Discussion
What events have caused this AD? The FAA has received accident reports on Air Tractor Models AT-301 and AT-401 airplanes. The reports indicate that the aircraft skids tail first after an overturn, the windshield and curved overturn tube act as a scoop, foreign material enters the cockpit if the top of the canopy is damaged, and this foreign material then enters into the cabin area and possibly contributes to pilot deaths.
Has FAA taken any action to this point? We issued a proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD that would apply to certain Air Tractor Models AT-250, AT-300, AT-301, AT-302, AT-400, AT-400A, AT-401, AT-401A, AT-402, AT- 402A, AT-501, AT-502, and AT-502A airplanes. This proposal was published in the Federal Register as a notice of proposed rulemaking (NPRM) on August 29, 2002 (67 FR 55360). The NPRM proposed to require you to install an overturn skid plate in the cockpit area. The actions specified by this proposed AD are intended to minimize the possibility of dirt or mud penetrating the cockpit in case of an aircraft overturn.
What is the potential impact if FAA took no action? Such mud and dirt penetration into the cockpit could lead to pilot asphyxia or injury.
Was the public invited to comment? The FAA encouraged interested persons to participate in the making of this amendment. The following presents the comments received on the proposal and FAA's response to each comment:
Comment Issue No. 1: Remove the Air Tractor Model AT-502A Designation From the Applicability
What is the commenter's concern? The commenter states that the Air Tractor Model AT-502A airplanes did not start production until after serial numbers applicable to the AD. Furthermore, the commenter states skid plates were installed on all Model AT-502A airplanes during factory production. The commenter wants Air Tractor Model AT-502A airplanes removed from theapplicability section of the final rule AD action.
What is FAA's response to the concern? We do not concur. Air Tractor confirms that there is the possibility of one Model AT-502A airplane (converted from an early production AT-503, and with one of the affected serial numbers) in operation that did not receive the skid plate installation.
We are not changing the final rule AD action based on this comment.
Comment Issue No. 2: Correct Wording in the Summary and Related AD Section
What is the commenter's concern? The commenter states that the following sentence in the NPRM Summary and proposed AD paragraph 2(c) is misleading: "The proposed AD is the result of reports of foreign material entering the cabin area and contributing to accidents of the affected airplanes." The commenter states that the sentence is misleading in that it implies that entering foreign material has caused an accident and does not indicate that an accident (an overturn of the aircraft) has already occurred. The commenter wants the sentence corrected to indicate the possibility of foreign material entering the cockpit after an accident where the aircraft has overturned.
What is FAA's response to the concern? We agree with the commenter. The final rule AD Summary and AD paragraph 2(c) will be changed to indicate the possibility of foreign material entering the cockpit after an accident where the aircraft has overturned.
We will change the final rule AD action to incorporate these changes.
FAA's Determination
What is FAA's final determination on this issue? We carefully reviewed all available information related to the subject presented above and determined that air safety and the public interest require the adoption of the rule as proposed except for the changes discussed above and minor editorial questions. We have determined that these changes and minor corrections:
--Provide the intent that was proposed in the NPRM for correcting the unsafe condition;and
--Do not add any additional burden upon the public than was already proposed in the NPRM.
Cost Impact
How many airplanes does this AD impact? We estimate that this AD affects 845 airplanes in the U.S. registry.
What is the cost impact of this AD on owners/operators of the affected airplanes? We estimate the following costs to accomplish the modification:
Labor cost
Parts cost
Total cost per airplane
Total cost U.S. operators
6 workhours x $60 = $360
$300
$660
845 x $660 = $557,700
Regulatory Impact
Does this AD impact various entities? The regulations adopted herein will not have a substantial direct effect 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, it is determined that this final rule does not have federalism implications under Executive Order 13132.
Does this AD involve a significant rule or regulatory action? 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 copy of the final 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, Incorporation by Reference, Safety.
Adoption of the Amendment
Accordingly, under 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. FAA amends 39.13 by adding a new AD to read as follows: