Source: https://www.federalregister.gov/documents/2002/12/10/02-31134/airworthiness-directives-boeing-model-737-600-737-700-737-800-757-200-and-757-300-series-airplanes
Timestamp: 2018-11-20 14:39:52
Document Index: 80307601

Matched Legal Cases: ['art 2', 'art 2', 'art 1', 'art 1', 'art 2', 'art 2', 'art 2', 'art 2']

Comments must be received by January 24, 2003.
https://www.federalregister.gov/d/02-31134 https://www.federalregister.gov/d/02-31134
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 737-600, 737-700, 737-800, 757-200, and 757-300 series airplanes. This proposal would require replacing existing video distribution unit (VDU) connectors with new, improved connectors or new wire assemblies (jumpers), and performing related actions, as applicable. This action is necessary to prevent a short circuit in a VDU connector and consequent arcing and damage to wiring within the connector, which could result in damage to adjacent systems or structure and possible smoke or fire in the airplane cabin. This action is intended to address the identified unsafe condition.
Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2001-NM-374-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9 a.m. and 3 p.m., Monday through Friday, except Federal holidays. Comments may be submitted via fax to (425) 227-1232. Comments may also be sent via the Internet using the following address: 9-anm-nprmcomment@faa.gov. Comments sent via fax or the Internet must contain “Docket No. 2001-NM-374-AD” in the subject line and need not be submitted in triplicate. Comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 for Windows or ASCII text.
The service information referenced in the proposed rule may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. This information may be examined at the FAA, Transport Start Printed Page 75825Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.
Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this action must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2001-NM-374-AD.” The postcard will be date stamped and returned to the commenter.
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. 2001-NM-374-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.
The FAA has received reports indicating that burned contacts have been found on certain video distribution unit (VDU) connectors installed on certain Boeing Model 737-700 and 737-800 series airplanes. In several cases, the mating connector on the VDU was damaged and, in one case, an insulation blanket near the connector was damaged. Investigation revealed that the burned contacts were caused by the presence of moisture and wire chafing in the backshell boot of the VDU connector. Moisture or chafed wiring may result in a short circuit that may cause internal arcing and damage to wiring within the connector. This condition, if not corrected, could result in damage to adjacent systems or structure, and possible smoke or fire in the airplane cabin.
The same type of VDU connectors is also installed on Boeing Model 737-600, 757-200, and 757-300 series airplanes. While the FAA has not received any reports of burned contacts on these airplane models, the VDU connectors may be subject to the same unsafe condition as those on Boeing Model 737-700 and -800 series airplanes.
We have reviewed and approved Boeing Service Bulletin 737-23A1169, Revision 2, dated June 21, 2001. Part 2 of this service bulletin describes procedures for replacing existing VDU connectors with new, improved connectors having better moisture resistance and longer wires, and adding a drip loop to the wiring at the new VDU connectors.
We also have reviewed and approved Boeing Alert Service Bulletin 757-23A0060, Revision 1, dated January 11, 2001; and Boeing Alert Service Bulletin 757-23A0061, Revision 1, dated January 11, 2001. Part 2 of these service bulletins describes procedures for replacing existing VDU connectors with new, improved connectors having better moisture resistance, or—if a drip loop does not exist—with new wire assemblies (jumpers).
Part 1 of the Accomplishment Instructions of the referenced service bulletins describes various interim actions intended to detect or prevent conditions that may lead to a short circuit, until the VDU connectors are replaced with new, improved VDU connectors or wire assemblies, as applicable. However, this proposed AD would not require the interim actions in part 1 of the service bulletins, but only the replacement of the VDU connectors with new, improved connectors or new wire assemblies, as applicable, as described in part 2 of the service bulletins. Mandating the replacement is based on our determination that long-term continued operational safety will be better assured by modifications or design changes to remove the source of the problem, rather than by inspections or other interim actions. Inspections and interim actions may not provide the degree of safety assurance necessary for the transport airplane fleet. This, coupled with a better understanding of the human factors associated with inspections, has led us to consider placing less emphasis on inspections and more emphasis on design improvements. The proposed replacement requirement is consistent with these conditions.
The service bulletins recommend that the part 2 replacement be done as soon as manpower, materials, and facilities are available. We find that such a compliance time would not ensure that the identified unsafe condition is addressed in a timely manner. In developing an appropriate compliance time for this proposed AD, we considered not only the manufacturer's recommendation, but also the degree of urgency associated with addressing the subject unsafe condition. In light of these factors, we find a compliance time of 18 months for completing the proposed actions would be warranted, in that it represents an appropriate interval of time allowable for affected airplanes to continue to operate without compromising safety.
There are approximately 280 airplanes of the affected design in the worldwide fleet. The FAA estimates that 28 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 16 work hours per airplane to accomplish the Start Printed Page 75826proposed connector replacement, and that the average labor rate is $60 per work hour. Required parts would cost between $334 and $13,944 per airplane. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be between $1,294 and $14,904 per airplane.
Boeing: Docket 2001-NM-374-AD.
Applicability: Model 737-600, -700, and “800 series airplanes, as listed in Boeing Service Bulletin 737-23A1169, Revision 2, dated June 21, 2001; Model 757-200 series airplanes, as listed in Boeing Alert Service Bulletin 757-23A0060, Revision 1, dated January 11, 2001; and Model 757-300 series airplanes as listed in Boeing Alert Service Bulletin 757-23A0061, Revision 1, dated January 11, 2001; certificated in any category.
To prevent a short circuit in a video distribution unit (VDU) connector and consequent arcing and damage to wiring within the connector, which could result in damage to adjacent systems or structure and possible smoke or fire in the airplane cabin, accomplish the following:
(a) For Model 737-600, -700, and -800 series airplanes: Within 18 months after the effective date of this AD, replace existing VDU connectors with new, improved connectors, and install a drip loop in the wiring at the new VDU connectors, per part 2 of the Accomplishment Instructions of Boeing Service Bulletin 737-23A1169, Revision 2, dated June 21, 2001.
(b) For Model 757-200 and -300 series airplanes: Within 18 months after the effective date of this AD, replace existing VDU connectors with new, improved connectors, or with new wire assemblies (jumpers), as applicable, per part 2 of the Accomplishment Instructions of Boeing Alert Service Bulletin 757-23A0060, Revision 1, dated January 11, 2001 (for Model 757-200 series airplanes); or Boeing Alert Service Bulletin 757-23A0061, Revision 1, dated January 11, 2001 (for Model 757-300 series airplanes); as applicable.
Issued in Renton, Washington, on December 4, 2002.
[FR Doc. 02-31134 Filed 12-9-02; 8:45 am]