2010-16514. Airworthiness Directives; Learjet Inc. Model 45 Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to adopt a new airworthiness directive (AD) for certain Learjet Inc. Model 45 airplanes. This proposed AD would require replacing aluminum fire extinguisher discharge tubes with new, improved tubes; checking the fire extinguisher container for certain serial numbers; replacing fire extinguisher containers that have affected serial numbers; inspecting the pressure indicator on certain fire extinguisher containers for discrepancies; and performing corrective action if necessary. This proposed AD results from a report of accidental discharge of a fire extinguisher container and damage to an aluminum discharge tube. Investigation revealed that following the discharge an inaccurate pressure indication, due to the indicator dial being incorrectly staked, showed that the container was fully charged. We are proposing this AD to prevent inaccurate pressure readings and subsequent damage to the discharge tubes during operation, which could result in failure of the fire extinguisher system and an uncontained fire in an emergency situation.

DATES:

We must receive comments on this proposed AD by August 23, 2010.

ADDRESSES:

You may send comments by any of the following methods:

• 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 Learjet, Inc., One Learjet Way, Wichita, Kansas 67209-2942; telephone [phone]; fax [phone]; e-mail [e-mail]; Internet http://www.bombardier.com. You may review copies of the referenced service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information on the availability of this material at the FAA, call 425-227-1221.

Examining the AD Docket

You may examine the AD docket 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 AD docket contains this proposed AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Office (telephone [phone]) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

James Galstad, 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 send any written relevant data, views, or arguments about this proposed AD. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2010-0676; Directorate Identifier 2010-NM-095-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the closing date and may amend this proposed AD because 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 about this proposed AD.

Discussion

We received a report of accidental discharge of a fire extinguisher container and damage to an aluminum discharge tube. Investigation revealed that following the discharge an inaccurate pressure indication, due to the indicator dial being incorrectly staked, showed that the container was fully charged. Inaccurate pressure readings, and subsequent damage to the discharge tubes during operation, could result in failure of the fire extinguisher system and an uncontained fire in an emergency situation.

Relevant Service Information

We have reviewed Bombardier Service Bulletins 40-26-05 and 45-26-9, both Revision 2, both dated May 4, 2009. The service information describes procedures for the following:

• For all airplanes: Installing new o-rings and stainless steel fire extinguisher discharge tubes and inspect the serial numbers on the fire extinguisher containers to determine whether any serial number is specified in Table 1 of the Accomplishment Instructions of the applicable service bulletin.
• For airplanes on which no serial number is specified in Table 1: Inspecting the pressure indicator on the fire extinguisher container to ensure that the indicator dial is not loose and is staked in the right location, and do a weight check of the fire extinguisher container. If the indicator is loose or not staked in the right location or if the weight check for any container fails, replacing the affected container.
• For airplanes on which any serial number is specified in Table 1: Replacing the affected fire extinguisher container, and do a weight check of the replaced containers. If the weight check for any replacement container fails, replacing the affected container.

FAA's Determination and Requirements of This Proposed AD

We are proposing this AD because we evaluated all relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of the same type design. This proposed AD would require accomplishing the actions specified in the service information described previously.

Costs of Compliance

We estimate that this proposed AD would affect 322 airplanes of U.S. registry. We also estimate that it would take 5 work-hours per product to comply with this proposed AD. The average labor rate is $85 per work-hour. Required parts cost would be minimal. Where the service information lists required parts costs that are covered under warranty, we have assumed that there will be no charge for these costs. As we do not control warranty coverage for affected parties, some parties may incur costs higher than estimated here. Based on these figures, we estimate the cost of this proposed AD to the U.S. operators to be $136,850, or $425 per product.

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 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 this 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.

You can find our regulatory evaluation and the estimated costs of compliance in the AD Docket.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Incorporation by reference
• 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:

Learjet Inc: Docket No. FAA-2010-0676; Directorate Identifier 2010-NM-095-AD.

Comments Due Date

(a) We must receive comments by August 23, 2010.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Learjet Inc. Model 45 airplanes, certificated in any category; as identified in Bombardier Service Bulletins 40-26-05 and 45-26-9, both Revision 2, both dated May 4, 2009.

Subject

(d) Air Transport Association (ATA) of America Code 26: Fire protection.

Unsafe Condition

(e) This AD results from a report of accidental discharge of a fire extinguisher container and damage to an aluminum discharge tube. Investigation revealed that following the discharge an inaccurate pressure indication, due to the indicator dial being incorrectly staked, showed that the container was fully charged. The Federal Aviation Administration is issuing this AD to prevent inaccurate pressure readings and subsequent damage to the discharge tubes during operation, which could result in failure of the fire extinguisher system and an uncontained fire in an emergency situation.

Compliance

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

Replacement, Check, Inspection, Corrective Action

(g) Within 12 months after the effective date of this AD: Replace the aluminum fire extinguisher discharge tubes with new, improved stainless steel tubes; check the fire extinguisher container for any serial number specified in Table 1 of Bombardier Service Bulletins 40-26-05 or 45-26-9, both Revision 2, both dated May 4, 2009; as applicable; replace any containers that have affected serial numbers, do a weight check of all containers, including the replacement container, if applicable; and inspect the pressure indicator on the containers for discrepancies, by doing all applicable actions in accordance with the Accomplishment Instructions of Bombardier Service Bulletins 40-26-05 or 45-26-9, both Revision 2, both dated May 4, 2009; as applicable. If any discrepancy is found, replace the container before further flight in accordance with the Accomplishment Instructions of Bombardier Service Bulletins 40-26-05 or 45-26-9, both Revision 2, both dated May 4, 2009; as applicable.

(h) Actions done before the effective date of this AD in accordance with the applicable service information listed in Table 1 of this AD are acceptable for compliance with the corresponding requirements in paragraph (g) of this AD.

Table 1—Credit Service Information

Affected serial numbers—	Bombardier service bulletin—	Revision—	Dated—
For Model 45 airplanes having serial numbers 2001 through 2114, inclusive	40-26-05	Basic Issue	November 24, 2008.
For Model 45 airplanes having serial numbers 2001 through 2114, inclusive	40-26-05	1	December 22, 2008.
For Model 45 airplanes having serial numbers 006 through 383, inclusive	45-26-9	Basic Issue	November 24, 2008.
For Model 45 airplanes having serial numbers 006 through 383, inclusive	45-26-9	1	December 22, 2008.

Alternative Methods of Compliance (AMOCs)

(i)(1) 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, 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].

(2) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Before using any approved AMOC on any airplane to which the AMOC applies, notify your principal maintenance inspector (PMI) or principal avionics inspector (PAI), as appropriate, or lacking a principal inspector, your local Flight Standards District Office. The AMOC approval letter must specifically reference this AD.

Issued in Renton, Washington, on June 29, 2010.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.