00-12357. Airworthiness Directives; Bell Helicopter Textron Canada Model 407 Helicopters

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the supersedure of an existing airworthiness directive (AD), applicable to Bell Helicopter Textron Canada (BHTC) Model 407 helicopters, that currently requires installing a tail rotor pitch-limiting left-pedal stop (pedal stop), installing an airspeed limitation placard, marking a never-exceed velocity (Vne) placard on all airspeed indicators, and revising the Limitations section of the Rotorcraft Flight Manual (RFM). This action would require installing a redesigned tail rotor system and modifying the vertical fin and horizontal stabilizer to allow restoring the Vne to 140 knots indicated airspeed (IAS). This proposal is prompted by design changes to the tail rotor system and modification of the pedal stop for airspeed actuation to eliminate a tail rotor strike to the tailboom. The actions specified by the proposed AD are intended to prevent the tail rotor blades from striking the tailboom, separation of the aft section of the tailboom with the tail rotor gearbox and vertical fin, and subsequent loss of control of the helicopter.

DATES:

Comments must be received on or before June 16, 2000.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Office of the Regional Counsel, Southwest Region, Attention: Rules Docket No. 2000-SW-10-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137. You may also send comments electronically to the Rules Docket at the following address: [e-mail]. Comments may be inspected at the Office of the Regional Counsel 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 BHTC, 12,800 Rue de l'Avenir, Mirabel, Quebec JON1LO, telephone [phone], fax [phone]. This information may be examined at the FAA, Office of the Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas.

FOR FURTHER INFORMATION CONTACT:

Sharon Miles, Aviation Safety Engineer, FAA, Rotorcraft Directorate, Regulations Group, Fort Worth, Texas 76193-0111, telephone [phone], fax [phone].

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 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 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 mailed comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket No. 2000-SW-10-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, Office of the Regional Counsel, Southwest Region, Attention: Rules Docket No. 2000-SW-10-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137.

Discussion

On March 30, 1999, the FAA issued AD 99-06-15, Amendment 39-11111 (64 FR 16801, April 7, 1999), to require installing a pedal stop and adjusting the rigging of the directional controls, installing an airspeed limitation placard, marking a new never-exceed velocity (Vne) limit on all airspeed indicators, and revising the Limitations section of the RFM. That action was prompted by three accidents involving in-flight tail rotor blade strikes against the tailboom. The requirements of that AD are intended to prevent the tail rotor blades from striking the tailboom, separation of the aft section of the tailboom with the tail rotor gearbox and vertical fin, and subsequent loss of control of the helicopter.

Since the issuance of that AD, the manufacturer has made a design change to the tail rotor system to eliminate tail rotor strikes to the tailboom, and also made design changes to the pedal stop.

BHTC has issued Bell Helicopter Textron Alert Service Bulletin (ASB) No. 407-99-27, Rev. A, dated June 9, 1999, and Bell Helicopter Textron Technical Bulletin No. 407-99-17, dated April 15, 1999, both of which concern replacing the tail rotor; ASB 407-99-33, Revision A, dated March 10, 2000, which concerns installing a pedal stop and restoring the Vne to 140 knots IAS; and Bell Helicopter Textron Technical Bulletin No. 407-96-2, Revision A, dated March 11, 1997, which concerns modifying the vertical fin and horizontal stabilizer. Transport Canada classified these service bulletins as mandatory and issued AD No. CF-1998-36R7, dated February 1, 2000, in order to assure the continued airworthiness of these helicopters in Canada.

This helicopter model is manufactured in Canada and is type certificated for operation in the United States under the provisions of § 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, Transport Canada, which is the airworthiness authority for Canada, has kept the FAA informed of the situation described above. The FAA has examined the findings of the Transport Canada, 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 BHTC Model 407 helicopters of the same type design, the proposed AD would supersede AD 99-06-15 to require installing a redesigned tail rotor system, modifying the vertical fin and horizontal stabilizer, and restoring the Vne to 140 knots IAS.

The FAA estimates that 200 helicopters of U.S. registry would be affected by this proposed AD, that it would take approximately 80 work hours per helicopter to perform the modifications and installations, and that the average labor rate is $60 per work hour. Required parts would cost approximately $24,161 per helicopter; however, the manufacturer has stated they will provide these parts at no cost. Additionally, the manufacturer has stated they will reimburse the cost of labor up to $4,400. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $5,792,200 or $28,961 per helicopter, assuming no costs are reimbursed.

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 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.

§ 39.13

[Amended]

2. Section 39.13 is amended by removing Amendment 39-11111 (64 FR 16801, April 7, 1999), and by adding a new airworthiness directive (AD), to read as follows:

Bell Helicopter Textron Canada: Docket No. 2000-SW-10-AD. Supersedes AD 99-06-15, Amendment 39-11111, Docket No. 99-SW-16-AD.

Applicability: Model 407 helicopters, certificated in any category.

Note 1:

This AD applies to each helicopter 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 helicopters 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 (d) 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 the tail rotor blades from striking the tailboom, which could result in separation of the aft section of the tailboom with the tail rotor gearbox and vertical fin, and subsequent loss of control of the helicopter, accomplish the following:

(a) Before further flight:

(1) Install a stop that limits the maximum distance that the left pedal can travel in accordance with Part I of the Accomplishment Instructions in Bell Helicopter Textron Canada Technical Bulletin 407-98-13, dated December 12, 1998 (TB).

(2) Adjust the rigging of the directional controls in accordance with Part II of the Accomplishment Instructions in the TB.

(3) Install the airspeed limitation placard shown in Figure 1 of this AD so that it completely covers and obscures the airspeed limitation placard, P/N 407-070-201-103. Ensure that the replacement placard is at least 2\1/16\-inches tall and 3 \9/16\-inches long.

Figure 1.—407 Airspeed Limitations—Knots—IAS

[AD 99-06-15]

OAT	Pressure altitude FX × 1000
C°	0	2	4	6	8	10	12	16	16	18	20
52	98	93	88
40	100	95	91	86	81	76
20	100	100	95	90	85	80	76	71	66	61
0	100	100	100	95	90	85	80	75	70	65	60
−20	100	100	100	100	95	90	85	80	75	70	65
−40	97	93	88	83	79	74	70	65	61
Maximum Autorotation VNE 100 KIAS

(4) Install a redline at a Vne of 100 KIAS on all airspeed indicators. Remove or obscure any previously installed lines or arcs above 100 KIAS. If the redline is installed on the instrument glass, also install a slippage mark on the glass and on the instrument case.

(5) Add the following statement to the Limitations section of the Rotorcraft Flight Manual (RFM):

When operating at an airspeed of 60 to 100 KIAS, maintain yaw trim within one ball diameter of the centered position of the turn and bank (slip) indicator, and avoid sudden or large directional control inputs in flight.

(6) Mark the airspeed limitations placard in Figure 1-3 in the RFM to indicate that it has been superseded by this AD, and insert a copy of this AD into the RFM. Also, mark the airspeed indicator in Figure 1-5 of the RFM to indicate a Vne of 100 KIAS.

(7) This AD revises the limitations section of BHTC Model 407 RFM by replacing sheet 1 of Figure 1-3 in the RFM with Figure 1 of this AD, revising sheet 3 of Figure 1-5 of the RFM, and adding an operational limitation for allowable yaw trim and directional control input.

(8) Report any uncommanded right yaw, uncommanded movement of the pedals during flight, or tail rotor blade contact with the tailboom within 24 hours of the occurrence to the Manager, Regulations Group, telephone [phone]. Reporting requirements have been approved by the Office of Management and Budget and assigned OMB control number 2120-0056.

(b) Before further flight after January 31, 2001:

(1) Remove and replace the existing tail rotor with tail rotor installation, P/N 407-012-100-109, in accordance with Part II of Bell Helicopter Textron Technical Bulletin 407-99-17, dated April 15, 1999.

(2) Modify the vertical fin and horizontal stabilizer in accordance with Bell Helicopter Textron Technical Bulletin No. 407-96-2, Revision A, dated March 11, 1997.

(3) Install the tail rotor airspeed-actuated pedal stop kit, install the new airspeed limitation decals, and remove the temporary instrument markings and RFM changes in accordance with the Accomplishment Instructions in Parts I, II, and III of Bell Helicopter Textron Alert Service Bulletin 407-99-33, Revision A, dated March 10, 2000.

(c) Accomplishing the requirements of paragraph (b) of this AD is terminating action for the requirements of this AD.

(d) 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, Regulations Group, Rotorcraft Directorate, FAA. Operators shall submit their requests through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Regulations Group.

Note 2:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Regulations Group.

(e) Special flight permits may be issued in accordance with §§ 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the helicopter to a location where the requirements of this AD can be accomplished.

Note 3:

The subject of this AD is addressed in Transport Canada (Canada) AD CF-98-36R7, dated February 1, 2000.

Issued in Fort Worth, Texas, on May 5, 2000.

Eric Bries,

Acting Manager, Rotorcraft Directorate,, Aircraft Certification Service.