AD 94-19-05

This amendment adopts a new airworthiness directive (AD) that is applicable to certain British Aerospace Model BAC 1-11-200 and -400 series airplanes. This action requires revising the Limitations Section of the FAA-approved Airplane Flight Manual (AFM) to limit reversion of the flight controls to manual (unpowered) operation. This action also provides optional terminating action for the AFM limitation. This amendment is prompted by reports of cracking of certain brackets and levers in the primary flight control system due to residual stresses, mechanical loading, and material properties changes associated with aging. The actions specified in this AD are intended to prevent loss of integrity of the primary flight control system due to structural failure of the brackets or levers.

Final rule; request for comments

94-19-05 BRITISH AEROSPACE AIRBUS LIMITED (FORMERLY BRITISH AEROSPACE COMMERCIAL AIRCRAFT LIMITED, BRITISH AEROSPACE AIRCRAFT GROUP): Amendment 39-9027. Docket 94-NM-138-AD.
Applicability: Model BAC 1-11-200 and -400 series airplanes having rudder pedal pivot brackets, elevator pivot levers, or aileron pulley brackets (manufactured from L53 aluminum alloy casting material) identified in British Aerospace Alert Service Bulletin 27-A-PM6025, Issue 1, dated March 23, 1994; certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent loss of the integrity of the primary flight control system, accomplish the following:

(a) Within 30 days after the effective date of this AD, revise the Limitations Section of the FAA-approved Airplane Flight Manual (AFM) to include the following limitation; and thereafter operate the airplane in accordance with that limitation. This may be accomplished by inserting a copy of this AD in the AFM.

"The flight controls shall not be reverted to manual (unpowered) operation unless an emergency situation exists during which the flight crew must revert the flight controls to manual operation in order to maintain control of the airplane."

(b) Accomplishment of a detailed visual inspection to detect cracking of the elevator pivot levers, in accordance with paragraph 2.2 of the Accomplishment Instructions of British Aerospace Alert Service Bulletin 27-A-PM6025, Issue 1, dated March 23, 1994; constitutes terminating action for the AFM limitation required by paragraph (a) of this AD, and that limitation may be removed from the AFM. Repeat the inspection thereafter at intervals not to exceed 18 months. If any elevator pivot lever is cracked, prior to further flight, replace it with a serviceable part and apply water displacing fluid to the levers, in accordance with the alert service bulletin.

(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, 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.

(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 inspection and corrective actions shall be done in accordance with British Aerospace Alert Service Bulletin 27-A-PM6025, Issue 1, dated March 23, 1994. This incorporation by reference was approved by the Director of theFederal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from British Aerospace, Inc., 22070 Broderick Drive, Sterling, Virginia 20166. 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 October 6, 1994.

The Civil Aviation Authority (CAA), which is the airworthiness authority for the United Kingdom, recently notified the FAA that an unsafe condition may exist on certain British Aerospace Model BAC 1-11-200 and -400 series airplanes. The CAA advises that it has received reports of cracking of certain brackets and levers in the primary flight control system. These brackets and levers were manufactured from L53 aluminum alloy casting material. Investigation has revealed that the cracking may be attributed to a combination of residual stresses, mechanical loading, and material properties changes associated with aging. Cracking of these brackets and levers could lead to structural failure of these components. This condition, if not corrected, could result in loss of integrity of the primary flight control system.

British Aerospace has issued Alert Service Bulletin 27-A-PM6025, Issue 1, dated March 23, 1994, which specifies a new operating restrictionfor reversion of the flight controls to manual (unpowered) operation. Limiting such reversion to emergency situations only will greatly reduce the probability that flight control system brackets and levers (manufactured from L53 aluminum alloy casting material) will experience higher stresses, and thereby higher probability of structural failure associated with manual operation of the flight control systems.

The alert service bulletin also describes procedures for repetitive detailed visual inspections to detect cracking of the rudder pedal pivot brackets, elevator pivot levers, and aileron pulley brackets (manufactured from L53 aluminum alloy casting material) in the primary flight control system, replacement of any cracked bracket or lever with a serviceable part, and application of water displacing fluid to the brackets and levers. The CAA classified this alert service bulletin as mandatory in order to assure the continued airworthiness of these airplanes in the United Kingdom.

This airplane model is manufactured in the United Kingdom and is type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the CAA has kept the FAA informed of the situation described above. The FAA has examined the findings of the CAA, 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 on other airplanes of the same type design registered in the United States, this AD is being issued to prevent loss of the integrity of the primary flight control system. This AD requires revising the Limitations Section of the FAA-approved Airplane Flight Manual (AFM) to limit reversion of the flight controls to manual (unpowered) operation. This AD also provides for an optional terminating action for the AFM limitation, consisting of inspections, replacement (as necessary), and application of water displacing fluid, as specified in the alert service bulletin described previously.

The FAA is considering further rulemaking to require accomplishment of the currently optional terminating action. However, the proposed compliance time for those actions is sufficiently long so that notice and time for public comment would not be impracticable.

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 forpublic 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 94-NM-138-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 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 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: