[Federal Register Volume 63, Number 5 (Thursday, January 8, 1998)]
[Proposed Rules]
[Pages 1070-1072]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-477]


 ========================================================================
 Proposed Rules
                                                 Federal Register
 ________________________________________________________________________
 
 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
 
 ========================================================================
 

  Federal Register / Vol. 63, No. 5 / Thursday, January 8, 1998 / 
Proposed Rules  

[[Page 1070]]


=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95-NM-278-AD]
RIN 2120-AA64


Airworthiness Directives; Airbus Model A300, A310, and A300-600 
Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain Airbus Model A300, A310, 
and A300-600 series airplanes. This proposal would require inspections 
to detect defects of the flanges of the bleed air ducts of the 
auxiliary power unit (APU), and to measure the material thickness of 
the flanges; and repair, replacement of the duct with a new or 
serviceable duct, or operation of the airplane with the bleed air 
system of the APU inoperative, if necessary. For certain airplanes, the 
proposal also would require an inspection to detect cracks of the 
flanges, and follow-on actions. This proposal is prompted by issuance 
of mandatory continued airworthiness information by a foreign civil 
airworthiness authority. The actions specified by the proposed AD are 
intended to prevent rupturing and cracking of the flanges of the bleed 
air ducts, which could damage the elevator control system and 
consequently reduce the controllability of the airplane.

DATES: Comments must be received by February 9, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 95-NM-278-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except 
Federal holidays.
    The service information referenced in the proposed rule 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.

FOR FURTHER INFORMATION CONTACT: International Branch, ANM-116, FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (425) 227-2110; fax (425) 227-1149.

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 notice may be changed in 
light of the comments received.
    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 notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 95-NM-278-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. 95-NM-278-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The Direction Generale de l'Aviation Civile (DGAC), which is the 
airworthiness authority for France, notified the FAA that an unsafe 
condition may exist on certain Airbus Model A300, A310, and A300-600 
series airplanes. The DGAC advises that it received a report indicating 
that the flightcrew noticed that greater force than usual was needed to 
actuate the elevator control system during takeoff of the airplane. 
Following the flight, an inspection of the elevator control linkages 
was performed. Results of that inspection revealed that the aft detent 
bellcrank mechanism was partially jammed with a piece of material from 
the bleed air duct of the auxiliary power unit (APU). Subsequent 
investigation revealed that one of the flanges of the bleed air duct of 
the APU had ruptured, and the adjacent duct was cracked. This 
occurrence has been attributed to the fact that the flange was 
manufactured with a material thickness that is outside appropriate 
tolerances.
    If the material thickness of the flanges is outside appropriate 
tolerances, cracking of the flanges could occur. This condition could 
lead to rupture of the duct, and pieces of debris from the ruptured 
duct could affect the elevator control system. This condition, if not 
corrected, could result in reduced controllability of the airplane.

Explanation of Relevant Service Information

    Airbus has issued All Operator Telex (AOT) 36-02, dated August 23, 
1995, which references the following Airbus service bulletins: A300-36-
0033 (for Model A300 series airplanes), A300-36-6024 (for Model A300-
600 series airplanes), and A310-36-2032 (for Model A310 series 
airplanes), all dated October 17, 1994. These service bulletins 
describe procedures for inspections to detect defects (recesses, sharp 
edges, or scratches) of the inner and outer surfaces of all flanges of 
the bleed air ducts of the APU between frames 83 and 93 (for Model A300 
series airplanes) or frames 85 and 93 (for Model A310 and A300-600 
series airplanes), and to measure the material thickness of the flanges 
with an appropriate gauge; and repair of defects.

[[Page 1071]]

    For airplanes on which the material thickness of the flanges is 
within specified limits, the service bulletins describe procedures for 
an inspection using a magnifying glass to detect cracks of the inner 
and outer surfaces of the flanges; and, if cracks are found, 
replacement of the duct with a new or serviceable duct, at the time 
specified in the applicable service bulletin, or operation of the 
airplane with the bleed air system of the APU inoperative.
    For airplanes on which the material thickness of the flanges is 
outside specified limits, the service bulletins recommend immediate 
replacement of the duct with a new or serviceable duct, or operation of 
the airplane with the bleed air system of the APU inoperative.
    The DGAC classified these service bulletins and the AOT as 
mandatory and issued French airworthiness directive 95-182-184(B), 
dated September 27, 1995, in order to assure the continued 
airworthiness of these airplanes in France.

FAA's Conclusions

    These airplane models are manufactured in France 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, 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 Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other airplanes of the same type design, the 
proposed AD would require inspections to detect defects of the flanges 
of the bleed air ducts of the APU, and to measure the material 
thickness of the flanges; and repair, replacement of the duct with a 
new or serviceable duct, or operation of the airplane with the bleed 
air system of the APU inoperative, if necessary. For certain airplanes, 
the proposal also would require an inspection to detect cracks of the 
flanges, and follow-on actions. These actions would be required to be 
accomplished in accordance with the service bulletins described 
previously, except as described in the following paragraph.

Differences Between Proposed AD and Service Bulletins

    Operators should note that, unlike the procedures described in the 
referenced service bulletins, this proposed AD would not permit further 
flight if cracking is detected in the flanges. The FAA has determined 
that, due to the safety implications and consequences associated with 
such cracking, all ducts that are found to be cracked must be replaced 
prior to further flight, or the airplane must be operated with the 
bleed air system of the APU inoperative.

Cost Impact

    The FAA estimates that 84 airplanes of U.S. registry would be 
affected by this proposed AD, that it would take approximately 9 work 
hours per airplane to accomplish the proposed actions, and that the 
average labor rate is $60 per work hour. Based on these figures, the 
cost impact of the proposed AD on U.S. operators is estimated to be 
$45,360, or $540 per airplane.
    The cost impact figure discussed above is 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.

Regulatory Impact

    The regulations proposed herein would 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 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    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:

Airbus: Docket 95-NM-278-AD.

    Applicability: Model A300, A310, and A300-600 series airplanes 
on which Airbus Modification 11308 has not been accomplished during 
manufacture; 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 otherwise 
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 (b) 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 rupturing and cracking of the flanges of the bleed 
air ducts of the auxiliary power unit (APU), and cracking of the 
adjacent duct, which could damage the elevator control system and 
consequently reduce the controllability of the airplane; accomplish 
the following:
    (a) Prior to the accumulation of 5,000 total flight cycles, or 
within 500 flight cycles after the effective date of this AD, 
whichever occurs later: Perform a visual inspection to detect 
defects (recesses, sharp edges, or scratches) of the inner and outer 
surfaces of all flanges of the bleed air ducts of the APU between 
frames 83 and 93 (for Model A300 series airplanes) or between frames 
85 and 93 (for Model A310 and A300-600 series airplanes), as 
applicable; and measure the material thickness of the flanges; in 
accordance with Airbus Service Bulletin A300-36-0033 (for Model A300 
series airplanes), A300-36-6024 (for Model A300-600 series 
airplanes), or A310-36-2032 (for Model A310 series airplanes), all 
dated October 17, 1994; as applicable. If any defect is found, prior 
to further flight, repair the defect in accordance with the 
applicable service bulletin.

[[Page 1072]]

    (1) If the material thickness of the flanges is within the 
limits [Area 1: greater than or equal to 0.56 mm (0.022 inch); Area 
2: greater than or equal to 0.48 mm (0.019 inch)] specified in 
Airbus Service Bulletin A300-36-0033 (for Model A300 series 
airplanes), A300-36-6024 (for Model A300-600 series airplanes), or 
A310-36-2032 (for Model A310 series airplanes), all dated October 
17, 1994; as applicable: Prior to further flight, perform an 
inspection using a magnifying glass or appropriate gauge to detect 
cracks of the inner and outer surfaces of the flanges, in accordance 
with the applicable service bulletin.
    (i) If no crack is found, and the material thickness of all 
flanges is within the limits [Area 1: greater than or equal to 0.9 
mm (0.035 inch)] specified in the applicable service bulletin: No 
further action is required by this AD.
    (ii) If no crack is found, and the material thickness of any 
flange is outside the limits [Area 1: less than 0.9 mm (0.035 inch)] 
specified in the applicable service bulletin:
    Repeat the inspection required by paragraph (a) of this AD at 
the time specified in the applicable service bulletin.
    (iii) If any crack is found: Prior to further flight, accomplish 
either paragraph (a)(1)(iii)(A) or (a)(1)(iii)(B) of this AD.
    (A) Replace the duct with a new or serviceable duct in 
accordance with the applicable service bulletin. Or
    (B) Operate the airplane with the bleed air system of the APU 
inoperative, in accordance with the provisions and limitations 
specified in the operator's FAA-approved Master Minimum Equipment 
List (MMEL).
    (2) If the material thickness of any flange is outside the 
limits [Area 1: less than 0.56 mm (0.022 inch); Area 2: less than 
0.48 mm (0.019 inch)] specified in Airbus Service Bulletin A300-36-
0033 (for Model A300 series airplanes), A300-36-6024 (for Model 
A300-600 series airplanes), and A310-36-2032 (for Model A310 series 
airplanes), all dated October 17, 1994; as applicable: Prior to 
further flight, accomplish either paragraph (a)(1)(iii)(A) or 
(a)(1)(iii)(B) of this AD.
    (b) 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, International Branch, ANM-116, FAA, 
Transport 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, International 
Branch, ANM-116.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the International Branch, ANM-116.

    (c) 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.

    Note 3: The subject of this AD is addressed in French 
airworthiness directive 95-182-184(B), dated September 27, 1995.

    Issued in Renton, Washington, on January 2, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-477 Filed 1-7-98; 8:45 am]
BILLING CODE 4910-13-P