E8-5005. Airworthiness Directives; Cessna Aircraft Company Model 525 Airplanes

AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to adopt a new airworthiness directive (AD) for certain Cessna Aircraft Company (Cessna) Model 525 airplanes. This proposed AD would require you to inspect for missing firewall sealant between the aft firewall assembly and seal assembly; and, if you find that firewall sealant is missing, seal with firewall sealant between the aft firewall assembly and seal assembly. This proposed AD results from a report that firewall sealant may not have been applied between the aft firewall assembly and seal assembly during manufacture of certain Model 525 airplanes. We are proposing this AD to detect and correct missing firewall sealant between the aft firewall assembly and seal assembly, which could result in failure of the fire extinguishing system to prevent the spread of fire through the firewall gap. This failure could lead to an uncontrolled fire.

DATES:

We must receive comments on this proposed AD by May 12, 2008.

ADDRESSES:

Use one of the following addresses to comment 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.

For service information identified in this proposed AD, contact Cessna Aircraft Company, Product Support, P.O. Box 7706, Wichita, Kansas 67277; telephone: [phone]; fax: [phone].

FOR FURTHER INFORMATION CONTACT:

James Galstad, Aerospace Engineer, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Wichita, Kansas 67209; telephone: [phone]; fax: [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or arguments regarding this proposed AD. Send your comments to an address listed under the ADDRESSES section. Include the docket number, “FAA-2008-0306; Directorate Identifier 2008-CE-014-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 we receive concerning this proposed AD.

Discussion

We have received a report that firewall sealant may not have been applied between the aft firewall assembly and seal assembly during manufacture of Model 525 airplanes, serial numbers 525-0600 through 525-0662.

A nacelle fire may pass through the gap where the firewall sealant is missing. Although the fire detection system and fire extinguishing system remain operational, the effectiveness of the fire extinguishing system has not been shown to prevent the spread of fire through the firewall gap. The fire could pass through the gap in the firewall or the effectiveness of the fire extinguishing system be defeated by the gap.

This condition, if not corrected, could result in an uncontrolled fire.

Relevant Service Information

We have reviewed Cessna Aircraft Company Citation Service Letter SL525-71-05, Revision 1, dated February 6, 2008. The service information describes procedures for:

• Inspecting for missing firewall sealant between the aft firewall assembly and seal assembly; and
• Sealing with firewall sealant between the aft firewall assembly and seal assembly.

FAA's Determination and Requirements of the Proposed AD

We are proposing this AD because we evaluated all information and determined the unsafe condition described previously is likely to exist or develop on other products of the same type design. This proposed AD would require you to inspect for missing firewall sealant between the aft firewall assembly and seal assembly; and, if you find that firewall sealant is missing, seal with firewall sealant between the aft firewall assembly and seal assembly.

Differences Between This Proposed AD and the Service Information

The service information requires compliance within 600 hours time-in-service (TIS) or 1 year after the date of receipt, whichever occurs first. Due to the severity of the safety issue (uncontrolled fire), this proposed AD has a compliance of within the next 60 hours TIS after the effective date of this AD or 60 days after the effective date of this AD, whichever occurs first. The requirements of this proposed AD, if adopted as a final rule, would take precedence over the provisions in the service information.

Costs of Compliance

We estimate that this proposed AD would affect 45 airplanes in the U.S. registry.

We estimate the following costs to do the proposed inspection:

Labor cost	Parts cost	Total cost per airplane	Total cost on U.S. operators
1 work-hour × $80 per hour = $80	Not Applicable	$80	$3,600

We estimate the following costs to do any necessary repairs that would be required based on the results of the proposed inspection. We have no way of determining the number of airplanes that may need this repair:

Labor cost	Parts cost	Total cost per airplane
4 work-hours × $80 per hour = $320	$30	$350

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 proposed AD would not have federalism implications under Executive Order 13132. 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 regulatory evaluation of the estimated costs to comply with this proposed AD and placed it in the AD docket.

Examining the AD Docket

You may examine the AD docket that contains the proposed AD, the regulatory evaluation, any comments received, and other information on the Internet at http://www.regulations.gov; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Office (telephone [phone]) is located at the street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 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. The FAA amends § 39.13 by adding the following new AD:

Cessna Aircraft Company: Docket No. FAA-2008-0306; Directorate Identifier 2008-CE-014-AD.

Comments Due Date

(a) We must receive comments on this airworthiness directive (AD) action by May 12, 2008.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Model 525 airplanes, serial numbers 525-0600 through 525-0662, that are certificated in any category.

Unsafe Condition

(d) This AD results from a report that firewall sealant may not have been applied between the aft firewall assembly and seal assembly during manufacture of certain Model 525 airplanes. We are issuing this AD to detect and correct missing firewall sealant between the aft firewall assembly and seal assembly, which could result in failure of the fire extinguishing system to prevent the spread of fire through the firewall gap. This failure could lead to an uncontrolled fire.

Compliance

(e) To address this problem, you must do the following, unless already done:

Actions	Compliance	Procedures
(1) Inspect between the 6352225 aft firewall assembly and 6352226 seal assembly for missing firewall sealant	Within the next 60 hours time-in-service (TIS) after the effective date of this AD or within 60 days after the effective date of this AD, whichever occurs first	Follow Cessna Aircraft Company Citation Service Letter SL525-71-05, Revision 1, dated February 6, 2008.
(2) If, as a result of the inspection required by paragraph (e)(1) of this AD, you find there is missing firewall sealant between the 6352225 aft firewall assembly and 6352226 seal assembly, seal with U000117S firewall sealant in the gap between the 6352225 aft firewall assembly and 6352226 seal assembly	Before further flight after the inspection required by paragraph (e)(1) of this AD	Follow Cessna Aircraft Company Citation Service Letter SL525-71-05, Revision 1, dated February 6, 2008.

Alternative Methods of Compliance (AMOCs)

(f) The Manager, Wichita Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to ATTN: James Galstad, Aerospace Engineer, Wichita ACO, 1801 Airport Road, Room 100, Wichita, Kansas 67209; telephone: [phone]; fax: [phone]. Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO.

Related Information

(g) To get copies of the service information referenced in this AD, contact Cessna Aircraft Company, Product Support, P.O. Box 7706, Wichita, Kansas 67277; telephone: [phone]; fax: [phone]. To view the AD docket, go to U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, or on the Internet at http://www.regulations.gov.

Issued in Kansas City, Missouri, on March 7, 2008.

Kim Smith,

Manager, Small Airplane Directorate, Aircraft Certification Service.