[Federal Register Volume 63, Number 102 (Thursday, May 28, 1998)]
[Proposed Rules]
[Pages 29155-29157]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-14039]


-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-136-AD]
RIN 2120-AA64


Airworthiness Directives; McDonnell Douglas Model MD-90-30 Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain McDonnell Douglas Model 
MD-90-30 series airplanes. This proposal would require modification of 
the wiring of the strake ice protection system (SIPS). This proposal is 
prompted by a report of a fire in the electrical and electronic 
compartment of a Model MD-90-30 series airplane. The actions specified 
by the proposed AD are intended to prevent an electrical short circuit 
of the wiring of the SIPS, which could result in a fire in the 
electrical and electronic compartment of the airplane.

DATES: Comments must be received by July 13, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 98-NM-136-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except 
Federal holidays.
    The service information referenced in the proposed rule may be 
obtained from The Boeing Company, Douglas Products Division, 3855 
Lakewood Boulevard, Long Beach, California 90846, Attention: Technical 
Publications Business Administration, Dept. C1-L51 (2-60). This 
information may be examined at the FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Transport 
Airplane Directorate, Los Angeles Aircraft Certification Office, 3960 
Paramount Boulevard, Lakewood, California.

FOR FURTHER INFORMATION CONTACT: George Y. Mabuni, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130L, FAA, Transport Airplane 
Directorate, Los Angeles Aircraft Certification Office, 3960 Paramount 
Boulevard, Lakewood, California 90712-4137; telephone (562) 627-5341; 
fax (562) 627-5210.

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 shall 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

[[Page 29156]]

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 Number 98-NM-136-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, Transport Airplane Directorate, ANM-114, Attention: Rules 
Docket No. 98-NM-136-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA received a report of a fire in the electrical and 
electronic compartment of a Model MD-90-30 series airplane which 
resulted in injury to a mechanic. Investigation revealed that the fire 
was caused by an electrical short circuit at the termination of a wire 
shield near the connector of the strake controller. The short circuit 
has been attributed to damaged insulation of certain wiring of the 
strake ice protection system (SIPS). This wiring insulation was damaged 
during manufacture because a shield termination was not being performed 
correctly. For this reason, this same condition may exist on other 
airplanes of the same type. Damaged insulation of the wiring of the 
SIPS could fail, which could cause an electrical short circuit between 
the exposed wire conductors and the shielded ground. Such an electrical 
short circuit of the wiring of the SIPS, if not corrected, could result 
in a fire in the electrical and electronic compartment of the airplane.

Explanation of Relevant Service Information

    The FAA has reviewed and approved McDonnell Douglas Alert Service 
Bulletin MD90-30A021, dated March 31, 1998, which describes procedures 
for modification of the wiring of the SIPS at the connectors of the 
strakes and the strake controller. The modification involves removing 
the pigtail ground wires at the connectors of the strakes and the 
strake controller, installing shrink tubing over each power wire, and 
performing a resistance test of the electrical insulation. (The alert 
service bulletin refers to this resistance test as a ``resistance 
check.'') If any strake heating wiring fails the resistance test, the 
discrepant wiring is to be replaced with new wiring and retested.
    Accomplishment of the actions specified in the alert service 
bulletin is intended to adequately address the identified unsafe 
condition.

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would require modification of the wiring of the strake ice 
protection system. The actions would be required to be accomplished in 
accordance with the alert service bulletin described previously.

Cost Impact

    There are approximately 66 Model MD-90-30 series airplanes of the 
affected design in the worldwide fleet. The FAA estimates that 23 
airplanes of U.S. registry would be affected by this proposed AD, that 
it would take approximately 15 work hours per airplane to accomplish 
the proposed actions, and that the average labor rate is $60 per work 
hour. The cost of the required parts would be minimal. Based on these 
figures, the cost impact of the proposed AD on U.S. operators is 
estimated to be $20,700, or $900 per airplane.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the proposed requirements of 
this AD action, and that no operator would accomplish those actions in 
the future if this AD were not adopted.

Regulatory Impact

    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 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 the following new 
airworthiness directive:

McDonnell Douglas: Docket 98-NM-136-AD.

    Applicability: Model MD-90-30 series airplanes, as listed in 
McDonnell Douglas Alert Service Bulletin MD90-30A021, dated March 
31, 1998; certificated in any category.

    Note 1: This AD applies to each airplane 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 airplanes 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 (b) 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 as indicated, unless accomplished 
previously.
    To prevent an electrical short circuit of the wiring of the 
strake ice protection system (SIPS), which could result in a fire in 
the electrical and electronic compartment of the airplane, 
accomplish the following:
    (a) Within 180 days after the effective date of this AD, modify 
the wiring of the SIPS and perform a resistance test of the 
electrical insulation in accordance with McDonnell Douglas Alert 
Service Bulletin MD90-30A021, dated March 31, 1998. If any strake 
heating wiring fails the resistance test, prior to further flight, 
replace the discrepant wiring with new wiring, and repeat the 
resistance test, in accordance with the alert service bulletin.
    (b) 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 (ACO),

[[Page 29157]]

FAA, Transport Airplane Directorate. Operators shall submit their 
requests through an appropriate FAA Principal Maintenance Inspector, 
who may add comments and then send it to the Manager, Los Angeles 
ACO.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Los Angeles ACO.

    (c) Special flight permits may be issued in accordance with 
Secs. 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 
21.197 and 21.199) to operate the airplane to a location where the 
requirements of this AD can be accomplished.

    Issued in Renton, Washington, on May 20, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-14039 Filed 5-27-98; 8:45 am]
BILLING CODE 4910-13-P