AD 2006-05-05

The FAA is adopting a new airworthiness directive (AD) for certain MT-Propeller Entwicklung GmbH variable pitch and fixed pitch propellers with serial numbers (SNs) below 95000, which have not been overhauled since April 1994. This AD requires overhauling the propeller blades of these propellers within 30 days after the effective date of the AD. This AD also requires performing initial and repetitive visual inspections of affected propeller blades. This AD also requires removing all propeller blades from service with damaged erosion sheath bonding or loose erosion sheaths and installing any missing or damaged polyurethane protective strips. This AD results from reports of stainless steel leading edge erosion sheaths separating from propeller blades and reports of propeller blades with damaged or missing polyurethane protective strips (PU-protection tape) due to insufficient inspection procedures in older MT-Propeller Entwicklung GmbH Operation & Installation Manuals. We are issuing this AD to prevent erosion sheath separation leading to damage of the airplane.

Final rule.

2006-05-05 MT-Propeller Entwicklung GmbH: Amendment 39-14502. Docket No. FAA-2005-20856; Directorate Identifier. 2004-NE-25-AD.

Effective Date

(a) This airworthiness directive (AD) becomes effective April 10, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to MT-Propeller Entwicklung GmbH, models MT, MTV-1, MTV-2, MTV-3, MTV-5, MTV-6, MTV-7, MTV-9, MTV-10, MTV-11, MTV-12, MTV-14, MTV-15, MTV-17, MTV-18, MTV-20, MTV-21, MTV-22, MTV- 24, and MTV-25 propellers with serial numbers (SNs) below 95000, which have not been overhauled since April 1994. These propellers may be installed on but not limited to, Sukhoi SU-26, SU-29, SU-31; Yakovlev YAK-52, YAK-54, YAK-55; and Technoavia SM-92 airplanes.

Unsafe Condition

(d) This AD results from reports of stainless steel leading edge erosion sheaths separating from propeller blades and reports of propeller blades with damaged or missing polyurethane protective strips (PU-protection tape) due to insufficient inspection procedures in older MT-Propeller Entwicklung GmbH Operation & Installation Manuals. We are issuing this AD to prevent erosion sheath separation leading to damage of the airplane.

Compliance

(e) You are responsible for having the actions required by this AD performed within the compliance times specified unless the actions have already been done.

Note 1: Information about inspection procedures and acceptable limits can be found in Table 1 of this AD.

Overhaul of Propeller Blades

(f) Overhaul all propeller blades of propellers listed in the applicability, within 30 days after the effective date of this AD.

Initial Visual Inspection of the Propeller Blade

(g) During the next preflight inspection or 100-hour inspection, whichever occurs first, after the effective date of this AD, inspect all MT and MTV propellers by doing the following:

(1) Determine if the erosion sheath of any propeller blade is cracked or loose; and

(2) Determine if any propeller blade has other damage out of acceptable limits.

(3) Before the next flight, remove from service those propeller blades with a cracked or loose erosion sheath, or other damage affecting airworthiness.

Table 1.--Service Information

For propeller model ...
See operation and in-stallation manual . . .

MT .............................
No. E 112, issued Nov. 1993 or later.

MTV 1, MTV 7,
MTV 10, MTV 17,
MTV 18, MTV 20.
No. E 118, issued March 1994 or later.

MTV 5, MTV 6,
MTV 9, MTV 11,
MTV 12, MTV 14,
MTV 15, MTV 21,
MTV 22, MTV 25.
No. E 124, issued March 1994 or later.

MTV 2, MTV 3 .........
No. E 148, issued March 1994 or later.

MTV 24 .....................
No. E 309, issued March 1994 or later.

Initial Visual Inspection of the Propeller Blade Polyurethane Strip

(h) During the next pilot's preflight inspection after the effective date of this AD, if the polyurethane protective strip on the leading edge of the inner portion of the blade is found to be damaged or missing, the polyurethane protective strip must be replaced or installed within 10-flight hours.

If electrical de-icing boots are installed, no polyurethane protective strips are required.

Repetitive Visual Inspection of the Propeller Blade

(i) If after the effective date of this AD, any propeller blade erosion sheath found to be cracked or loose during the pilot's preflight inspection, or 100-hour inspection, or annual inspection, must be repaired, replaced, or overhauled before the next flight.

Repetitive Visual Inspection of the Propeller Blade Polyurethane Strip

(j) If after the effective date of this AD, any propeller blade polyurethane protective strip found to be damaged or missing during the pilot's preflight inspection, or 100-hour inspection, or annual inspection, must be replaced or installed within 10-flight hours. If electrical de-icing boots are installed, polyurethane protective strips are not required.

Alternative Methods of Compliance

(k) The Manager, Boston Aircraft Certification Office, has the authority to approve alternative methods of compliance for this AD if requested using the procedures found in 14 CFR 39.19.

Special Flight Permits

(l) Special flight permits are prohibited.

Related Information

(m) MT-Propeller Entwicklung GmbH, Service Bulletin No. 8A, dated July 4, 2003, pertains to the subject of this AD. LBA airworthiness directive 1994-098/2, dated September 24, 2003, also addresses the subject of this AD.

The FAA proposed to amend 14 CFR part 39 with a proposed AD. The proposed AD applies to certain MT-Propeller Entwicklung GmbH variable pitch and fixed pitch propellers with serial numbers (SNs) below 95000, which have not been overhauled since April 1994. We published the proposed AD in the Federal Register on April 6, 2005 (70 FR 17359). That action proposed to require overhaul of the propeller blades on these propellers by December 31, 2005. That action also proposed to require performing initial and repetitive visual inspections of those propeller blades. That action also proposed to require removing all propeller blades from service with damaged erosion sheath bonding or loose erosion sheaths and to install any missing or damaged polyurethane protective strips.

Examining the AD Docket

You may examine the docket that contains the AD, any comments received, and any final disposition in person at the Docket Management Facility Docket Office between9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Office (telephone (800) 647-5227) is located on the plaza level of the Department of Transportation Nassif Building at the street address stated in ADDRESSES. Comments will be available in the AD docket shortly after the DMS receives them.

Comments

We provided the public the opportunity to participate in the development of this AD. We received no comments on the proposal or on the determination of the cost to the public.

Changes to Blade Overhaul Paragraph

Although paragraph (j) of the proposed AD states to overhaul all affected blades by December 31, 2005, for clarification, we changed that paragraph in this AD to read "Overhaul all propeller blades of propellers listed in the applicability, within 30 days after the effective date of the AD''. We also changed the codification and moved this paragraph to paragraph (f).

Conclusion

We have carefully reviewed the available data and determined that air safety and the public interest require adopting the AD with the change described previously.

Costs of Compliance

We estimate that 103 of these MT-Propeller Entwicklung GmbH variable pitch and fixed pitch propellers installed on aircraft of U.S. registry will be affected by this AD. We also estimate that it will take about 2 work hours to inspect and install the polyurethane protective strip of each affected propeller and 4 work hours to remove each affected propeller, and that the average labor rate is $65 per work hour. Required parts to inspect and install the polyurethane protective strip of each affected propeller will cost about $20. We estimate that 10% (20) of the propellers will require blade overhaul, at an average cost of $1,500 per propeller. Based on these figures, we estimate the total cost of the AD to U.S. operators to be $45,780.

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.

Regulatory Findings

We have determined that this AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the national government andthe States, or on the distribution of power and responsibilities among the various levels of government.

For the reasons discussed above, I certify that this AD:

(1) Is not a "significant regulatory action'' under Executive Order 12866;

(2) Is not a "significant rule'' under 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 summary of the costs to comply with this AD and placed it in the AD Docket. You may get a copy of this summary at the address listed under ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Safety.

Adoption of the Amendment

Accordingly, under the authority delegated to me by the Administrator, the Federal Aviation Administration amends 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.

Sec. 39.13 [Amended]

2. The FAA amends Sec. 39.13 by adding the following new airworthiness directive: