
[Federal Register: April 29, 2010 (Volume 75, Number 82)]
[Rules and Regulations]               
[Page 22503-22506]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr29ap10-1]                         


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Rules and Regulations
                                                Federal Register
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[[Page 22503]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2010-0431; Directorate Identifier 2010-NM-072-AD; 
Amendment 39-16272; AD 2010-09-07]
RIN 2120-AA64

 
Airworthiness Directives; Bombardier, Inc. Model DHC-8-400 Series 
Airplanes

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

ACTION: Final rule; request for comments.

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

SUMMARY: We are adopting a new airworthiness directive (AD) for the 
products listed above. This AD results from mandatory continuing 
airworthiness information (MCAI) originated by an aviation authority of 
another country to identify and correct an unsafe condition on an 
aviation product. The MCAI describes the unsafe condition as:

    * * * 1. A potential freezing of the AOA [angle of attack] Vane 
Resolver * * * may restrict the dynamic behavior (lag) of the vane 
and could lead to a potential seize-up condition at lower 
temperatures. This condition, if not corrected, may provide 
inaccurate AOA data to the Stall Protection System (SPS).
    2. As a result of ageing, the AOA vane heating element could 
degrade to a point where there is insufficient heat to prevent ice 
build-up on the AOA vanes. The ice build-up may lead to a change in 
the aerodynamic properties of the AOA vane and, under certain 
conditions, send inaccurate information to the SPS. This ageing 
condition cannot be detected by the aircraft AOA vane heater current 
monitor.

These conditions, if not corrected, could result in inaccurate AOA data 
provided to the SPS and could lead to a change in the aerodynamic 
properties of the AOA vane and reduced ability of the flight crew to 
maintain safe flight and landing of the airplane. This AD requires 
actions that are intended to address the unsafe condition described in 
the MCAI.

DATES: This AD becomes effective May 14, 2010.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in the AD as of May 14, 2010.
    We must receive comments on this AD by June 14, 2010.

ADDRESSES: You may send comments by any of the following methods:
     Federal eRulemaking Portal: Go to http://
www.regulations.gov. Follow the instructions for submitting comments.
     Fax: (202) 493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590.
     Hand Delivery: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-40, 1200 New 
Jersey Avenue, SE., Washington, DC, between 9 a.m. and 5 p.m., Monday 
through Friday, except Federal holidays.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://
www.regulations.gov; or in person at the Docket Operations office 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The AD docket contains this AD, the regulatory evaluation, 
any comments received, and other information. The street address for 
the Docket Operations office (telephone (800) 647-5527) is in the 
ADDRESSES section. Comments will be available in the AD docket shortly 
after receipt.

FOR FURTHER INFORMATION CONTACT: Joseph Licata, Aerospace Engineer, 
Avionics and Flight Test Branch, ANE-172, FAA, New York Aircraft 
Certification Office, 1600 Stewart Avenue, Suite 410, Westbury, New 
York 11590; telephone (516) 228-7361; fax (516) 794-5531.

SUPPLEMENTARY INFORMATION:

Discussion

    Transport Canada Civil Aviation (TCCA), which is the aviation 
authority for Canada, has issued Canadian Airworthiness Directive CF-
2010-05, dated February 2, 2010 (referred to after this as ``the 
MCAI''), to correct an unsafe condition for the specified products. The 
MCAI states:

    Although there have been no in-service reported incidents 
related to AOA [angle of attack] failures on the DHC-8 Series 400 
aeroplanes, two separate issues have been identified that would 
affect proper operation of the AOA vane, P/N [part number] C16177AC. 
These issues are:
    1. A potential freezing of the AOA Vane Resolver, which may 
restrict the dynamic behavior (lag) of the vane and could lead to a 
potential seize-up condition at lower temperatures. This condition, 
if not corrected, may provide inaccurate AOA data to the Stall 
Protection System (SPS).
    2. As a result of ageing, the AOA vane heating element could 
degrade to a point where there is insufficient heat to prevent ice 
build-up on the AOA vanes. The ice build-up may lead to a change in 
the aerodynamic properties of the AOA vane and, under certain 
conditions, send inaccurate information to the SPS. This ageing 
condition cannot be detected by the aircraft AOA vane heater current 
monitor.
    This directive mandates replacement of the vanes equipped with 
suspect resolvers and a periodic inspection of the in-rush current 
to verify the AOA vane heating capability.

These conditions, if not corrected, could result in inaccurate AOA data 
provided to the SPS and could lead to a change in the aerodynamic 
properties of the AOA vane and reduced ability of the flight crew to 
maintain safe flight and landing of the airplane. You may obtain 
further information by examining the MCAI in the AD docket.

Relevant Service Information

    Bombardier has issued Alert Service Bulletin A84-27-46, dated 
October 20, 2009; and Alert Service Bulletin A84-27-51, dated December 
22, 2009. The actions described in this service information are 
intended to correct the unsafe condition identified in the MCAI.

FAA's Determination and Requirements of This AD

    This product has been approved by the aviation authority of another 
country, and is approved for operation in the United States. Pursuant 
to our bilateral agreement with the State of Design Authority, we have 
been notified of the unsafe condition described in the MCAI and service 
information referenced above. We are issuing this AD because we 
evaluated all pertinent information and determined the unsafe

[[Page 22504]]

condition exists and is likely to exist or develop on other products of 
the same type design.

Differences Between the AD and the MCAI or Service Information

    We have reviewed the MCAI and related service information and, in 
general, agree with their substance. But we might have found it 
necessary to use different words from those in the MCAI to ensure the 
AD is clear for U.S. operators and is enforceable. In making these 
changes, we do not intend to differ substantively from the information 
provided in the MCAI and related service information.
    We might also have required different actions in this AD from those 
in the MCAI in order to follow FAA policies. Any such differences are 
highlighted in a Note within the AD.

FAA's Determination of the Effective Date

    An unsafe condition exists that requires the immediate adoption of 
this AD. The FAA has found that the risk to the flying public justifies 
waiving notice and comment prior to adoption of this rule because 
potential freezing of the vane resolver of the angle of attack could 
restrict the dynamic behavior (lag) of the vane and could lead to a 
potential seize-up condition at lower temperatures. As a result of 
aging, the vane heating element of the AOA could degrade to a point 
where there is insufficient heat to prevent ice buildup on the AOA 
vanes. These conditions, if not corrected, could result in inaccurate 
AOA data provided to the SPS and could lead to a change in the 
aerodynamic properties of the AOA vane and reduced ability of the 
flight crew to maintain safe flight and landing of the airplane. 
Therefore, we determined that notice and opportunity for public comment 
before issuing this AD are impracticable and that good cause exists for 
making this amendment effective in fewer than 30 days.

Comments Invited

    This AD is a final rule that involves requirements affecting flight 
safety, and we did not precede it by notice and opportunity for public 
comment. We invite you to send any written relevant data, views, or 
arguments about this AD. Send your comments to an address listed under 
the ADDRESSES section. Include ``Docket No. FAA-2010-0431; Directorate 
Identifier 2010-NM-072-AD'' at the beginning of your comments. We 
specifically invite comments on the overall regulatory, economic, 
environmental, and energy aspects of this AD. We will consider all 
comments received by the closing date and may amend this AD because of 
those comments.
    We will post all comments we receive, without change, to http://
www.regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact we 
receive about this AD.

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 determined that this AD will not have federalism implications 
under Executive Order 13132. This AD 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.
    For the reasons discussed above, I certify this AD:
    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 AD and placed it in the AD docket.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator, 
the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The FAA amends Sec.  39.13 by adding the following new AD:

2010-09-07 Bombardier, Inc.: Amendment 39-16272. Docket No. FAA-
2010-0431; Directorate Identifier 2010-NM-072-AD.

Effective Date

    (a) This airworthiness directive (AD) becomes effective May 14, 
2010.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Bombardier, Inc. Model DHC-8-400, -401, 
and -402 airplanes; certificated in any category, that are equipped 
with Thales angle of attack (AOA) vanes having part number (P/N) 
C16177AC.

Subject

    (d) Air Transport Association (ATA) of America Code 27: Flight 
Controls.

Reason

    (e) The mandatory continued airworthiness information (MCAI) 
states:
    Although there have been no in-service reported incidents 
related to AOA failures on the DHC-8 Series 400 aeroplanes, two 
separate issues have been identified that would affect proper 
operation of the AOA vane, P/N C16177AC. These issues are:
    1. A potential freezing of the AOA Vane Resolver, which may 
restrict the dynamic behavior (lag) of the vane and could lead to a 
potential seize-up condition at lower temperatures. This condition, 
if not corrected, may provide inaccurate AOA data to the Stall 
Protection System (SPS).
    2. As a result of ageing, the AOA vane heating element could 
degrade to a point where there is insufficient heat to prevent ice 
build-up on the AOA vanes. The ice build-up may lead to a change in 
the aerodynamic properties of the AOA vane and, under certain 
conditions, send inaccurate information to the SPS. This ageing 
condition cannot be detected by the aircraft AOA vane heater current 
monitor. This directive mandates replacement of the vanes equipped 
with suspect resolvers and a periodic inspection of the in-rush 
current to verify the AOA vane heating capability.

These conditions, if not corrected, could result in inaccurate AOA 
data provided to the SPS and could lead to a change in the 
aerodynamic properties of the AOA vane and

[[Page 22505]]

reduced ability of the flight crew to maintain safe flight and 
landing of the airplane.

Compliance

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

Actions

    (g) Within 250 flight hours after the effective date of this AD: 
Do an inspection to determine the serial number of the AOA sensors 
installed on the airplane, in accordance with the Accomplishment 
Instructions of Bombardier Alert Service Bulletin A84-27-51, dated 
December 22, 2009. A review of airplane maintenance records is 
acceptable in lieu of this inspection if the serial number of the 
AOA sensors can be conclusively determined from that review.
    (1) If neither serial number is specified in paragraph 1.A., 
Table 1, of Bombardier Alert Service Bulletin A84-27-51, dated 
December 22, 2009, do the actions required by paragraph (h) of this 
AD.
    (2) If the serial numbers of both AOA sensors are specified in 
paragraph 1.A., Table 1, of Bombardier Alert Service Bulletin A84-
27-51, dated December 22, 2009, and both serial numbers have suffix 
``B,'' do the actions required by paragraph (h) of this AD.
    (3) If the serial numbers of both AOA sensors are specified in 
paragraph 1.A., Table 1, of Bombardier Alert Service Bulletin A84-
27-51, dated December 22, 2009, do the actions required by either 
paragraph (g)(3)(i) or (g)(3)(ii) of this AD.
    (i) Before further flight, replace the AOA sensors with new or 
serviceable sensors, in accordance with the Accomplishment 
Instructions of Bombardier Alert Service Bulletin A84-27-51, dated 
December 22, 2009.
    (ii) Before further flight, replace one of the two AOA sensors 
with a new or serviceable sensor, in accordance with the 
Accomplishment Instructions of Bombardier Alert Service Bulletin 
A84-27-51, dated December 22, 2009. Replace the remaining sensor 
with a new or serviceable sensor within 750 flight hours after the 
inspection required by paragraph (g) of this AD.
    (4) If only one of the serial numbers of the AOA sensors is 
specified in paragraph 1.A., Table 1, of Bombardier Alert Service 
Bulletin A84-27-51, dated December 22, 2009, replace that sensor 
with a new or serviceable sensor within 750 flight hours after the 
inspection required by paragraph (g) of this AD.
    (h) At the applicable compliance time specified in Table 1 of 
this AD: Measure the inrush current of the AOA vane, in accordance 
with the Accomplishment Instructions of Bombardier Alert Service 
Bulletin A84-27-46, dated October 20, 2009.
    (1) If, during any measurement required by paragraph (h) of this 
AD, an AOA vane is found to have an inrush current less than or 
equal to 1.6 amps, before further flight, replace the vane with a 
new or serviceable vane, in accordance with the Accomplishment 
Instructions of Bombardier Alert Service Bulletin A84-27-46, dated 
October 20, 2009. Repeat the measurement of the newly installed vane 
within 2,000 flight hours after replacement.
    (2) If, during any measurement required by paragraph (h) of this 
AD, an AOA vane is found to have an inrush current greater than 1.6 
amps, repeat the measurement of the vane at the applicable 
compliance time specified in Table 2 of this AD.

                      Table 1--Initial Measurement
------------------------------------------------------------------------
    For any AOA vane that, as of the
     effective date of this AD, has       Do the initial inrush current
             accumulated--                        measurement--
------------------------------------------------------------------------
Less than 5,000 total flight hours.....  Before the AOA vane has
                                          accumulated 5,900 total flight
                                          hours.
5,000 or more total flight hours, but    Within 900 flight hours after
 less than 6,000 total flight hours.      the effective date of this AD,
                                          or before the AOA vane has
                                          accumulated 6,500 total flight
                                          hours, whichever occurs first.
6,000 or more total flight hours.......  Within 500 flight hours after
                                          the effective date of this AD.
------------------------------------------------------------------------


                Table 2--Repetitive Measurement Intervals
------------------------------------------------------------------------
 If the last inrush current measurement
 of the serviceable AOA transducer is--   Then repeat the measurement--
------------------------------------------------------------------------
More than 1.60 amps, but less than or    Within 1,000 flight hours after
 equal to 1.70 amps.                      the last inrush current
                                          measurement of the serviceable
                                          AOA transducer.
More than 1.70 amps....................  Within 2,000 flight hours after
                                          the last inrush current
                                          measurement of the serviceable
                                          AOA transducer.
------------------------------------------------------------------------

     (i) As of the effective date of this AD, no person may install, 
on any airplane, an AOA sensor having P/N C16177AC with any serial 
number specified in paragraph 1.A., Table 1, of Bombardier Alert 
Service Bulletin A84-27-51, dated December 22, 2009, unless the 
sensor has been inspected in accordance with this AD and unless the 
serial number has a suffix ``B.''

FAA AD Differences

    Note 1:  This AD differs from the MCAI and/or service 
information as follows:
    (1) Canadian Airworthiness Directive CF-2010-05, dated February 
2, 2010, requires an inspection to determine the serial number of 
the AOA vanes installed on the airplane. However, for clarification, 
we are requiring an inspection to determine the serial number of the 
AOA sensors (which are part of the vane), as specified in Bombardier 
Alert Service Bulletin A84-27-51, dated December 22, 2009.
    (2) Canadian Airworthiness Directive CF-2010-05, dated February 
2, 2010, states that an airplane may be dispatched with one 
serviceable unit for a maximum of 1,000 flight hours. However, 
paragraph (g)(3)(ii) of this AD allows an airplane to be dispatched 
with one serviceable unit for a maximum of 750 flight hours. This 
difference has been coordinated with Transport Canada Civil Aviation 
(TCCA).
    (3) Canadian Airworthiness Directive CF-2010-05, dated February 
2, 2010, states that if only one of the serial numbers of the 
affected AOA sensors is found, replace that sensor with a new or 
serviceable sensor within 1,000 flight hours. However, paragraph 
(g)(4) of this AD requires replacement with a new or serviceable 
sensor within 750 flight hours. This difference has been coordinated 
with TCCA.

Other FAA AD Provisions

    (j) The following provisions also apply to this AD:
    (1) Alternative Methods of Compliance (AMOCs): The Manager, New 
York Aircraft Certification Office (ACO), FAA, has the authority to 
approve AMOCs for this AD, if requested using the procedures found 
in 14 CFR 39.19. Send information to ATTN: Program Manager, 
Continuing Operational Safety, FAA, New York ACO, 1600 Stewart 
Avenue, Suite 410, Westbury, New York 11590; telephone 516-228-7300; 
fax 516-794-5531. Before using any approved AMOC on any airplane to 
which the AMOC applies, notify your principal maintenance inspector 
(PMI) or principal avionics inspector (PAI), as appropriate, or 
lacking a principal inspector, your local Flight Standards District 
Office. The AMOC approval letter must specifically reference this 
AD.
    (2) Airworthy Product: For any requirement in this AD to obtain 
corrective actions from

[[Page 22506]]

a manufacturer or other source, use these actions if they are FAA-
approved. Corrective actions are considered FAA-approved if they are 
approved by the State of Design Authority (or their delegated 
agent). You are required to assure the product is airworthy before 
it is returned to service.
    (3) Reporting Requirements: For any reporting requirement in 
this AD, under the provisions of the Paperwork Reduction Act (44 
U.S.C. 3501 et seq.), the Office of Management and Budget (OMB) has 
approved the information collection requirements and has assigned 
OMB Control Number 2120-0056.

Related Information

    (k) Refer to MCAI Canadian Airworthiness Directive CF-2010-05, 
dated February 2, 2010; Bombardier Alert Service Bulletin A84-27-46, 
dated October 20, 2009; and Bombardier Alert Service Bulletin A84-
27-51, dated December 22, 2009; for related information.

Material Incorporated by Reference

    (l) You must use Bombardier Alert Service Bulletin A84-27-46, 
dated October 20, 2009; and Bombardier Alert Service Bulletin A84-
27-51, dated December 22, 2009; as applicable; to do the actions 
required by this AD, unless the AD specifies otherwise.
    (1) The Director of the Federal Register approved the 
incorporation by reference of this service information under 5 
U.S.C. 552(a) and 1 CFR part 51.
    (2) For service information identified in this AD, contact 
Bombardier, Inc., 400 C[ocirc]te-Vertu Road West, Dorval, 
Qu[eacute]bec H4S 1Y9, Canada; telephone 514-855-5000; fax 514-855-
7401; e-mail thd.qseries@aero.bombardier.com; Internet http://
www.bombardier.com.
    (3) You may review copies of the service information at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington. For information on the availability of this material at 
the FAA, call 425-227-1221.
    (4) You may also review copies of the service information that 
is incorporated by reference at the National Archives and Records 
Administration (NARA). For information on the availability of this 
material at NARA, call 202-741-6030, or go to: http://
www.archives.gov/federal_register/code_of_federal_regulations/
ibr_locations.html.

    Issued in Renton, Washington, on April 15, 2010.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2010-9520 Filed 4-28-10; 8:45 am]
BILLING CODE 4910-13-P

