AD 2000-07-27

[Federal Register Volume 65, Number 75 (Tuesday, April 18, 2000)]
[Rules and Regulations]
[Pages 20717-20719]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 00-9111]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-83-AD; Amendment 39-11683; AD 2000-07-27]
RIN 2120-AA64


Airworthiness Directives; Various Transport Category Airplanes 
Equipped With Certain Honeywell Air Data Inertial Reference Units

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to various transport category airplanes equipped with 
certain Honeywell air data inertial reference units (ADIRU). This 
action requires inspection of a failed ADIRU to determine its 
modification status, and replacement of an unmodified failed ADIRU with 
a serviceable ADIRU. This action also provides for optional terminating 
action for the requirements of the AD. This amendment is prompted by 
reports of dual critical failures of inertial reference units on 
ADIRU's during flight. The actions specified in this AD are intended to 
prevent loss of the main sources of attitude data, consequent high 
pilot workload, and a significant increase in the likelihood of pilot 
error.

DATES: Effective May 3, 2000.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of May 3, 2000.
    Comments for inclusion in the Rules Docket must be received on or 
before June 19, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2000-NM-83-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056.
    The service information referenced in this AD may be obtained from 
Honeywell, Publications, P.O. Box 21111, Mail Stop DV-10, Phoenix, 
Arizona 85036. This information may be examined at the FAA, Transport 
Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at 
the FAA, Chicago Aircraft Certification Office, 2350 East Devon Avenue, 
Room 323, Des Plaines, Illinois; or at the Office of the Federal 
Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Wess Rouse, Aerospace Engineer, 
Systems and Flight Test Branch, ACE-117C, FAA, Chicago Aircraft 
Certification Office, 2350 East Devon Avenue, Room 323, Des Plaines, 
Illinois 60018; telephone (847) 294-8113; fax (847) 294-7834.

SUPPLEMENTARY INFORMATION: The FAA has recently received three reports 
of dual inertial reference (IR) critical faults of the air data 
inertial reference system comprising two or more air data inertial 
reference units (ADIRU) on transport category airplanes during flight. 
Three days prior to one of the dual IR critical fault incidents, one of 
those ADIRU's

[[Page 20718]]

had an IR critical fault in flight. During the subsequent ground check, 
the failed ADIRU passed the built-in test and aligned, functioning 
normally.
    The subject ADIRU's are subject to IR critical faults related to 
the power supply margin. The demand for voltage increases as operating 
hours and temperature increase. Once the demand for voltage exceeds the 
capability of the power supply, the inertial reference portion of the 
ADIRU will exhibit an IR critical fault, while the air data portion of 
the ADIRU will continue to function normally. It may be possible to 
reset the failed inertial reference unit on the ground after the 
temperature of the ADIRU decreases; however, the risk of the dual 
critical fault increases when an ADIRU with a failed inertial reference 
power supply is returned to service. If two inertial reference units 
fail, the airplane is left with only one functioning source of attitude 
data. This condition could result in loss of the main sources of 
attitude data, consequent high pilot workload, and a significant 
increase in the likelihood of pilot error.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Honeywell Alert Service Bulletins 
HG2030AD-34-A0009, and HG2050AC-34-A0008, both dated March 9, 2000, 
which describe procedures for determining the modification status of 
the ADIRU. For any ADIRU part number (P/N) HG2050AC not marked as 
modification 2 or 3 and any ADIRU P/N HG2030AD not marked as 
modification 3 or 6, the alert service bulletins also describe 
procedures for replacement of the ADIRU with a serviceable ADIRU.

Explanation of the Requirements of the Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of the same type design, this AD is 
being issued to prevent loss of the main sources of attitude data, 
consequent high pilot workload, and a significant increase in the 
likelihood of pilot error. This AD requires inspection of a failed 
ADIRU to determine its modification status, and replacement of any 
unmodified failed ADIRU with a serviceable ADIRU. This AD also provides 
for optional terminating action for the requirements of the AD. The 
actions are required to be accomplished in accordance with the alert 
service bulletins described previously.

Determination of Rule's Effective Date

    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the 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 that 
summarizes each FAA-public contact concerned with the substance of this 
AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2000-NM-83-AD.'' The postcard will be date stamped and 
returned to the commenter.

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.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and that it is not a ``significant regulatory 
action'' under Executive Order 12866. It has been determined further 
that this action involves an emergency regulation under DOT Regulatory 
Policies and Procedures (44 FR 11034, February 26, 1979). If it is 
determined that this emergency regulation otherwise would be 
significant under DOT Regulatory Policies and Procedures, a final 
regulatory evaluation will be prepared and placed in the Rules Docket.
    A copy of it, if filed, 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

    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

    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:

2000-07-27  Transport Category Airplanes: Amendment 39-11683. Docket 
2000-NM-83-AD.

    Applicability: Transport category airplanes including but not 
limited to those listed below, certificated in any category; 
equipped with any Honeywell air data inertial reference unit (ADIRU) 
having a serial number below 0841 and a part number (P/N) listed 
below:

------------------------------------------------------------------------
     Airplane manufacturer            Model              ADIRU P/N
------------------------------------------------------------------------
Boeing........................  757-300            HG2050AC02
                                737-600            HG2050AC03
                                737-700            HG2050AC04
                                737-800            HG2050AC05
Airbus........................  A319-111           HG2030AD09
                                A319-112
                                A319-113
                                A319-114
                                A319-131
                                A319-132
                                A320-111
                                A320-211
                                A320-212

[[Page 20719]]

 
                                A320-214
                                A320-231
                                A320-232
                                A320-233
                                A321-111
                                A321-112
                                A321-131
                                A330-202
                                A330-301
                                A330-223
                                A330-321
                                A330-322
                                A330-323
                                A340-211
                                A340-311
                                A340-212
                                A340-312
                                A340-213
                                A340-313
Airbus........................  A330-202           HG2030AD10
                                A330-301
                                A330-223
                                A330-321
                                A330-322
                                A330-323
                                A340-211
                                A340-311
                                A340-212
                                A340-312
                                A340-213
                                A340-313
------------------------------------------------------------------------


    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
modified, altered, or repaired in the area subject to the 
requirements of this AD. For airplanes that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must request approval for an 
alternative method of compliance in accordance with paragraph (c) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and, if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent loss of the main sources of attitude data, consequent 
high pilot workload, and a significant increase in the likelihood of 
pilot error, accomplish the following:

Inspection and Replacement

    (a) Prior to the next flight following any critical inertial 
reference failure of an ADIRU: Inspect the identification plate of 
the ADIRU to determine its modification status, in accordance with 
Honeywell Alert Service Bulletin HG2030AD-34-A0009 (for an ADIRU 
having P/N HG2030AD09 or HG2030AD10) or HG2050AC-34-A0008 (for an 
ADIRU having P/N HG2050AC02, HG2050AC03, HG2050AC04, or HG2050AC05), 
both dated March 9, 2000; as applicable.
    (1) If any ADIRU having P/N HG2050AC02, HG2050AC03, HG2050AC04, 
or HG2050AC05 is not marked as modification 2 or 3: Prior to further 
flight, replace the ADIRU with an ADIRU as specified in either 
paragraph (a)(1)(i) or (a)(1)(ii) of this AD, in accordance with 
Honeywell Alert Service Bulletin HG2050AC-34-A0008, dated March 9, 
2000.
    (i) Replace with an ADIRU that has P/N HG2050AC03, HG2050AC04, 
or HG2050AC05; and that is marked as modification 2 or 3. Or
    (ii) Replace with a serviceable ADIRU that has P/N HG2050AC03, 
HG2050AC04, or HG2050AC05; and that is not marked as modification 2 
or 3; and that has been determined to have accumulated less than 
7,000 operating hours in accordance with the alert service bulletin.
    (2) If any ADIRU having P/N HG2030AD09 or HG2030AD10 is not 
marked with modification 3 or 6: Prior to further flight, replace 
the ADIRU with an ADIRU as specified in either paragraph (a)(2)(i) 
or (a)(2)(ii), in accordance with Honeywell Alert Service Bulletin 
HG2030AD-34-A0009, dated March 9, 2000.
    (i) Replace with an ADIRU having P/N HG2030AD09 or HG2030AD10 
that is marked as modification 3 or 6; or
    (ii) Replace with a serviceable ADIRU having P/N HG2030AD09 or 
HG2030AD10 that is not marked as modification 3 or 6, and that has 
been determined to have accumulated less than 7,000 operating hours 
in accordance with the alert service bulletin.

    Note 2: For purposes of this AD, a ``serviceable'' ADIRU is one 
that satisfies the replacement requirements of paragraph (a)(1)(ii) 
or (a)(2)(ii), and on which no critical inertial reference failure 
has occurred.

    (b) Installation of all ADIRUs on the airplane that meet the 
criteria of paragraph (b)(1) or (b)(2) of this AD constitutes 
terminating action for the requirements of this AD:
    (1) ADIRUs that have P/N HG2050AC03, HG2050AC04, or HG2050AC05; 
and that are marked as modification 2 or 3; or
    (2) ADIRUs that have P/N HG2030AD09 or HG2030AD10, and that are 
marked as modification 3 or 6.

Alternative Methods of Compliance

    (c) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Chicago Aircraft Certification 
Office (ACO), FAA, Small Airplane Directorate. Operators shall 
submit their requests through an appropriate FAA Principal 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Chicago ACO.

    Note 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Chicago ACO.

Special Flight Permits

    (d) Special flight permits may be issued in accordance with 
Secs. 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 
21.197 and 21.199) to operate the airplane to a location where the 
requirements of this AD can be accomplished, provided that the 
remaining, functioning ADIRU(s) has accumulated less than 7,000 
total operating hours, as specified by Honeywell Alert Service 
Bulletin HG2030AD-34-A0009 (for ADIRU P/N's HG2030AD09 and 
HG2030AD10) or HG2050AC-34-A0008 (for an ADIRU P/N HG2050AC), both 
dated March 9, 2000; as applicable.

Incorporation by Reference

    (e) The actions shall be done in accordance with Honeywell Alert 
Service Bulletin HG2050AC-34-A0008, dated March 9, 2000; or 
Honeywell Alert Service Bulletin HG2030AD-34-A0009, dated March 9, 
2000; as applicable. 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 Honeywell, 
Publications, P.O. Box 21111, Mail Stop DV-10, Phoenix, Arizona 
85036. Copies may be inspected at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the 
FAA, Chicago Aircraft Certification Office, 2350 East Devon Avenue, 
Room 323, Des Plaines, Illinois; or at the Office of the Federal 
Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
    (f) This amendment becomes effective on May 3, 2000.

    Issued in Renton, Washington, on April 6, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-9111 Filed 4-17-00; 8:45 am]
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