Discussion
What Events Have Caused This AD?
The Civil Airworthiness Authority (CAA), which is the airworthiness authority for the United Kingdom, recently notified FAA that an unsafe condition may exist on all Pilatus Britten-Norman BN-2, BN-2A, BN-2B, BN-2T, BN-2T-4, and BN2A MK. III series airplanes. The CAA reports an incident where the throttle friction adjuster loosened too far, causing the split pin and the washer on the shaft to break.
What Is the Potential Impact if FAA Took No Action?
The loosening of the throttle friction adjustment beyond its normal limits could lead to damage to the throttle friction-adjuster or the retaining washer and split pin. This could allow the throttle quadrant shaft to laterally shift and impede the operation of the engine controls.
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 all Pilatus Britten-Norman Ltd. (Pilatus Britten-Norman) BN-2, BN-2A, BN-2B, BN-2T, BN-2T-4, and BN2A MK. III series airplanes. This proposal was published in the Federal Register as a notice of proposed rulemaking (NPRM) on November 7, 2001 (66 FR 56248). The NPRM proposed to repetitively inspect the throttle friction-shaft and replace the shaft if damaged.
Was the Public Invited To Comment?
The FAA encouraged interested persons to participate in the making of this amendment. We did not receive any comments on the proposed rule or on our determination of the cost to the public.
FAA's Determination
What Is FAA's Final Determination on This Issue?
After careful review of all available information related to the subject presented above, we have determined that air safety and the public interest require the adoption of the rule as proposed except for minor editorial corrections. We have determined that these 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 118 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 inspection:
Labor cost
Parts cost
Total cost per airplane
Total cost on U.S. operators
1 work hour x $60 per hour = $60
$1
$61
$61 x 118 = $7,198.
We estimate the following costs to accomplish any necessary replacements that will be required based on the results of the inspection. We have no way of determining the number of airplanes that may need such replacement:
Labor cost
Parts cost
Total cost per airplane
16 work hour x $60 per hour = $960
$230
$1,190
Is There a Modification I Can Incorporate Instead of RepetitivelyInspecting the Throttle Friction-Shaft?
The FAA has determined that long-term continued operational safety would be better assured by design changes that remove the source of the problem rather than by repetitive inspections or other special procedures. With this in mind, we will continue to work with Pilatus Britten-Norman in collecting information and in performing fatigue analysis to determine whether a future design change may be necessary.
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.
Sec. 39.13 [Amended]
2. FAA amends Sec. 39.13 by adding a new AD to read as follows: