[Federal Register Volume 65, Number 198 (Thursday, October 12, 2000)]
[Proposed Rules]
[Pages 60595-60597]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-26093]


-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-181-AD]
RIN 2120-AA64


Airworthiness Directives; Bombardier Model DHC-7-100, -101, -102, 
and -103 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain Bombardier Model DHC-7-
100, -101, -102, and -103 series airplanes. This proposal would require 
inspecting the endcaps of the main landing gear selector valve for 
leaks of hydraulic oil and, if leaks are detected, replacing the 
leaking endcaps or the entire selector valve. This proposal would also 
require eventual replacement or rework of certain selector valves, 
which would terminate the repetitive inspections. This action is 
prompted by a report of the collapse of the main landing gear due to an 
external leak of hydraulic oil in the landing gear selector valve, 
resulting from a fracture of the endcap. This action is intended to 
prevent leaks of hydraulic oil from the main landing gear selector 
valve, which could result in the collapse of the main landing gear.

DATES: Comments must be received by November 13, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2000-NM-181-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. Comments may be submitted via fax to (425) 227-1232. 
Comments may also be sent via the Internet using the following address: 
[email protected]. Comments sent via fax or the Internet must 
contain ``Docket No. 2000-NM-181-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., Canadair, Aerospace Group, P.O. Box 
6087, Station Centreville, Montreal, Quebec H3C 3G9, 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.

FOR FURTHER INFORMATION CONTACT: James E. Delisio, Aerospace Engineer, 
ANE-171, FAA, New York Aircraft Certification Office, 10 Fifth Street, 
Third Floor, Valley Stream, New York 11581; telephone (516) 256-7521; 
fax (516) 568-2716.

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 notice 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,

[[Page 60596]]

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 notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket No. 2000-NM-181-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. 2000-NM-181-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    Transport Canada Civil Aviation (TCCA), which is the airworthiness 
authority for Canada, notified the FAA that an unsafe condition may 
exist on certain Bombardier Model DHC-7-100, -101, -102, and -103 
series airplanes. TCCA advises that an investigation of the collapse of 
the main landing gear of a Model DHC-8 series airplane identified the 
cause as an external hydraulic oil leak in the landing gear selector 
valve due to a fracture of the endcap. Model DHC-7 series airplanes 
have the same parts in their main landing gears.
    TCCA further advises that inspection of main landing gear selector 
valves undergoing bench testing have revealed additional cases of 
fatigue failure in the endcaps. In addition, main landing gear selector 
valves which have not been upgraded to part number (P/N) 57420-5 
configuration are more susceptible to internal leaks, and excessive 
internal leaks can also contribute to the collapse of the main landing 
gear. This condition, if not corrected, could result in leaks of 
hydraulic oil from the main landing gear selector valve, which could 
result in the collapse of the main landing gear.

Explanation of Relevant Service Information

    Bombardier has issued Alert Service Bulletin A7-32-103, dated 
September 3, 1999, which describes procedures for repetitive visual 
inspection of the endcaps of the main landing gear selector valve for 
leaks of hydraulic oil and replacement of the endcaps with new 
serviceable parts, if leaks are found. The service bulletin also 
describes procedures for rework or replacement of certain selector 
valves with new improved parts, which would eliminate the need for the 
repetitive inspections. 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-99-31, dated December 
21, 1999, in order to assure the continued airworthiness of these 
airplanes in Canada.

FAA's Conclusions

    These airplane models are manufactured in Canada and are type 
certificated for operation in the United States under the provisions of 
Sec. 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 require accomplishment of 
the actions specified in the service bulletin described previously. The 
FAA is also preparing a proposed AD, which will address a similar 
unsafe condition on Bombardier Model DHC-8-100, -200, and -300 series 
airplanes.

Cost Impact

    The FAA estimates that 32 airplanes of U.S. registry would be 
affected by this proposed AD, that it would require 1 work hour per 
airplane to accomplish the proposed inspection, and that the average 
labor rate is $60 per work hour. Based on these figures, the cost 
impact of the proposed inspection on U.S. operators is estimated to be 
$1,920, or $60 per airplane.
    The FAA also estimates that it would require 5 work hours per 
airplane to rework or replace the main landing gear selector valve and 
that the average labor rate is $60 per work hour. Based on these 
figures, the cost impact of the proposed rework or replacement on U.S. 
operators is estimated to be $9,600 or $300 per airplane.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the proposed requirements 
of this AD action, and that no operator would accomplish those actions 
in the future if this proposed AD were not adopted. The cost impact 
figures discussed in AD rulemaking actions represent only the time 
necessary to perform the specific actions actually required by the AD. 
These figures typically do not include incidental costs, such as the 
time required to gain access and close up, planning time, or time 
necessitated by other administrative actions.
    Should an operator elect to replace the endcaps and perform the 
optional repetitive inspections prior to replacing the main landing 
gear selector valve, it would take approximately 1 work hour per 
airplane to conduct each inspection. Based on these figures, the cost 
impact of the optional repetitive inspections is estimated to be $60 
per inspection per airplane.

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 me by the 
Administrator, the Federal Aviation Administration proposes to amend 
part

[[Page 60597]]

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.


Sec. 39.13  [Amended]

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

Bombardier, Inc. (Formerly de Havilland, Inc.): Docket 2000-NM-181-
AD.

    Applicability: Model DHC-7-100, -101, -102, and -103 series 
airplanes, serial numbers 003 through 113 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 (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 prevent the collapse of the main landing gear due to leaks of 
hydraulic oil from the main landing gear selector valve, accomplish 
the following:

Inspection

    (a) Within 100 flight cycles after the effective date of this 
AD, perform a general visual inspection of both endcaps of the main 
landing gear selector valve for the presence of hydraulic oil, in 
accordance with the Accomplishment Instructions of Bombardier Alert 
Service Bulletin A7-32-103, dated September 3, 1999. If no hydraulic 
oil is detected on either endcap, repeat the inspection at intervals 
not to exceed 400 flight hours until the requirements of paragraph 
(c) are accomplished.

    Note 2: For the purposes of this AD, a general visual inspection 
is defined as: ``A visual examination of an interior or exterior 
area, installation, or assembly to detect obvious damage, failure, 
or irregularity. This level of inspection is made under normally 
available lighting conditions such as daylight, hangar lighting, 
flashlight, or drop-light, and may require removal or opening of 
access panels or doors. Stands, ladders, or platforms may be 
required to gain proximity to the area being checked.''

Replacement or Modification

    (b) If any hydraulic oil is detected on either endcap: Prior to 
further flight, perform the actions specified in either paragraph 
(b)(1) or (b)(2) of this AD.
    (1) Replace the existing aluminum endcaps, part number (P/N) 
34629, with new stainless steel endcaps having P/N 52982, in 
accordance with the Accomplishment Instructions of Bombardier Alert 
Service Bulletin A7-32-103, dated September 3, 1999.
    (2) Replace the main landing gear selector valve with a valve 
having P/N 57420-5A, in accordance with the Accomplishment 
Instructions of Bombardier Alert Service Bulletin A7-32-103, dated 
September 3, 1999.

    Note 3: Use care when removing the endcaps, so that the internal 
components do not fall on the ground and get damaged.

    (c) Within 12 months after the effective date of this AD: 
Perform the actions specified in either paragraph (c)(1) or (c)(2) 
of this AD, in accordance with the Accomplishment Instructions of 
Bombardier Alert Service Bulletin A7-32-103, dated September 3, 
1999. Accomplishment of either paragraph (c)(1) or (c)(2) terminates 
the repetitive inspection requirement of this AD.
    (1) If a main landing gear selector valve having P/N 57420-1 or 
57420-3 is installed, remove it and replace it with a valve having 
P/N 57420-5A.
    (2) If a main landing gear selector valve having P/N 57420-5 is 
installed, remove it and replace it with a valve having P/N 57420-5A 
or modify the valve to the P/N 57420-5A configuration (Modification 
7/2742).

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 4: 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 
Secs. 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 5: The subject of this AD is addressed in Canadian 
airworthiness directive CF-99-31, dated December 21, 1999.


    Issued in Renton, Washington, on October 4, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-26093 Filed 10-11-00; 8:45 am]
BILLING CODE 4910-13-P