Airworthiness Directives; Boeing Model 777 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the supersedure of an existing airworthiness directive (AD), applicable to all Boeing Model 777 series airplanes, that currently requires repetitive testing of the engine fire shutoff switch (EFSS) to determine if the override mechanism and the switch handle are operational, and replacement of the EFSS, if necessary. That AD also requires, for certain airplanes, installation of a collar on a specific circuit breaker of the standby power management panel, and installation of placards to advise the flightcrew that the override mechanism must be pushed in order to pull the fire switch. That AD was prompted by a report indicating that a solenoid and an override mechanism of the EFSS were not operational due to overheating of the solenoid. The actions specified by the proposed AD are intended to prevent damage to the EFSS solenoid and to the override mechanism, and consequent failure of the EFSS due to overheating of the solenoid; such failure could result in the inability of the flightcrew to discharge the fire extinguishing agent in the event of an engine fire. This action would add various actions that would terminate the repetitive testing requirements.

DATES:

Comments must be received by July 3, 2000.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 99-NM-163-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 Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT:

Larry Reising, Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Transport Airplane Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2683; fax (425) 227-1181.

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 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 99-NM-163-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. 99-NM-163-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

On May 5, 1997, the FAA issued AD 97-10-11, amendment 39-10023 (62 FR 25837, May 12, 1997), applicable to all Boeing Model 777 series airplanes, to require repetitive testing of the engine fire shutoff switch (EFSS) to determine if the override mechanism and the switch handle are operational, and replacement of the EFSS, if necessary. That AD also requires, for certain airplanes, installation of a collar on a specific circuit breaker of the standby power management panel, and installation of placards to advise the flightcrew that the override mechanism must be pushed in order to pull the fire switch. That action was prompted by a report indicating that a solenoid and an override mechanism of the EFSS were not operational due to overheating of the solenoid. The actions specified by that AD are intended to prevent damage to the EFSS solenoid and to the override mechanism due to overheating of the solenoid; such failure of the EFSS could result in the inability of the flightcrew to discharge the fire extinguishing agent in the event of an engine fire.

Actions Since Issuance of Previous Rule

In the preamble to AD 97-10-11, the FAA specified that the actions required by that AD were considered “interim action” and that once a final action is identified, the FAA may consider additional rulemaking action. The FAA has determined that further rulemaking action is indeed necessary; this proposed AD follows from that determination.

Explanation of Relevant Service Information

The FAA has reviewed and approved Boeing Alert Service Bulletin 777-26A0009, dated October 23, 1997. The service bulletin describes procedures for activating the circuit breaker C26612 in the P310 panel; removing the placards in the flight compartment; and replacing the EFSS with a new EFSS. Accomplishment of these actions eliminates the need for repetitive testing of the EFSS required by AD 97-10-11. Accomplishment of the actions specified in the 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 supersede AD 97-10-11 to continue require repetitive testing of the EFSS to determine if the override mechanism and the switch handle are operational, and replacement of the EFSS, if necessary. The proposed AD also would continue to require, for certain airplanes, installation of a collar on a specific circuit breaker of the standby power management panel, and installation of placards to advise the flightcrew that the override mechanism must be pushed in order to pull the fire switch. In addition, the proposed AD would require accomplishment of the actions specified in the service bulletin described previously, except as discussed below.

Differences Between the Proposed AD and the Service Bulletin

Operators should note that the effectivity listing of Boeing Alert Service Bulletin 777-26A0009 affects airplanes having line positions 1 through 93 inclusive. The FAA has determined that, although the engine fire control switches, part number (P/N) 233W6201-1, and P/N's S231W263-1 and -2, were installed on affected airplanes during manufacture, it may be possible that these switches have been installed on Model 777 series airplanes during maintenance activities. Therefore, the FAA has determined that the applicability of the proposed AD would affect all Model 777 series airplanes.

Cost Impact

There are approximately 196 airplanes of the affected design in the worldwide fleet. The FAA estimates that 48 airplanes of U.S. registry would be affected by this proposed AD.

The actions that are currently required by AD 97-10-11, and retained in this proposed AD, take approximately 1 work hour per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the currently required actions on the U.S. operators is estimated to be $2,880, or $60 per airplane, per testing cycle.

The new actions that are proposed in this AD action would take approximately 1 work hour per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts would cost approximately $4,054 per airplane. Based on these figures, the cost impact of the new proposed requirements of this AD on U.S. operators is estimated to be $197,472, or $4,114 per airplane.

The cost impact figures discussed above is based on assumptions that no operator has yet accomplished any of the current or 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 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.

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.