On October 15, 1997, the FAA issued AD 97-19-16, amendment 39-10169 (62 FR 54579, October 21, 1997), applicable to certain Fokker Model F28 Mark 0100 series airplanes, to require a revision to the FAA-approved Airplane Flight Manual (AFM) to include procedures to prohibit use of reverse engine thrust power settings between idle and emergency maximum. That AD also requires submission of a report to the airplane manufacturer if the limits are exceeded. That action was prompted by a report that, during preparation for takeoff, an engine fan blade failure occurred, followed by an engine fire. The actions required by that AD are intended to prevent uncontained engine fan blade failure due to high cycle fatigue cracking, which could result in loss of thrust from the affected engine and secondary damage to aircraft and/or fire.
Actions Since Issuance of Previous Rule
Since the issuance of that AD, the Rijksluchtvaartdienst (RLD), which is the airworthiness authority for the Netherlands, notified the FAA that new engine operating limitations are necessary to prevent high cycle fatigue cracking of the engine fan blades. The RLD advises that stabilized engine operation in the speed range between 60 and 75 percent low pressure rotational speed (N1) during ground operations in forward or reverse thrust may cause high fan blade stresses and resultant high cycle fatigue cracking. This condition, if not corrected, could result in uncontained engine fan blade failure.
The RLD classified these limitations as mandatory and issued Dutch airworthiness directive 1997-110/2 (A), dated January 30, 1998, in order to assure the continued airworthiness of these airplanes in the Netherlands. The Dutch airworthiness directive adds certain statements to clarify the operating limitation that prohibits use of reverse engine thrust power settings between idle and emergency maximum. In addition, the Dutch airworthiness directive also specifies that inspections of Rolls-Royce Tay 650 series engines are to be accomplished if the operating limits discussed previously have been exceeded.
FAA's Conclusions
This airplane model is manufactured in the Netherlands and is type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the RLD has kept the FAA informed of the situation described above. The FAA has examined the findings of the RLD, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.
Explanation of Requirements of Rule
Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design registered in the United States, this AD supersedes AD 97-19- 16 to continueto require revising the AFM to prohibit use of reverse thrust power settings between idle and emergency maximum. This AD also deletes the reporting requirement contained in AD 97-19-16, since engine inspections have been defined for cases where limits have been exceeded.
This AD adds a requirement to revise the AFM to prohibit stabilized engine operation in the speed range between 60 and 75 percent low pressure rotational speed (N1) during ground operations in forward or reverse thrust.
Differences Between This AD and the Dutch Airworthiness Directive
This AD differs from the parallel Dutch airworthiness directive in that it does not mandate the accomplishment of certain engine inspections for airplanes on which the new engine limits are exceeded. (These inspections also are specified in British airworthiness directive 001-12-97.) The FAA may consider further rulemaking to address the associated engine inspection requirements.
In addition, this AD differs from theparallel Dutch airworthiness directive in that this AD specifically limits the maximum reverse thrust lever positions to the idle detent position for normal operation. This change is necessary to ensure that the limitations are clearly understood by the flightcrew.
Interim Action
This is considered to be interim action until final action is identified, at which time the FAA may consider further rulemaking. Determination of Rule's Effective Date
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 commenton 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-39-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 39-10169 (62 FR 54579, October 21, 1997), and by adding a new airworthiness directive (AD), amendment 39-10384, to read as follows: