[Federal Register Volume 61, Number 94 (Tuesday, May 14, 1996)]
[Rules and Regulations]
[Pages 24220-24222]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-11959]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 96-SW-02-AD; Amendment 39-9615; AD 96-10-09]
RIN 2120-AA64
Airworthiness Directives; McDonnell Douglas Helicopter Systems
Model 369, 369A, 369D, 369E, 369F, 369FF, 369H, 369HE, 369HM, 369HS,
and 500N Helicopters
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
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SUMMARY: This amendment adopts a new airworthiness directive (AD) that
is applicable to McDonnell Douglas Helicopter Systems (MDHS) Model 369,
369A, 369D, 369E, 369F, 369FF, 369H, 369HE, 369HM, 369HS, and 500N
helicopters. This action requires initial and repetitive inspections of
each main rotor blade (blade) root for either cracks or paint and
sealant cracking or separation between the lower surface root end
fitting and the doubler. This amendment is prompted by one accident in
which a blade separated from the helicopter, as well as eight other
reports of cracked blades. The actions specified in this AD are
intended to prevent failure of a blade resulting in separation of the
blade and subsequent loss of control of the helicopter.
DATES: Effective May 29, 1996.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of 15 days after the date of publication in the Federal Register.
Comments for inclusion in the Rules Docket must be received on or
before July 15, 1996.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Office of the Assistant Chief Counsel, Attention:
Rules Docket No. 96-SW-02-AD, 2601 Meacham Blvd., Room 663, Fort Worth,
Texas 76137.
The service information referenced in this AD may be obtained from
MDHS, Technical Publications, Bldg. 530/B111, 5000 E. McDowell Rd.,
Mesa, Arizona 85215-9797. This information may be examined at the FAA,
Office of the Assistant Chief Counsel, 2601 Meacham Blvd., Room 663,
Fort Worth, Texas 76137; or at the Office of the Federal Register, 800
North Capitol Street NW., suite 700, Washington, DC.
FOR FURTHER INFORMATION CONTACT: Mr. John Cecil, Aerospace Engineer,
ANM-120L, Los Angeles Aircraft Certification Office, Northwest Mountain
Region, 3960 Paramount Blvd., Lakewood, California, telephone (310)
627-5322, fax (310) 627-5210.
SUPPLEMENTARY INFORMATION: This amendment adopts a new AD that is
applicable to MDHS Model 369, 369A, 369D, 369E, 369F, 369FF, 369H,
369HE, 369HM, 369HS, and 500N helicopters. One accident occurred in
August 1995 in which one blade separated from the rotor system while
the helicopter was on the ground. Additionally, there were eight
reports of blade cracking prior to the one accident, all of which were
discovered during either routine inspections or inspections resulting
from reported abnormal vibrations. Subsequent investigations revealed
that bonding separation occurred between the lower surface root end
fitting and the doubler. This condition, if not corrected, could result
in failure of a blade resulting in separation of the blade and
subsequent loss of control of the helicopter.
[[Page 24221]]
The FAA has reviewed McDonnell Douglas Helicopter Systems Service
Information Notice No. HN-239, DN-188, EN-81, FN-67, and NN-008, dated
October 27, 1995, which describes procedures for a one-time visual
inspection of the blade root end for chordwise cracking and paint or
sealant cracking between the lower surface root end fitting and the
doubler, and then repetitive inspections at intervals of 100 hours
time-in-service (TIS).
Since an unsafe condition has been identified that it is likely to
exist or develop on other MDHS Model 369, 369A, 369D, 369E, 369F,
369FF, 369H, 369HE, 369HM, 369HS, and 500N helicopters of the same type
design, this AD is being issued to prevent failure of a blade at the
root end due to fatigue cracking that initiates at the outboard bolt
hole and usually travels in a chordwise direction. This AD requires,
within 10 hours TIS after the effective date of this AD, a one-time
visual inspection of each blade root end near the doubler paying
particular attention to chordwise cracks and paint or sealant cracking
or separation between the lower surface root end fitting and the
doubler. Additionally, this AD requires repetitive visual inspections
of each blade, at intervals not to exceed 100 hours TIS, for bond
separation between the lower surface root end fitting and doubler
paying particular attention to chordwise cracks. The actions are
required to be accomplished in accordance with the service information
notice described previously.
Due to the critical need to ensure the integrity of the main rotor
system, and to comply with the requirements of this AD within 10 hours
TIS, this rule must be issued immediately to correct an unsafe
condition in the affected helicopters.
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 No. 96-SW-02-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 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:
AD 96-10-09 McDonnell Douglas Helicopter Systems: Amendment 39-
9615. Docket No. 96-SW-02-AD.
Applicability: Model 369, 369A, 369D, 369E, 369F, 369FF, 369H,
369HE, 369HM, 369HS, and 500N helicopters, 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 (c) 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 failure of a main rotor blade (blade) resulting in
separation of the blade and subsequent loss of control of the
helicopter, accomplish the following:
(a) Within 10 hours time-in-service (TIS) after the effective
date of this AD, perform a visual inspection of each blade root end
for cracking and paint or sealant cracking, paying particular
attention to chordwise cracking, and for separation between the
lower surface root end fitting and doubler, in accordance with Part
I of the Accomplishment Instructions of McDonnell Douglas Helicopter
Systems Service Information Notice (SIN) HN-239, DN-188, EN-81, FN-
67, and NN-008, dated October 27, 1995. If any blade crack is noted,
before further flight, remove the blade and replace it with an
airworthy blade. If paint or sealant cracking or separation is
noted, accomplish the inspection in paragraph 3E of Part II of the
Accomplishment Instructions of SIN HN-239, DN-188, EN-81, FN-67, and
NN-008, dated October 27, 1995, using a piece of Mylar/viewfoil that
is no thicker than .004-inch and that is cut to a size between 0.9
inch
[[Page 24222]]
and 1.1 inches wide and between 3.9 inches and 4.1 inches long. If
any corner of the Mylar can be inserted between the lower surface
root end fitting and doubler surface to a depth of 0.1 inch or
greater, remove the blade from service and replace it with an
airworthy blade.
(b) Thereafter, at intervals not to exceed 100 hours TIS, remove
the blades and inspect for cracking, paying particular attention to
chordwise cracking, and separation between the lower surface root
end fitting and doubler in accordance with Part II of the
Accomplishment Instructions of McDonnell Douglas Helicopter Systems
SIN HN-239, DN-188, EN-81, FN-67, and NN-008, dated October 27,
1995. If missing or cracked adhesive or paint is detected at the
lower surface root end fitting to doubler bonding line, accomplish
the inspection in paragraph 3E of Part II of the Accomplishment
Instructions of SIN HN-239, DN-188, EN-81, FN-67, and NN-008, dated
October 27, 1995 using a piece of Mylar/viewfoil that is no thicker
than .004-inch that is cut to a size between 0.9 inch and 1.1 inches
wide and between 3.9 inches and 4.1 inches long. If any corner of
the Mylar can be inserted between the lower surface root end fitting
and doubler surface to a depth of 0.1 inch or greater, remove the
blade from service and replace it with an airworthy blade.
(c) 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, Los Angeles 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, Los Angeles 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 Los Angeles Aircraft Certification Office.
(d) Special flight permits will not be issued.
(e) The inspections shall be done in accordance with McDonnell
Douglas Helicopter Systems Service Information Notice (SIN) HN-239,
DN-188, EN-81, FN-67, and NN-008, dated October 27, 1995. This
incorporation by reference was approved by the Director of the
Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part
51. Copies may be obtained from McDonnell Douglas Helicopter
Systems, Technical Publications, Bldg. 530/B111, 5000 E. McDowell
Rd., Mesa, Arizona 85215-9797. Copies may be inspected at the FAA,
Office of the Assistant Chief Counsel, 2601 Meacham Blvd., Room 663,
Fort Worth, Texas; or at the Office of the Federal Register, 800
North Capitol Street, NW., suite 700, Washington, DC.
(f) This amendment becomes effective May 29, 1996.
Issued in Fort Worth, Texas, on May 2, 1996.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 96-11959 Filed 5-13-96; 8:45 am]
BILLING CODE 4910-13-U
