[Federal Register Volume 62, Number 61 (Monday, March 31, 1997)]
[Rules and Regulations]
[Pages 15096-15098]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-7519]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 97-NM-22-AD; Amendment 39-9974; AD 97-07-01]
RIN 2120-AA64
Airworthiness Directives; Airbus Model A330 and A340 Series
Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
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SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to certain Airbus Model A330 and A340 series airplanes. This
action requires the deactivation of the avionics ground refrigeration
unit (GRU) of the air conditioning system until a modification of
avionics ventilation circuit and the GRU is accomplished. This
amendment is prompted by reports of water accumulation found in the Air
Data/Inertial Reference Unit (ADIRU) trays of the avionics rack; the
accumulation is the result of operation of the GRU in high ambient
humidity. The actions specified in this AD are intended to prevent
water accumulating in this area, which could result in the failure of
the ADIRU and consequent loss of air data and navigational information
to the flightcrew.
DATES: Effective April 15, 1997.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of April 15, 1997.
Comments for inclusion in the Rules Docket must be received on or
before May 30, 1997.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 97-NM-22-AD, 1601 Lind Avenue, SW., Renton,
Washington 98055-4056.
The service information referenced in this AD may be obtained from
Airbus Industrie, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex,
France. This information may be examined at the FAA, Transport Airplane
Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the
Office of the Federal Register, 800 North Capitol Street, NW., suite
700, Washington, DC.
FOR FURTHER INFORMATION CONTACT: Charles Huber, Aerospace Engineer,
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate,
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206)
227-2589; fax (206) 227-1149.
SUPPLEMENTARY INFORMATION: The Direction Generale de l'Aviation Civile
(DGAC), which is the airworthiness authority for France, recently
notified the FAA that an unsafe condition may exist on certain Airbus
Model A330 and A340 series airplanes. The DGAC advises that there have
been reports of water accumulation found in the Air Data/Inertial
Reference Unit (ADIRU) trays of the avionics racks on in-service
airplanes. All of the airplanes on which this phenomenon occurred were
equipped with a ground cooling system, identified as Airbus
Modification No. 40063S10052. (This is an optional modification
available to Model A330 and A340 series airplanes.)
Investigation revealed that water droplets can accumulate on the
evaporator cores of the ground refrigeration unit (GRU) as a result of
[[Page 15097]]
high ambient humidity. The water droplets are then carried within the
airflow and accumulate in the low points of the avionics ventilation
ducting.
In at least two cases, this accumulation of water resulted in the
failure of one or two ADIRU's during flight. In one of these incidents,
both inertial reference systems on one airplane were lost, and the
flight crew was compelled to execute an in-flight turn-back. Upon the
subsequent approach, all instrument landing system data disappeared
from the airplane's primary flight displays.
Failure of the ADIRU(s) during flight, which can occur as a result
of the consequences associated with water accumulation in the relevant
avionics rack, could result in loss of air data and navigational
information to the flightcrew. This could compromise the ability of the
flight crew to maintain the safe flight and landing of the airplane.
Explanation of Relevant Service Information
Airbus has issued All Operators Telex (AOT) 21-01, dated March 28,
1995, which describes procedures for deactivating the avionics GRU, if
one is installed on the airplane. The DGAC classified this AOT as
mandatory and issued French airworthiness directives (CN) 95-089-010(B)
(for Model A330 series airplanes) and 95-093-020(B) (for Model A340
series airplanes), both dated May 24, 1995, in order to assure the
continued airworthiness of these airplanes in France.
Airbus also has issued Service Bulletin A330-21-3028, Revision 2,
dated May 5, 1995 (for Model A330 series airplanes), and Service
Bulletin A340-21-4046, Revision 2, dated May 5, 1995 (for Model A340
series airplanes). These service bulletins describe procedures for
modifying the avionics equipment ventilation system and the GRU on
airplanes equipped with one. The modification procedures include:
1. Air tappings for relocation of ADIRU ventilation from the lower
to the upper side of the ventilation ducting;
2. Installing water drains at the lower side of the ventilation
ducting;
3. Drilling a hole in each ADIRU tray; and
4. On airplanes equipped with a GRU, increasing the inner diameter
of the existing GRU drain line.
Accomplishment of this modification will prevent water from
accumulating in the ventilation ducting low points and subsequently
damaging the ADIRU's. [This modification was installed during
production on Model A330 series airplanes beginning at manufacturer's
serial number (MSN) 107, and on Model A340 series airplanes beginning
at MSN 114.]
The DGAC has classified Revision 2 of Airbus Service Bulletins
A330-21-3028 and A340-21-4046 as ``recommended.''
FAA's Conclusions
This airplane model is manufactured in France and is type
certificated for operation in the United States under the provisions of
section 21.29 of the Federal Aviation Regulations (14 CFR 21.19) and
the applicable bilateral airworthiness agreement. Pursuant to this
bilateral airworthiness agreement, the DGAC has kept the FAA informed
of the situation described above. The FAA has examined the findings of
the DGAC, 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 the 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, this AD is being issued to prevent water from
accumulating in the ADIRU trays of the avionics racks, which could
result in the damage to or failure of the ADIRU(s) and consequent loss
of air data and navigational information to the flightcrew. This AD
requires the deactivation of the GRU on those airplanes equipped with a
GRU. The deactivation must be accomplished in accordance with the
Airbus AOT described previously.
Should an operator want to reactivate the GRU, it must first modify
the avionics equipment ventilation system in accordance with the
procedures contained in the Airbus service bulletin, described
previously.
Cost Impact
None of the Model A330 and A340 series airplanes affected by this
action are on the U.S. Register. All airplanes included in the
applicability of this rule currently are operated by non-U.S. operators
under foreign registry; therefore, they are not directly affected by
this AD action. However, the FAA considers that this rule is necessary
to ensure that the unsafe condition is addressed in the event that any
of these subject airplanes are imported and placed on the U.S. Register
in the future.
Should an affected airplane be imported and placed on the U.S.
Register in the future, it would require approximately 1 work hour to
accomplish the deactivation of the GRU at an average labor charge of
$60 per work hour. Based on these figures, the cost impact of this
required action would be $60 per airplane.
If an operator elected to the modify avionics equipment ventilation
system so that the GRU could be reactivated, it would take 4 work hours
to accomplish the modification, at an average labor charge of $60 per
work hour. Required parts would be provided to operators free of charge
by the manufacturer. Based on these figures, the cost impact of this
optional action would be $240 per airplane.
Determination of Rule's Effective Date
Since this AD action does not affect any airplane that is currently
on the U.S. register, it has no adverse economic impact and imposes no
additional burden on any person. Therefore, prior notice and public
procedures hereon are unnecessary and the amendment may be made
effective in less than 30 days after publication in the Federal
Register.
Comments Invited
Although this action is in the form of a final rule and was not
preceded by notice and 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
[[Page 15098]]
Docket Number 97-NM-22-AD.'' The postcard will be date stamped and
returned to the commenter.
Regulatory Impact
The regulations adopted herein will not have substantial direct
effects 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, in
accordance with Executive Order 12612, it is determined that this final
rule does not have sufficient federalism implications to warrant the
preparation of a Federalism Assessment.
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
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:
97-07-01 Airbus: Amendment 39-9974. Docket 97-NM-22-AD.
Applicability: Model A330-301 series airplanes having
manufacturer's serial number (MSN) 1 through 106, inclusive; and
Model A340-211, -212, -311, and -312 series airplanes having MSN 1
through 113, inclusive; on which Airbus Modification No. 40063S10052
(ground cooling system) has been installed; certificated in any
category.
Note 1: This AD applies to each airplane identified in the
preceding applicability provision, regardless of whether it has been
otherwise 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 water from accumulating in the Air Data/Inertial
Reference Unit (ADIRU) trays of the avionics racks, which could
result in the damage to or failure of the ADIRU(s) and consequent
loss of air data and navigational information to the flightcrew,
accomplish the following:
(a) Within 500 hours time-in-service after the effective date of
this AD, deactivate the avionics ground refrigeration unit (GRU) in
accordance with Airbus All Operators Telex 21-01, dated March 28,
1995.
(b) Modification of the avionics equipment ventilation system in
accordance with Airbus Service Bulletin A330-21-3028, Revision 2,
dated May 5, 1995 (for Model A330 series airplanes); or Airbus
Service Bulletin A340-21-4046, Revision 2, dated May 5, 1995 (for
Model A340 series airplanes); as applicable; constitutes terminating
action for the requirements of paragraph (a) of this AD. Once the
modification is completed, the avionics GRU may be reactivated.
(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, Standardization Branch, ANM-113.
Operators shall submit their requests through an appropriate FAA
Principal Maintenance Inspector, who may add comments and then send
it to the Manager, Standardization Branch, ANM-113.
Note 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Standardization Branch, ANM-113.
(d) Special flight permits may be issued in accordance with
sections 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.
(e) The modification, if accomplished, shall be done in
accordance with the following Airbus service bulletins, which
contain the specified list of effective pages:
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Service bulletin revision and date Page No. Revision level shown on page Date shown on page
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A330-21-3028, Revision 2, May 5, 1995........ 1, 3-6 2.................................. May 5, 1995.
2, 11, 23, 24, 29-30 1.................................. March 3, 1995.
7-10, 12-22, 25-28 Original........................... January 19, 1995.
A340-21-4046, Revision 2, May 5, 1995........ 1-4, 2.................................. May 5, 1995.
5-12, 14-24, 27-30 Original........................... January 19, 1995.
13, 25, 26, 31, 32 1.................................. March 3, 1995.
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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 Airbus Industrie, 1 Rond Point
Maurice Bellonte, 31707 Blagnac Cedex, France. Copies may be
inspected at the FAA, Transport Airplane Directorate, 1601 Lind
Avenue, SW., Renton, Washington; or at the Office of the Federal
Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
(f) This amendment becomes effective on April 15, 1997.
Issued in Renton, Washington, on March 19, 1997.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 97-7519 Filed 3-28-97; 8:45 am]
BILLING CODE 4910-13-U
