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Proposed Rule

Airworthiness Directives; Eurocopter France Model AS350B, B1, B2, B3, BA, C, D, D1, and AS355E, F, F1, F2, and N Helicopters

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Start Preamble


Federal Aviation Administration, DOT.


Supplemental notice of proposed rulemaking; reopening of comment period.


This document revises an earlier proposed airworthiness directive (AD) for the specified Eurocopter France (ECF) model helicopters that proposed a daily inspection of the tail rotor pitch control rod (control rod) outboard spherical bearing (bearing), a radial and axial play limit, a revised AD compliance interval, and adding the ECF Model AS350B3 helicopter and an additional control rod to the applicability. That proposal was prompted by two comments received and the FAA determination that the AD inspection interval should coincide with the normal maintenance interval and that the AD should apply to the ECF Model AS350B3 helicopter. This action retains the original proposals but changes the daily inspection to a daily check and makes other editorial changes for clarification. The actions specified by the proposed AD are intended to prevent separation of the bearing ball from its outer race, rubbing of the body of the control rod against the tail rotor blade pitch horn clevis, failure of the control rod, and subsequent loss of control of the helicopter.


Comments must be received on or before June 23, 2003.


Submit comments in triplicate to the Federal Aviation Administration (FAA), Office of the Regional Counsel, Southwest Region, Attention: Rules Docket No. 2000-SW-12-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137. You may also send comments electronically to the Rules Docket at the following address: Comments may be inspected at the Office of the Regional Counsel between 9 a.m. and 3 p.m., Monday through Friday, except Federal holidays.

Start Further Info


Uday Garadi, Aviation Safety Engineer, FAA, Rotorcraft Directorate, Rotorcraft Standards Staff, Fort Worth, Texas 76193-0110, telephone (817) 222-5123, fax (817) 222-5961.

End Further Info End Preamble Start Supplemental 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 should 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 document 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 mailed comments submitted in response to this proposal must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket No. 2000-SW-12-AD.” The postcard will be date stamped and returned to the commenter.


On November 19, 1998, the FAA issued AD 98-24-35, Amendment 39-10921, Docket 98-SW-41-AD (63 FR 66418, December 2, 1998), to require measuring the control rod bearing radial and axial play every 50 hours time-in-service (TIS). That action was prompted by an accident and an incident involving ECF Model AS350B2 helicopters. There were two other unconfirmed incidents cited by the National Transportation Safety Board (based on manufacturer's reports) involving the same control rod, part number (P/N) 350A33-2145-00.

After issuing AD 98-24-35, ECF issued Service Letter No. 1367-64-98, dated January 12, 1999, to provide operators with an easy way to determine the looseness of the bearing by adding an axial play limit of 0.016 inch and a daily check. When the FAA issued AD 98-24-35, neither the Direction Generale De L'Aviation Civile nor the manufacturer had issued any service information addressing this unsafe condition.

Subsequently, the FAA received comments from two commenters, the manufacturer and an operator, stating that a larger axial play limit and a 30-hour time-in-service (TIS) visual check would provide a satisfactory degree of safety for this control rod and an adequate inspection interval.

The FAA agreed and issued a proposal to amend 14 CFR part 39, published as an NPRM in the Federal Register on April 9, 2001 (66 FR 18416), to supersede AD 98-24-35. The NPRM Start Printed Page 19762proposed adding ECF Model AS350B3 helicopters and control rod, P/N 350A33-3145-00, to the applicability; increasing the frequency of the inspection interval from every 50 hours TIS to every 30 hours TIS; establishing a daily inspection of the control rod bearing; and establishing an axial play limit of 0.016-inch. The actions of that proposed AD were intended to prevent separation of the bearing ball from its outer race, rubbing of the body of the control rod against the tail rotor blade pitch horn clevis, failure of the control rod, and subsequent loss of control of the helicopter.

Since issuing that NPRM, the FAA has received various comments from 12 commenters.

Three commenters state that the proposed daily inspection of the bearing should be deleted because the requirement already exists in the maintenance work cards and in the preflight checklist in the rotorcraft flight manual (RFM). In addition, another commenter states that the daily inspection should be changed to a daily check and that a trained pilot should do the check. The FAA agrees that a pilot can do the check but believes that due to the accidents caused by failure of the control rods and because the RFM and the maintenance work cards are unclear a daily check should be required. However, we are revising our proposal to allow an owner/operator (pilot) to perform the daily check of the bearing for movement because no tools are required and the check can be accomplished by observation and feel. However, the pilot must enter compliance with those requirements into the helicopter maintenance records in accordance with 14 CFR 43.11 and 91.417(a)(2)(v).

One commenter, the manufacturer, states that the control rod P/N is incorrectly stated in three places. Also, in its Service Letter No. 1367-64-98, which details the most effective checking conditions, the term “easy” is more suitable than the term “accurate” as used in the proposed AD. The FAA agrees and has made those changes as requested.

The manufacturer requests that the proposed Figures 1 and 2, relating to the axial and radial play measurements, be replaced with three clearer figures provided by them. The FAA agrees. Published Figure 1 gives the method only for a visual check. Published Figure 2 shows the complete assembly of the control rod and makes it appear that the measurements can be made without removing the control rod from the helicopter. Therefore, the FAA is inserting the three clearer figures in the proposal to clearly depict the measurement of radial and axial play and is including references in the text accordingly.

Seven commenters state that the inspection interval of the bearing should be changed from the proposed 30 to 100 hours TIS. One commenter states that the inspection interval should not be less than 50 hours TIS. The FAA mistakenly proposed an inspection of all affected control rods at intervals not to exceed 30 hours TIS. The 30-hour TIS inspection interval was intended to apply only to the control rods that were removed from the helicopter because play was detected, not to newly installed or in-service control rods. Therefore, we have changed the proposed paragraph numbering and added the word “thereafter” to clearly indicate that the 30-hour TIS inspection interval applies to control rods in which play has been detected. We do not agree that the inspection interval for these control rods should be extended above 30 hours TIS.

The manufacturer further states that the compliance time in paragraph (a) should be changed from “before the first flight” (BFF) to “after the last flight” (ALF) of the day. The commenter states that if maintenance is required for operational reasons, ALF is preferable to BFF because the mechanic has more time to do the work and states that the ALF visit is longer and a more important daily visit compared with the BFF. The FAA does not agree. The intent is to check the helicopter for safety of flight in accordance with the requirements of this AD regardless of whether it is done ALF or BFF.

The manufacturer further states that we should add a requirement that if the ball shows evidence of scoring and/or discoloration, the control rod should be replaced with an airworthy control rod before further flight. The FAA agrees and has changed the wording of the proposed AD to state that if discoloration or scoring on the bearing is found, the bearing is unairworthy.

Another commenter with 20 years of experience with these helicopters states that neither the current AD nor this proposed AD is needed. The FAA disagrees. The FAA has determined that an AD is required based on the occurrence of accidents due to failure of these control rods.

One commenter fully agrees with the proposal and suggests adding a warning to the RFM alerting pilots that violent vibration due to a pitch control rod failure will result in separation of the tail boom. The FAA disagrees. The RFM Emergency Procedures address the tail rotor malfunction including tail rotor control failure. The daily check should preclude any impending failure of the control rod based on the conditions addressed by this AD.

Other commenters agree with the proposal to increase the axial play from .008 inch to .016 inch; however, one commenter asks if leaving the allowable play at .008 inch would not be safer. The FAA believes that a sufficient margin of safety is provided if the play is increased to .016 inch.

On July 10, 2002, the FAA issued a new version of 14 CFR part 39 (67 FR 47997, July 22, 2002), which governs the FAA's AD system. The regulation now includes material that relates to altered products, special flight permits, and alternative methods of compliance. Because we have now included this material in part 39, we no longer need to include it in each individual AD. Therefore, Notes 1 and 2 and paragraph (c) as published in AD 98-24-35 and the NPRM in this action are not included in this supplemental notice of proposed rulemaking. However, a revised paragraph (c) is added to the proposed action.

Some of these changes expand the scope of the originally proposed rule. Therefore, the FAA has determined that it is necessary to reopen the comment period to provide additional opportunity for public comment.

The FAA estimates that the AD would affect 610 helicopters of U.S. registry, that it would take approximately 1 work hour per helicopter to accomplish the inspections, and that the average labor rate is $60 per work hour. Required parts would cost approximately $1,224 for two control rods per helicopter. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $783,240.

The regulations proposed herein would 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 proposal would not have federalism implications under Executive Order 13132.

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 Start Printed Page 19763action 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.

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List of Subjects in 14 CFR Part 39

  • Air transportation
  • Aircraft
  • Aviation safety
  • Safety
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The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 14 CFR part 39 as follows:

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1. The authority citation for part 39 continues to read as follows:

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Authority: 49 U.S.C. 106(g), 40113, 44701.

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2. Section 39.13 is amended by adding a new airworthiness directive to read as follows:

Eurocopter France: Docket No. 2000-SW-12-AD.

Applicability: Eurocopter France Model AS350B, B1, B2, B3, BA, C, D, D1, and AS355E, F, F1, F2, and N helicopters, with tail rotor pitch control rod (control rod), part number (P/N) 350A33-2145-00 or 350A33-2145-01, installed, certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent separation of the control rod outboard spherical bearing (bearing) ball from its outer race, rubbing of the body of the control rod against the tail rotor blade pitch horn clevis, failure of the control rod, and subsequent loss of control of the helicopter, accomplish the following:

(a) Before the first flight of each day, place the tail rotor pedals in the neutral position. If the helicopter is fitted with a tail rotor load compensator, discharge the accumulator as described in the rotorcraft flight manual. Check the bearing for play on the helicopter, by observation and feel, by slightly moving the tail rotor blade in the flapping axis while monitoring the bearing for movement. See the following Figure 1 of this AD:

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(1) If the Teflon cloth is coming out of its normal position within the bearing, totally or partially, or if there is discoloration or scoring on the bearing, the bearing is unairworthy.

(2) An owner/operator (pilot) holding at least a private pilot certificate may perform this check and must enter compliance into the aircraft maintenance records in accordance with 14 CFR 43.11 and 91.417(a)(2)(v).

(b) If a pilot or mechanic detects play, a mechanic must remove the control rod from the helicopter, and using a dial indicator, measure the bearing wear according to the following and as shown in Figures 2 and 3 of this AD:

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(1) Remove the control rod from the helicopter.

(2) Mount the control rod in a vise as shown in Figure 2 of this AD.

(3) Using a dial indicator, take axial play readings by moving the spherical bearing in the direction F (up and down) as shown in Figure 2 of this AD.

(4) Install a bolt washer and nut to secure the bearing after removing it from the vise.

(5) Mount the bearing in a vise as shown in Figure 3 of this AD.

(6) Using a dial indicator, take radial play measurements by moving the control rod in the direction F as shown in Figure 3 of this AD.

(7) Record the hours of operation on each control rod.

(8) If the radial play exceeds 0.008 inch or axial play exceeds 0.016 inch, replace the control rod with an airworthy control rod before further flight.

(9) If the radial and axial play are within limits, reinstall the control rod.

(10) Thereafter, at intervals not to exceed 30 hours TIS, remove the control rod and again measure the bearing play with a dial indicator in accordance with this paragraph.

(c) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR Start Printed Page 1976639.19. Contact the Manager, Regulations Group, Rotorcraft Directorate, FAA, for information about previously approved alternative methods of compliance.

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Issued in Fort Worth, Texas, on April 15, 2003.

David A. Downey,

Manager, Rotorcraft Directorate, Aircraft Certification Service.

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[FR Doc. 03-9862 Filed 4-21-03; 8:45 am]