AD 98-24-18

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Bombardier Model DHC-8-102 and -103 series airplanes, that currently requires a one-time inspection to detect disbonding of the upper and lower skin panels of the horizontal stabilizer, and repair, if necessary. This amendment establishes repetitive intervals for the inspection to detect disbonding of the upper and lower skin panels of the horizontal stabilizer. This amendment also revises the applicability of the existing AD to include certain additional airplanes, and to exclude certain other airplanes. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to prevent reduced strength capability and consequent failure of the horizontal stabilizer, which could result in loss of controllability of the airplane.

Final Rule

98-24-18 BOMBARDIER, INC. (Formerly de Havilland, Inc.): Amendment 39-10903. Docket 98-NM-299-AD. Supersedes AD 98-05-03, Amendment 39-10389.

Applicability: Model DHC-8-100 and -300 series airplanes, equipped with Canadian Aviation Products (CAP) horizontal stabilizers having serial numbers CAP 003 through CAP 214 inclusive, certificated in any category.

NOTE 1: It may be necessary to check the data plate on the left side of the horizontal stabilizer to determine the serial number of the horizontal stabilizer, because the serial number of the horizontal stabilizer may not be the same as the airplane serial number.

NOTE 2: 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/operatormust request approval for an alternative method of compliance in accordance with paragraph (f)(1) 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 reduced strength capability and consequent failure of the horizontal stabilizer, which could result in loss of controllability of the airplane, accomplish the following:

RESTATEMENT OF REQUIREMENTS OF AD 98-05-03:

NOTE 3: Accomplishment of the actions required by paragraph (a) of this AD is not intended to supersede the ongoing requirements of the Airworthiness Limitation identified in the Maintenance Review Board (MRB) report as Task 5500/01.

(a) For Model DHC-8-102 and -103 series airplanes having serial numbers 003through 050 inclusive: Perform a one-time ultrasonic bond inspection to detect disbonding of the upper and lower skin panels of the horizontal stabilizer, at the time specified in paragraph (a)(1) or (a)(2) of this AD, as applicable; in accordance with de Havilland Product Support Manual (PSM) 1-8-7A, part 5, section 55-00-01, dated July 15, 1996.

(1) For airplanes having serial numbers 010 through 040 inclusive: Inspect within 20 flight cycles or 7 days after March 17, 1998 (the effective date of AD 98-05-03, amendment 39-10389), whichever occurs first.

(2) For airplanes having serial numbers 003 through 009 inclusive and 041 through 050 inclusive: Inspect within 60 flight cycles or 7 days after March 17, 1998, whichever occurs first.

(b) If any disbonding is found during the inspection required by paragraph (a) of this AD: Prior to further flight, accomplish the actions specified by paragraph (b)(1), (b)(2), or (b)(3) of this AD, as applicable.

(1) If the disbonding is below (smaller than) the limits specified in the PSM, no further action is required by this paragraph.

(2) If the disbonding is within the limits specified in the PSM, repair the disbonded area in accordance with the DHC-8 Structural Repair Manual PSM 1-8-3.

(3) If the disbonding exceeds the limits specified in the PSM or if a repair is not provided by the PSM, repair the disbonded area in accordance with a method approved by the Manager, New York Aircraft Certification Office (ACO), FAA, Engine and Propeller Directorate.

NOTE 4: Where differences between this AD and the parallel Canadian airworthiness directive exist, this AD prevails.

(c) Within 2 days after performing the inspection required by paragraph (a) of this AD: Submit a report of inspection findings, regardless of the results, to the Manager, New York ACO, FAA, Engine and Propeller Directorate, 10 Fifth Street, Third Floor, Valley Stream, New York 11581; fax (516) 568-2716. The report must includethe airplane serial number, the stringer number, and the extent (length or surface area) of disbonding. For inspections performed after the effective date of this AD, reports also must include the horizontal stabilizer CAP number. (Operators may follow the guidelines provided in Figure 2 of de Havilland PSM 1-8-7A for reporting requirements.) Information collection requirements contained in this regulation have been approved by the Office of Management and Budget (OMB) under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have been assigned OMB Control Number 2120-0056.

NEW REQUIREMENTS OF THIS AD:

(d) For Model DHC-8-100 and -300 series airplanes equipped with CAP horizontal stabilizers having serial numbers CAP 003 through CAP 214 inclusive: Perform an ultrasonic bond inspection to detect disbonding of the upper and lower skin panels of the horizontal stabilizer, in accordance with de Havilland Product Support Manual (PSM) 1-8-7A, part 5,section 55-00-01, dated July 15, 1996; at the time specified in paragraph (d)(1) or (d)(2) of this AD, as applicable.

(1) For Model DHC-8-100 and -300 series airplanes equipped with CAP horizontal stabilizers having serial numbers CAP 003 through CAP 050 inclusive: Inspect within 1 month after the effective date of this AD, unless accomplished within 1 month prior to the effective date of this AD.

(i) If no disbonding is detected, repeat the inspection one time within 14 months after the most recent inspection, but no earlier than 12 months after the most recent inspection. Thereafter, repeat the inspection at intervals not to exceed 2 years after the most recent inspection.

(ii) If any disbonding is detected, prior to further flight, accomplish the actions specified by paragraph (b)(1), (b)(2), or (b)(3) of this AD, as applicable. Repair of the disbonded area in accordance with the DHC-8 Structural Repair Manual PSM 1-8-3 constitutes terminating action for the repetitive inspection requirements specified in paragraph (d)(1)(i) of this AD.

(2) For Model DHC-8-100 and -300 series airplanes equipped with CAP horizontal stabilizers having serial numbers CAP 051 through CAP 214 inclusive: Inspect at the next regularly scheduled maintenance period, but no later than 90 days after the effective date of this AD, unless the inspection was accomplished within 10 months prior to the effective date of this AD.

(i) If no disbonding is detected, repeat the inspection thereafter at intervals not to exceed 2 years. For airplanes that were inspected within 10 months prior to the effective date of this AD, repeat the inspection at an interval not to exceed 2 years after the most recent inspection, and thereafter at intervals not to exceed 2 years.

(ii) If any disbonding is detected, prior to further flight, accomplish the actions specified by paragraph (b)(1), (b)(2), or (b)(3) of this AD, as applicable. Repair of the disbonded area in accordance withthe DHC-8 Structural Repair Manual PSM 1-8-3 constitutes terminating action for the repetitive inspection requirements specified in paragraphs (d)(2)(i) of this AD for the repaired area.

(e) For any inspection performed in accordance with paragraph (d) of this AD, submit a report of inspection findings, regardless of the results, to Bombardier Aerospace Regional Aircraft Technical Services, phone (416) 375-4000, fax (416) 375-4539. Submit the report at the time specified in paragraph (e)(1), (e)(2), or (e)(3) of this AD, as applicable. The report must include the airplane serial number, horizontal stabilizer CAP number, and the extent (length or surface area) of disbonding. (Operators may follow the guidelines provided in Figure 2 of de Havilland PSM 1-8-7A for reporting requirements.) Information collection requirements contained in this regulation have been approved by the OMB under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have been assigned OMB Control Number 2120-0056.

(1) For any inspection performed after the effective date of this AD: Submit a report within 7 days after the inspection.

(2) For inspections performed within 1 month prior to the effective date of this AD, as specified in paragraph (d)(1) of this AD: Submit a report within 7 days after the effective date of this AD.

(3) For inspections performed within 10 months prior to the effective date of this AD, as specified in paragraph (d)(2) of this AD: Submit a report within 7 days after the effective date of this AD.

(f)(1) 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, New York ACO. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, New York ACO.

(g)(2) Alternative methods of compliance, approved previously in accordance with AD 98-05-03, amendment 39-10389, are approved as alternative methods of compliance with this AD.

NOTE 5: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the New York ACO.

(h) 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.

NOTE 6: The subject of this AD is addressed in Canadian airworthiness directive CF-98-24, dated August 19, 1998.

(i) This amendment becomes effective on December 8, 1998.

On March 5, 1998, the FAA issued AD 98-05-03, amendment 39-10389 (63 FR 11987, March 12, 1998), applicable to certain Bombardier (formerly de Havilland) Model DHC-8-102 and -103 series airplanes, to require a one-time inspection to detect disbonding of the upper and lower skin panels of the horizontal stabilizer, and repair, if necessary. That action was prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions required by that AD are intended to prevent reduced strength capability and consequent failure of the horizontal stabilizer, which can result in loss of controllability of the airplane.

Actions Since Issuance of Previous Rule

Transport Canada Aviation (TCA), which is the airworthiness authority for Canada, notified the FAA that, during the one-time inspection performed in accordance with AD 98-05-03 and the parallel Canadian airworthiness directive CF-98-01, disbonding of doublers and stringers from the upper and lower skin of the horizontal stabilizer was detected on several Model DHC-8-102 and -103 series airplanes. Because these airplanes were close together in serial number, the problem of disbonding was attributed to discrepancies in the bonding process on a single batch of skin panels installed on certain Bombardier Model DHC-8-102 and -103 series airplanes.

As a result of these findings, TCA issued Canadian airworthiness directive CF-98-24, dated August 19, 1998, to require repetitive ultrasonic inspections to detect disbonding of the upper and lower skin panels of the horizontal stabilizer. During repeat inspections performed in accordance with that airworthiness directive, disbonding was detected on several airplanes on which no disbonding was detected during the initial inspection.

Based on the information provided by TCA, the FAA has determined that the one-time inspection required by AD 98-05-03 may not be adequate to detect disbonding of the upper and lower skin panels of the horizontal stabilizer and, therefore, may not be providing an adequate level of safety for the transport airplane fleet.

FAA's Conclusions

This airplane model is manufactured in Canada 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, TCA has kept the FAA informed of the situation described above. The FAA has examined the findings of TCA, 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 Rule

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, this AD supersedes AD 98-05-03 to require repetitive ultrasonic inspections to detect disbonding of the upper and lower skin panels of the horizontal stabilizer, and repair, if necessary. In addition, this AD also revises the applicability of the existing AD to include certain additional airplanes, and to exclude certain other airplanes. This AD also requires that operators report inspection results, both positive and negative findings, to Bombardier.

Interim Action

This is considered to be interim action until final action is identified, at which time the FAA may consider further rulemaking.

Differences Between This Rule and the Foreign Airworthiness Directive

Operators should note that the parallel Canadian airworthiness directive CF-98-24 specifies that any disbonding that is detected that is beyond the local disbonding limits specified in de Havilland Product Support Manual (PSM) 1-8-7A, part 5, section 55-00-01, dated July 15, 1996, shall be repaired prior to further flight. However, this ADrequires that all disbonding, whether it is within or beyond the limits, be repaired prior to further flight. This AD also specifies that disbonding that exceeds the limits specified in the PSM must be repaired in accordance with a method approved by the FAA.

Explanation of Applicability

Operators should note that AD 98-05-03 and parallel Canadian airworthiness directive CF-98-01, dated February 19, 1998, are applicable to Model DHC-8-102 and -103 series airplanes having serial numbers 003 through 050 inclusive. Since the issuance of AD 98-05-03, TCA has advised the FAA that the serial numbers of the airplanes may differ from the Canadian Aviation Products (CAP) serial number of the horizontal stabilizer. Therefore, it may be necessary for operators to check the data plate located on the left side of the horizontal stabilizer to determine the serial number of the horizontal stabilizer. Also, the applicability of Canadian airworthiness directive CF-98-24 includes additional airplanes. For these reasons, this AD (and parallel Canadian airworthiness directive CF-98-24) is applicable to Model DHC-8-100 and -300 series airplanes equipped with a CAP horizontal stabilizer having serial numbers CAP 003 through CAP 214 inclusive.

Determination of Rule's Effective Date

Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days.

Comments Invited

Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted intriplicate to the address specified under the caption "ADDRESSES." All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the 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 that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 98-NM-299-AD." The postcard will be date stamped and returned to the commenter.

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.

The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policiesand Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, 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, 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 removing amendment 39-10389 (63 FR 11987, March 12, 1998), and by adding a new airworthiness directive (AD), amendment 39-10903, to read as follows: