[Federal Register Volume 64, Number 65 (Tuesday, April 6, 1999)]
[Proposed Rules]
[Pages 16656-16658]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-8408]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 99-SW-11-AD; Amendment 39-11113; AD 99-08-07]
RIN 2120-AA64
Airworthiness Directives; McDonnell Douglas Helicopter Systems
(MDHS) Model 369E, 369FF, 500N, and 600N Helicopters
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
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SUMMARY: This amendment supersedes an existing priority letter
airworthiness directive (AD) 98-17-14, applicable to MDHS Model 369E,
369FF, 500N, and 600N helicopters, that currently requires, within the
next 14 calendar days, inspecting each relay receptacle contact socket
for correct size of the contact socket holes and replacing incorrectly-
sized contact sockets with airworthy contact sockets. This amendment
requires the same inspections and replacements as the existing priority
letter AD, but changes the serial numbers affected for the MDHS Model
500N and 600N helicopters and changes a part number that was
incorrectly referenced in the existing AD. This amendment is prompted
by three incidences in which a MDHS Model 600 helicopter's Engine
Control Unit (ECU) Fail light illuminated, even though the ECU
continued to automatically control the engine. The cause of the ECU
malfunction indication was determined to be contact sockets that did
not properly fit the corresponding pins of the affected relay.
Improperly sized contact sockets could create multiple unsafe
conditions. These conditions, if not corrected, could result in the
loss of various engine control or warning systems including the
undetected loss of the auto-reignition function after an engine
flameout, failure of an engine to reignite, and a subsequent forced
landing and the inability to immediately detect an engine-out condition
or to properly govern main rotor speed following loss of the Full
Authority Digital Engine Control (FADEC), and subsequent loss of
control of the helicopter.
DATES: Effective April 21, 1999.
Comments for inclusion in the Rules Docket must be received on or
before June 7, 1999.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Office of the Regional Counsel, Southwest Region,
Attention: Rules Docket No. 99-SW-11-AD, 2601 Meacham Blvd., Room 663,
Fort Worth, Texas 76137.
FOR FURTHER INFORMATION CONTACT: Bruce Conze, Aerospace Engineer, FAA,
Los Angeles Aircraft Certification Office, 3960 Paramount Blvd.,
Lakewood, California 90712, telephone (562) 627-5261, fax (562) 627-
5210.
SUPPLEMENTARY INFORMATION: On August 14, 1998, the FAA issued Priority
Letter AD 98-17-14, applicable to MDHS Model 369E, 369FF, 500N and 600N
helicopters, that requires, within the next 14 calendar days,
inspecting each relay receptacle, part number (P/N) HS4256-1, contact
sockets for correct size of the contact socket holes, and
[[Page 16657]]
replacing incorrectly-sized contact sockets with airworthy contact
sockets, P/N 019-0075-002. That action was prompted by an incident in
which a MDHS Model 600 helicopter's ECU Fail light illuminated, even
though the ECU continued to automatically control the engine. The
helicopter manufacturer reported two additional similar incidents on
other MDHS Model 600N helicopters. The cause of the ECU malfunction
indication was determined to be contact sockets that did not properly
fit the corresponding pins of the affected relay. That condition, if
not corrected, could result in the loss of the Battery Hi Temp. relay
and the Auto-Re-Ignition Igniter relay on MDHS Model 369E, 369FF, and
500N helicopters. The loss of these engine control or warning systems
could result in multiple unsafe conditions, including the undetected
loss of the auto-reignition function after an engine flameout, failure
of an engine to reignite, and a subsequent forced landing. Also, that
condition, if not corrected, could result in the undetected loss of the
Battery Hi Temp. relay and the FADEC-related relays (which includes the
ECU Fail relay, the Engine-Out relay, the Manual Mode relay, the FADEC
Start relay, and the Voice Warning Unit) on MDHS Model 600N
helicopters. The undetected loss of these engine control or warning
systems could result in multiple unsafe conditions, including the
inability to immediately detect an engine-out condition or to properly
govern main rotor speed following loss of the FADEC, and subsequent
loss of control of the helicopter.
Since the issuance of that AD, the FAA has determined that not all
of the previously affected MDHS Model 600N helicopters have the unsafe
condition; the prefix ``RN'' for the serial number for the MDHS Model
500N helicopters is incorrect; and the part number for the relay
receptacle was incorrectly stated in Figure 1.
Since an unsafe condition has been identified that is likely to
exist or develop on other MDHS Model 369E, 369FF, 500N and 600N
helicopters of the same type design, this AD supersedes Priority Letter
AD 98-17-14 to require, within the next 14 calendar days, inspecting
each affected relay receptacle contact socket for correct size of the
contact socket holes, and replacing incorrectly-sized sockets with
airworthy contact sockets. The short compliance time involved is
required because the previously described critical unsafe condition can
adversely affect the controllability of the helicopter. Therefore,
inspecting each suspect relay receptacle contact socket for correct
size of the contact socket holes and replacing incorrectly-sized
sockets with airworthy contact sockets is required within the next 14
calendar days, and this AD must be issued immediately.
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.
The FAA estimates that 156 helicopters of U.S. registry will be
affected by this AD, that it will take approximately 4 work hours per
helicopter to inspect and replace all contact sockets, and that the
average labor rate is $60 per work hour. Required parts will cost
approximately $864 per helicopter. Based on these figures, the total
cost impact of the AD on U.S. operators is estimated to be $172,224
assuming one inspection per helicopter and replacement of all contact
sockets on all the helicopters in the U.S. fleet.
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. 99-SW-11-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, 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. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding a new airworthiness directive
(AD) to read as follows:
AD 99-08-07 McDonnell Douglas Helicopter Systems: Amendment 39-
11113. Docket No. 99-SW-11-AD. Supersedes Priority Letter AD 98-17-
14, Docket No. 98-SW-32-AD.
Applicability: Model 369E (serial numbers (S/N) 384E through
0539E); Model 369FF (S/
[[Page 16658]]
N 076FF through 0128FF); Model 500N (serial numbers up to and
including LN085); and Model 600N (serial numbers RN002 through
RN039) 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
otherwise 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 request approval for an
alternative method of compliance in accordance with paragraph (e) of
this AD. The request should include an assessment of the effect of
the modification, alteration, or repair on the unsafe condition
addressed by this AD; and, if the unsafe condition has not been
eliminated, the request should include specific proposed actions to
address it.
Compliance: Required within the next 14 calendar days, unless
accomplished previously.
To prevent undetected loss of engine control or warning systems,
accomplish the following:
(a) Access relays K1, K2, K3, K5, K104, and K200 (relays, part
number (P/N) HS4240).
(b) Remove each relay specified in paragraph (a) from its relay
receptacle (receptacle), P/N HS4256-1.
(c) Using a No. 60 drill bit or a 0.040-in. diameter wire as a
gauge, attempt to insert the gauge into every contact socket
(socket) of each relay. Ensure the gauge is inserted perpendicular
to the face of the receptacle, to prevent damage to the receptacle
and the socket (Figure 1). If the gauge can be inserted into a
socket, it is unairworthy and must be replaced with an airworthy
socket, P/N 019-0075-002.
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(d) Any replacement relay, P/N HS4240, must be inspected prior
to further flight, in accordance with paragraph (c) of this AD.
Note 2: Boeing MDHS Service Bulletin, SB369E-090, SB369F-077,
SB500N-017, SB600N-014, dated July 6, 1998, pertains to the subject
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 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 3: 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.
(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.
Issued in Fort Worth, Texas, on March 30, 1999.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 99-8408 Filed 4-5-99; 8:45 am]
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