Airworthiness Directives; Bombardier Model DHC-8-400 Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain Bombardier Model DHC-8-400 airplanes. That AD currently requires revising the Normal and Abnormal sections of the airplane flight manual (AFM) to include procedures that enable the flightcrew to determine if the main landing gear (MLG) is extended before landing, and to take appropriate actions if necessary. This new action would add an airplane to the applicability, and require replacing the existing MLG downlock proximity sensors with new, improved sensors. After the replacement, this action would also require removing from the AFM the revision to the Normal and Abnormal sections require by the existing AD. The actions specified by the proposed AD are intended to prevent failure of the MLG downlock proximity sensors on the same MLG at the same time, which could result in the MLG's failure to extend during landing, and cause injury to flightcrew and passengers.

DATES:

Comments must be received by June 7, 2004.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2002-NM-234-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. Commments 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-234-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 for Windows or ASCII text.

The service information referenced in the proposed rule may be obtained from Bombardier, Inc., Bombardier Regional Aircraft Division, 123 Garratt Boulevard, Downsview, Ontario M3K 1Y5, Canada. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, New York Aircraft Certification Office, 1600 Stewart Avenue, Westbury, New York 11590.

FOR FURTHER INFORMATION CONTACT:

Dan Parillo, Aerospace Engineer, Systems and Flight Test Branch, ANE-172, FAA, New York Aircraft Certification Office, 1600 Stewart Avenue, Westbury, New York 11590; telephone (516) 228-7305; fax (516) 794-5531.

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-234-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-234-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

On May 25, 2001, the FAA issued AD 2001-11-10, amendment 39-12253 (66 FR 30305, June 6, 2001), applicable to certain Bombardier Model DHC-8-400 series airplanes, to require revising the Normal and Abnormal sections of the airplane flight manual (AFM) to include procedures that enable the flightcrew to determine if the main landing gear (MLG) is extended before landing and to take appropriate actions if necessary. That action was prompted by notification from Transport Canada Civil Aviation (TCCA), which is the airworthiness authority for Canada, that MLG downlock proximity sensors may fail concurrently on the same gear. The requirements of that AD are intended to ensure that the flightcrew is advised of a potential gear-up landing due to misleading indications for the MLG extension, and has the procedures necessary to address that potential condition.

Actions Since Issuance of Previous Rule

The preamble to AD 2001-11-10 explains that we considered the requirements of that AD “interim action” and were considering further rulemaking. We now have determined that further rulemaking is indeed necessary, and this proposed AD follows from that determination.

We also have revised the applicability of the existing AD to include an additional airplane that was inadvertently omitted from the applicability of Canadian airworthiness directive CF-2001-16, dated April 11, 2001, which was used as a source of applicability information for AD 2001-11-10. Canadian airworthiness directive CF-2001-16R1, dated June 3, 2002, has since been issued to include the additional airplane and is used as a source for applicability information in this proposed AD.

Explanation of Relevant Service Information

Bombardier has issued Service Bulletin 84-32-09, Revision A, dated November 20, 2001, which describes procedures for replacing the existing MLG downlock proximity sensors with new, improved proximity sensors, and rigging the new sensors in accordance with the airplane maintenance manual. Accomplishment of the actions specified in the service bulletin is intended to adequately address the identified unsafe condition.

TCCA classified this service bulletin as mandatory and issued Canadian airworthiness directive CF-2001-16R1, dated June 3, 2002, to ensure the continued airworthiness of these airplanes in Canada.

The Bombardier service bulletin references Menasco Aerospace Service Bulletin 46400-32-09, dated May 15, 2001, as an additional source of service information for accomplishment of the replacement. The Menasco service bulletin is included in the Bombardier service bulletin.

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, TCCA has kept the FAA informed of the situation described above. The FAA has examined the findings of TCCA, 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 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, the proposed AD would supersede AD 2001-11-10 to continue to require revising the Normal and Abnormal sections of the AFM to include procedures that enable the flightcrew to determine if the MLG is extended before landing, and to take appropriate actions if necessary. This new action would add an airplane to the applicability. This new action also would require replacing the existing MLG downlock proximity sensors with new, improved proximity sensors and rigging the new sensors in accordance with the airplane maintenance manual. After the replacement, this new action would also require removing from the AFM the revision to the Normal and Abnormal sections required by the existing AD. The actions would be required to be accomplished in accordance with the service bulletin described previously, except as discussed below.

Differences Between the Proposed AD and the Menasco Service Bulletin

Operators should note that, although the Menasco service bulletin contains procedures for returning certain parts to the manufacturer (BF Goodrich), this proposed AD would not include this requirement.

Changes to 14 CFR Part 39/Effect on the Proposed AD

On July 10, 2002, the FAA issued a new version of 14 CFR part 39 (67 FR 47997, July 22, 2002), which governs the FAA's airworthiness directives system. The regulation now includes material that relates to altered products, special flight permits, and alternative methods of compliance. Because we have now included this material in part 39, we no longer need to include it in each individual AD; therefore, paragraphs (b) and (c) and Note 1 of AD 2001-11-10 are not included in this proposed AD. However, this proposed AD identifies the office authorized to approve alternative methods of compliance.

Cost Impact

There are approximately 15 airplanes of U.S. registry that would affected by this proposed AD.

The revision of the AFM that is currently required by AD 2001-11-10 takes approximately 1 work hour per airplane to accomplish, at an average labor rate of $65 per work hour. Based on these figures, the cost impact of the currently required actions on U.S. operators is estimated to be $975, or $65 per airplane.

The replacement that is proposed in this AD action would take approximately 4 work hours per airplane to accomplish, at an average labor rate of $65 per work hour. Required parts would be provided free of charge. Based on these figures, the cost impact of the proposed requirements of this AD on U.S. operators is estimated to be $3,900, or $260 per airplane.

The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the current or proposed 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 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 my be the Administrator, the Federal 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.