AD 98-11-05

This amendment adopts a new airworthiness directive (AD), applicable to certain Saab Model SAAB 2000 series airplanes, that requires performing a one-time inspection of the dropout boxes of the passenger oxygen system to detect discrepancies and determine whether the system operates properly; correcting any discrepancy found; and reworking or installing new components, if necessary. This amendment is prompted by a report indicating that the oxygen system failed to operate correctly after activation at a low cabin pressure due to the incorrect installation of the oxygen masks or oxygen generators during manufacturing. The actions specified by this AD are intended to ensure that a sufficient supply of oxygen is provided to airplane passengers in the event of rapid decompression of the airplane.

Final rule

98-11-05 SAAB AIRCRAFT AB: Amendment 39-10532. Docket 96-NM-211-AD.
Applicability: Model SAAB 2000 series airplanes, having serial numbers -003 through -039 inclusive; certificated in any category.

NOTE 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (b) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required as indicated, unless accomplished previously.

To prevent an insufficient supply of oxygen being provided to airplane passengers in the event of rapid decompression of the airplane, accomplish the following:

(a) Within 30 days after the effective date of this AD, perform a one-time inspection of the dropout boxes of the passenger oxygen system to detect discrepancies and determine whether the system operates properly, in accordance with the Accomplishment Instructions of Saab Service Bulletin 2000-35-001, dated February 20, 1996.

(1) If the passenger oxygen system operates properly and no discrepancy is found in this system, no further action is required by this AD.

(2) If any discrepancy is found in the passenger oxygen system, prior to further flight, perform rework or install new components, as applicable, in accordance with the service bulletin.

(b) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, International Branch, ANM-116.

NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the International Branch, ANM-116.

(c) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.

(d) The actions shall be done in accordance with Saab Service Bulletin 2000-35-001, dated February 20, 1996. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Saab Aircraft AB, SAAB Aircraft Product Support, S-581.88, Linkoping, Sweden. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

NOTE 3: The subject of this AD is addressed in Swedish airworthiness directive (SAD) 1-091, dated February 20, 1996.

(e) This amendment becomes effective on July 2, 1998.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain Saab Model SAAB 2000 series airplanes was published in the Federal Register on May 22, 1997 (62 FR 27986). That action proposed to require performing a one-time inspection of the dropout boxes of the passenger oxygen system to detect discrepancies and determine whether the system operates properly; correcting any discrepancy found; and reworking or installing new components, if necessary.

Comments
Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received.

One commenter supports the proposed AD; however, it notes that many different types of failures were discovered upon review by the Luftfartsverket (LFV), which is the airworthiness authority for Sweden. Additionally, the commenter states that the repair work performed to correct the errors also could be performed incorrectly. The commenter requests that because of these two factors, the FAA should require repetitive inspections in lieu of the proposed one-time inspection.

The FAA does not concur with the commenter's request to include repetitive inspections in this rulemaking action at this point. According to Saab, the problem was found to originate from the interior supplier's repacking of the oxygen equipment after installing the dropout boxes in the passenger service units. This finding led to several improvements and related instructions by Saab and the interior and systems suppliers regarding the packing method. These improvements also included hands-on training. Saab is not aware of any further problems occurring with the dropout boxes after implementation of these improvements. Therefore, the FAA has determined that repetitive inspections to ensure the continued proper functioning of the system are notnecessary.

The same commenter states that it is unacceptable to operate aircraft with emergency equipment that would not work when needed, and suggests that it would be prudent to periodically perform functional tests of all the emergency equipment to ensure that it will work when needed.

The FAA acknowledges the concerns of the commenter. The FAA has determined that an unsafe condition exists, and that the actions required by this AD are adequate in order to ensure the continued safety of the affected fleet. While there may be merit to the commenter's suggestions, this AD is not the appropriate context in which to evaluate those suggestions. Since the suggested changes would alter the actions currently required by this AD, additional rulemaking would be required. The FAA finds that to delay this action would be inappropriate in light of the identified unsafe condition. No change to this final rule is necessary.

Conclusion
After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed. Cost Impact

The FAA estimates that 3 Saab Model SAAB 2000 series airplanes of U.S. registry will be affected by this AD, that it will take approximately 3 work hours per airplane to accomplish the required actions, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $540, or $180 per airplane.

The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted.

Regulatory Impact
The regulations adopted herein will not have substantial direct effects 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, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

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 final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from 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, pursuant to 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. Section 39.13 is amended by adding the following new airworthiness directive: