Discussion
What Events Have Caused This AD?
The Federal Office for Civil Aviation (FOCA), which is the airworthiness authority for Switzerland, recently notified FAA that an unsafe condition may exist on certain Pilatus Models PC-12 and PC-12/45 airplanes. The FOCA reports that drill and/or rivet tool damage could have occurred in areas around the edges of the rear pressure dome during assembly of the Models PC-12 and PC-12/45 airplanes.
Pilatus has received 19 reports of damaged pressure domes. The reported damage included nicks and scratches. This type of damage could also occur on the forward surface of the pressure dome.
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 Pilatus Models PC-12 and PC-12/45 airplanes. This proposal was published in the Federal Register as a notice of proposed rulemaking (NPRM) on January 14, 2003 (68 FR 1802). The NPRM proposed to require you to inspect the front and rear surfaces of the pressure dome for damage and cracks, and, if necessary, accomplish repairs.
What Is the Potential Impact if FAA Took No Action?
The damage to the pressure dome could result in cracks in the pressure dome and lead to rapid decompression.
Was the Public Invited To Comment?
The FAA encouraged interested persons to participate in the making of this amendment. The following presents the comment received on the proposal and FAA's response to the comment:
Comment Issue: How To Obtain a Repair Scheme Is Unclear
What Is the Commenter's Concern?
The commenter states that the current wording in the proposed AD is incorrect and implies that the repair scheme will come from FAA. Additionally, the commenter states that the repair scheme will come from the manufacturer; FAA will provide approval of the repair.
What Is FAA's Response to the Concern?We do not concur that the current wording of the proposed AD is incorrect. Since the service information, which is referenced in the proposed AD, does not address repairs for this type of damage, FAA has to individually approve each repair as needed. This gives the manufacturer the option to develop other generic repair procedures, which were not developed at the time of the NPRM, for this type of damage and submit them to FAA for approval. Therefore, we have not changed the final rule AD based on this comment.
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 280 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
8 workhours x $60 per hour = $480.
No parts required
$480
$480 x 280 = $134,400.
We estimate the following costs to accomplish any necessary repairs that would be required based on the results of the inspection. We have no way of determining the number of airplanes that may need such repair:
Labor cost
Parts cost
Total cost per airplane
16 workhours x $60 per hour = $960
No parts required
$960.
Compliance Time of This AD
What Will Be the Compliance Time of This AD?
The compliance time of this AD is within 90 days after the effective date of this AD, unless already accomplished.
Why Is the Compliance Time Presented in Calendar Time Instead of Hours Time-in-Service (TIS)?
Failure of the pressure dome is only unsafe during airplane operation. However, this unsafe condition is not a result of the number of times the airplane is operated. The chance of this situation occurring is the same for an airplane with 10 hours TIS as it would be for as airplane with 500 hours TIS. For this reason, FAA has determined that a compliance based on calendar time will be utilized in this AD in order to assure that the unsafe condition is addressed on all airplanes in a reasonable time period.
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 AmendmentAccordingly, 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: