Airworthiness Directives; Fairchild Aircraft SA26, SA226, and SA227 Series Airplanes

[FR Doc No: 96-10308] DEPARTMENT OF TRANSPORTATION 14 CFR Part 39 [Docket No. 94-CE-22-AD] RIN 2120-AA64 Airworthiness Directives; Fairchild Aircraft SA26, SA226, and SA227 Series Airplanes AGENCY: Federal Aviation Administration, DOT. ACTION: Supplemental notice of proposed rulemaking (NPRM); Reopening of the comment period. SUMMARY: This document proposes to revise an earlier proposed airworthiness directive (AD), which would have superseded AD 93-19-06. That AD currently requires repetitively inspecting acrylic cabin and cockpit side windows for cracks on certain Fairchild Aircraft SA26, SA226, and SA227 series airplanes, and, if cracks are found that exceed certain limitations, replacing that window. The previous document included the following: the proposed requirement of modifying certain cockpit side windows; more fully-defined crack limitations; and more clear repetitive inspection intervals for the affected airplanes over those included in AD 93-19-06. Comments received regarding the NPRM have prompted the Federal Aviation Administration to change the proposal and allow the public a further opportunity to participate in the rulemaking process. The actions specified by the proposed AD are intended to prevent acrylic cabin or cockpit side window failures, which, if not detected and corrected, could result in airframe damage and decompression injuries. DATES: Comments must be received on or before June 24, 1996. ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Central Region, Office of the Assistant Chief Counsel, Attention: Rules Docket No. 94-CE-22-AD, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106. Comments may be inspected at this location between 8 a.m. and 4 p.m., Monday through Friday, holidays excepted. Service information that applies to the proposed AD may be obtained from Fairchild Aircraft, P.O. Box 790490, San Antonio, Texas 78279- 0490; telephone (210) 824-9421. This information also may be examined at the Rules Docket at the address above. FOR FURTHER INFORMATION CONTACT: Mr. Hung Viet Nguyen, Aerospace Engineer, FAA, Airplane Certification Office, 2601 Meacham Boulevard, Fort Worth, Texas 76193-0150; telephone (817) 222-5155; facsimile (817) 222-5960. 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 should 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 that summarizes 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 No. 94-CE-22-AD.'' The postcard will be date stamped and returned to the commenter. Availability of Supplemental NPRM Any person may obtain a copy of this supplemental NPRM by submitting a request to the FAA, Central Region, Office of the Assistant Chief Counsel, Attention: Rules Docket No. 94-CE-22-AD, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106. Discussion A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD that would apply to certain Fairchild Aircraft SA26, SA226, and SA227 series airplanes was published in the Federal Register on February 21, 1995 (60 FR 9649). The action proposed to supersede AD 93-19-06 with a new AD that would maintain the requirement of repetitively inspecting acrylic cabin and cockpit side windows for cracks, and replacing any window where cracks are found that exceed certain limitations. That NPRM proposed to require modifying windows that do not have inner window panes installed. Accomplishment of the modification proposed in the NPRM would be in accordance with the following service bulletins (SB), as applicable: Page No. Date Fairchild SB 26-56-10-045, which incorporates the following pages and revision levels: 3, 4, 5, and 9......................................... Revised: December 1, 1994. 1, 2, 6, 7, 8, and 10 through 14....................... Issued: August 11, 1994. Fairchild SB 226-56-005, which incorporates the following pages and revision levels: 3 through 7, and 9..................................... Revised: December 1, 1994. 1, 2, and 8............................................ Revised: August 11, 1994. 10 through 16.......................................... Issued: July 31, 1991. and Fairchild SB 227-56-005, which incorporates the following pages and revision levels: 3 through 7, and 9..................................... Revised: December 1, 1994. 1, 2, and 8............................................ Revised: August 11, 1994. 10 through 16.......................................... Issued: July 31, 1991. Accomplishment of the repetitive inspections proposed in the NPRM would be in accordance with the following SB's, as applicable: Fairchild SB 26-56-20-042, Issued: November 28, 1988; Revised: February 7, 1991. Fairchild SB 226-56-001, Issued: February 2, 1983; Revised: November 26, 1991. Fairchild SB 227-56-001, Issued: February 2, 1983; Revised: November 26, 1991. Fairchild SB 226-56-002, Issued: March 3, 1983; Revised: May 29, 1992. Fairchild SB 227-56-002, Issued: January 5, 1984; Revised: May 29, 1992, and April 1, 1993. Fairchild SB 226-56-003, Issued: September 13, 1984; Revised: November 2, 1989. Fairchild SB 227-56-003, Issued: September 13, 1984; Revised: November 2, 1989. Fairchild SB 26-56-10-038, Issued: October 8, 1984; Revised: February 7, 1991. Interested persons have been afforded an opportunity to participate in the making of this amendment. After reviewing all the comments received on the NPRM, the FAA is revising the proposal to eliminate the proposed dual-pane cockpit side window modification, and is proposing repetitive single-pane cockpit side window replacements (every 5,000 hours time-in-service). The repetitive inspections would remain as originally proposed. Due consideration has been given to the comments that follow. Fifteen comments were received in reference to the dual-pane cockpit side window modification. These comments present the view that the compliance times for the modification are unrealistic, that there is no justification for the FAA to mandate the dual-pane modification, and that a new improved cockpit side window defogging system should be developed instead of the modification. Since the FAA has revised the NPRM to include repetitive single-pane cockpit side window replacements instead of the dual-pane cockpit side window modification, these comments no longer apply to the rule as now proposed. Seven commenters state that the FAA miscalculated the economic impact of the AD upon the operators, specifically that the 14 hours proposed to accomplish the modification is closer to 50 workhours for each side or 100 workhours per airplane. The FAA concurs that it miscalculated the economic impact and agrees that the proposed modification would take approximately 100 workhours per airplane (50 workhours each side). However, since the proposal is being revised to incorporate a life limit on the single-pane windows and since mandatory dual-pane modification is no longer proposed, the economic portion to the preamble of this proposal has been adjusted to reflect the single- pane installation costs instead of the double pane modification costs. After examining the circumstances and reviewing all available information related to the subject described above including the comments received, the FAA has determined that the NPRM should be revised and that AD action should still be taken to prevent acrylic cabin or cockpit side window failures, which, if not detected and corrected, could result in airframe damage and decompression injuries. Since this revision of the NPRM to add a life limit for the single- pane cockpit side windows proposes actions that go beyond the scope of what was already proposed, the FAA is reopening the comment period to allow the public additional time to comment on this proposed action. Since an unsafe condition has been identified that is likely to exist or develop in other Fairchild Aircraft SA26, SA226, and SA227 series airplanes of the same type design, the proposed AD would supersede AD 93-19-06 with a new AD that would maintain the requirement of repetitively inspecting the cabin and cockpit side windows, and would add a life limit for the single-pane cockpit side windows. Accomplishment of the single-pane window installation would be in accordance with the applicable maintenance manual. The proposed inspections would continue to be accomplished in accordance with the service bulletins previously referenced. The compliance time for the proposed AD is presented in both hours time-in-service (TIS) and calendar time. The referenced acrylic cabin and cockpit side windows are affected whether the airplane is in flight or on the ground. In addition, the utilization rates of the affected airplanes vary among operators. For example, operators in unscheduled service utilize their airplanes an average of approxi ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 27k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━