A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to all Bombardier Model CL-44 series airplanes was published in the Federal Register on May 28, 1997 (62 FR 28813). That action proposed to require revising the Limitations Section of the FAA-approved Airplane Flight Manual (AFM) to modify the limitation that prohibits the positioning of the power levers below the flight idle stop while the airplane is in flight, and to add a statement of the consequences of positioning the power levers below the flight idle stop while the airplane is in flight.
Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received.
Request to Withdraw the Proposal
One commenter, the manufacturer, considers that a revision to the Limitations Section of the AFM, issued on December 6, 1996, fully meets the intent of the proposed rule. Therefore, the manufacturer concludes that an AD for the Model CL-44 series airplane is not required.
The FAA does not concur that inserting the AFM revision referenced by the commenter into the AFM provides an adequate method of compliance with the final rule. That revision does not contain reference to the fact that failure to observe the prohibition may cause loss of airplane control, and as such, does not completely meet the intent of the rule. The FAA acknowledges that revising the AFM to add the phrase loss of airplane control as a consequence of failure to observe the prohibition would provide adequate compliance with the requirements of the final rule. Therefore, the FAA will consider requests for approval of an alternative method of compliance in accordance with the provisions of paragraph (b) of this AD.
Request to Clarify That No Accidents Occurred on the CL-44
This same commenter notes that the text of the proposed rule does not make it clear that no accidents have occurred on Model CL-44 series airplanes as a result of ground propeller beta range being used improperly during flight. The commenter requests that the FAA clarify this in the final rule.
The FAA acknowledges that no accidents have occurred involving Model CL-44 series airplanes that have been attributed to ground propeller beta range being used improperly during flight. However, the FAA considers that the wording of the Summary section of the proposed rule that states, "This proposal is prompted by incidents and accidents involving airplanes equipped with turboprop engines in which the ground propeller beta range was used improperly during flight," is correct. The fact that the FAA did not specifically name each manufacturer and airplane model on which those incidents or accidents occurred does not negate the fact that such incidents and accidents did occur on airplanes equipped with turboprop engines. The FAA finds thatno change to the final rule is necessary.
Clarification of the Rule
Since the issuance of the NPRM, the FAA has noted that operations manuals for certain airplanes equipped with Dart turboprop engines may contain reference to "ground fine pitch" rather than "operations below the flight idle stop," as specified in the proposed rule. Although the operations manuals refer to both of those phrases, the FAA finds that some clarification is necessary. Therefore, the FAA has added the phrase "(i.e., ground fine pitch)" in paragraph (a) of the final rule as a parenthetical definition of "operations below the flight idle stop" in the final rule.
Conclusion
After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes previously described. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.
Cost Impact
The FAA estimates that 1 Bombardier Model CL-44 series airplane of U.S. registry will be affected by this AD, that it will take approximately 1 work hour to accomplish the proposed actions, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the AD on the single U.S. operator is estimated to be $60 for the one affected airplane.
The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the 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 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.
For the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it 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 39of 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 adding the following new airworthiness directive: