[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