[Federal Register Volume 64, Number 222 (Thursday, November 18, 1999)] [Proposed Rules] [Pages 62991-62993] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 99-30149] ----------------------------------------------------------------------- DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [Docket No. 99-NM-138-AD] RIN 2120-AA64 Airworthiness Directives; Gulfstream Model G-159 Series Airplanes AGENCY: Federal Aviation Administration, DOT. ACTION: Supplemental notice of proposed rulemaking; reopening of comment period. ----------------------------------------------------------------------- SUMMARY: This document revises an earlier proposed airworthiness directive (AD), applicable to certain Gulfstream Model G-159 series airplanes, that would have required revising the Airplane Flight Manual (AFM) to include requirements for activation of the airframe pneumatic deicing boots. That proposal was prompted by reports of inflight incidents and an accident that occurred in icing conditions where the airframe pneumatic deicing boots were not activated. This new action revises the proposed rule by adding an inspection to determine the type of pneumatic deicing boots, and requiring the AFM change only for those airplanes equipped with ``modern'' boots. The actions specified by this new proposed AD are intended to ensure that flightcrews activate the pneumatic wing and tail deicing boots at the first signs of ice accumulation. This action will prevent reduced controllability of the aircraft due to adverse aerodynamic effects of ice adhering to the airplane prior to the first deicing cycle. DATES: Comments must be received by December 13, 1999. ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 99-NM-138-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. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Small Airplane Directorate, Atlanta Aircraft Certification Office, One Crown Center, 1895 Phoenix Boulevard, suite 450, Atlanta, Georgia 30349. FOR FURTHER INFORMATION CONTACT: Neil Berryman, Aerospace Engineer, Systems and Flight Test Branch, ACE-116A, FAA, Small Airplane Directorate, Atlanta Aircraft Certification Office, One Crown Center, 1895 Phoenix Boulevard, suite 450, Atlanta, Georgia 30349; telephone (770) 703-6098; fax (770) 703-6097. 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-138-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-138-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Discussion A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to add an airworthiness directive (AD), applicable to certain Gulfstream Model G-159 series airplanes, was published as a notice of proposed rulemaking (NPRM) in the Federal Register on July 16, 1999 (64 FR 38341). That NPRM would have required revising the Airplane Flight Manual (AFM) to include requirements for activation of the airframe pneumatic deicing boots. That NPRM was prompted by reports of inflight incidents and an accident that occurred in icing conditions where the airframe pneumatic deicing boots were not activated. The actions specified by that proposed AD are intended to ensure that flightcrews activate the pneumatic wing and tail deicing boots at the first signs of ice accumulation. Such ice accumulation, if not corrected, could result in reduced controllability of the aircraft due to adverse aerodynamic effects of ice adhering to the airplane prior to the first deicing cycle. Distinction Between ``Older'' and ``Modern'' Boots For the purposes of this supplemental NPRM, the FAA considers that a definition of the terms ``older'' and ``modern'' pneumatic deicing boots is necessary. ``Modern'' pneumatic boot systems may be characterized by short segmented, small diameter tubes, which are operated at relatively high pressures [18-23 pounds per square inch (psi)] by excess bleed air that is provided by turbine engines. ``Older'' pneumatic boot systems may be characterized by long, uninterrupted, large diameter tubes, which were operated at low pressures by engine driven pneumatic pumps whose pressure varied with engine revolutions per minute (rpm). This low pressure coupled with long and large diameter tubes caused early de-ice systems to have very lengthy inflation and deflation cycles and dwell times. (Dwell time is the period of time that the boot remains fully expanded following the completion of the inflation cycle until the beginning of the deflation cycle.) The FAA has specified these definitions in a new Note 1 in the final rule. Actions Since Issuance of Previous Proposal Due consideration has been given to the comments received in response to the NPRM. Two commenters request that the proposed rules applying to Gulfstream Model G-159 series airplanes and [[Page 62992]] McDonnell Douglas Model DC-3 and DC-4 series airplanes be withdrawn. Both commenters state that those airplane models do not meet the common definition of the word ``modern.'' One commenter states that the current AFM specifically directs the flight crew to wait for \1/2\-inch of ice before activating the boots. Further, the commenter asserts that the current procedure was developed during certification and is the basis for the airplane's approval for flight into known icing. Additionally, the commenters assert that the in-service safety records for more than 40 years indicate that the existing procedures are appropriate for these airplanes. The commenters conclude that the proposed AFM revision is in direct opposition to the certification findings. As discussed in the original NPRM, the FAA recognizes that early activation of the ``older'' pneumatic deicing boots may create the hazard of ice bridging on the ``older'' systems. The FAA also acknowledges that ``older'' boots may be susceptible to ice bridging because they operate at lower pressure and have larger diameter tubes. The FAA concurs that requiring activation of the boots at the first sign of icing may actually introduce an unsafe condition on those airplanes. In order to address this issue, the FAA is taking the following steps. First, to accommodate certain Gulfstream Model G-159 airplanes that may be equipped with the ``older'' pneumatic deicing boot system, the FAA is issuing this supplemental Notice of Proposed Rulemaking (NPRM). This supplemental NPRM proposes to require an inspection to determine which type of pneumatic deicing boots are installed on the airplanes, and to require operation of the boots at the first sign of ice accretion if the airplanes have been retrofitted with ``modern'' boots. Second, for aircraft with ``older'' pneumatic boots installed, the FAA will continue to investigate other solutions to the unsafe condition of reduced handling qualities or controllability of the airplane due to ice accumulations on the protected surfaces. If other solutions are identified, the FAA may consider further rulemaking. Additionally, the FAA is issuing a similar supplemental NPRM to accommodate certain McDonnell Douglas Model DC-3 and DC-4 series airplanes that may be equipped with ``older'' pneumatic deicing boot systems. In response to the commenter's assertion that existing procedures are appropriate for these airplanes, the FAA has reviewed the icing- related incident history of certain airplanes, and has determined that icing incidents may have occurred because pneumatic deicing boots were not activated at the first evidence of ice accretion. As a result, the handling qualities or the controllability of the airplane may have been reduced due to the accumulated ice. In the previous NPRM, the FAA also discussed an accident that occurred as a result of the failure of the flight crew to activate the wing and tail pneumatic deicing boots. Although there may have been no reported cases of incidents or accidents on a specific airplane model, the potential still exists for reduced controllability of all airplanes equipped with pneumatic deicing boots due to adverse aerodynamic effects of ice adhering to the airplane. This supplemental NPRM addresses that unsafe condition. Conclusion Since this change expands the scope of the originally proposed rule, the FAA has determined that it is necessary to reopen the comment period to provide additional opportunity for public comment. Cost Impact The FAA estimates that 141 airplanes of U.S. registry would be affected by this proposed AD. The FAA estimates that it would take approximately 2 work hours per airplane to accomplish the proposed AFM revisions, at the average labor rate of $60 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $16,920, or $120 per airplane. The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the 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 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 proposal would not have sufficient federalism implications to warrant the preparation of a Federalism Assessment. 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. Sec. 39.13 [Amended] 2. Section 39.13 is amended by adding the following new airworthiness directive: Gulfstream Aerospace Corporation (Formerly Grumman): Docket 99-NM- 138-AD. Applicability: Model G-159 series airplanes equipped with pneumatic deicing boots, certificated in any category. Compliance: Required as indicated, unless accomplished previously. To ensure that flightcrews activate the wing and tail pneumatic deicing boots at the first signs of ice accumulation on the airplane, accomplish the following: Note 1: For the purposes of this AD, the following definitions of ``older'' and ``modern'' apply: ``Modern'' pneumatic boot systems may be characterized by short segmented, small diameter tubes, which are operated at relatively high pressures [18-23 pounds per square inch (psi)] by excess bleed air that is provided by turbine engines. ``Older'' pneumatic boot systems may be characterized by long, uninterrupted, large diameter tubes, which were operated at low pressures by engine driven pneumatic pumps whose pressure varied with engine revolutions per minute (rpm). This low pressure coupled with long and large diameter tubes caused early de-ice systems to have very lengthy inflation and deflation cycles and dwell times. (Dwell time is the period of time that the boot remains fully expanded following the completion of the [[Page 62993]] inflation cycle until the beginning of the deflation cycle.) (a) Within 10 days after the effective date of this AD: Perform a visual inspection to determine if the type of pneumatic deicing boots installed are either ``older'' or ``modern'' boots. (1) For those airplanes equipped with ``older'' pneumatic deicing boots, no further action is required by this AD. (2) For those airplanes equipped with ``modern'' pneumatic deicing boots: Within 10 days after the inspection required by paragraph (a) of this AD, revise the Limitations Section of the FAA- approved Airplane Flight Manual (AFM) to include the following requirements for activation of the ice protection systems. This may be accomplished by inserting a copy of this AD in the AFM. ``Except for certain phases of flight where the AFM specifies that deicing boots should not be used (e.g., take-off, final approach, and landing), compliance with the following is required. Wing and Tail Leading Edge Pneumatic Deicing Boot System, if installed, must be activated: --At the first sign of ice formation anywhere on the aircraft, or upon annunciation from an ice detector system, whichever occurs first; and --The system must either be continued to be operated in the automatic cycling mode, if available; or the system must be manually cycled as needed to minimize the ice accretions on the airframe. The wing and tail leading edge pneumatic deicing boot system may be deactivated only after leaving icing conditions and after the airplane is determined to be clear of ice.'' (b) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Atlanta Aircraft Certification Office, FAA, Small Airplane Directorate. The request shall be forwarded through an appropriate FAA Operations Inspector, who may add comments and then send it to the Manager, Atlanta ACO. Note 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Atlanta ACO. (c) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished. Issued in Renton, Washington, on November 10, 1999. John J. Hickey, Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 99-30149 Filed 11-17-99; 8:45 am] BILLING CODE 4910-13-P