120-AA64


Airworthiness Directives; Boeing Defense and Space Group Model 
234 Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

-----------------------------------------------------------------------

SUMMARY: This document publishes in the Federal Register an amendment 
adopting Airworthiness Directive (AD) 2004-06-51, which was sent 
previously to all known U.S. owners and operators of Boeing Defense and 
Space Group (Boeing) Model 234 helicopters by individual letters. This 
AD requires, before further flight, inspecting the upper shaft 
extension for a crack and modifying the aft vertical shaft assembly 
(assembly). Thereafter, this AD requires, before the first flight of 
each day, inspecting the upper shaft extension for any crack. If any 
crack is found during any of the inspections, replacing the assembly 
with an airworthy assembly is required before further flight. This 
amendment is prompted by the discovery of a crack in the upper shaft 
extension of an assembly. The actions specified by this AD are intended 
to detect a crack in the upper shaft extension, which could result in 
catastrophic failure of the assembly and subsequent loss of control of 
the helicopter.

DATES: Effective June 18, 2004, to all persons except those persons to 
whom it was made immediately effective by Emergency AD 2004-06-51, 
issued on March 18, 2004, which contained the requirements of this 
amendment.
    Comments for inclusion in the Rules Docket must be received on or 
before August 2, 2004.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Regional Counsel, Southwest Region, 
Attention: Rules Docket No. 2004-SW-09-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].

FOR FURTHER INFORMATION CONTACT: George Duckett, Aviation Safety 
Engineer, FAA, New York Aircraft Certification Office, Airframe and 
Propulsion Branch, 1600 Stewart Ave., suite 410, Westbury, New York 
11590, telephone (516) 228-7325, fax (516) 794-5531.

SUPPLEMENTARY INFORMATION: On March 18, 2004, the FAA issued Emergency 
AD 2004-06-51 for the specified model helicopters, which requires, 
before further flight, inspecting the upper shaft extension for a crack 
and modifying the assembly. Thereafter, the AD requires, before the 
first flight of each day, inspecting the upper shaft extension for any 
crack. If any crack is found during any of the inspections, replacing 
the assembly with an airworthy assembly is required before further 
flight. That action was prompted by the discovery of a crack in the 
upper shaft extension of an assembly. The discovery was made by an 
operator who was in the process of troubleshooting a lateral vibration 
and noticed a slight wobble in the assembly when the rotors were turned 
by hand. The manufacturer subsequently determined that the crack 
initiated at an arc burn that occurred during the silver-plating 
process of the part. The actions specified by the AD are intended to 
detect a crack in the upper shaft extension, which could result in 
catastrophic failure of the assembly and subsequent loss of control of 
the helicopter.
    The FAA has reviewed Boeing BV234 Service Bulletin No. 234-63-1055, 
Revision 2, dated March 16, 2004, which describes procedures for 
inspecting the inside diameter surfaces of the 114D3248 upper shaft 
extension of the 234D3300 aft vertical shaft assembly for cracks. The 
service bulletin also describes procedures for fabricating and 
installing an aluminum inspection plug. Further, the service bulletin 
provides for recurring inspections.
    Since the unsafe condition described is likely to exist or develop 
on other Boeing Model 234 helicopters of the same type design, the FAA 
issued Emergency AD 2004-06-51. The AD requires, before further flight, 
inspecting the upper shaft extension for a crack and, if no crack is 
found, modifying the assembly. Thereafter, before the first flight of 
each day, inspecting the upper shaft extension for any crack is 
required. If any crack is found during any of the inspections, 
replacing the assembly with an airworthy assembly is required before 
further flight. The requirements of the AD are interim actions that are 
necessary until an arc-burn free replacement assembly is installed. 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 actions 
previously described are required before further flight and before the 
first flight of each day, 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 March 18, 2004 to all known U.S. owners and operators of 
Boeing Model 234 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 this AD will affect 7 helicopters of U.S. 
registry. The required actions will take approximately 17\1/2\ work 
hours per helicopter to accomplish (4\1/2\ work hours for the initial 
inspection and modification, 1 work hour for each recurring inspection, 
and 12 work hours to replace an assembly, if necessary), at an average 
labor rate of $65 per work hour. Required parts will cost approximately 
$250,000 per assembly. Based on these figures, we estimate the total 
cost impact of the AD on U.S. operators to be $1,871,257.50 (assuming 
$2,047.50 for each initial inspection and modification, $113,750 for 
250 recurring

[[Page 31288]]

inspections on each helicopter, $1,755,460 to replace one assembly on 
each helicopter, and negligible parts costs associated with the 
modifications and inspections).

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. 2004-SW-09-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, 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 adding a new airworthiness directive to 
read as follows:

2004-06-51 Boeing Defense and Space Group: Amendment 39-13651. 
Docket No. 2004-SW-09-AD.

    Applicability: Model 234 helicopters, with aft vertical shaft 
assembly, part number (P/N) 234D3300, serial number-181 or lower 
with a prefix of A, installed, certificated in any category.
    Compliance: Required as indicated.
    To detect a crack in the upper shaft extension, which could 
result in catastrophic failure of the aft vertical shaft assembly 
and subsequent loss of control of the helicopter, accomplish the 
following:

    Note 1: Prepare the helicopter for safe ground maintenance and 
disconnect the battery.

    (a) Before further flight, unless accomplished previously, 
perform the following initial inspection and modification:
    (1) Remove the screws, P/N MS51957-63 or MS51958-63, and 
washers, P/N AN960-D10L, from the oil tank assembly. Remove the 
retainer, P/N 114R2059-1, cover, P/N 14R2054-1, and packing, P/N 
M83248/1-264, from the oil tank assembly.
    (2) Cut the sealant around the upper shaft extension plug, P/N 
114D1246-1. Remove the (adhesive) sealant from the plug and the 
inside diameter of the upper shaft extension, P/N 114D3248, before 
removing the plug.
    (3) Tap one side of the rubber plug, P/N 114D1246-1, with a 
hammer and drift to raise and offset the opposite edge of the plug. 
Pull the plug from the upper shaft extension.
    (4) Remove any loose sealant that remains on the inside diameter 
of the aft vertical shaft assembly using care not to drop debris 
into the shaft.
    (5) Inspect the upper shaft extension, P/N 114D3248, using a 
borescope or other lighted device that provides direct visual 
observation of the interior of the aft rotor shaft. Inspect 360 
degrees around the entire interior length of the upper shaft 
extension. If any crack is found, replace the aft vertical shaft 
assembly, P/N 234D3300, with an airworthy assembly before further 
flight. See the following Figure 1 of this AD for the area to 
inspect:
BILLING CODE 4910-13-P

[[Page 31289]]

[GRAPHIC] [TIFF OMITTED] TR03JN04.025

    (6) If no crack is found, using a light source, visually inspect 
the aft vertical shaft assembly for debris or foreign object damage 
(FOD) inside the diameter of the assembly.
    (7) Manufacture an aluminum-threaded plug to replace the rubber 
plug, P/N 114D1246-1. The replacement plug is to be installed in the 
internal threads on the top of the upper shaft extension. Machine 
the plug from a block of 7050-T7451, 7075-T6 or 6061-T6, with 
4.000'' -16 UNS-3A threads and a minor thread diameter of 3.920''. 
Machine a hex head to the center of the cap to aid in removal. 
Machine the hex head to fit a 1\1/4\'' wrench. See the following 
Figure 2 of this AD:

[[Page 31290]]

[GRAPHIC] [TIFF OMITTED] TR03JN04.026

BILLING CODE 4910-13-C

    Note 2: All dimensions stated in this AD are in inches.

    (8) Install the aluminum-threaded plug with an o-ring, P/N 
M83248-1-153, in the internal threads on the top of the upper shaft 
extension (hand tighten only). Assure the safety wire for the rotor 
hub nut is clear of the plug.
    (9) Install packing, P/N M83248/1-264, into the o-ring groove of 
the oil tank assembly. Install the cover, P/N 114R2054-2, retainer, 
P/N 114R2059-1, washer, P/N AN960D10L, and screws, P/N MS51957-63 or 
MS51958-63, into the oil tank assembly that is installed on the aft 
rotary wing head assembly. Torque screws to 23 pounds-inches dry.
    (b) Before the first flight of each day, perform the following 
recurring inspection:
    (1) Remove the screws, P/N MS51957-63 or MS51958-63, and 
washers, P/N AN960D10L, from the oil tank assembly. Remove the 
retainer, P/N 114R2059-1, cover, P/N 114R2054-1, and packing, P/N 
M83248/1-264, from the oil tank assembly.
    (2) Remove the aluminum-threaded plug from the internal threads 
on the top of the upper shaft extension.
    (3) Inspect the upper shaft extension, P/N 114D3248, using a 
borescope or other lighted device that provides direct visual 
observation of the interior of the aft rotor shaft. Inspect 360 
degrees around the entire interior length of the upper shaft 
extension (see Figure 1 of this AD). If any crack is found, replace 
the aft vertical shaft assembly, P/N 234D3300,

[[Page 31291]]

with an airworthy assembly before further flight.
    (4) If no crack is found, install the aluminum-threaded plug 
with an o-ring, P/N M83248-1-153, in the internal threads on the top 
of the upper shaft extension (hand tighten only). Assure the safety 
wire for the rotor hub nut is clear of the plug.
    (5) Install packing, P/N M83248/1-264, into the o-ring groove of 
the oil tank assembly. Install the cover, P/N 114R2054-2, retainer, 
P/N 114R2059-1, washer, P/N AN960D10L, and screws, P/N MS51957-63 or 
MS51958-63, into the oil tank assembly that is installed on the aft 
rotary wing head assembly. Torque screws to 23 pounds-inches dry.

    Note 3: Boeing BV234 Service Bulletin No. 234-63-1055, Revision 
2, dated March 16, 2004, pertains to the subject of this AD.

    (c) 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 Manager, New York Aircraft Certification Office (NYACO), 
Engine and Propeller Directorate, FAA, for information about 
previously approved alternative methods of compliance.
    (d) Special flight permits will not be issued.
    (e) This amendment becomes effective on June 18, 2004, to all 
persons except those persons to whom it was made immediately 
effective by Emergency AD 2004-06-51, issued March 18, 2004, which 
contained the requirements of this amendment.

    Issued in Fort Worth, Texas, on May 21, 2004.
David A. Downey,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 04-12442 Filed 6-2-04; 8:45 am]
BILLING CODE 4910-13-P