AD 95-04-01

Recently, the FAA has received a report of an accident during which the flight crew executed a missed approach following an instrument landing system (ILS) approach. A McDonnell Douglas Model DC-9-31 series airplane equipped with Honeywell Windshear Detection and Recovery Guidance System (WSS) was involved in this accident. Investigation into the cause of this accident revealed that the airplane encountered severe windshear during the missed approach. The FAA has determined that a design feature in the windshear computer delayed detection of windshear when the airplane's flaps were in transition. This condition, if not corrected, could result in the flight crew being unaware of the potential for significant delays in the WSS detecting windshear when the flaps of the airplane are in transition.

The Honeywell WSS is also installed on certain Boeing Models 727, 737, and 747 series airplanes; McDonnell Douglas Models DC-8 and DC-9-10, -21, -41, -51, and-80 series airplanes, Model MD-88 airplanes, and Models MD-11 and MD-90-30 series airplanes; Lockheed Models L-1011-385 series airplanes; and Fokker Models F28 Mark 1000, 2000, 3000, 4000, and 0100 series airplanes. In light of this, the FAA has determined that these airplanes are also subject to this same unsafe condition.

Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design, this AD is being issued to ensure that the flight crew is aware that there may be significant delays in the Honeywell WSS detecting windshear when the flaps of the airplane are in transition. This AD requires a revision to the FAA-approved Airplane Flight Manual (AFM) to alert the flight crew of the potential for such delays in windshear detection.

This is considered to be interim action. The FAA may consider additional rulemaking once a modification is developed that will positively address the problems experienced with the currentversion of the subject Honeywell WSS.

Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, 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 supportsthe 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 95-NM-11-AD." The postcard will be date stamped and returned to the commenter.

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. App. 1354(a), 1421 and 1423; 49 U.S.C. 106(g); and 14 CFR 11.89.

§ 39.13 - (Amended) 2. Section 39.13 is amended by adding the following new airworthiness directive: