[Federal Register Volume 61, Number 211 (Wednesday, October 30, 1996)]
[Proposed Rules]
[Pages 55937-55939]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-27755]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 96-SW-10-AD]
Airworthiness Directives; Schweizer Aircraft Corporation and
Hughes Helicopters, Inc. Model 269A, 269A-1, 269B, 269C, 269D, and TH-
55A Series Helicopters
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: This document proposes the adoption of a new airworthiness
directive (AD) that is applicable to Schweizer Aircraft Corporation and
Hughes Helicopters, Inc. Model 269A, 269A-1, 269B, 269C, 269D, and TH-
55A series helicopters. This proposal would require a visual inspection
of the bond line between the main rotor blade (blade) abrasion strip
(abrasion strip) and the blade for voids, separation, or lifting of the
abrasion strip; a visual inspection of the adhesive bead around the
perimeter of the abrasion strip for erosion, cracks, or blisters; a tap
(ring) test of the blade abrasion strip for evidence of debonding or
hidden corrosion voids; and removal of any blade with an unairworthy
abrasion strip and replacement with an airworthy blade. This proposal
is prompted by four reports that indicate that debonding and corrosion
have occurred on certain blades where the blade abrasion strip attaches
to the blade skin. The actions specified by the proposed AD are
intended to prevent loss of the abrasion strip from the blade and
subsequent loss of control of the helicopter.
DATES: Comments must be received by December 30, 1996.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Office of the Assistant Chief Counsel, Attention:
Rules Docket No. 96-SW-10-AD, 2601
[[Page 55938]]
Meacham Blvd., Room 663, Fort Worth, Texas 76137. Comments may be
inspected at this location between 9:00 a.m. and 3:00 p.m., Monday
through Friday, except Federal holidays.
FOR FURTHER INFORMATION CONTACT: Mr. Jeff Casale, Aerospace Engineer,
FAA, New York Aircraft Certification Office, Airframe and Propulsion
Branch, Engine and Propeller Directorate, 10 Fifth Street, 3rd Floor,
Valley Stream, New York 11581-1200, telephone (516) 256-7521, fax (516)
568-2716.
SUPPLEMENTARY INFORMATION
Comments Invited
Interested persons are invited to participate in the making of the
proposed 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 above. All
communications received on or before the closing date for comments,
specified above, will be considered before taking action on the
proposed rule. The proposals contained in this notice may be changed in
light of the comments received.
Comments are specifically invited on the overall regulatory,
economic, environmental, and energy aspects of the proposed rule. All
comments submitted will be available, both before and after the closing
date for comments, in the Rules Docket for examination by interested
persons. A report summarizing each FAA-public contact concerned with
the substance of this proposal will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments
submitted in response to this notice must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket No. 96-SW-10-AD.'' The postcard will be date stamped and
returned to the commenter.
Availability of NPRMs
Any person may obtain a copy of this NPRM by submitting a request
to the FAA, Office of the Assistant Chief Counsel, Attention: Rules
Docket No. 96-SW-10-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas
76137.
Discussion
This document proposes to adopt a new airworthiness directive (AD)
that is applicable to certain serial-numbered main rotor blades
installed on Schweizer Aircraft Corporation and Hughes Helicopters,
Inc. Model 269A, 269A-1, 269B, 269C, 269D, and TH-55A series
helicopters. Reports indicate that debonding and corrosion have
occurred on certain main rotor blades where the main rotor blade
abrasion strip attaches to the main rotor blade skin. This condition,
if not corrected, could result in loss of the abrasion strip from the
main rotor blade and subsequent loss of control of the helicopter.
The FAA has reviewed Schweizer Service Bulletin (SB) B-259.1, dated
August 22, 1995, for the Model 269A, 269A-1, 269B, 269C, and TH-55A
series helicopters, and SB DB-001.1, dated August 22, 1995, for the
Model 269D series helicopters, which describe procedures for a visual
inspection of the bond line between the abrasion strip and the main
rotor blade for voids, separation, or lifting of the abrasion strip; a
visual inspection of the adhesive bead around the perimeter of the
abrasion strip for erosion, cracks, or blisters; a tap (ring) test of
the blade abrasion strip for evidence of debonding or hidden corrosion
voids; and removal of any blade with a defective abrasion strip for
return to Schweizer Aircraft Corporation or an FAA-approved repair
facility for repair. If any deterioration of the abrasion strip
adhesive bead is discovered, the service bulletins prescribe
restoration of the bead in accordance with the applicable maintenance
manual. If an abrasion strip void is found or suspected, the blade must
be removed and may be returned to Schweizer Aircraft Corporation or an
FAA-approved repair facility for repair.
Since an unsafe condition has been identified that is likely to
exist or develop on other Schweizer Aircraft Corporation and Hughes
Helicopters, Inc. Model 269A, 269A-1, 269B, 269C, 269D, and TH-55A
series helicopters of the same type design, the proposed AD would
require, on each blade, a visual inspection of the bond line between
the abrasion strip and the main rotor blade for voids, separation, or
lifting of the abrasion strip; a visual inspection of the adhesive bead
around the perimeter of the abrasion strip for erosion, cracks, or
blisters; a tap (ring) test of the blade abrasion strip for evidence of
debonding or hidden corrosion voids; and removal of any blade with a
defective abrasion strip and replacement with an airworthy blade. If
any deterioration of the abrasion strip adhesive bead is discovered,
restoration of the bead in accordance with the applicable maintenance
manual is proposed. If an abrasion strip void is found or suspected,
removing and replacing the blade with an airworthy blade is proposed.
The FAA estimates that 100 helicopters of U.S. registry would be
affected by this proposed AD, that it would take approximately one-
third of a work hour per helicopter to conduct the initial inspections;
approximately one-third of a work hour to conduct the repetitive
inspections; approximately 11 work hours to remove and reinstall a
blade; and approximately 32 work hours to repair the blade; and that
the average labor rate is $60 per work hour. Required parts
(replacement abrasion strips) would cost approximately $57 per main
rotor blade abrasion strip (each helicopter has three main rotor
blades). Based on these figures, the total cost impact of the proposed
AD on U.S. operators is estimated to be $135,850 per year for the first
year and $133,850 for each year thereafter, assuming one-sixth of the
affected blades in the fleet are removed, repaired, and reinstalled
each year, and that all affected helicopters are subjected to one
repetitive inspection each year.
The regulations proposed herein would not have substantial direct
effects 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, in
accordance with Executive Order 12612, it is determined that this
proposal would not have sufficient federalism implications to warrant
the preparation of a Federalism Assessment.
For the reasons discussed above, I certify that this proposed
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) if promulgated, 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 copy of the draft
regulatory evaluation prepared for this action is contained in the
Rules Docket. A copy of it may be obtained by contacting 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.
The Proposed Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration proposes to amend
part
[[Page 55939]]
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 USC 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding a new airworthiness directive
to read as follows:
Schweizer Aircraft Corporation and Hughes Helicopters, Inc.: Docket
No. 96-SW-10-AD.
Applicability: Model 269A, 269A-1, 269B, and TH-55A series
helicopters with main rotor blades, part number (P/N) 269A1190-1,
serial numbers (S/N) S0001 through S0012 installed; and Model 269C
and Model 269D series helicopters with main rotor blades, P/N
269A1185-1, S/N S222, S312, S313, S325 through S327, S339, S341,
S343, S346, S347, S349 through S367, S369 through S377, S379 through
S391, S393 through S395, S397, S399, S401 through S417, S419 through
S424, S426 through S449, S451 through S507, S509 through S513, S516
through S527, S529 through S540, S542, S544 through S560, S562
through S584, S586 through S595, S597 though S611, S620 through
S623, S625, S628, S633, S641 through S644, S646, S653, S658, S664,
S665, and S667, installed, certificated in any category.
Note 1: This AD applies to each helicopter identified in the
preceding applicability provision, regardless of whether it has been
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 use the authority
provided in paragraph (d) to request approval from the FAA. This
approval may address either no action, if the current configuration
eliminates the unsafe condition, or different actions necessary to
address the unsafe condition described in this AD. Such a request
should include an assessment of the effect of the changed
configuration on the unsafe condition addressed by this AD. In no
case does the presence of any modification, alteration, or repair
remove any helicopter from the applicability of this AD.
Compliance: Required as indicated, unless accomplished
previously.
To prevent loss of the abrasion strip from the main rotor blade
and subsequent loss of control of the helicopter, accomplish the
following:
(a) Within the next 50 hours time-in-service (TIS), or within 90
calendar days after the effective date of this AD, whichever is
earlier, or prior to installing an affected replacement main rotor
blade, and thereafter at intervals not to exceed 50 hours TIS from
the date of the last inspection or replacement installation:
(1) Visually inspect the adhesive bead around the perimeter of
each main rotor blade abrasion strip for erosion, cracks, or
blisters.
(2) Visually inspect the bond line between each abrasion strip
and each main rotor blade skin for voids, separation, or lifting of
the abrasion strip.
(3) Inspect each main rotor blade abrasion strip for debonding
or hidden corrosion voids using a tap (ring) test as described in
the applicable maintenance manual.
(b) If any deterioration of an abrasion strip adhesive bead is
discovered, prior to further flight, restore the bead in accordance
with the applicable maintenance manual.
(c) If abrasion strip debonding, separation, or a hidden
corrosion void is found or suspected, prior to further flight,
remove the blade with the defective abrasion strip and replace it
with an airworthy blade.
(d) 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, New York Aircraft Certification
Office, FAA. Operators shall submit their requests through an FAA
Principal Maintenance Inspector, who may concur or comment and then
send it to the Manager, New York Aircraft Certification Office.
Note 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the New York Aircraft Certification Office.
(e) Special flight permits may be issued in accordance with
sections 21.197 and 21.199 of the Federal Aviation Regulations (14
CFR 21.197 and 21.199) to operate the helicopter to a location where
the requirements of this AD can be accomplished, provided the
abrasion strip has not started to separate or debond from the main
rotor blade.
Issued in Fort Worth, Texas, on October 22, 1996.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 96-27755 Filed 10-29-96; 8:45 am]
BILLING CODE 4910-13-P