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Rule

Airworthiness Directives; Bombardier Model DHC-8-400, -401, and -402 Series Airplanes

Document Details

Information about this document as published in the Federal Register.

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Start Preamble

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule; request for comments.

SUMMARY:

This amendment adopts a new airworthiness directive (AD) that is applicable to certain Bombardier Model DHC-8-400, -401, and -402 series airplanes. This action requires revising the Airplane Flight Manual to advise the flight crew of appropriate procedures to follow in the event that a main landing gear (MLG) fails to extend following a gear-down selection. This action also requires replacement of the left and right MLG uplock assemblies with new assemblies; and an inspection of the left and right MLG uplock rollers for the presence of an inner low friction liner, and corrective actions if necessary. This action is necessary to ensure that the flight crew has the procedures necessary to address failure of an MLG to extend following a gear-down selection; and to detect and correct such failure, which could result in a gear-up landing and possible injury to passengers and crew.

DATES:

Effective April 23, 2002.

The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of April 23, 2002.

Comments for inclusion in the Rules Docket must be received on or before May 20, 2002.

Start Printed Page 19102

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2002-NM-35-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9:00 a.m. and 3:00 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-iarcomment@faa.gov. Comments sent via the Internet must contain “Docket No. 2002-NM-35-AD” in the subject line and need not be submitted in triplicate. Comments sent via fax or the Internet as attached electronic files must be formatted in Microsoft Word 97 for Windows or ASCII text.

The service information referenced in this AD 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, 10 Fifth Street, Third Floor, Valley Stream, New York; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

Start Further Info

FOR FURTHER INFORMATION CONTACT:

Ezra Sasson, Aerospace Engineer, Systems and Flight Test Branch, ANE-172, FAA, New York Aircraft Certification Office, 10 Fifth Street, Third Floor, Valley Stream, New York 11581; telephone (516) 256-7520; fax (516) 568-2716.

End Further Info End Preamble Start Supplemental Information

SUPPLEMENTARY INFORMATION:

Transport Canada Civil Aviation (TCCA), which is the airworthiness authority for Canada, recently notified the FAA that an unsafe condition may exist on certain Bombardier Model DHC-8-400, -401, and -402 series airplanes. TCCA advises that the flight crew of a Bombardier Model DHC-8-400 series airplane experienced difficulties in extending the right main landing gear (MLG) following a gear-down selection. During that event, when subsequent use of the alternate landing gear extension procedure failed to extend the affected gear, the MLG was retracted and a second alternate gear extension was performed. This resulted in the MLG successfully extending to the down and locked position.

Inspection of the MLG revealed a groove in the lower jaw of the uplock hook on the MLG uplock assembly due to premature wear. Findings indicate that excessive wear to the uplock hook could prevent release of the roller, and the inability to extend the MLG with either the normal, or alternate, landing gear extension procedure. Findings also indicate that the low friction (black-colored) liner of the uplock rollers was omitted on a batch lot of uplock rollers, including the subject airplane.

Conditions that could cause failure of the MLG to extend, following a gear-down selection, include the absence of an uplock roller, absence of an approved liner, or presence of an unapproved or damaged uplock roller. These conditions, if not corrected, could result in the inability of the flight crew to extend the MLG, which could result in a gear-up landing and possible injury to passengers and crew.

Explanation of Relevant Service Information

Bombardier has issued DHC-8 Alert Service Bulletin A84-32-15, dated February 4, 2002, which describes procedures for a one-time inspection of the inside surface of the uplock roller on the shock strut of the MLG for the presence of an inner low friction (black-colored) liner, and corrective actions if necessary. If a low friction liner is present, operators may reinstall the existing uplock roller, or replace the uplock roller with a new uplock roller having a low friction liner. If the bore of the uplock roller has a bright metal finish, indicating the absence of a liner, operators must replace the existing uplock roller with a new uplock roller having a low friction liner. In addition, the alert service bulletin references Chapter 32-11-01, dated January 5, 2001, of Bombardier Series 400 Aircraft Maintenance Manual (AMM), PSM 1-84-2, as a secondary source of service information for replacing the MLG uplock roller with a new roller having a low friction liner.

Chapter 32-31-21, dated January 5, 2001, of Bombardier Series 400 AMM, PSM 1-84-2, describes procedures for replacing existing MLG uplock assemblies with new assemblies.

Transport Canada Civil Aviation (TCCA), which is the airworthiness authority for Canada, has issued Canadian airworthiness directive CF-2002-13, dated February 4, 2002, to assure the continued airworthiness of these airplanes in Canada. That airworthiness directive specifies procedures for revising the Airplane Flight Manual (AFM); replacing the left and right MLG uplock assemblies with new assemblies per Chapter 32-31-21 of Bombardier Series 400 AMM, PSM 1-84-2; and inspecting the uplock roller, and taking corrective action if necessary.

FAA's Conclusions

These airplane models are manufactured in Canada and are type certificated for operation in the United States under the provisions of § 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the TCCA has kept the FAA informed of the situation described above. The FAA has determined that the primary cause of the failure of the right MLG to extend and the uplock assembly to disengage, following a gear-down selection, is the design of the uplock assembly. However, we also consider that the uplock roller, which involves a quality control problem, may have contributed to such failure. The FAA has examined the findings of the 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 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 is being issued to require a revision to the Limitations section, and certain paragraphs of the Normal and Alternate Extension Procedures, of the FAA-approved AFM, to advise the flight crew of appropriate procedures to follow in the event that an MLG fails to extend following a gear-down selection; replacement of the left and right MLG uplock assemblies; and a one-time inspection of the left and right MLG uplock rollers for the presence of an inner low friction liner, and corrective actions if necessary. The actions required by this AD must be accomplished per the alert service bulletin and the AMM, except as described below.

Differences Between Alert Service Bulletin, and the Canadian Airworthiness Directive and This AD

The Bombardier alert service bulletin specifies procedures only for an inspection of the left and right MLG uplock rollers, and corrective actions if necessary. However, in addition to that procedure, the Canadian airworthiness directive and this AD also specify procedures for revising the AFM and replacing the MLG uplock assemblies.

Differences Between the Canadian Airworthiness Directive and This AD

The Canadian airworthiness directive specifies inspection/replacement of the left and right MLG uplock rollers per Bombardier DHC-8 Alert Service Start Printed Page 19103Bulletin A84-32-15, dated February 4, 2002, “or later revisions of the alert service bulletin.” However, paragraph (c) of this AD requires accomplishment of the one-time inspection of the MLG uplock rollers, and corrective actions if necessary, per the alert service bulletin, dated February 4, 2002. Where a specific service bulletin is referenced in an AD, the use of the phrase “or later revisions of the service bulletin,” violates Office of the Federal Register regulations regarding approval of materials that are incorporated by reference, and, therefore may not be specified in this AD.

Interim Action

This is considered to be interim action. Bombardier has advised that it is currently evaluating a possible modification to the uplock assembly to minimize wear to the uplock hook and to ensure a more positive uplock release, which will positively address the unsafe condition addressed by this AD. Once this modification is developed, approved, and available, the FAA may consider additional rulemaking.

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 in triplicate 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.

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 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 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 2002-NM-35-AD.” The postcard will be date stamped and returned to the commenter.

Regulatory Impact

The regulations adopted herein will 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 final rule does not have federalism implications under Executive Order 13132.

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 Policies and 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.

Start List of Subjects

List of Subjects in 14 CFR Part 39

End List of Subjects

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:

Start Part

PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Start Authority

Authority: 49 U.S.C. 106(g), 40113, 44701.

End Authority
[Amended]

2. Section 39.13 is amended by adding the following new airworthiness directive:

2002-08-05 Bombardier, Inc: Amendment 39-12713. Docket 2002-NM-35-AD.

Applicability: Model DHC-8-400, -401, and -402 series airplanes; serial numbers 4001 and subsequent; 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, unless accomplished previously.

To ensure that the flight crew has the procedures necessary to address failure of the main landing gears (MLG) to extend following a gear-down selection; and to detect and correct such failure, which could result in a gear-up landing and possible injury to passengers and crew; accomplish the following:

Revision of FAA-Approved Airplane Flight Manual (AFM)

(a) Within 3 days after the effective date of this AD, amend all copies of the FAA-approved Bombardier Series 400 AFM, PSM 1-84-1A (for Models 400, 401, and 402), by adding the following procedure to the Limitations section of the AFM, and opposite page 4-21-1 of the AFM; and advise all flight crew members of these changes; (the revision may be accomplished by inserting a copy of this AD into the Limitations section of the AFM and affected paragraphs of the AFM):

“If ONE main landing gear fails to extend after performing landing gear extension per normal procedures given in paragraph 4.3.7 and alternate extension procedures per paragraph 4.21.1 of the AFM:

1. Visually confirm that the affected gear has not extended and that the associated doors have opened.

2. Ensure No. 2 hydraulic system pressure and quantity are normal and the following landing gear advisory lights are illuminated: Start Printed Page 19104selector lever amber, gear green locked down (nose and non-affected main gear), red gear unlocked (affected main gear) and all amber doors open.

3. NOSE L/G RELEASE handle—Return to the stowed position.

4. LANDING GEAR ALTERNATE EXTENSION door—Close fully.

5. MAIN L/G RELEASE handle—Return to the stowed position.

6. LANDING GEAR ALTERNATE RELEASE door—Close fully.

7. LANDING GEAR lever—DN.

8. L/G DOWN SELECT INHIBIT SW—Normal and guarded. Check amber doors open advisory lights out (nose and non-affected main gear) and LDG GEAR INOP caution light out.

9. LANDING GEAR lever—UP Check all gear, door and LANDING GEAR lever advisory lights out.

10. With minimum delay, LANDING GEAR lever—DN. Check 3 green gear locked down advisory lights illuminate, all amber doors open, red gear unlocked and selector lever amber advisory lights out.

11. Items 9 and 10 may be repeated in an effort to achieve 3 gear down and locked.

CAUTION

Should the LDG GEAR INOP caution light illuminate, or loss of no. 2 hydraulic system pressure or quantity, or any abnormality in landing gear system indication other than those associated with the affected main landing gear be experienced, see paragraph 4.21.1 ALTERNATE LANDING GEAR EXTENSION.”

Replacement of Uplock Assembly

(b) At the later of the times specified in paragraph (b)(1) or (b)(2) of this AD: Replace the left and right MLG uplock assemblies, part number (P/N) 46500-3, with new uplock assemblies, P/N 46500-3, per Chapter 32-31-21, dated January 5, 2001, of Bombardier Series 400 Aircraft Maintenance Manual, PSM 1-84-2. Do the replacement thereafter at intervals not to exceed 2,500 flight hours or 3,000 flight cycles, whichever occurs earlier.

(1) Before the accumulation of 2,500 total flight hours or 3,000 total flight cycles, whichever occurs earlier; or

(2) Within 14 days after the effective date of this AD.

Note 2:

Bombardier DHC-8 Alert Service Bulletin A84-32-15, dated February 4, 2002, references Chapter 32-11-01, dated January 5, 2001, of Bombardier Series 400 AMM, PSM 1-84-2, as an additional source of service information for procedures to replace an MLG uplock roller.

One-Time Inspection of MLG Uplock Rollers

(c) Within 30 days after the effective date of this AD, inspect the left and right MLG uplock rollers for the presence of an inner low friction (black-colored) liner, per the Accomplishment Instructions of Bombardier DHC-8 Alert Service Bulletin A84-32-15, dated February 4, 2002; and, before further flight, do the actions required by paragraph (c)(1) or (c)(2) of this AD.

Corrective Actions

(1) If a low friction liner is present, reinstall the existing uplock roller; or install a new uplock roller, P/N 46575-1, having a low friction liner; on the shock strut of the MLG; per the alert service bulletin.

(2) If a low friction liner is NOT present, replace the existing uplock roller with a new uplock roller, P/N 46575-1, having a low friction liner, on the shock strut of the MLG; per the alert service bulletin.

Alternative Methods of Compliance

(d) 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 Aircraft Certification Office (ACO), FAA. 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.

Note 3:

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

Special Flight Permits

(e) Special flight permits may be issued in accordance with §§ 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.

Incorporation by Reference

(f) The inspection of the uplock rollers and corrective actions shall be done per Bombardier DHC-8 Alert Service Bulletin A84-32-15, dated February 4, 2002. (The manufacturer's name is listed only on the first page of the document; no other page contains this information.) 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, 123 Garratt Boulevard, Downsview, Ontario M3K 1Y5, Canada. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, New York Aircraft Certification Office, 10 Fifth Street, Third Floor, Valley Stream, New York; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

Note 4:

The subject of this AD is addressed in Canadian airworthiness directive CF-2002-13, dated February 4, 2002.

Effective Date

(g) This amendment becomes effective on April 23, 2002.

Start Signature

Issued in Renton, Washington, on April 11, 2002.

Vi L. Lipski,

Manager, Transport Airplane Directorate, Aircraft Certification Service.

End Signature End Part End Supplemental Information

[FR Doc. 02-9391 Filed 4-17-02; 8:45 am]

BILLING CODE 4910-13-U