[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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