05-19568. Airworthiness Directives; Cessna Model 500, 550, S550, 560, 560XL, and 750 Airplanes

AGENCY:

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

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for certain Cessna Model 500, 550, S550, 560, 560XL, and 750 airplanes. This proposed AD would require installing identification sleeves on the wires for the positive and negative terminal studs of the engine and/or auxiliary power unit (APU) fire extinguishing bottles, as applicable, and re-connecting the wires to the correct terminal studs. This proposed AD results from a report of mis-wired fire extinguishing bottles. We are proposing this AD to ensure that the fire extinguishing bottles are activated in the event of an engine or APU fire, and that flammable fluids are not supplied during a fire, which could result in an unextinguished fire in the nacelle or APU.

DATES:

We must receive comments on this proposed AD by November 14, 2005.

ADDRESSES:

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

• DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
• Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
• Mail: Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., Nassif Building, Room PL-401, Washington, DC 20590.
• Fax: [phone].
• Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Contact Cessna Aircraft Co., P.O. Box 7706, Wichita, Kansas 67277, for the service information identified in this proposed AD.

FOR FURTHER INFORMATION CONTACT:

Robert D. Adamson, Aerospace Engineer, Systems and Propulsion Branch, ACE-116W, FAA, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas 67209; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to submit any relevant written data, views, or arguments regarding this proposed AD. Include the docket number “FAA-2005-22558; Directorate Identifier 2005-NM-107-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://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 proposed AD. Using the search function of that 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 may review 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 AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone [phone]) is located on the plaza level of the Nassif Building at the DOT street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the Docket Management System receives them.

Discussion

We have received a report indicating that the auxiliary power unit (APU) fire extinguishing system was mis-wired on some Cessna Model 750 airplanes. Although the main engine fire extinguishing system on all Cessna Model 750 airplanes is wired correctly, further investigation revealed that the fire extinguishing systems on the main engines of Cessna Model 500, 550, S550, 560 airplanes, and on the main engines and APUs of Cessna Model 560XL airplanes may not be wired correctly. Therefore, all of these models may be subject to the same or similar unsafe condition found on the Cessna Model 750 APU installation. The engine and APU fire extinguishing bottles on these airplane models have positive and negative terminal studs that are the same size, so it is possible to cross-connect the wiring of the positive and negative leads. If the wiring is cross-connected and the fire extinguishing bottles are activated, the circuit breaker may trip due to the direct ground on the positive lead, and no fire extinguishing agent would be expelled. In addition, with the exception of the Model 750 APU installation, the tripped circuit breaker removes power from the fuel and hydraulic firewall shutoff valves, which are powered closed from a normally open state, and from the associated cockpit indications. As a result, flammable fluids could continue to be supplied to the area during a fire. It should be noted that the APU installation on the Cessna Model 750 airplanes has a solenoid valve that is powered open from the normally closed state and would close to shut off fuel with the disruption of power. The circuit breaker that provides power to the extinguishing bottle differs from the circuit breaker that controls the shutoff valve that is powered on. Finally, the flightcrew would know that the fire had not been extinguished because the engine fire annunciator would stay illuminated, and the annunciators for the firewall shutoff valve may not illuminate if the valve does not close. Thus, the flightcrew would not know why the fire had not been extinguished. These conditions, if not corrected, could result in an unextinguished fire in the nacelle or APU.

Relevant Service Information

We have reviewed the Cessna service bulletins in the table below.

Cessna Service Bulletins

For Cessna airplane model	Service bulletin	Revision	Date
500	500-26-02	Original	April 1, 2005.
550	550-26-05	Original	April 1, 2005.
S550	S550-26-02	Original	April 1, 2005.
560	560-26-01	Original	April 1, 2005.
560XL	560XL-26-02	1	December 22, 2004.
750	750-26-05	Original	November 24, 2004.

The service bulletins describe procedures for installing identification sleeves on the wires for the positive and negative terminal studs of the engine and/or APU fire extinguishing bottles; re-connecting the wires to the correct studs; testing the connection; and, for all but the Cessna Model 750 airplanes, re-connecting the wires if necessary until the connection tests correctly. For Cessna Model 500, 550, S550, and 560 airplanes, these actions are done for the engine fire extinguishing bottles only. For Cessna Model 750 airplanes, these actions are done for the APU fire extinguishing bottle only. For Cessna Model 560XL airplanes, this action is done for both the engine and the APU fire extinguishing bottles. The service bulletins also specify that operators should send a maintenance transaction report to the manufacturer. Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition.

FAA's Determination and Requirements of the Proposed AD

We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other airplanes of this same type design. For this reason, we are proposing this AD, which would require accomplishing the actions specified in the service information described previously, except as discussed under “Differences Between the Proposed AD and the Service Bulletins.”

Differences Between the Proposed AD and the Service Bulletins

Operators should note that, although the Accomplishment Instructions of the referenced service bulletins describe procedures for submitting a maintenance transaction report to the manufacturer, this proposed AD would not require that action. We do not need this information from operators.

Clarification of Service Bulletin 750-26-05

Although Cessna Service Bulletin 750-26-05 does not specify procedures for re-connecting the wires if necessary until the connection tests correctly, that action is implied in the service bulletin and would be required in this proposed AD.

Costs of Compliance

There are about 2,801 airplanes of the affected design in the worldwide fleet. The following table provides the estimated costs for U.S. operators to comply with this proposed AD.

Estimated Costs

Modification for Cessna model—	Work hours	Average labor rate per hour	Parts	Cost per airplane	Number of U.S.-registered airplanes	Fleet cost
500, 550, S550, and 560 airplanes	3	$65	$50	$245	1,827	$447,615
560XL airplanes	4	65	100	360	331	119,160
750 airplanes	2	65	25	155	211	32,705

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. 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
• 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 Federal Aviation Administration (FAA) amends § 39.13 by adding the following new airworthiness directive (AD):

Cessna Aircraft Company: Docket No. FAA-2005-22558; Directorate Identifier 2005-NM-107-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by November 14, 2005.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Cessna Model 500, 550, S550, 560, 560XL, and 750 airplanes, certificated in any category; as identified in the service bulletins in Table 1 of this AD.

Table 1.—Cessna Service Bulletins

Service bulletin	Revision	Date	Cessna model (airplanes)
500-26-02	Original	April 1, 2005	500
550-26-05	Original	April 1, 2005	550
S550-26-02	Original	April 1, 2005	S550
560-26-01	Original	April 1, 2005	560
560XL-26-02	1	December 22, 2004	560XL
750-26-05	Original	November 24, 2004	750

Unsafe Condition

(d) This AD results from a report of mis-wired fire extinguishing bottles. We are issuing this AD to ensure that the fire extinguishing bottles are activated in the event of an engine or auxiliary power unit (APU) fire, and that flammable fluids are not supplied during a fire, which could result in an unextinguished fire in the nacelle or APU.

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.

Installation

(f) Within 100 flight hours or 60 days after the effective date of this AD, whichever occurs first: Install identification sleeves on the wires for the positive and negative terminal studs of the applicable fire extinguishing bottles identified in paragraphs (f)(1), (f)(2), and (f)(3) of this AD; re-connect the wires to the correct studs; test the connection; and re-connect the wires again as applicable until the connection tests correctly. Do all actions in accordance with the Accomplishment Instructions of the applicable service bulletin in Table 1 of this AD.

(1) For Cessna Model 500, 550, S550, and 560 airplanes: The engine fire extinguishing bottles.

(2) For Cessna Model 560XL airplanes: The engine and the APU fire extinguishing bottles.

(3) For Cessna Model 750 airplanes: The APU fire extinguishing bottle.

No Reporting Requirement

(g) Although the Accomplishment Instructions of the service bulletins identified in Table 1 of this AD describe procedures for submitting a maintenance transaction report to the manufacturer, this AD does not require that action.

Actions Accomplished in Accordance With Earlier Revision of Service Bulletin

(h) Actions done before the effective date of this AD in accordance with the Accomplishment Instructions of Cessna Service Bulletin 560XL-26-02, dated November 22, 2004, are acceptable for compliance with the corresponding action in this AD.

Parts Installation

(i) After the effective date of this AD, no person may install on any airplane a fire extinguishing bottle unless identification sleeves on the wires for the positive and negative terminal studs have been installed in accordance with paragraph (f) of this AD.

Alternative Methods of Compliance (AMOCs)

(j)(1) 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 CFR 39.19.

(2) Before using any AMOC approved in accordance with § 39.19 on any airplane to which the AMOC applies, notify the appropriate principal inspector in the FAA Flight Standards Certificate Holding District Office.

Issued in Renton, Washington, on September 21, 2005.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.