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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
 AGENCY: Federal Aviation Administration (FAA), Department of Transportation (DOT).
 ACTION: Notice of proposed rulemaking (NPRM).
 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: 
                    ( print page 16290) Table.—AFM Temporary Amendments
For model—
Bombardier temporary amendment—
Issue—
Dated—
To Bombardier Dash 8 Q400 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
Action
Work hours
Average 
                             labor rate  
                             per hour
Parts
Cost per 
                             airplane
Number 
                             of U.S.-  
                             registered  
                             airplanes
Fleet costAFM revision
1
$80
$0
$80
21
$1,680
 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. § 39.13
  2. The Federal Aviation Administration (FAA) amends § 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 
                                ( print 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
For Model—
Use Bombardier Temporary Amendment—
Issue—
Dated—
To Bombardier Dash 8 Q400 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 § 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] BILLING CODE 4910-13-P