Airworthiness Directives; Saab Model SAAB 2000 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Saab Model SAAB 2000 series airplanes. This proposal would require various repetitive inspections for cracking of the drag and shear angles that attach the nacelle to the front spar of the wing, and related corrective action. The proposal also would require eventual modification of the drag and shear angles, which would end the repetitive inspections. This action is necessary to prevent fatigue cracking of the drag and shear angles, which could result in reduced structural integrity of the nacelle and wing. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by June 18, 2004.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2002-NM-347-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9 a.m. and 3 p.m., Monday through Friday, except Federal holidays. Comments may be submitted via fax to (425) 227-1232. Comments may also be sent via the Internet using the following address: 9-anm-nprmcomment@faa.gov. Comments sent via fax or the Internet must contain “Docket No. 2002-NM-347-AD” in the subject line and need not be submitted in triplicate. Comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 or 2000 or ASCII text.

The service information referenced in the proposed rule may be obtained from Saab Aircraft AB, SAAB Aircraft Product Support, S-581.88, Linköping, Sweden. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT:

Dan Rodina, Aerospace Engineer, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4057; telephone (425) 227-2125; fax (425) 227-1149.

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to participate in the making of the proposed rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this action may be changed in light of the comments received.

Submit comments using the following format:

• Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.
• For each issue, state what specific change to the proposed AD is being requested.
• Include justification (e.g., reasons or data) for each request.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this action must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2002-NM-347-AD.” The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2002-NM-347-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The Luftfartsverket (LFV), which is the airworthiness authority for Sweden, notified the FAA that an unsafe condition may exist on certain Saab Model SAAB 2000 series airplanes. The LFV advises that inspections done by a full-scale fatigue unit have revealed cracks in the drag angles that attach the nacelle to the wing box via the upper and lower wing skin; and in the shear angles that attach the nacelle to the front spar of the wing. Fatigue cracking of the drag and shear angles of the front spar of the wing could result in reduced structural integrity of the nacelle and wing.

Explanation of Relevant Service Information

The manufacturer has issued Saab Service Bulletins 2000-54-026, Revision 01, and 2000-54-028, Revision 01, both dated June 20, 2002. The service bulletins describe procedures for repetitive inspections for cracking and related corrective action. Service Bulletin 2000-54-026, Revision 01, describes procedures for detailed visual and eddy current inspections of the shear angles which attach the nacelle to the front spar of the wing; Service Bulletin 2000-54-028, Revision 01, describes procedures for endoscope inspections of the drag angles which attach the nacelle to the wing box via the upper and lower wing skin. If any cracking is found, both service bulletins specify following Table 1 of the Accomplishment Instructions to determine the proper action (which includes repeating the inspections at certain intervals, depending on the length of the crack). Both service bulletins also recommend contacting the manufacturer if the cracking exceeds certain damage specifications in Table 1, and sending an inspection report to the manufacturer for further corrective action.

Additionally, the manufacturer has issued Saab Service Bulletins 2000-54-027, and 2000-54-029, both dated November 4, 2002, which describe procedures for modification of the upper and lower drag angles and the shear angles which attach the nacelle to the front spar of the wing. Accomplishment of both modifications eliminates the need for the repetitive inspections. The modification procedures in Service Bulletin 2000-54-027 include an eddy current inspection of the surface of the shear angles and a rotating probe inspection of the hi-lok holes for cracking. If no cracking is found, the service bulletin describes procedures for installation of pressure pads on the shear angles. The modification procedures in Service Bulletin 2000-54-029 include an eddy current (rotating probe) inspection of the upper and lower drag angles for cracking. If no cracking is found, the service bulletin describes procedures for installation of pressure pads on the drag angles. If any cracking is found, both service bulletins describe procedures for determining the length and position of each crack, and sending a report to the manufacturer for further corrective action.

Accomplishment of the actions specified in the service information is intended to adequately address the identified unsafe condition. The LFV classified this service information as mandatory and issued Swedish airworthiness directives 1-174 and 1-175, both dated April 30, 2002; and 1-180 and 1-181, both dated November 8, 2002; to ensure the continued airworthiness of these airplanes in Sweden.

FAA's Conclusions

This airplane model is manufactured in Sweden and is type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the LFV has kept us informed of the situation described above. We have examined the findings of the LFV, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.

Explanation of Requirements of Proposed AD

Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design registered in the United States, the proposed AD would require accomplishment of the actions specified in the service information described previously, except as discussed below.

Differences Among Swedish Airworthiness Directives, Service Information, and Proposed AD

Unlike the procedures described in the service bulletins, and referenced in the Swedish airworthiness directives, this proposed AD would not permit further flight if cracks are found in the drag and shear angles. We have determined that, because of the safety implications and consequences associated with such cracking, any cracked drag or shear angle must be repaired before further flight.

The compliance time specified in the table in paragraph 1.D., ‘Compliance,’ of Service Bulletin 2000-54-029 does not recommend a specific compliance time for the modification of the drag angles. The table cites cracking damage and different compliance times depending on the severity of the damage; however, we have determined the modification must be done before the accumulation of 24,000 flight cycles, as specified in the column citing no crack damage.

Swedish airworthiness directives 1-174 and 1-175 require following the repetitive inspection intervals specified in Table 1 of the referenced service bulletins (determined by the severity of the cracking); however, this proposed AD follows the repetitive inspection interval in the column citing no crack damage as specified in Table 1 of Service Bulletin 2000-54-028, Revision 01, for all airplanes.

The compliance times specified above represent an appropriate interval of time for affected airplanes to continue to operate without compromising safety.

The referenced service bulletins specify that operators may contact the manufacturer for disposition of certain repair (cracking) conditions; however, this proposed AD would not allow this option but would require operators to repair any cracking per a method approved by either the FAA or the LFV (or its delegated agent). In light of the type of repair that would be required to address the unsafe condition, and consistent with existing bilateral airworthiness agreements, we have determined that, for this proposed AD, a repair approved by either the FAA or the LFV would be acceptable for compliance with this proposed AD.

The referenced service bulletins also specify that operators may contact the manufacturer to obtain repetitive inspection intervals if the cracking exceeds certain parameters; however, we have determined that operators must obtain appropriate repetitive inspection/repair procedures from either the FAA or the LFV (or its delegated agent).

Although the service bulletins recommend that operators send the manufacturer a report of the inspection results, this proposed AD would not require submission of such a report.

The above differences have been coordinated with the LFV.

Clarification of Inspection Type

This proposed AD would specify a “detailed” inspection for cracking of the shear angles which attach the nacelle to the front spar of the wing, in lieu of a detailed “visual” inspection, as specified in Service Bulletin 2000-54-026, Revision 01. A note has been added to this proposed AD to define that inspection.

Cost Impact

We estimate that 3 airplanes of U.S. registry would be affected by this proposed AD.

It would take about 6 work hours per airplane to do the proposed inspections, at an average labor rate of $65 per work hour. Based on these figures, the cost impact of the proposed inspections on U.S. operators is estimated to be $1,170, or $390 per airplane, per inspection cycle.

It would take about 40 work hours per airplane to do the proposed modification of the shear angles, at an average labor rate of $65 per work hour. Required parts would cost about $6,200 per airplane. Based on these figures, the cost impact of the proposed modification on U.S. operators is estimated to be $26,400, or $8,800 per airplane.

It would take about 400 work hours per airplane to do the proposed modification of the drag angles, at an average labor rate of $65 per work hour. Required parts would cost about $41,794 per airplane. Based on these figures, the cost impact of the proposed modification on U.S. operators is estimated to be $203,382, or $67,794 per airplane.

The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the proposed requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions.

Regulatory Impact

The regulations proposed herein would 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 proposal would not have federalism implications under Executive Order 13132.

For the reasons discussed above, I certify that this proposed regulation (1) is not a “significant regulatory action” under Executive Order 12866; (2) is not a “significant rule” under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) if promulgated, 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 draft regulatory 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
• Safety

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 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.