[Federal Register Volume 72, Number 64 (Wednesday, April 4, 2007)]
[Proposed Rules]
[Pages 16289-16291]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-6267]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-27755; Directorate Identifier 2006-NM-289-AD]
RIN 2120-AA64


Airworthiness Directives; Bombardier Model DHC-8-400 Series 
Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for certain Bombardier Model DHC-8-400 series airplanes. This proposed 
AD would require revising the Limitations section of the airplane 
flight manual to include procedures for pulling the ``HYD PWR XFER'' 
circuit breaker in the event of the loss of all hydraulic fluid in the 
No. 1 or No. 2 hydraulic system. This proposed AD results from reports 
of fluid loss in the No. 2 hydraulic system, causing the power transfer 
unit to overspeed, increasing the fluid flow within the No. 1 hydraulic 
system. We are proposing this AD to prevent possible loss of both the 
No. 1 and No. 2 hydraulic systems, resulting in the potential loss of 
several functions essential for safe flight and landing of the 
airplane.

DATES: We must receive comments on this proposed AD by May 4, 2007.

ADDRESSES: Use one of the following addresses to submit comments on 
this proposed AD.
     DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility, U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, 
Washington, DC 20590.
     Fax: (202) 493-2251.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    Contact Bombardier, Inc., Bombardier Regional Aircraft Division, 
123 Garratt Boulevard, Downsview, Ontario M3K 1Y5, Canada, for service 
information identified in this proposed AD.

FOR FURTHER INFORMATION CONTACT: Ezra Sasson, Aerospace Engineer, 
Systems and Flight Test Branch, ANE-172, FAA, New York Aircraft 
Certification Office, 1600 Stewart Avenue, Suite 410, Westbury, New 
York 11590; telephone (516) 228-7320; fax (516) 794-5531.

SUPPLEMENTARY INFORMATION: 

Comments Invited

    We invite you to submit any relevant written data, views, or 
arguments regarding this proposed AD. Send your comments to an address 
listed in the ADDRESSES section. Include the docket number ``FAA-2007-
27755; Directorate Identifier 2006-NM-289-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of the proposed AD. We will 
consider all comments received by the closing date and may amend the 
proposed AD in light of those comments.
    We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will 
also post a report summarizing each substantive verbal contact with FAA 
personnel concerning this proposed AD. Using the search function of 
that web site, anyone can find and read the comments in any of our 
dockets, including the name of the individual who sent the comment (or 
signed the comment on behalf of an association, business, labor union, 
etc.). You may review the DOT's complete Privacy Act Statement in the 
Federal Register published on April 11, 2000 (65 FR 19477-78), or you 
may visit http://dms.dot.gov.

Examining the Docket

    You may examine the AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility office 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The Docket Management Facility office (telephone (800) 647-
5227) is located on the plaza level of the Nassif Building at the DOT 
street address stated in the ADDRESSES section. Comments will be 
available in the AD docket shortly after the Docket Management System 
receives them.

Discussion

    Transport Canada Civil Aviation (TCCA), which is the airworthiness 
authority for Canada, notified us that an unsafe condition may exist on 
certain Bombardier Model DHC-8-400 series airplanes. TCCA advises that 
it has received several reports of fluid loss in the No. 2 hydraulic 
system, causing the power transfer unit (PTU) to overspeed. This 
resulted in pressure fluctuations and increased fluid flow within the 
No. 1 hydraulic system. In one case, the hydraulic system control logic 
did not shut down the PTU, and the overspeed condition persisted, 
resulting in the illumination of the No. 1 ``HYD FLUID HOT'' caution 
light. This caution light indicated that the hydraulic fluid 
temperature had exceeded 225 degrees Fahrenheit. Had the temperature of 
the hydraulic fluid continued to increase to 275 degrees Fahrenheit, 
the No. 1 system hydraulic firewall shutoff would have closed, leaving 
only the standby power unit (SPU) available. The SPU is not capable of 
meeting the increased flow demands of the PTU and other No. 1 hydraulic 
system services. Therefore, the No. 1 hydraulic system would have also 
been lost, leaving only the No. 3 hydraulic system available. 
Inoperative systems would include flaps, brakes and emergency brakes, 
nose wheel steering, and all primary flight controls other than 
elevator control and degraded aileron control.
    This condition, if not corrected, could result in the potential 
loss of several functions essential for safe flight and landing of the 
airplane.

Relevant Service Information

    Bombardier has issued the following airplane flight manual (AFM) 
temporary amendments:

[[Page 16290]]



                                        Table.--AFM Temporary Amendments
----------------------------------------------------------------------------------------------------------------
                                    Bombardier
           For model--               temporary        Issue--           Dated--        To Bombardier Dash 8 Q400
                                    amendment--                                        airplane flight manual--
----------------------------------------------------------------------------------------------------------------
-400 airplanes..................              13               1  July 14, 2005.....  PSM 1-84-1A
-401 airplanes..................              13               1  July 14, 2005.....  PSM 1-84-1A
-402 airplanes..................              13               1  July 14, 2005.....  PSM 1-84-1A
----------------------------------------------------------------------------------------------------------------

The temporary amendments describe procedures for pulling the ``HYD PWR 
XFER'' circuit breaker in the event of the loss of all hydraulic fluid 
in the No. 1 or No. 2 hydraulic system. TCCA mandated the service 
information and issued Canadian airworthiness directive CF-2006-08, 
dated April 26, 2006, to ensure the continued airworthiness of these 
airplanes in Canada.

FAA's Determination and Requirements of the Proposed AD

    These airplanes are manufactured in Canada and are 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. We have examined TCCA's findings, 
evaluated all pertinent information, and determined that we need to 
issue an AD for airplanes of this type design that are certificated for 
operation in the United States. Therefore, we are proposing this AD, 
which would require revising the Limitations section of the AFM to 
include procedures for pulling the ``HYD PWR XFER'' circuit breaker in 
the event of the loss of all hydraulic fluid in the No. 1 or No. 2 
hydraulic system.

Interim Action

    We consider this proposed AD interim action. The manufacturer is 
currently developing a modification that will address the unsafe 
condition identified in this proposed AD. Once this modification is 
developed, approved, and available, we might consider additional 
rulemaking.

Costs of Compliance

    The following table provides the estimated costs for U.S. operators 
to comply with this proposed AD.

                                                 Estimated Costs
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                                                                                       Number  of
                                               Average                    Cost per        U.S.-
           Action              Work hours    labor rate       Parts       airplane     registered    Fleet cost
                                              per hour                                  airplanes
----------------------------------------------------------------------------------------------------------------
AFM revision................            1           $80            $0           $80            21        $1,680
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Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, Section 106, describes the 
authority of the FAA Administrator. Subtitle VII, Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701, ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Findings

    We have determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD 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.
    For the reasons discussed above, I certify that the 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. 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.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this proposed AD and placed it in the AD docket. See the 
ADDRESSES section for a location to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 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. The Federal Aviation Administration (FAA) amends Sec.  39.13 by 
adding the following new airworthiness directive (AD):

Bombardier, Inc. (Formerly de Havilland, Inc.): Docket No. FAA-2007-
27755; Directorate Identifier 2006-NM-289-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by May 4, 
2007.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Bombardier Model DHC-8-400, DHC-8-401, 
and DHC-8-402

[[Page 16291]]

airplanes, certificated in any category; serial numbers 4001 and 
4003 and subsequent.

Unsafe Condition

    (d) This AD results from reports of fluid loss in the No. 2 
hydraulic system, causing the power transfer unit to overspeed, 
increasing the fluid flow within the No. 1 hydraulic system. We are 
issuing this AD to prevent possible loss of both the No. 1 and No. 2 
hydraulic systems, resulting in the potential loss of several 
functions essential for safe flight and landing of the airplane.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified, unless the 
actions have already been done.

Airplane Flight Manual (AFM) Revision

    (f) Within 14 days after the effective date of this AD, revise 
the Limitations section of the applicable AFM to include the 
information in the applicable Bombardier temporary amendment 
specified in Table 1 of this AD, as specified in the temporary 
amendment. These temporary amendments introduce procedures for 
pulling the ``HYD PWR XFER'' circuit breaker in the event of the 
loss of all hydraulic fluid in the No. 1 or No. 2 hydraulic system. 
Operate the airplane according to the limitations and procedures in 
the applicable temporary amendment.

                                       Table 1.--AFM Temporary Amendments
----------------------------------------------------------------------------------------------------------------
                                  Use Bombardier
                                     Temporary                                         To Bombardier Dash 8 Q400
           For Model--              Amendment--       Issue--           Dated--        Airplane Flight Manual--
 
----------------------------------------------------------------------------------------------------------------
-400 airplanes..................              13               1  July 14, 2005.....  PSM 1-84-1A.
-401 airplanes..................              13               1  July 14, 2005.....  PSM 1-84-1A.
-402 airplanes..................              13               1  July 14, 2005.....  PSM 1-84-1A.
----------------------------------------------------------------------------------------------------------------


    Note 1: This may be done by inserting a copy of the applicable 
temporary amendment into the applicable AFM. When the applicable 
temporary amendment has been included in general revisions of the 
AFM, the general revisions may be inserted into the AFM, provided 
the relevant information in the general revisions is identical to 
that in the temporary amendment.

Alternative Methods of Compliance (AMOCs)

    (g)(1) The Manager, New York Aircraft Certification Office, FAA, 
has the authority to approve AMOCs for this AD, if requested in 
accordance with the procedures found in 14 CFR 39.19.
    (2) Before using any AMOC approved in accordance with Sec.  
39.19 on any airplane to which the AMOC applies, notify the 
appropriate principal inspector in the FAA Flight Standards 
Certificate Holding District Office.

Related Information

    (h) Canadian airworthiness directive CF-2006-08, dated April 26, 
2006, also addresses the subject of this AD.

    Issued in Renton, Washington, on March 26, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E7-6267 Filed 4-3-07; 8:45 am]
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