[Federal Register Volume 59, Number 172 (Wednesday, September 7, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-21906]


[[Page Unknown]]

[Federal Register: September 7, 1994]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 93-SW-03-AD; Amendment 39-9021; AD 94-18-08]

 

Airworthiness Directives; McDonnell Douglas Helicopter Company 
and Hughes Helicopters, Inc. Model 369, 369A (OH-6A), 369D, E, F, FF, 
H, HE, HS, and HM Series Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment supersedes an existing airworthiness directive 
(AD), applicable to McDonnell Douglas Helicopter Company and Hughes 
Helicopters, Inc. Model 369, 369A (OH-6A), 369D, E, F, FF, H, HE, HS, 
and HM series helicopters, that requires daily preflight checks and 100 
hours time-in-service (TIS) inspections for tail rotor blade abrasion 
strip (abrasion strip) debonding until abrasion strip rivets (rivets) 
are installed. This amendment also supersedes a Priority Letter AD that 
currently requires installation of rivets, corrects tail rotor blade 
part numbers listed in the previous AD, and retains the daily preflight 
checks of the previous AD until rivets are installed to secure the 
abrasion strip. This AD provides a terminating action for the abrasion 
strip debonding and also seeks to clear up any confusion among 
operators caused by having a published AD and a Priority Letter that 
are applicable to the same helicopter part. This AD replaces both of 
those documents. This amendment is prompted by an accident resulting 
from the separation of an abrasion strip from a tail rotor blade and 
subsequent tail rotor separation. The actions specified by this AD are 
intended to prevent loss of the abrasion strip, separation of the tail 
rotor, and subsequent loss of control of the helicopter.

DATES: Effective September 27, 1994.
    The incorporation by reference of certain publications listed in 
the regulations was previously approved by the Director of the Federal 
Register as of March 10, 1992 at 57 FR 5379 (February 14, 1992).
    Comments for inclusion in the Rules Docket must be received by 
November 7, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Assistant Chief Counsel, Attention: 
Rules Docket No. 93-SW-03-AD, 2601 Meacham Boulevard, Room 663, Fort 
Worth, Texas 76137.
    The service information referenced in this AD may be obtained from 
McDonnell Douglas Helicopter Company, Technical Publications, Bldg. 
530/B111, 5000 E. McDowell Road, Mesa, Arizona 85205-9797. This 
information may be examined at the FAA, Office of the Assistant Chief 
Counsel, Rules Docket No. 93-SW-03-AD, 2601 Meacham Boulevard, Room 
663, Fort Worth, Texas; or at the Office of the Federal Register, 800 
North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Mr. Brent Bandley, Aerospace Engineer, 
Airframe Branch, ANM-123L, FAA, Northwest Mountain Region, Los Angeles 
Aircraft Certification Office, 3229 E. Spring Street, Long Beach, 
California 90806-2425, telephone (310) 988-5237, fax (310) 988-5210.

SUPPLEMENTARY INFORMATION: On December 31, 1991, the FAA issued AD 92-
02-15, Amendment 39-8151 (57 FR 5379, February 14, 1992), to require 
daily preflight checks and 100 hours TIS repetitive inspections for 
abrasion strip debonding until rivets are installed. That AD requires 
installation of the rivets within 300 hours TIS.
    As a result of a more recent helicopter accident involving the 
separation of an abrasion strip, on October 16, 1992, the FAA issued 
Priority Letter (PL) AD 92-22-14 that superseded the existing AD 92-02-
15. The PL AD corrects certain tail rotor blade part numbers as listed 
in AD 92-02-15 and retains the daily preflight checks of the previous 
AD 92-02-15 until rivets are installed. The PL AD further requires 
installation of the rivets within 25 hours TIS or within 7 days, 
whichever comes first.
    Both AD 92-02-15, issued December 31, 1991 and the PL AD 92-22-14, 
issued October 16, 1992, require a visual check for evidence of 
debonding before the first flight of each day. However, AD 92-02-15 
requires installation of rivets within 300 hours TIS while PL AD 92-22-
14 requires installation of the rivets within 25 hours TIS or on or 
before 7 days after the effective date of that AD. Both of these ADs 
require the same corrective action but have different compliance times. 
Additionally, the PL AD did not specify whether the 7-day compliance 
time was in terms of ``work'' days or ``calendar'' days. As a result of 
having two ADs that require the same corrective action with only 
differing compliance times, and additionally failing to specifically 
describe the type of compliance day as that term was used in the PL AD, 
operators may be confused about when compliance is required. Such 
confusion may lead an operator to inadvertently fail to comply with the 
necessary safety requirements for these rotorcraft and result in an 
unsafe condition. Therefore, due to the criticality of the abrasion 
strip, the short compliance times, and the possible confusion as a 
result of having two effective ADs that require the same corrective 
action with one containing a potentially confusing compliance time, 
this rule must be issued immediately to correct an unsafe condition.
    In addition to correcting the unsafe conditions described, this AD 
also provides that installation of the rivets to secure the abrasion 
strip constitutes terminating action for the requirements of this AD.
    The checks required by this AD before the first flight of each day 
may be performed by an owner/operator (pilot) but must be entered into 
the aircraft records showing compliance with this AD in accordance with 
sections 43.11 and 91.417 (a)(2)(v) of the Federal Aviation 
Regulations. This AD allows a pilot to perform this check because it 
involves only a visual check for debonding of the abrasion strip from 
the tail rotor blade and is required only until rivets are installed. 
This check can be performed equally well by a pilot or a mechanic. It 
involves checking items similar to those items that a pilot checks 
during a preflight. Safety does not require that this check be 
performed by a mechanic before the first flight of each day. The AD 
does require that a mechanic inspect the tail rotor blades within 25 
hours TIS or within 7 calendar days, whichever occurs first.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other helicopters of the same type design, this AD 
supersedes the PL, AD 92-22-14, and AD 92-02-15 to require more prompt 
installation of rivets, to specify that the 7 days compliance time 
refers to calendar days, and to correct tail rotor blade part numbers 
as listed in AD 92-02-15. The daily preflight checks required by 
paragraph (a) of AD 92-02-15 are retained until rivets are installed. 
The actions are required to be accomplished in accordance with Part II 
of McDonnell Douglas Helicopter Company Service Information Notice HN-
232, DN-179, EN-70 and FN-57, dated September 27, 1991.
    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.

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, both before and after the closing date for comments, 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 comments 
submitted in response to this rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 93-SW-03-AD.'' The postcard will be date stamped and 
returned to the commenter.
    The regulations adopted herein will 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 final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    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, 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

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13   [Amended]

    2. Section 39.13 is amended by removing Amendment 39-8151 (57 FR 
5379, February 14, 1992), and by adding a new airworthiness directive 
(AD), Amendment 39-9021, to read as follows:

AD 94-18-08 McDonnell Douglas Helicopter Company (MDHC) and Hughes 
Helicopters, Inc.: Amendment 39-9021. Docket Number 93-SW-03-AD. 
Supersedes Priority Letter AD 92-22-14, issued October 16, 1992, and 
AD 92-02-15, Amendment 39-8151.

    Applicability: Model 369, 369A (OH-6A), 369D, E, F, FF, H, HE, 
HS, and HM series helicopters, equipped with the following tail 
rotor blades with bonded tail rotor abrasion strips (abrasion 
strips) installed, but without abrasion strip rivets (rivets) 
installed as described in paragraph (c) of this AD: part numbers (P/
N) 421-088; 369A1613-7, -503, -505; 369D21606; 369D21613-11, -31, -
41, -51; 369D21615, -21; or 369A1613-3M; and any of these P/N with a 
suffix (such as the letters ``M'' or ``M-STC'') added to the dash 
numbers, certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent the loss of abrasion strips, separation of the tail 
rotor, and subsequent loss of control of the helicopter, accomplish 
the following:
    (a) Before the first flight of each day, until two rivets are 
installed as required by paragraph (c) of this AD, visually check 
each abrasion strip for any evidence of debonding along the entire 
abrasion strip bond line. This visual check may be performed by the 
owner/operator holding at least a private pilot certificate and must 
be entered into the aircraft records showing compliance with this AD 
in accordance with sections 43.11 and 91.417 (a)(2)(v) of the 
Federal Aviation Regulations.
    (b) If performance of the visual check required by paragraph (a) 
results in evidence of debonding, conduct the following inspections 
before further flight:
    (1) Remove the tail rotor blade from the helicopter, and perform 
a dye-penetrant and a tap-test inspection in accordance with the 
applicable helicopter maintenance manual to ensure that the abrasion 
strip is secure.

    Note: MDHC Service Information Notice HN-197.2, DN-130.2, EN-
19.2, and FN-17.1, dated March 23, 1987, contains additional 
information on the inspections required by paragraph (b).

    (2) If debonding is confirmed, remove the tail rotor blade from 
service and replace it with an airworthy blade, which has been 
modified by the installation of rivets.
    (c) Within 25 hours time-in-service or on or before 7 calendar 
days after the effective date of this AD, whichever comes first:
    (1) Inspect the tail rotor blades in accordance with paragraph 
(b)(1) of this AD, and if no evidence of debonding exists, install 
rivets in accordance with Part II of MDHC Service Information Notice 
(SIN) HN-232, DN-179, EN-70 and FN-57, dated September 27, 1991.
    (2) If evidence of debonding exists, remove the blade from 
service and replace it with an airworthy blade, which has been 
modified by the installation of rivets, prior to further flight.
    (d) Installation of the abrasion strip rivets in accordance with 
MDHC SIN HN-232, DN-179, EN-70, and FN-57, dated September 27, 1991, 
constitutes a terminating action for the requirements of this AD.
    (e) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used when approved by the Manager, Los Angeles Aircraft 
Certification Office, FAA, Northwest Mountain Region, 3229 E. Spring 
Street, Long Beach, California 90806-2425. Operators shall submit 
their requests through an FAA Principal Maintenance Inspector, who 
may concur or comment and then send it to the Manager, Los Angeles 
Aircraft Certification Office.

    Note: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Manager, Los Angeles Aircraft Certification 
Office.

    (f) 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 there is 
no evidence of debonding of the abrasion strip at any point along 
the entire abrasion strip bond line of the tail rotor blades.
    (g) The inspection, removal, modification, and replacement, if 
necessary, shall be done in accordance with McDonnell Douglas 
Helicopter Corporation (MDHC) SIN HN-232, DN-179, EN-70, and FN-57, 
dated September 27, 1991. This incorporation by reference was 
previously approved by the Director of the Federal Register as of 
March 10, 1992 (57 FR 5379, February 14, 1992) in accordance with 5 
U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from MDHC 
Technical Publications, Bldg. 530/B111, 5000 E. McDowell Road, Mesa, 
Arizona 85205-9797. Copies may be inspected at the FAA, Office of 
the Assistant Chief Counsel, 2601 Meacham Boulevard, Room 663, Fort 
Worth, Texas; or at the Office of the Federal Register, 800 North 
Capitol Street, NW., suite 700, Washington, DC.
    (h) This amendment becomes effective on September 27, 1994.
    Issued in Fort Worth, Texas, on August 30, 1994.

James D. Erickson,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 94-21906 Filed 9-6-94; 8:45 am]
BILLING CODE 4910-13-P