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Proposed Rule

Airworthiness Directives; Marathon Power Technologies Company

Document Details

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Federal Aviation Administration, DOT.


Notice of proposed rulemaking (NPRM).


This document proposes adopting a new airworthiness directive (AD) for certain nickel cadmium batteries produced by Marathon Power Technologies Company (Marathon). The AD would require visually inspecting screws installed on Marathon batteries and replacing certain unairworthy screws. This proposal is prompted by an explosion of a G.E./Saft battery due to failure of an unairworthy screw. Certain Marathon batteries are a similar design and could have the same unairworthy screws. The actions specified by the proposed AD are intended to prevent an explosion of a battery, structural damage, and subsequent loss of power to the electrical systems.


Comments must be received on or before April 16, 2001.


Submit comments in triplicate to the Federal Aviation Administration (FAA), Office of the Regional Counsel, Southwest Region, Attention: Rules Docket No. 2000-SW-38-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137. You may also send comments electronically to the Rules Docket at the following address: Comments may be inspected at the Office of the Regional Counsel between 9 a.m. and 3 p.m., Monday through Friday, except Federal holidays.

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Aaron Cornelius, Aviation Safety Engineer, FAA, Special Certification Office, Fort Worth, TX 76193-0190; telephone (817) 222-4637, fax (817) 222-5785.

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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 should 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 will be considered before taking action on the proposed rule. The proposals contained in this document 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 in the Rules Docket for examination by interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their mailed comments submitted in response to this proposal must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket No. 2000-SW-38-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, Office of the Regional Counsel, Southwest Region, Attention: Rules Docket No. 2000-SW-38-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137.


This document proposes adopting a new AD for certain nickel cadmium batteries produced by Marathon. The AD would require inspecting any affected battery to verify that each #10-32 socket head cap screw (screw) is part number (P/N) 10488-020 with two rows of straight knurls, which is the correct screw hardware. This AD also requires, before further flight, replacing any screw found with only one knurl or no knurl with a screw, P/N 10488-020, with two knurls. This proposal is Start Printed Page 10242prompted by an explosion of a G.E./Saft battery during routine maintenance on a McDonnell Douglas DC-9 aircraft. Marathon battery, P/N 27183-001, is similar to the GE/Saft battery that exploded. A battery cell screw head broke off causing an electrical short circuit between the internal battery cell positive and negative posts. This resulted in a rapid discharge of energy, heat, and gases. Investigation revealed unapproved screws were installed, and maintenance procedures did not comply with the manufacturer's recommendations. Metallurgical tests cited chloride as a factor in causing the heads of the failed screws to shear and the eventual explosion of the battery. The actions specified by the proposed AD are intended to prevent an explosion of a battery, structural damage, and subsequent loss of power to the electrical systems.

We have identified an unsafe condition that is likely to exist or develop on other aircraft with Marathon batteries installed that are similar in design to the GE/Saft battery that exploded. Both are designed with similar #10-32 screws, P/N 10488-020. The proposed AD would require visually inspecting each #10-32 screw in certain Marathon batteries within 12 months or the next scheduled battery maintenance and, before further flight, replacing any unairworthy screw with an airworthy screw, P/N 10488-020.

The FAA estimates that 1814 aircraft would be affected by this proposed AD, that it would take approximately 2 work hours to replace any unairworthy screws with airworthy screws for each battery, and that the average labor rate is $60 per work hour. Required parts would cost approximately $100 per battery if all screws were replaced. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $399,080.

The regulations proposed herein would not have a substantial direct effect 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, it is determined that this proposal would not have federalism implications under Executive Order 13132.

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.

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List of Subjects in 14 CFR Part 39

  • Air transportation
  • Aircraft
  • Aviation safety
  • Safety
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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:

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

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Authority: 49 U.S.C. 106(g), 40113, 44701.

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2. Section 39.13 is amended by adding a new airworthiness directive to read as follows:

Marathon Power Technologies Company: Docket No. 2000-SW-33-AD.

Applicability: Marathon Power Technologies Company (Marathon) nickel cadmium batteries, installed in but not limited to the aircraft models shown in Table 1, certificated in any category:

Table 1

Marathon P/NBattery typeAirframe manufacturerModel aircraft
31718-002TCA-1742AerospatialeATR 42, 72 Series
27515-002CTCA-21H-1Agusta119 Koala
29365-01CCA-1700Bell Helicopter Textron, Inc. (BHTI)206A, B, L
30450-001CA-170ABHTI206L-1, L-3
30135-001SP-1700BHTI206A, B, L
30135-002SP-1700LBHTI206A, B, L
30554-01CSP-170ABHTI206L-1, L-3
32007-001SP-170ALBHTI206l-1, 206l-2
32703-001TMA-5-20BHTI204B, 205A, 205A-1, 212, 222, 222B, 222U, 412
31871-001TSP-1722BHTI222, 222B
26069-001KCA-727Boeing727 Series
31918-001TSP-1760LBombardier/CanadairCL 600-2B19
29094-002BTCA-5-20British Aerospace (Jetstream)3101, 3201
31392-002TSP-940British Aerospace (Raytheon Corporate Jets Ltd)146 Series 100A, 200A
30250-001BTCA-9-20ABritish Aerospace (Jetstream)3101, 3201
29094-001BTCA-5DeHavilland (Boeing Canada)DHC-6-1, -100, 200, 300, DHC-7-1, -100, -101, -102, -103
29360-002BTMA-5-20EmbraerEMB 110P1, 110P2
29206-001CA-91-20Fairchild (Swearingen)SA26AT, SA226T, SA226AT, SA226T(B), SA226TC
28974-001CA-9-20Fairchild (Swearingen)SA26AT, SA226T, SA226AT, SA226T(B), SA226TC
29341-001CA-20H-20FokkerF27 Series
29017-002TCA-5-20-1Learjet24, 25, 35
30839-001CA-139McDonnell DouglasDC-9 Series
30695-001TCA-1753McDonnell Douglas (Hughes)369D, H, HM, HE, serial number (S/N) 001 thru 1308, 369HS S/N 781S thru 874S
30896-001TCA-1754McDonnell Douglas (Hughes)369HS S/N 001S thru 780S
30695-002TCA-1753McDonnell Douglas (Hughes)369D, H, HM, HE, S/N 001 thru 1308, 369HS S/N 781S thru 874S
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30900-001TSP-1754McDonnell Douglas (Hughes)369HS S/N 001S thru 780S
30949-001TSP-1755McDonnell Douglas (Hughes)369D S/N 1309 & Sub., E S/N 125 & Sub., F S/N 55 & sub., FF S/N 55 & Sub.
30703-001TMA-5-20PiaggioP-166DL3, P-166
29248-001KTCA-21H-20Short BrothersSD3-30
29487-002CA-176SikorskyS76A Series
29490-001CA-376SikorskyS76A Series
31202-001SP-276SikorskyS76B Series
27183-001CA-13McDonnell DouglasDC-9, MD-80

Note 1:

This AD applies to each aircraft identified in the preceding applicability provision that incorporates one or more of the affected batteries, regardless of whether it has been otherwise modified, altered, or repaired in the area subject to the requirements of this AD. For aircraft 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 within 12 months or the next scheduled battery maintenance, whichever occurs first.

To prevent an explosion of the battery, structural damage, and subsequent loss of power to the electrical systems, accomplish the following:

(a) Visually inspect each #10-32 screw in the battery at the terminals to verify that each screw has two (2) rows of straight knurls (see Figure 1). If a screw is found with only one knurl or no knurl (see Figure 1), before further flight, fully discharge the battery, remove the unairworthy screw and replace it with an airworthy screw, P/N 10488-020.

(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, Special Certification Office, Rotorcraft Directorate, FAA. Operators shall submit their requests through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Special Certification Office.

Note 2:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Special Certification Office.

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

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Issued in Fort Worth, Texas, on February 2, 2001.

Eric Bries,

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.

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[FR Doc. 01-3673 Filed 2-13-01; 8:45 am]