AD 2005-09-01

The FAA is adopting a new airworthiness directive (AD) for certain Cessna Model 750 airplanes. The AD requires repetitive inspections for clearance and chafing of an auxiliary power unit (APU) fuel tube assembly in the tail cone area of the airplane, and corrective actions if necessary. For certain airplanes, this AD also requires replacing the APU fuel line. This AD is prompted by reports of chafed APU fuel tubes leaking into the tail cone area due to interference between the fuel tube assembly and elevator flight control cables, hydraulic lines, and high-temperature bleed air couplings. We are issuing this AD to detect and correct this interference, which could result in chafing, fuel leaking into an area where ignition sources are present, and possible fire in an area without fire detection or extinguishing provisions.

Final rule; request for comments.

2005-09-01 Cessna Aircraft Company: Amendment 39-14069. Docket No. FAA-2005-21026; Directorate Identifier 2005-NM-069-AD.

Effective Date

(a) This AD becomes effective May 10, 2005.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Cessna Model 750 airplanes, certificated in any category, serial numbers-0001 through-0240 inclusive.

Unsafe Condition

(d) This AD was prompted by reports of chafed auxiliary power unit (APU) fuel tubes leaking into the tail cone area of the airplane due to interference between the APU fuel tube assembly and elevator flight control cables, hydraulic lines, and high temperature bleed air couplings. The FAA is issuing this AD to detect and correct this interference, which could result in chafing, leaking into an area where ignition sources are present, and possible fire in an area without fire detection or extinguishing provisions.

Compliance

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

Inspections

(f) For all airplanes: Within 25 flight hours or 48 days, whichever occurs first after the effective date of this AD, do a detailed inspection to verify the clearance and detect chafing of one of the APU fuel tube assemblies in the tail cone area of the airplane due to interference between the APU fuel tube and elevator flight control cables, hydraulic lines, and high temperature bleed air couplings. Do the actions in accordance with the Accomplishment Instructions of Cessna Alert Service Letter (ASL) ASL750-49-09, Revision 2, dated March 10, 2005. Do applicable corrective actions before further flight in accordance with the ASL. Repeat the inspection thereafter at the earlier of the times specified in paragraphs (f)(1) and (f)(2) of this AD.

(1) At intervals not to exceed 250 flight hours or 3 months, whichever occurs first.

(2) Before further flight after access to the inspection area for any other inspection or maintenance.

Note 1: For the purposes of this AD, a detailed inspection is: "An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirror, magnifying lenses, etc., may be necessary. Surface cleaning and elaborate procedures may be required."

APU Replacement

(g) For airplanes having serial numbers -0001 through -0031 inclusive and -0033 through -0107 inclusive: Before the first inspection required by paragraph (f) of this AD, replace the APU fuel tube in the tail cone area of the airplane, in accordance with Cessna Service Bulletin SB750-49-05, Revision 1, dated January 17, 2000. The replacement APU fuel tube must be a new APU fuel tube having part number 6756605-23.

Report

(h) At the applicable time specifiedin paragraph (h)(1) or (h)(2) of this AD, report the results (both positive and negative findings) of the initial inspection required by paragraph (f) of this AD, in accordance with Cessna ASL ASL750-49-09, Revision 2, dated March 10, 2005. 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.

(1) If the inspection was done after the effective date of this AD: Submit the report within 30 days after the inspection.

(2) If the inspection was done before the effective date of this AD: Submit the report within 30 days after the effective date of this AD.

Alternative Methods of Compliance (AMOCs)

(i) The Manager, Wichita Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR39.19.

Material Incorporated by Reference

(j) To perform the actions that are required by this AD, you must use Cessna Alert Service Letter ASL750-49-09, Revision 2, dated March 10, 2005; and Cessna Service Bulletin SB750-49-05, Revision 1, dated January 17, 2000; as applicable, unless the AD specifies otherwise. The Director of the Federal Register approves the incorporation by reference of these documents in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. For copies of the service information, contact Cessna Aircraft Co., PO Box 7706, Wichita, Kansas 67277. To view the AD docket, go to the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., room PL-401, Nassif Building, Washington, DC. To review copies of the service information contact the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call (202) 741-6030, or go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

We have received reports of severely chafed auxiliary power unit (APU) fuel tubes found during routine maintenance on Cessna Model 750 airplanes. The APU fuel tubes were leaking into the tail cone area of the airplane due to chafing from interference between the fuel tube and elevator flight control cables, hydraulic lines, and high temperature bleed air couplings. This condition, if not corrected, could result in fuel leaking into an area where ignition sources are present, and consequent fire in an area without fire detection or extinguishing provisions.

Relevant Service Information

We have reviewed Cessna Alert Service Letter (ASL) ASL750-49-09, Revision 2, dated March 10, 2005. The ASL describes procedures for repetitive inspections to verify the clearance and detect chafing of one of the APU fuel tube assemblies in the tail cone area of the airplanes. The inspections specifically are intended to detect and correct possible interference between the APU fuel tube and elevator flight control cables, hydraulic lines, and high-temperature bleed air couplings. Corrective actions include the following:

Corrective Actions

Inspect
And
If you find

For chafing damage on the APU fuel tube assembly.
Replace the APU fuel tube assembly with new parts.
Any lengthwise scratch.
Other nicks/scratches, and chafing and dents that exceed certain limits.

For chafing damage on the elevator control cables.
Replace the elevator control cable with new parts.
Blend out the damage
Chafing with visible wire braids and broken wires.
Chafing with visible wire braids and no broken wires.
Chafing with no visible wire braids.

The clearance of the APU fuel tube assembly ..
Adjust routing of the APU fuel tube assembly
Inadequate clearance between APU fuel tube
assembly and
elevator cables.
high-temperature bleed air lines.
electricalwiring.
airframe structure.
hydraulic lines.

The ASL specifies sending a report of the inspection results to the manufacturer.

For certain airplanes, the ASL also specifies replacing, with new parts, and relocating the APU fuel tube in the tail cone area of the airplane. Those procedures are described in Cessna Service Bulletin SB750-49-05, Revision 1, dated January 17, 2000. The ASL specifies installing the new APU fuel tube before the initial inspection specified in the ASL.

FAA's Determination and Requirements of This AD

The unsafe condition described previously is likely to exist or develop on other airplanes of the same type design. Therefore, we are issuing this AD to prevent fuel from leaking into an area where ignition sources are present, which could result in a fire in an area without fire detection or extinguishing provisions. This AD requires accomplishing the actions specified in the service information described previously. This AD also requires reporting the inspection results to Cessna.

Interim Action

We consider this AD interim action. The manufacturer is currently developing a modification that may terminate the repetitive inspections required by this AD action. Once this modification is developed, approved, and available, we may consider additional rulemaking.

FAA's Determination of the Effective Date

An unsafe condition exists that requires the immediate adoption of this AD; therefore, providing notice and opportunity for public comment before the AD is issued is impracticable, and good cause exists to make this AD effective in less than 30 days.

Comments Invited

This AD is a final rule that involves requirements that affect flight safety and was not preceded by notice and an opportunity for public comment; however, we invite you to submit any relevant written data, views, or arguments regarding this AD. Send your comments to an address listed under ADDRESSES. Include "Docket No. FAA-2005-21026; Directorate Identifier 2005-NM-069-AD" at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the AD. We will consider all comments received by the closing date and may amend the AD in light of those comments.

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

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 effecton 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 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 regulatory evaluation of the estimated costs to comply with this AD. See the ADDRESSES section for a location to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.

Adoption of the Amendment

Accordingly, under the authority delegated to me bythe Administrator, the FAA 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 (AD):