AD 96-04-11 R1

On February 15, 1996, the FAA issued AD 96-04-11, amendment 39-9523 (61 FR 6935, February 23, 1996), applicable to certain Boeing Model 757-200 series airplanes, to require a revision to the FAA-approved Airplane Flight Manual to ensure that the flightcrew activates the engine cowl thermal anti-ice (CTAI) system for both engines at the top of descent to avoid engine rundown (loss of engine power). That action was prompted by reports that, after the flightcrew activated the engine CTAI during descent, engine rundown occurred due to unknown reasons. The actions required by that AD are intended to ensure that the flightcrew activates the engine CTAI system for both engines prior to descent; activation of the engine CTAI system in the middle of descent could result in a compressor stall and subsequent engine rundown of multiple engines.

In the preamble to AD 96-04-11, the FAA indicated that the actions required by that AD were considered interim action.Rolls Royce had advised the FAA that it was developing a modification that will positively address the identified unsafe condition.

Actions Since Issuance of Previous Rule

Since the issuance of that AD, the FAA issued AD 97-02-12, amendment 39-9897 (62 FR 4899, February 3, 1997). That AD applies to Rolls Royce Model RB211-535E4 and -535E4-B turbofan engines installed on Boeing Model 757-200 series airplanes. It requires installation of an improved fuel flow governor that incorporates revised minimum compressor discharge P4 stop settings. That AD indicates that installation of these improved fuel flow governors on both engines of Model 757 series airplanes constitutes terminating action for the requirements of AD 96-04-11.

Consequently, the FAA has determined that further rulemaking is necessary to revise AD 96-04-11 to clarify the relationship of that AD to AD 97-02-12 by indicating that installation of the improved fuel flow governors (as required by AD 97-02-12) terminates the requirements of AD 96-04-11.

Explanation of Requirements of Rule

Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of this same type design, this AD revises AD 96-04-11 to continue to require a revision to the Airplane Flight Manual to ensure that the flightcrew activates the engine cowl thermal anti-ice (CTAI) system for both engines at the top of descent to avoid engine rundown (loss of engine power). This AD merely clarifies the relationship between AD 96-04-11 and AD 97-02-12.

Determination of Rule's Effective Date

Since this AD merely provides information regarding the effect of another AD, and does not change the existing requirements, it is found that notice and opportunity for prior public comment hereon are unnecessary, and that good cause exists for making this amendment effective in less than 30 days.

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 shall 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 Number 98-NM-294-AD." The postcard will be date stamped and returned to the commenter.

Regulatory Impact

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. § 39.13 (Amended)

2. Section 39.13 is amended by removing amendment 39-9523 (61 FR 6935, February 23, 1996), and by adding a new airworthiness directive (AD), amendment 39-10887, to read as follows