AD 99-15-07

This amendment adopts a new airworthiness directive (AD) that applies to all deHavilland Inc. (deHavilland) Models DHC-2 Mk. I, DHC-2 Mk. II, and DHC-2 Mk. III airplanes. This AD requires repetitively inspecting the rear fuselage bulkhead at Station 228 for cracks. This AD also requires repairing any crack found or replacing any cracked rear fuselage bulkhead in accordance with a repair or replacement scheme obtained from the manufacturer through the Federal Aviation Administration (FAA). This AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Canada. The actions specified by this AD are intended to detect and correct cracking of the rear fuselage bulkhead at Station 228, which could result in structural damage of the fuselage to the point of failure with consequent loss of airplane control.

Final rule.

99-15-07 DEHAVILLAND INC.: Amendment 39-11226; Docket No. 99-CE-05-AD.

Applicability: Models DHC-2 Mk. I, DHC-2 Mk. II, and DHC-2 Mk. III airplanes, all serial numbers, 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 (d) 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 in the bodyof this AD, unless already accomplished.

To detect and correct cracking of the rear fuselage bulkhead at Station 228, which could result in structural damage of the fuselage to the point of failure with consequent loss of airplane control, accomplish the following:

(a) Within the next 400 hours time-in-service (TIS) after the effective date of this AD or within the next 12 calendar months after the effective date of this AD, whichever occurs first, and thereafter at intervals not to exceed 2,000 hours TIS or 5 years, whichever occurs first, inspect the rear fuselage bulkhead at Station 228 for cracks. Inspect in accordance with the Accomplishment Instructions section of whichever of the following service bulletins that is applicable:

(1) For the Models DHC-2 Mk. I and DHC-2 Mk. II airplanes: deHavilland Beaver Service Bulletin 2/52, dated August 30, 1998; or

(2) For the Model DHC-2 Mk. III airplanes: deHavilland Beaver Service Bulletin TB/60, dated August 30,1998.

(b) If any crack(s) is/are found in the rear fuselage bulkhead at Station 228 during any inspection required by paragraph (a) of this AD, prior to further flight, accomplish the following:

(1) Obtain a repair or replacement scheme from the manufacturer through the FAA, New York Aircraft Certification Office (ACO), 10 Fifth Street, 3rd Floor, Valley Stream, New York 11581-1200; facsimile: (516) 568-2716.

(2) Incorporate this repair or replacement scheme.

(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) An alternative method of compliance or adjustment of the initial or repetitive compliance times that provides an equivalent level of safety may be approved by the Manager, New York ACO, 10 Fifth Street, 3rd Floor, Valley Stream, New York 11581-1200. The requestshall be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, New York ACO.

NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the New York ACO.

(e) Questions or technical information related to deHavilland Beaver Service Bulletin TB/60, dated August 30, 1998, and deHavilland Beaver Service Bulletin 2/52, dated August 30, 1998, should be directed to Bombardier Inc., Bombardier Regional Aircraft Division, Garratt Boulevard, Downsview, Ontario, Canada M3K 1Y5; telephone: (416) 633-7310. This service information may be examined at the FAA, Central Region, Office of the Regional Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106.

(f) The inspections required by this AD shall be done in accordance with deHavilland Beaver Service Bulletin TB/60, dated August 30, 1998, or deHavilland Beaver Service Bulletin 2/52, dated August 30, 1998. 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 Bombardier Inc., Bombardier Regional Aircraft Division, Garratt Boulevard, Downsview, Ontario, Canada M3K 1Y5. Copies may be inspected at the FAA, Central Region, Office of the Regional Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri, 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 Canadian AD No. CF-98-38, dated October 15, 1998.

(g) This amendment becomes effective on September 10, 1999.

Events Leading to the Issuance of This AD

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD that would apply to all deHavilland Models DHC-2 Mk. I, DHC-2 Mk. II, and DHC-2 Mk. III airplanes was published in the Federal Register as a notice of proposed rulemaking (NPRM) on April 23, 1999 (64 FR 19932). The NPRM proposed to require repetitively inspecting the rear fuselage bulkhead at Station 228 for cracks. Accomplishment of the proposed repetitive inspections as specified in the NPRM would be required in accordance with deHavilland Beaver Service Bulletin 2/52, dated August 30, 1998, and deHavilland Beaver Service Bulletin TB/60, dated August 30, 1998. The NPRM also proposed to require repairing any crack found or replacing any cracked rear fuselage bulkhead. Accomplishment of the proposed repair or replacement as specified in the NPRM would be required in accordance with a repair or replacement scheme obtained from the manufacturer through the FAA.

The NPRM was the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Canada.

Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were received on the proposed rule or the FAA's determination of the cost to the public.

The FAA's Determination

After careful review of all available information related to the subject presented above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed except for minor editorial corrections. The FAA has determined that these minor corrections will not change the meaning of the AD and will not add any additional burden upon the public than was already proposed.

Compliance Time of This AD

The compliance time of this AD is presented in both calendar time and hours time-in-service (TIS). While cracks are generally a result of classic fatigue (i.e., aging and cyclic operation), the FAA believes that cracks could develop over time regardless of how often the airplane is operated. In order to assure that rear fuselage bulkhead cracking does not go undetected, a compliance time of specific hours TIS and calendar time (whichever occurs first) is utilized.

Cost Impact

The FAA estimates that 350 airplanes in the U.S. registry will be affected by this AD, that it will take approximately 1 workhour per airplane to accomplish the initial inspection, and that the average labor rate is approximately $60 an hour. Based on these figures, the total cost impact of the initial inspection on U.S. operators is estimated to be $21,000, or $60 per airplane.

These figures only take into the account the costs of the initial inspection and do not take into account the costs of the repetitive inspections or the cost of any repair or replacement necessary if any rear fuselage bulkhead is found cracked. The FAA has no way of determining the number of repetitive inspections each owner/operator will incur over the life of his/her affected airplane or the number of airplanes that will have a cracked rear fuselage bulkhead and need repair or replacement.

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 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, 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 a new airworthiness directive (AD) to read as follows: