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 Models SC-7 Series 2 and SC-7 Series 3 airplanes. The CAA reports 27 flight control rods with corrosion beyond acceptable limits and 15 rods with cracks. This is on a total of 26 different aircraft.
What is the potential impact if FAA took no action? Cracked or corroded flight control rods, if not detected or corrected, could lead to complete failure of the flight control system with consequent loss of control of the airplane.
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 Shorts Models SC-7 Series 2 and SC-7 Series 3 airplanes. This proposal was published in the Federal Register as a notice of proposed rulemaking (NPRM) on April 10, 2003 (68 FR 17563). The NPRM proposed to require you to repetitively inspect all flight control system rods for corrosion and cracks, replace any cracked rod, and repair corrosion damage or replace any corroded rod depending on the extent of the damage.
The NPRM also proposed to give initial inspection credit to those operators who had previously inspected the flight control rods in accordance with Shorts Service Bulletin 27-74 (any revision level).
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 minoreditorial 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.
How does the revision to 14 CFR part 39 affect this AD? On July 10, 2002, FAA published a new version of 14 CFR part 39 (67 FR 47997, July 22, 2002), which governs FAA's AD system. This regulation now includes material that relates to special flight permits, alternative methods of compliance, and altered products. This material previously was included in each individual AD. Since this material is included in 14 CFR part 39, we will not include it in future AD actions.
Cost Impact
How many airplanes does this AD impact? We estimate that this AD affects 24 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 initial inspection:
Labor cost
Parts cost
Total cost per airplane
Total cost on U.S. operators
250 hours x $60 per hour =$15,000.
No parts necessary to accomplish inspection
$15,000 per airplane.
$15,000 x 24 airplanes = $360,000.
The follow-up inspections will be substantially less than the initial inspection because the flight control rods only have to be removed in the initial inspection. Replacement control rods cost $2,000. We have no way of determining the number of airplanes that may need such repair/replacement.
Compliance Time of This AD
What will be the compliance time of this AD? The initial inspection compliance time of this AD is "within the next 3 months after the effective date of this AD or within 24 months after the last inspection accomplished in accordance with Shorts Service Bulletin 27-74 (any revision level), whichever occurs later." The repetitive inspection compliance time of this AD is "thereafter at intervals not to exceed 24 months."
Why is the compliance time presented in calendar time instead of hours time-in-service (TIS)? The unsafe condition specified by this AD is caused by corrosion. Corrosion can occur regardless of whether the aircraft is in operation or is in storage. Therefore, to ensure that the unsafe condition specified in this AD does not go undetected for a long period of time, the compliance is presented in calendar time instead of hours TIS.
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 continuesto 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: