[Federal Register Volume 68, Number 222 (Tuesday, November 18, 2003)]
[Proposed Rules]
[Pages 65003-65005]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-28732]



[[Page 65003]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2002-NM-311-AD]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain Bombardier Model DHC-8-
400, -401, and -402 airplanes. This proposal would require replacing 
certain flight guidance modules with improved modules, and certain 
flight control electronic control units with improved units. This 
action is necessary to prevent loss of the autopilot or manual pitch 
trim, which may increase the workload of the flightcrew and, under 
certain conditions, could result in reduced controllability of the 
airplane. This action is intended to address the identified unsafe 
condition.

DATES: Comments must be received by December 18, 2003.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2002-NM-311-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. 2002-NM-311-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 or 2000 or 
ASCII text.
    The service information referenced in the proposed rule 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.

FOR FURTHER INFORMATION CONTACT: Ezra Sassoon, 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.

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 action may be changed in 
light of the comments received.
    Submit comments using the following format:
    [sbull] 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.
    [sbull] For each issue, state what specific change to the proposed 
AD is being requested.
    [sbull] 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 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 action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2002-NM-311-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. 2002-NM-311-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 two unsafe conditions may 
exist on certain Bombardier Model DHC-8-400, -401, and -402 airplanes. 
TCCA advises that, on certain airplanes, a malfunction in the pitch 
trim system may occur due to asynchrony between the autopilot pitch 
trim commands of flight guidance modules (FGMs) 1 and 2. This 
asynchrony is due to noise at frequencies close to the sampling rate in 
the signal on the FGM's acquisition channel. This could result in loss 
of the autopilot pitch trim, which would require the flightcrew to 
disengage the autopilot and fly the airplane manually.
    TCCA also advises that, on certain airplanes, a malfunction in the 
manual pitch trim system may occur in which the monitoring/modeling 
circuitry in the flight control electronic control units (FCECU) 
disables the pitch trim system. This may occur due to unidirectional 
cycling and rapid reversals of pitch trim commands by the flightcrew. 
This results in a nuisance warning of pitch trim runaway or loss of the 
pitch trim system.
    These two conditions, if not corrected, could significantly 
increase the workload of the flightcrew, and in adverse conditions, 
could result in reduced controllability of the airplane.

Explanation of Relevant Service Information

    Bombardier has issued Service Bulletin 84-22-04, Revision ``B,'' 
dated April 17, 2002, which describes procedures for replacing FGM1 and 
FGM2 with improved FGMs, and performing a Return-to-Service procedure. 
That service bulletin refers to Thales Service Bulletin C12429A-22-003, 
dated November 29, 2001, as an additional source of service information 
for modifying the FGMs to the improved configuration. The Thales 
service bulletin is included in the Bombardier service bulletin.
    Bombardier has also issued Service Bulletin 84-27-14, Revision 
``A,'' dated April 2, 2002, which describes procedures for replacing 
FCECUs with improved FCECUs. That service bulletin refers to Parker 
Service Bulletin 398500-27-235, dated January 9, 2002, as an additional 
source of service information for modifying the FCECUs to the improved 
configuration. The Parker service bulletin is included in the 
Bombardier service bulletin.
    Accomplishment of the actions specified in the applicable 
Bombardier service bulletin is intended to

[[Page 65004]]

adequately address the identified unsafe condition. TCCA classified the 
Bombardier service bulletins as mandatory and issued Canadian 
airworthiness directive CF-2002-25, dated April 25, 2002, to ensure 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 
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. 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 applicable Bombardier service bulletins 
described previously.

Difference Between Proposed AD and Parallel TCCA Airworthiness 
Directive

    Operators should note that, although the parallel Canadian 
airworthiness directive includes maintenance procedures that may be 
used as interim procedures until the affected FGMs and FCECUs can be 
replaced with improved parts, this proposed AD does not reference such 
interim procedures.

Cost Impact

    We estimate that 12 airplanes of U.S. registry would be affected by 
the proposed replacement of FGMs, that it would take approximately 1 
work hour per airplane to accomplish this proposed replacement, and 
that the average labor rate is $65 per work hour. Required parts would 
be provided at no charge. Based on these figures, the cost impact of 
this proposed requirement on U.S. operators is estimated to be $780, or 
$65 per airplane.
    We estimate that 15 airplanes of U.S. registry would be affected by 
the proposed replacement of the FCECUs, that it would take 
approximately 4 work hours per airplane to accomplish this proposed 
replacement, and that the average labor rate is $65 per work hour. 
Required parts would be provided at no charge. Based on these figures, 
the cost impact of this proposed requirement on U.S. operators is 
estimated to be $3,900, or $260 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 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. The manufacturer may cover the cost of 
replacement parts associated with this proposed AD, subject to warranty 
conditions. As a result, the costs attributable to the proposed AD may 
be less than stated above.

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 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 2002-NM-311-
AD.

    Applicability: Model DHC-8-400, -401, and -402 airplanes; 
certificated in any category; having serial numbers (S/Ns) 4001 
through 4065 inclusive.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent loss of the autopilot or manual pitch trim, which may 
increase the workload of the flightcrew and, under certain 
conditions, could result in reduced controllability of the airplane, 
accomplish the following:

Replacement of Flight Guidance Modules

    (a) For airplanes with S/Ns 4001 through 4003 inclusive and 4005 
through 4058 inclusive: Within 60 days after the effective date of 
this AD, replace flight guidance modules (FGMs) FGM1 and FGM2, part 
number (P/N) C12429AA06, with improved FGMs, P/N C12429AA07, and 
perform a Return-to-Service procedure, per Bombardier Service 
Bulletin 84-22-04, Revision ``B,'' dated April 17, 2002.

    Note 1: Bombardier Service Bulletin 84-22-04, Revision ``B,'' 
refers to Thales Service Bulletin C12429A-22-003, dated November 29, 
2001, as an additional source of service information for modifying 
FGMs from P/N C12429AA06 to P/N C12429AA07. The Thales service 
bulletin is included in the Bombardier service bulletin.

Replacement of Flight Control Electronic Control Units

    (b) For all airplanes: Within 8 months after the effective date 
of this AD, replace flight control electronic control units 
(FCECUs), P/N 398500-1001 or -1003, with improved FCECUs, P/N 
398500-1005, and perform a Return-to-Service procedure, per 
Bombardier Service Bulletin 84-27-14, Revision ``A,'' dated April 2, 
2002.

    Note 2: Bombardier Service Bulletin 84-27-14, Revision ``A,'' 
refers to Parker Service Bulletin 398500-27-235, dated January 9, 
2002, as an additional source of service information for modifying 
FCECUs from P/N 398500-1001 or -1003 to P/N 398500-1005. The Parker 
service bulletin is included in the Bombardier service bulletin.

Alternative Methods of Compliance

    (c) In accordance with 14 CFR 39.19, the Manager, New York 
Aircraft Certification Office (ACO), FAA, is authorized to approve 
alternative methods of compliance for this AD.


[[Page 65005]]


    Note 3: The subject of this AD is addressed in Canadian 
airworthiness directive CF-2002-25, dated April 25, 2002.


    Issued in Renton, Washington, on November 12, 2003.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 03-28732 Filed 11-17-03; 8:45 am]
BILLING CODE 4910-13-P