AD 2004-16-06

[Federal Register Volume 69, Number 153 (Tuesday, August 10, 2004)]
[Rules and Regulations]
[Pages 48368-48369]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 04-17756]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2003-NM-92-AD; Amendment 39-13762; AD 2004-16-06]
RIN 2120-AA64


Airworthiness Directives; BAE Systems (Operations) Limited Model 
Avro 146-RJ Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to all BAE Systems (Operations) Limited Model Avro 146-RJ 
series airplanes, that requires replacing the existing digital flight 
guidance computer(s) (DFGC) with a new or modified DFGC(s). This action 
is necessary to prevent a premature flare from occurring on approach 
due to erroneous data being provided to the DFGC(s); and also to 
prevent uncertainty about autopilot engagement status, which could 
cause the pilot to apply unneeded force to the control column and 
possibly result in a runaway condition of the autotrim. Either 
condition could lead to reduced controllability of the airplane. This 
action is intended to address the identified unsafe conditions.

DATES: Effective September 14, 2004.
    The incorporation by reference of a certain publication listed in 
the regulations is approved by the Director of the Federal Register as 
of September 14, 2004.

ADDRESSES: The service information referenced in this AD may be 
obtained from British Aerospace Regional Aircraft American Support, 
13850 Mclearen Road, Herndon, Virginia 20171. This information may be 
examined 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: <a href="http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html">http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html</a>.

FOR FURTHER INFORMATION CONTACT: Todd Thompson, Aerospace Engineer; 
International Branch, ANM-116, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-1175; fax (425) 227-1149.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to all BAE Systems (Operations) 
Limited Model Avro 146-RJ series airplanes was published in the Federal 
Register on March 24, 2004 (69 FR 13760). That action proposed to 
require replacing the existing digital flight guidance computer(s) 
(DFGC) with a new flight computer(s).

Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Request To Revise the Explanation of Unsafe Conditions and Results

    Two commenters state that the unsafe condition and results 
specified in the AD are derived from an incorrect combination of two 
completely unrelated conditions. Both commenters state that the 
premature flare condition is due to erroneous radio altimeter data 
provided to the DFGCs being undetected. One of the commenters, the 
airplane manufacturer, states that inappropriate force that the pilot 
applied to the control stick resulted from the flightcrew's uncertainty 
as to whether the autopilot was engaged or not. The commenter requests 
that the Summary and Discussion sections of the proposed AD be 
rewritten to reflect that the two unsafe conditions are unrelated. The 
other commenter, the DFGC manufacturer, requests that the body of the 
proposed AD be rewritten to reflect that the two unsafe conditions are 
unrelated.
    The FAA agrees that the premature flare condition and application 
of inappropriate force to the control stick are unrelated. Therefore, 
we have rewritten the statement of unsafe conditions in the Summary and 
body of the AD to reflect the commenters' statements. However, the 
Discussion section of the AD is not repeated in the final rule, so no 
change to the final rule is necessary in that regard.

Request To Revise Wording Describing the Action to Replace

    One commenter, the DFGC manufacturer, requests that the wording of 
paragraph (a) of the proposed AD describing the replacement of the 
``existing * * * DFGC'' with a ``new DFGC(s) * * *'' be revised to read 
``a modified DFGC.'' The commenter states that the unsafe conditions 
result from erroneous data from external sources being supplied to 
DFGCs that are in perfect working order. The commenter indicates that 
specifying replacement of an existing DFGC with a new DFGC implies that 
the DFGC was seriously flawed and required a major redesign. The 
commenter states that only minor software adjustments were necessary to 
enhance DFGC monitoring capabilities and no redesign was needed to 
address the unsafe conditions. Following the

[[Page 48369]]

same reasoning, the commenter requests that the heading of paragraph 
(a) be changed from ``Replacement'' to ``Modification.''
    We understand the commenter's position and agree that clarification 
is necessary. DFGCs returned to the manufacturer for upgrade, then 
returned to service certainly have been modified. However, we do not 
agree that the word ``new'' carries such negative impact, since any new 
DFGC produced by the manufacturer will also contain the upgrade. 
Therefore, the wording of the summary of the section and paragraph (a) 
of this AD has been changed to read ``with a new or modified DFGC(s).''
    We do not agree that the heading of paragraph (a) should be changed 
from ``Replacement'' to ``Modification.'' Though the DFGC is being 
switched for an upgraded DFGC, and will itself be upgraded by the 
manufacturer for return to service, the DFGC is still being replaced 
with another DFGC, not modified by the operator. No change to the final 
rule is necessary in this regard.

Conclusion

    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the changes described 
previously. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.

Cost Impact

    The FAA estimates that 36 airplanes of U.S. registry will be 
affected by this AD, that it will take approximately 1 work hour per 
airplane to accomplish the required actions, and that the average labor 
rate is $65 per work hour. Required parts will cost approximately 
$4,250 per DFGC (some airplanes may have 2 DGFCs). Based on these 
figures, the cost impact of the AD on U.S. operators is estimated to be 
between $4,315 and $8,565 per airplane.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the 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.

Regulatory Impact

    The regulations adopted herein 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. Therefore, it 
is determined that this final rule does not have federalism 
implications under Executive Order 13132.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under 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. A final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it may be obtained 
from the Rules Docket at the location provided under the caption 
ADDRESSES.

List of Subjects in 14 CFR Part 39

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

Adoption of the Amendment

0
Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends part 39 of 
the Federal Aviation Regulations (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. Section 39.13 is amended by adding the following new airworthiness 
directive:

2004-16-06 BAE Systems (Operations) Limited (Formerly British 
Aerospace Regional Aircraft): Amendment 39-13762. Docket 2003-NM-92-
AD.

    Applicability: All Model Avro 146-RJ series airplanes, 
certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent a premature flare from occurring on approach due to 
erroneous data being provided to the DFGC(s); and also prevent 
uncertainty about autopilot engagement status, which could cause the 
pilot to apply unneeded force to the control column and possibly 
result in a runaway condition of the autotrim; either of which 
conditions could lead to reduced controllability of the airplane; 
accomplish the following:

Replacement

    (a) Within 29 months after the effective date of this AD, 
replace the existing DFGC(s) with a new or modified DFGC(s), in 
accordance with the Accomplishment Instructions of BAE Systems 
(Operations) Limited Modification Service Bulletin SB.22-068-70628B, 
dated November 4, 2002.

Reporting Requirements

    (b) Although the service bulletin referenced in paragraph (a) of 
this AD specifies to submit information to the manufacturer, this AD 
does not include such a requirement.

Alternative Methods of Compliance

    (c) In accordance with 14 CFR 39.19, the Manager, International 
Branch, ANM-116, FAA, Transport Airplane Directorate, is authorized 
to approve alternative methods of compliance for this AD.

Incorporation by Reference

    (d) The actions shall be done in accordance with BAE Systems 
(Operations) Limited Modification Service Bulletin SB.22-068-70628B, 
dated November 4, 2002. This incorporation by reference was approved 
by the Director of the Federal Register in accordance with 5 U.S.C. 
552(a) and 1 CFR part 51. Copies may be obtained from British 
Aerospace Regional Aircraft American Support, 13850 Mclearen Road, 
Herndon, Virginia 20171. Copies may be inspected 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: <a href="http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html">http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html</a>.

    Note 1: The subject of this AD is addressed in British 
airworthiness directive 001-11-2002.

Effective Date

    (e) This amendment becomes effective on September 14, 2004.


    Issued in Renton, Washington, on July 27, 2004.
Kyle L. Olsen,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 04-17756 Filed 8-9-04; 8:45 am]
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