E7-25411. Airworthiness Directives; Erickson Air-Crane Incorporated Model S-64E and S-64F Helicopters

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes adopting a new airworthiness directive (AD) for the specified Erickson Air-Crane Incorporated (Erickson) model helicopters. The AD would require determining whether each specified tail rotor blade assembly (blade assembly) has an affected serial number or part marking. If a blade assembly has a certain serial number or part marking, the AD would also require initially and repetitively inspecting the tail rotor blade for a crack in the strap and pocket areas. If a crack is found, this AD would also require, before further flight, replacing the blade assembly with an airworthy blade assembly that does not have an affected serial number or part marking. This proposal is prompted by several reports of cracking in the strap and pocket areas of the tail rotor blade. The actions specified by the proposed AD are intended to prevent failure of the tail rotor blade and subsequent loss of control of the helicopter.

DATES:

Comments must be received on or before February 29, 2008.

ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
• Fax: [phone].
• Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.
• Hand Delivery: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

You may get the service information identified in this proposed AD from Erickson Air-Crane Incorporated, P. O. Box 3247, Central Point, OR 97502, telephone [phone], fax [phone], or at http://www.ericksonaircrane.com.

You may examine the comments to this proposed AD in the AD docket on the Internet at http://www.regulations.gov.

FOR FURTHER INFORMATION CONTACT:

Michael Kohner, Aviation Safety Engineer, FAA, Rotorcraft Directorate, Rotorcraft Certification Office, Fort Worth, Texas 76193-0170, telephone [phone], fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to submit any written data, views, or arguments regarding this proposed AD. Send your comments to the address listed under the caption ADDRESSES. Include the docket number “FAA-2007-0373, Directorate Identifier 2006-SW-14-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.

We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed rulemaking. Using the search function of our docket web site, you can find and read the comments to any of our dockets, including the name of the individual who sent or signed the comment. You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78) or you may visit http://dms.dot.gov.

Examining the Docket

You may examine the docket that contains the proposed AD, any comments, and other information in person at the Docket Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Operations office (telephone [phone]) is located in Room W12-140 on the ground floor of the West Building at the street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

Discussion

This document proposes adopting a new AD for the specified Erickson model helicopters. The AD would require determining whether certain tail rotor blade assemblies have an affected serial number or part marking. If a blade assembly has a certain serial number or part marking, the AD would also require initially and repetitively inspecting the tail rotor blade for a crack in the strap and pocket areas. If a crack is found, this AD would also require, before further flight, replacing the blade assembly with an airworthy blade assembly that does not have an affected serial number or part marking. This proposal is prompted by several reports of cracking in the strap or pocket areas of the tail rotor blade. This condition, if not corrected, could result in failure of the tail rotor blade and subsequent loss of control of the helicopter.

We have reviewed Erickson Alert Service Bulletin 64B15-9, Revision B, dated October 6, 2006 (ASB), which describes procedures for determining and inspecting certain marked or serial numbered tail rotor blades. The ASB specifies repetitive inspections not to exceed 6 flight hours for the S-64F model and not to exceed 15 flight hours for the S-64E model. Alternate inspection schedules are also included for “ferry flights” used for delivering the helicopter from one area of operation to another. The “ferry flight” time would be the flight time beginning at the end of the last operation in one area to the beginning of the first operation in another area. If a crack is found in the strap or pocket, the ASB specifies removing and replacing the blade.

We propose to depart from the language of the ASB and propose to use the terms hours time-in-service (TIS) instead of maximum ground-air-ground (GAG) cycles. We propose to define a “ferry flight” as a helicopter flight used for delivering the helicopter from one area of operation to another. During the “ferry flight” the helicopter would not drop off an external load or pick up an external load. A GAG cycle as defined in the ASB for the purposes of these inspections is any maneuver that results in a climb-out similar to one following takeoff. The proposed inspection intervals for the ferry flights were also modified to accommodate a new range of values based on specifications supplied by Erickson. The proposed inspection intervals were determined by multiplying the maximum GAG cycles in the ASB for the given takeoff weight by the flight endurance of 2.5 hours TIS for the Model S-64E and 2.2 hours TIS for the Model S-64F helicopters and rounding the result to a near whole number as deemed appropriate.

This unsafe condition is likely to exist or develop on other helicopters of these same type designs. Therefore, the proposed AD would require for each blade assembly, part number (P/N) 65161-00001-042 or -043, the following actions:

• Within 25 hours TIS, unless done previously, determine if the blade assembly has a serial number listed in the ASB. Also, determine if the blade assembly is marked with an “RS503” near the part number.
• If the blade assembly serial number is not listed in the ASB and does not have “RS503” marked near the part number, no further action would be required by this AD.
• If a blade assembly has either an affected serial number or part marking, before further flight, using a 10-power or higher magnifying glass, inspect both sides of the blade assembly for a crack in the strap and pocket areas paying particular attention to the circled area as depicted in Figure 1 of the ASB.
• If no crack is found, inspect the blade assembly at intervals not to exceed those TIS intervals specified in Table 1 of the AD.
• If a crack is found, before further flight, replace the unairworthy blade assembly with an airworthy FAA approved blade assembly that does not have a serial number listed in the ASB and does not have “RS503” marked near the part number.

The actions would be required to be done by following the specified portions of the ASB described previously.

We estimate that this proposed AD would:

• Affect 20 helicopters of U.S. registry; 13 Model S-64E and 7 Model S-64F;
• Require about 1 work hour to determine whether an affected blade is installed;
• Require about 1 work hour to inspect the blade assembly, assuming about 40 inspections a year for each Model S-64E (total 520) and about 100 inspections a year for each Model S-64F (total 700);
• Require about 4 work hours to replace each tail rotor blade, assuming 10 tail rotor blade assemblies are replaced;
• Cost about $80 per work hour; and
• Cost about $60,000 per blade assembly.

Based on these figures, the estimated total cost impact of the proposed AD on U.S. operators would be $702,400, based on the stated assumptions.

Regulatory Findings

We have determined that this proposed AD would not have federalism implications under Executive Order 13132. Additionally, this proposed AD 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.

For the reasons discussed above, I certify that the 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. 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.

We prepared a draft economic evaluation of the estimated costs to comply with this proposed AD. See the DMS to examine the draft economic evaluation.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, Section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's authority.

We are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701, “General requirements.” Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

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 adding a new airworthiness directive to read as follows:

Erickson Air-Crane Incorporated: Docket No. FAA-2007-0373; Directorate Identifier 2006-SW-14-AD.

Applicability

Model S-64E and S-64F helicopters, with tail rotor blade assembly (blade assembly), part number (P/N) 65161-00001-042 or -043, installed, certificated in any category.

Compliance

Required as indicated.

To prevent failure of the tail rotor blade and subsequent loss of control of the helicopter, do the following:

(a) Within 25 hours time-in-service (TIS), unless accomplished previously:

(1) Determine if the blade assembly has a serial number listed in the Accomplishment Instructions, paragraph 2.A., of Erickson Air-Crane Incorporated Alert Service Bulletin No. 64B15-9, Revision B, dated October 6, 2006 (ASB). Also, determine if the blade assembly has “RS503” marked near the P/N.

(2) If the blade assembly serial number is not listed in the ASB and does not have “RS503” marked near the P/N, no further action is required by this AD.

(3) If a blade assembly has either a serial number listed in paragraph 2.A of the ASB or has “RS503” marked near the part number, before further flight, using a 10-power or higher magnifying glass, inspect both sides of the blade assembly for a crack in the strap and pocket areas paying particular attention to the circled area as depicted in Figure 1 of the ASB.

(i) If no crack is found, inspect the blade assembly as specified in paragraph (a)(3) of this AD at intervals not to exceed those shown in the following table:

Table 1

Mission type	Gross takeoff weight (lbs)	Maximum time between inspections (hours TIS)
Model S-64E Tail Rotor Blade Strap Inspection Intervals
Ferry Only	Above 35,000	30
Ferry Only	Above 30,000 and less than or equal to 35,000	35
Ferry Only	Below or equal to 30,000	40
All Others	All	15
Model S-64F Tail Rotor Blade Strap Inspection Intervals
Ferry Only	Above 35,000	8
Ferry Only	Above 30,000 and less than or equal to 35,000	15
Ferry Only	Below or equal to 30,000	17
All Others	All	6

Note:

For the purposes of this AD, a ferry flight is defined as a helicopter flight used for delivering the helicopter from one area of operation to another. During the ferry flight, the helicopter would not drop off an external load or pick up an external load.

(ii) If a crack is found, before further flight, replace the unairworthy blade assembly with an airworthy FAA approved blade assembly that does not have a serial number listed in paragraph 2.A of the ASB and does not have “RS503” marked near the P/N.

(b) Installing an airworthy blade assembly that does not have a serial number listed in paragraph 2.A of the ASB and does not have “RS503” marked near the P/N is terminating action for the requirements of this AD.

(c) 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 Manager, Rotorcraft Directorate, Rotorcraft Certification Office, FAA, ATTN: Michael Kohner, Aviation Safety Engineer, Fort Worth, Texas 76193-0170, telephone [phone], fax [phone].

Issued in Fort Worth, Texas, on November 28, 2007.

Mark R. Schilling,

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.