The FAA proposed to amend 14 CFR part 39 by superseding AD 2008-08-01, Amendment 39-15453 (73 FR 19971, April 14, 2008). The proposed AD applies to McCauley Propeller Systems propeller models B5JFR36C1101/114GCA-0, C5JFR36C1102/L114GCA-0, B5JFR36C1103/ 114HCA-0, and C5JFR36C1104/L114HCA-0. We published the proposed AD in the Federal Register on January 21, 2009 (74 FR 3462). That action proposed to require an FPI and ECI of propeller blades for cracks, visual inspection of the blade shank for a step condition, and a new propeller blade life limit of 3,500 hours TSN. That action also proposed to require removal of blades with more than 10,000 operating hours TSN before further flight. That action also proposed to require removal from service of all the propeller blades and the propeller hub if one or more propeller blades have been found cracked on a propeller assembly. That action also proposed to require removing from service all C-5963 split retainers at time of next inspection.
Guidance From McCauley Product Support
If there is any question as to the acceptability of a blade shank "step condition'', the ability to accurately measure 0.005-inch wear, or the acceptability of any other wear present, we recommend that you contact McCauley Product Support for guidance.
Examining the AD Docket
You may examine the AD docket on the Internet at http:// www.regulations.gov; or in person at the Docket Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Operations office (telephone (800) 647-5527) is provided in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.
Comments
We provided the public the opportunity to participate in the development of this AD. We have considered the comments received.
Claim That Blade Failure Is Primarily Due to a Blade Material Condition
Four commenters provided numerous observations that infer the probable cause for propeller blade failure is primarily due to a propeller blade material condition, which is the result of a manufacturing defect. The commenters did not present any examination or determination as to the cause of initiation of the propeller blade fatigue cracks. They did not present any evaluation or determination of the effect airplane operations in the restricted propeller RPM ranges have on propeller blade cracking, or any evaluation or determination of the effect the propeller blade material condition has, with respect to propeller fatigue life and thus propeller blade operating life.
We respect the commenters' observations, but the observations do not provide factual data to state a singular probable cause of propeller blade cracking. Therefore, as stated in the NPRM we have not yet determined if the blade cracking is the result of a design issue, an operational issue, or a combination of the two. We did not change the AD.
Concern Over Cost of Airplane Operations
Three commenters highlight and express their concern with the increase in cost of airplane operations associated with the proposed AD.
Per Order FAA-IR-M-8040.1B, we must consider the cost impact of an AD, including the direct cost to operators. We performed the economic analysis to include initial labor and parts costs, but we did not include the cost of aircraft down time, as we are not required to include it. Since we published the proposed AD, we became aware there are more affected airplanes with the subject propeller on the U.S. registry, bringing the number of propellers from 8 to 34. We also became aware that the total cost estimate we gave in the proposed AD was for the worldwide fleet. We changed the cost of compliance paragraph to cover only the U.S. fleet, and to reflect a corrected estimated cost, including the cost of proratedpropeller life lost, which is a total of $1,523,049.
Revise the AD To Include the BAE Systems Regional Aircraft Proposal To Increase the Propeller Blade Life to 5,000 Hours
Five commenters, including BAE Systems (Operations) Ltd., point out that European Aviation Safety Agency (EASA) AD 2009-0038 mandates the installation of a propeller speed warning system per BAE Systems (Operations) Ltd. Service Bulletin No. SB J41-61-014. BAE Systems (Operations) Ltd. proposed that the propeller blade life could be increased to 5,000 hours with the installation of new, zero-time-since- new propeller blades. The commenters suggest that we revise our AD to do the same actions.
We do not agree. The above suggestions were not proposed as part of the proposed AD. The commenters state the reason for cracking as that stated in the McCauley Propeller Systems Service Bulletin No. ASB255A, included in the NPRM by reference; which is "The blade cracks are caused by operation in the restricted andplacarded regions.'' We have not yet determined if the blade cracking is the result of a design issue, an operational issue, or a combination of the two. The commenters presented observations that propellers have operated beyond the proposed AD 3,500-hour life limit satisfactorily without cracking. The commenters present that EASA is mandating by AD the propeller speed warning system and state that this system will provide a means to keep the propeller out of the restricted operating range. The proposed AD does not mandate a propeller speed warning system. We agree that this type of system has the potential to help limit the amount of time a propeller is operated in the restricted range. However, this type of system does not guarantee operations of the propeller will be conducted outside of the restricted operating range. The commenters did not examine or determine the cause of initiation of the propeller blade fatigue cracks, nor evaluate or determine the effect airplane operations in the restricted propeller RPM ranges have on propeller blade cracking. The commenters did not evaluate or determine the effect the propeller blade material condition has with respect to propeller fatigue life and thus propeller blade operating life. The commenters did not present any factual data to support increasing the life limit to 5,000 hours. Since May of 2006, we have received reports of eight propeller blades which were found cracked at fewer than 5,000 hours time-since-new. We did not change the AD.
Credit for Monitoring Propeller Operations
Two commenters present observations that infer credit should be given to operators for Digital Flight Data Recorder (DFDR) downloads to monitor operations of the airplane and hence monitor operations of the propeller in the restricted RPM ranges.
We do not agree. We find merit in monitoring of propeller operations, but as stated in the NPRM we have not yet determined if the blade cracking is the result of a design issue, an operational issue, or a combination of the two. We do not have any control over how the airplane is operated, as this AD relates to the type certification of the propeller. We did not change the AD.
Revise AD To Include a Wear Measurement Technique That Is Not Difficult and Is Practical
One commenter believes the wear measurement technique provided in the McCauley Propeller Systems Service Bulletin No. ASB255A and included in the proposed AD by reference, will be difficult and not practical, and requests a revised and more appropriate procedure be developed and included in the AD. McCauley Propeller Systems has defined this wear measurement criteria in the past in other Service Bulletins related to this propeller model. FAA has previously mandated the same criteria in now superseded ADs. There were no adverse comments to the superseded ADs while they were being proposed, from the propeller repair shops that are tasked with addressing the AD requirements at the propeller hardwarelevel.
We find some merit to elaborate on the criticality of the wear measurement criteria and we have added wording to the Supplementary Information section of this AD, recommending that McCauley Product Support be contacted for additional guidance with this measurement.
Correction to Paragraph (i)
We found incorrect compliance information that was inadvertently placed in the first sentence of paragraph (i) of the proposed AD. We corrected that sentence in the AD from "Remove the serial number (SN) propeller blades and the hubs listed in Table 1 of this AD from service, using the inspection compliance schedule in Table 2 of this AD'' to "Before further flight, remove the serial number (SN) propeller blades and the hubs listed in Table 1 of this AD from service.''
Paragraph Added To Address Parts Not Reported on
We realized that since we state in paragraph (i) of the proposed AD that there may be other affected propeller assemblies, blades, hubs, or hub assembliesthat we have not received reports on, and that we should address that population in a separate paragraph. We added a new paragraph (j) to the AD that states: "Before further flight, remove from service any propeller blades and hubs found or documented to have been installed in any propeller assembly that has had one or more cracked propeller blades at any time. Propeller blades and the propeller hub of a propeller assembly that has had one or more cracked propeller blades are prohibited from installation in any configuration on any airframe.''
Conclusion
We have carefully reviewed the available data, including the comments received, and determined that air safety and the public interest require adopting the AD with the changes described previously. We have determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.
Costs of Compliance
We estimate that this AD will affect 34 propeller assemblies installed on airplanes of U.S. registry. We estimate that it will take about 44 work-hours per propeller to perform the required actions, and that the average labor rate is $80 per work-hour. Required parts will cost about $260 per propeller, if no cracks are found. We estimate that one propeller will fail the blade inspection required by this AD, and the propeller replacement cost will be about $67,067. Prorated life lost for the propeller assembly will cost about $39,043 per propeller. Based on these figures, we estimate the total cost of the AD to U.S. operators to be $1,523,049.
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 promoting safe 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 summary of the costs to comply with this AD and placed it in the AD Docket. You may get a copy of this summary at the address listed under 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 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 FAA amends Sec. 39.13 by removing Amendment 39-15453 (73 FR 19971, April 14, 2008) and by adding a new airworthiness directive, Amendment 39-16021, to read as follows: