AD 94-04-05 SUPERSEDED

This amendment adopts a new airworthiness directive (AD) that is applicable to certain Airbus Industrie Models A300, A310, and A300-600 series airplanes. This action requires repetitive deployment tests of the ram air turbine (RAT) and checks of the adjustment of the locking rod. This amendment is prompted by reports of failure of the RAT to rotate when necessary, due to maladjustment of the locking rod. The actions specified in this AD are intended to ensure the availability of the RAT in case of need.

Final rule; request for comments.

94-04-05 AIRBUS: Amendment 39-8823. Docket 94-NM-10-AD.

Applicability: Models A300, A310, and A300-600 series airplanes, certificated in any category; equipped with the following Dowty ram air turbines (RAT), part numbers:

RAT 16C 100 VG
RAT 16C 101 VG
RAT 16C 102 VG
RAT 16C 103 VG
RAT 16C 104 VG
RAT 16C 105 VG
RAT 16C 109 VG
RAT 16C 110 VG
RAT 16C 116 VG
RAT 16C 117 VG

Compliance: Required as indicated, unless accomplished previously.

To ensure the availability of the ram air turbine (RAT) in case of need, accomplish the following:

(a) Within 60 days after the effective date of this AD, or prior to accumulation of 500 hours time-in-service after the effective date of this AD, whichever occurs first, perform a deployment test of the RAT and check the adjustment of the locking rod, in accordance with Airbus All Operator Telex (AOT) 29-09, dated November 16, 1993. Repeat the deployment test and adjustment check thereafter at intervals not to exceed 10 months.
(1) If no discrepancy is found, prior to further flight, apply grease to the RAT leg at the entry and exit positions of the locking rod spring housing, in accordance with the AOT.
(2) If any discrepancy is found, prior to further flight correct it and apply grease to the RAT leg at the entry and exit positions of the locking rod spring housing, in accordance with the AOT.

(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, Standardization Branch, ANM-113, 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, Standardization Branch, ANM-113.

NOTE: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Standardization Branch, ANM-113.(c) Special flight permits may be issued in accordance with Federal Aviation Regulations (FAR) 21.197 and 21.199 to operate the airplane to a location where the requirements of this AD can be accomplished.

(d) The actions shall be done in accordance with Airbus All Operator Telex (AOT) 29-09, dated November 16, 1993. 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.

(e) This amendment becomes effective on March 17, 1994.

The Direction G n rale de l'Aviation Civile (DGAC), recently notified the FAA that an unsafe condition may exist on Airbus Models A300, A310, and A300-600 series airplanes. The DGAC advises that there has been a report of a RAT failing to rotate during an in-flight deployment test. The locking rod did not move sufficiently to release the turbine and, consequently, no rotation of the spinner was possible. Initial investigations revealed that this situation was caused by a combination of (1) corrosion inside of the spring housing located at the upper part of the leg, where the upper part of the locking rod goes through; and (2) probable maladjustment of the locking rod itself. Further investigation revealed that the lubricating grease in this area had decomposed into solid particles, and the resulting friction appeared high enough to contribute to the stiff movement of the locking rod assembly. This condition, if not corrected, could result in the unavailability of the RAT in case of need.

In response to this situation, Airbus Industrie issued an All Operator Telex (AOT) in July 1993, recommending that operators perform repetitive ground extension tests of the RAT to ensure that it was in proper working condition, and repetitive checks of the locking rod for proper movement. That AOT instructed operators to adjust the locking rod at 5 to 10 degrees from full travel of the extended position. (By adjusting to that point, alignment with the surface of the lock plate was expected to be reached.) The AOT also recommended that operators apply additional lubricating grease at the top and bottom of the spring housing, so that the area would be sealed against moisture and corrosion would be inhibited.

Subsequent to the issuance of that AOT, a report was received indicating that, during an in-flight deployment test on a Model A300 series airplane, one of the blades of the RAT was damaged. Investigation of this incident revealed thatthe RAT locking rod had been adjusted to 10 degrees from full travel of the leg in extended position, as was recommended in the previously-issued AOT. Consequently, this had allowed the RAT blades to start to rotate too early and contact the RAT door. Potential contact between the RAT blades and RAT doors is not readily detectable during a normal RAT ground functional test, since the RAT does not rotate during the extension phase of the test. If this latent failure occurs, it can lead to damage of the RAT blades and subsequent reduced performance of the RAT during times when its use is needed.

In order to address this situation, Airbus Industrie issued All Operator Telex 29-09, dated November 16, 1993, which recommends similar inspection, adjustment, and lubrication actions to those called for in the previous AOT, but reduces the tolerances for adjustment of the RAT locking rod to 5 (+0.5 to -1.0) degrees. This reduction of the adjustment tolerances will prevent the previously described situation from occurring and thereby preclude the problems associated with the RAT blades rotating too early. The DGAC classified this service bulletin as mandatory and issued French Airworthiness Directive 93-136-146(B)R1, dated December 22, 1993, in order to assure the continued airworthiness of these airplanes in France.

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 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.

Since an unsafe condition has been identified that is likely to exist or develop onother airplanes of the same type design registered in the United States, this AD is being issued to prevent reduced performance of the RAT in case of need. This AD requires repetitive ground extension test of the RAT to ensure that it is in proper working condition, and repetitive checks of the locking rod for proper movement and adjustment, if necessary. This AD also requires application of additional lubricating grease at the top and bottom of the spring housing. The actions are required to be accomplished in accordance with Airbus AOT 29-09, described previously.

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 notice must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 94-NM-10-AD." The postcard will be date stamped and returned to the commenter.

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.

The FAA has determined that this regulation is an emergency regulation that must beissued immediately to correct an unsafe condition in aircraft, and 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 14 CFR part 39 of the Federal Aviation Regulations as follows:

PART 39 - AIRWORTHINESS DIRECTIVES1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 106(g); and 14 CFR 11.89.

39.13 - [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-103, Attention: Rules Docket No. 94-NM-10-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.

Stephen Slotte, Aerospace Engineer, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, Washington 98055-4056; telephone (206) 227-2797; fax (206) 227-1320.