03-16687. Airworthiness Directives; MD Helicopters, Inc. Model 369A, D, E, H, HE, HM, HS, F, and FF Helicopters

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule; request for comments.

SUMMARY:

This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 2003-08-51, which was sent previously to all known U.S. owners and operators of the specified model MD Helicopters, Inc. helicopters by individual letters. This AD requires reducing the retirement life of certain tail rotor blades, performing a one-time visual inspection of each tail rotor blade pitch horn (pitch horn) for a crack or corrosion, and replacing unairworthy tail rotor blades with airworthy tail rotor blades. This AD also requires revising the Airworthiness Limitations section of the helicopter maintenance manual to reflect the reduced retirement life, and reporting information to the FAA within 24 hours following the one-time inspection. The actions specified by this AD are intended to prevent a pitch horn from separating from the tail rotor blade, leading to an unbalanced condition, vibration, loss of tail rotor pitch control, and loss of directional control of the helicopter.

DATES:

Effective July 17, 2003, to all persons except those persons to whom it was made immediately effective by Emergency AD 2003-08-51, issued on April 15, 2003, which contained the requirements of this amendment.

Comments for inclusion in the Rules Docket must be received on or before September 2, 2003.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Office of the Regional Counsel, Southwest Region, Attention: Rules Docket No. 2003-SW-17-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].

FOR FURTHER INFORMATION CONTACT:

Fred Guerin, Aviation Safety Engineer, FAA, Los Angeles Aircraft Certification Office, Airframe Branch, 3960 Paramount Blvd., Lakewood, California 90712, telephone [phone], fax [phone].

SUPPLEMENTARY INFORMATION:

On April 15, 2003, the FAA issued Emergency AD 2003-08-51 for the specified model helicopters, which requires, before further flight, reducing the retirement life of certain tail rotor blades from 5,140, 5,200, or 10,000 hours time-in-service (TIS) to 400 hours TIS, performing a one-time visual inspection of each pitch horn for a crack or corrosion, and replacing unairworthy tail rotor blades with airworthy tail rotor blades. The Emergency AD also requires revising the Airworthiness Limitations section of the helicopter maintenance manual to reflect the reduced retirement life, and reporting information to the FAA within 24 hours following the one-time inspection. That action was prompted by two reports of cracked pitch horns that failed during flight. In both occurrences, the pilot was able to land the helicopter without further incident. Investigation revealed that the cause of the failures was a fatigue crack in the pitch horns that developed before the tail rotor blade reached its retirement life. This condition, if not corrected, could result in a pitch horn separating from the tail rotor blade, leading to an unbalanced condition, vibration, loss of tail rotor pitch control, and loss of directional control of the helicopter.

Since the unsafe condition described is likely to exist or develop on other MD Helicopters, Inc. Model 369A, D, E, H, HE, HM, HS, F, and FF helicopters of the same type designs, the FAA issued Emergency AD 2003-08-51 to prevent a pitch horn from separating from the tail rotor blade, leading to an unbalanced condition, vibration, loss of tail rotor pitch control, and loss of directional control of the helicopter. The AD requires, before further flight, reducing the retirement life of certain tail rotor blades from 5,140, 5,200, or 10,000 hours TIS to 400 hours TIS, performing a one-time visual inspection of each pitch horn for a crack or corrosion, and replacing unairworthy tail rotor blades with airworthy tail rotor blades. The AD also requires revising the Airworthiness Limitations section of the helicopter maintenance manual to reflect the reduced retirement life, and reporting information to the FAA within 24 hours following the one-time inspection. The short compliance time involved is required because the previously described critical unsafe condition can adversely affect the structural integrity of the helicopter. Therefore, reducing the retirement life of certain tail rotor blades; performing a one-time visual inspection of each pitch horn; replacing unairworthy tail rotor blades; and revising the Airworthiness Limitations section of the helicopter maintenance manual to reflect the reduced retirement life are required before further flight, and this AD must be issued immediately.

Since it was found that immediate corrective action was required, notice and opportunity for prior public comment thereon were impracticable and contrary to the public interest, and good cause existed to make the AD effective immediately by individual letters issued on April 15, 2003, to all known U.S. owners and operators of MD Helicopters, Inc. Model 369A, D, E, H, HE, HM, HS, F, and FF helicopters. These conditions still exist, and the AD is hereby published in the Federal Register as an amendment to 14 CFR 39.13 to make it effective to all persons.

The Emergency AD contained two typographical errors that are corrected in this AD. Paragraph (c) of the Emergency AD stated “400 hours TIS” twice, and the “or” in the listing of part numbers should have been “and”.

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.

The FAA estimates that this AD will affect 213 helicopters of U.S. registry, and replacing the tail rotor blades will take approximately 2 work hours per helicopter to accomplish at an average labor rate of $60 per work hour. Required parts will cost approximately $2,000 per helicopter. Based on these figures, we estimate the total cost impact of the AD on U.S. operators to be $2,120 per helicopter, or $451,560 to replace all the blades in the fleet.

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 should 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 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 mailed comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket No. 2003-SW-17-AD.” The postcard will be date stamped and returned to the commenter.

The regulations adopted herein will 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 final rule does not have federalism implications under Executive Order 13132.

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
• 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 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 adding a new airworthiness directive to read as follows:

2003-08-51 MD Helicopters, Inc.: Amendment 39-13215. Docket No. 2003-SW-17-AD.

Applicability: Model 369A, D, E, H, HE, HM, HS, F, and FF helicopters, with tail rotor blades, part number (P/N) 369D21640-501, 369D21641-501, 369D21642-501, 369D21643-501, 500P3100-101, 500P3100-301, 500P3300-501, or 500P3500-701, installed, certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent a tail rotor blade pitch horn (pitch horn) from separating from the tail rotor blade, leading to an unbalanced condition, vibration, loss of tail rotor pitch control, and loss of directional control of the helicopter, accomplish the following:

(a) This airworthiness directive (AD) establishes a new retirement life of 400 hours time-in-service (TIS) for the tail rotor blades listed in the Applicability section. For helicopters with an affected tail rotor blade installed that has 390 through 700 hours TIS, remove and replace the tail rotor blade with an airworthy tail rotor blade within 10 hours TIS.

(b) Before further flight, perform a one-time visual inspection of each pitch horn for a crack or corrosion in the area indicated by Note 2 in Figure 1 of this AD. Paint removal in accordance with Note 1 of Figure 1 of this AD is not required for the visual inspection.

(c) Revise the helicopter Airworthiness Limitations section of the maintenance manual by making pen-and-ink changes to indicate the new retirement life of 400 hours TIS for the tail rotor blades, P/N 369D21640-501, 369D21641-501, 369D21642-501, 369D21643-501, 500P3100-101, 500P3100-301, 500P3300-501, and 500P3500-70.

(d) For helicopters with a tail rotor blade installed that has more than 700 hours TIS, a one-time special flight permit to fly it to a repair facility may be issued only upon completion of an eddy current surface scan of each affected pitch horn (see Figure 1 of this AD). Paint removal in accordance with Note 1 of the Figure 1 of this AD IS required for the surface scan. If a crack is found, remove the tail rotor blade and replace it with an airworthy tail rotor blade before further flight.

(e) Within 24 hours after completing the requirements of this Emergency AD, report the information requested in Appendix A for all tail rotor blades listed in the Applicability section, including the tail rotor blades that were removed as a result of this AD. Report the information to: Manager, Los Angeles Aircraft Certification Office, ATTN: Fred Guerin, 3960 Paramount Blvd., Lakewood, California 90712, telephone [phone]. Reports may also be faxed to [phone] or emailed to [e-mail].

(f) Information collection requirements contained in this AD have been approved by the Office of Management and Budget (OMB) under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have been assigned OMB Control Number 2120-0056.

(g) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Contact the Los Angeles Aircraft Certification Office, Transport Airplane Directorate, FAA, for information about previously approved alternative methods of compliance.

(h) This amendment becomes effective on July 17, 2003, to all persons except those persons to whom it was made immediately effective by Emergency AD 2003-08-51, issued April 15, 2003, which contained the requirements of this amendment.

Appendix A—Tail Rotor Blade Inspection (Sample Format)

Send within 24 hours to:

Manager, Los Angeles Aircraft Certification Office, ATTN: Fred Guerin, 3960 Paramount Blvd., Lakewood, California 90712.

Fax: [phone].

Email: [e-mail].

Date:

Operator or Company Name:

Name of Contact Person:

Address:

Telephone:

Fax:

Aircraft Serial Number:

Aircraft Registration Number:

Estimated average flight hours per year:

T/R Blade Part Number: Serial Number: Total Time:

Crack found? (Yes/No): Corrosion Found? (Yes/No)

T/R Blade Part Number: Serial Number: Total Time:

Crack found? (Yes/No): Corrosion Found? (Yes/No)

T/R Blade Part Number: Serial Number: Total Time:

Crack found? (Yes/No): Corrosion Found? (Yes/No)

T/R Blade Part Number: Serial Number: Total Time:

Crack found? (Yes/No): Corrosion Found? (Yes/No)

Comments/Additional Information:

Issued in Fort Worth, Texas, on June 3, 2003.

Mark R. Schilling,

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.