Examining the Docket
You may examine the airworthiness directive (AD) docket on the Internet at http://dms.dot.gov or in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone (800) 647-5227) is located on the plaza level of the Nassif Building at the street address stated in the ADDRESSES section.
Discussion
The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that would apply to certain Bombardier Model DHC-8-400 series airplanes. That NPRM was published in the Federal Register on September 5, 2006 (71 FR 52300). That NPRM proposed to require repetitive cleaning/inspecting of the drain hole of each pitot static probe and repetitive cleaning of the pitot lines in the pitot static system.
Comments
We provided the public the opportunity to participate in the development of thisAD. We have considered the single comment received.
Request To Include Terminating Action for the Repetitive Inspections of the Pitot Static Drain Holes
Horizon Air has no objection to the NPRM, but requests that we add a terminating action for the repetitive inspections of the pitot static drain holes specified in paragraph (f) of the NPRM. Horizon states that Bombardier has issued Service Bulletin 84-34-59, Revision A, dated January 9, 2006, to correct the moisture in the pitot static system. Horizon states that the service bulletin specifies installing new tube assemblies with a larger diameter; these tube assemblies are designed to improve the water drainage characteristics of the pitot static system and reduce airspeed mismatch events.
We do agree that the procedures provided in Bombardier Service Bulletin 84-34-59, Revision A, dated January 9, 2006, would improve drainage; however, we have learned that Bombardier is in the process of revising this service bulletin.Once this service bulletin is revised and approved, we may consider issuing additional rulemaking to mandate the actions specified in the revised service bulletin, along with a modification to prevent the freezing of moisture once the modification is developed, approved, and available, which will be provided in a separate service bulletin. Together, the actions in these service bulletins are intended to terminate the requirements of this AD. We have made no change to the final rule in this regard.
Conclusion
We have carefully reviewed the available data, including the single comment received, and determined that air safety and the public interest require adopting the AD as proposed.
Interim Action
We consider this AD interim action. The manufacturer is currently developing a modification that will address the unsafe condition identified in this AD. Once this modification is developed, approved, and available, we may consider additional rulemaking.
Costs of Compliance
The following table provides the estimated costs for U.S. operators to comply with this AD. There are about 181 airplanes of U.S. registry.
Estimated Costs
Action
Work hours
Average labor rate per hour
Cost per airplane
Fleet cost
Clean/inspect pitot drain holes
1, per clean/inspection cycle
$80
$80, per clean/inspection cycle
$14,480, per clean/inspection cycle
Clean pitot lines
2, per clean cycle
$80
$160, per clean cycle
$28,960, per clean cycle
Authority for This Rulemaking
Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, Section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's authority.
We are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701, "General requirements.'' Under that section, Congress charges the FAA with promotingsafe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.
Regulatory Findings
We have determined that this AD will not have federalism implications under Executive Order 13132. This AD 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.
For the reasons discussed above, I certify that this AD:
(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.
We prepared a regulatory evaluation of the estimated costs to comply with this AD and placed it in the AD docket. See the ADDRESSES section for a location to examine the regulatory evaluation.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Safety.
Adoption of the Amendment
Accordingly, under the authority delegated to me by the Administrator, the FAA amends 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. The Federal Aviation Administration (FAA) amends Sec. 39.13 by adding the following new airworthiness directive (AD):