2011-15537. Airworthiness Directives; Gulfstream Aerospace Corporation Model GV and GV-SP Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to adopt a new airworthiness directive (AD) for the products listed above. This proposed AD would require inspecting to determine whether a third Halon fire extinguisher bottle is installed in the auxiliary power unit (APU) fragment impact zone, revising the limitations section of the airplane flight manual to add restrictions for APU usage for certain airplanes having a third fire extinguisher bottle, and removing the third fire extinguisher bottle from certain airplanes. This proposed AD was prompted by notification from the airplane manufacturer that the third fire extinguisher bottle is mounted in a small-fragment impact zone. We are proposing this AD to prevent penetration of the bottle by fragments released due to a failure of the APU rotor system. The bottle could rupture and cause substantial damage to primary airframe structure and primary flight controls.

DATES:

We must receive comments on this proposed AD by August 8, 2011.

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: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this proposed AD, contact Gulfstream Aerospace Corporation, Technical Publications Dept., P.O. Box 2206, Savannah, Georgia 31402-2206; telephone [phone]; fax [phone]; e-mail [e-mail]; Internet http://www.gulfstream.com/​product_​support/​technical_​pubs/​pubs/​index.htm. 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 (phone: [phone]) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

Sanford Proveaux, Aerospace Engineer, Continued Operational Safety and Certificate Management Branch, ACE-102A, FAA, Atlanta Aircraft Certification Office (ACO) 1701 Columbia Avenue, College Park, Georgia 30337; phone: [phone]; fax: [phone]; e-mail: [e-mail].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or arguments about this proposal. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2011-0572; Directorate Identifier 2011-NM-009-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 have received reports from Gulfstream that the third Halon bottle (third fire extinguisher bottle) is mounted in the auxiliary power unit (APU) small-fragment impact zone (rotor burst zone). Some operators might have installed this third fire extinguisher bottle in accordance with Supplemental Type Certificate ST01822AT-D; other operators might have installed the bottle under FAA approval means other than the supplemental type certificate. The bottle is mounted in a very confined area surrounded by primary airframe structure that carries the empennage loads. Primary flight controls for pitch and yaw are also routed through the area adjacent to the third fire extinguisher bottle. Failure of the APU rotor system could release fragments that could strike the bottle and cause explosive rupture of the high-pressure Halon bottle, and result in substantial damage to primary airframe structure and primary flight controls.

Related Rulemaking

We previously issued AD 2009-17-01, Amendment 39-15991 (74 FR 40061, August 11, 2009), for all Model GV airplanes and certain Model GV-SP airplanes (and other Gulfstream airplanes). That AD requires, for certain airplanes, an inspection for sealant applied to the exterior of the APU enclosure (firewall), and, for certain airplanes, a revision of the airplane flight manual to prohibit operation of the APU during certain ground and flight operations. That AD was issued to prevent the flammable sealant from igniting the exterior surfaces of the firewall under certain anomalous conditions such as an APU failure or APU compartment fire, which could result in propagation of an uncontained fire to other critical areas of the airplane.

We are considering revising AD 2009-17-01 to provide an optional terminating action (modification of the APU enclosure), which would allow removal of the APU limitations after the requirements of this new AD have been met.

Relevant Service Information

We reviewed Gulfstream V Alert Customer Bulletin 30A (for Model GV airplanes) Gulfstream G500 Alert Customer Bulletin 10A (for Model GV-SP airplanes); and Gulfstream G550 Alert Customer Bulletin 10A (for Model GV-SP airplanes), all dated December 20, 2010, all including Gulfstream GV/GV-SP Airplane Flight Manual (AFM) Supplement CE51 628M001, Revision A, dated December 20, 2010, to the Gulfstream GV and GV-SP AFMs. These customer bulletins describe procedures for inspecting to determine whether a third fire extinguisher bottle is installed for engines, and, if so, determining whether the third bottle is installed as a spare or in a dedicated configuration. These bulletins also describe procedures for removing the third bottles installed as spares on Model GV and GV-SP airplanes. The Gulfstream GV/GV-SP AFM Supplement CE51 628M001, Revision A, dated December 20, 2010, adds restrictions for APU usage on Model GV and GV-SP airplanes having a third bottle in a dedicated or non-dedicated (spare) configuration.

FAA's Determination

We are proposing this AD because we evaluated all the relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of these same type designs.

Proposed AD Requirements

This proposed AD requires accomplishing the actions specified in the service information described previously.

Certain airplanes have a third Halon fire extinguisher bottle carried as a spare. These “spare” bottles are not connected to the aircraft fire suppression system electrical or plumbing provisions. In these cases, the bottle can be easily removed without affecting the aircraft fire suppression system. Operators can also leave the spare bottle installed, but must implement the revised APU operating limitations in this case. In some Model GV airplanes only, the third Halon fire extinguisher bottle is a functioning part of the aircraft fire suppression system. In these cases the bottle must remain installed in the airplane, and the revised APU operating limitations must be implemented.

Interim Action

We consider this proposed AD interim action. The manufacturer is currently developing a modification that will address the unsafe condition identified in this proposed AD. Once this modification is developed, approved, and available, we might consider additional rulemaking.

Costs of Compliance

We estimate that this proposed AD affects 1,000 airplanes of U.S. registry.

We estimate the following costs to comply with this proposed AD:

Estimated Costs

Action	Labor cost	Parts cost	Cost per product	Cost on U.S. operators
Inspection	1 work-hour × $85 per hour = $85	$0	$85	$85,000

We estimate the following costs to do any necessary actions that would be required based on the results of the proposed inspection.

On-condition Costs

Action	Labor cost	Parts cost	Cost per product
AFM revision	1 work-hour × $85 per hour = $85	$0	$85 (about 70 GV/GV-SP airplanes)
Bottle removal	1 work-hour × $85 per hour = $85	$0	$85 (about 30 GV-SP airplanes)

According to the manufacturer, some of the costs of this proposed AD may be covered under warranty, thereby reducing the cost impact on affected individuals. We do not control warranty coverage for affected individuals. As a result, we have included all costs in our cost estimate.

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),

(3) Will not affect intrastate aviation in Alaska, and

(4) 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.

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 airworthiness directive (AD):

Gulfstream Aerospace Corporation: Docket No. FAA-2011-0572; Directorate Identifier 2011-NM-009-AD.

Comments Due Date

(a) We must receive comments by August 8, 2011.

Affected ADs

(b) None.

Applicability

(c) This AD applies to the Gulfstream Aerospace Corporation airplanes, certificated in any category, identified in paragraphs (c)(1) and (c)(2) of this AD.

(1) Model GV airplanes having serial numbers (S/Ns) 501 and subsequent.

(2) Model GV-SP airplanes having S/Ns 5001 through 5308 inclusive.

Subject

(d) Joint Aircraft System Component (JASC)/Air Transport Association (ATA) of America Code 2621, Fire bottle-fixed.

Unsafe Condition

(e) This AD was prompted by notification from the airplane manufacturer that the third fire extinguisher bottle is mounted in a small-fragment impact zone. We are issuing this AD to prevent penetration of the bottle by fragments released due to a failure of the auxiliary power unit (APU) rotor system. The bottle could rupture and cause substantial damage to primary airframe structure and primary flight controls.

Compliance

(f) Comply with this AD within the compliance times specified, unless already done.

Inspection

(g) For all airplanes: Within 21 days after the effective date of this AD, or before removing the APU flight restrictions required by AD 2009-17-01, Amendment 39-15991, whichever occurs first, inspect to determine whether a third Halon fire extinguisher bottle for engines is installed in the APU fragment impact zone (rotor fragment impact zone), in accordance with the Accomplishment Instructions of the applicable Gulfstream alert customer bulletin identified in table 1 of this AD.

Table 1—Applicable Gulfstream Alert Customer Bulletins

For Model—	Use—	Which includes—	To the—
GV airplanes	Gulfstream V Alert Customer Bulletin 30A, dated December 20, 2010	Gulfstream GV/GV-SP Airplane Flight Manual (AFM) Supplement CE51 628M001, Revision A, dated December 20, 2010	Gulfstream GV AFM.
GV-SP (G500) airplanes	Gulfstream G500 Alert Customer Bulletin 10A, dated December 20, 2010	Gulfstream GV/GV-SP AFM Supplement CE51 628M001, Revision A, dated December 20, 2010	Gulfstream GV-SP AFM.
GV-SP (G550) airplanes	Gulfstream G550 Alert Customer Bulletin 10A, dated December 20, 2010	Gulfstream GV/GV-SP AFM Supplement CE51 628M001, Revision A, dated December 20, 2010	Gulfstream GV-SP AFM.

(1) If the third fire extinguisher bottle is not installed, no further work is required by this paragraph.

(2) For Model GV airplanes in which the third fire extinguisher bottle is installed as a dedicated APU fire bottle configuration, as defined in Gulfstream V Alert Customer Bulletin 30A, dated December 20, 2010 (as a functioning part of the aircraft fire suppression system): Before further flight, revise the Limitations section of the Gulfstream GV AFM to include the information in Gulfstream GV/GV-SP AFM Supplement CE51 628M001, Revision A, dated December 20, 2010 (which is included in Gulfstream V Alert Customer Bulletin 30A, dated December 20, 2010). This AFM supplement adds restrictions for APU usage. Operate the airplane thereafter according to the limitations in this AFM supplement.

Note 1:

This may be done by inserting a copy of Gulfstream GV/GV-SP AFM Supplement CE51 628M001, Revision A, dated December 20, 2010, in the applicable AFM. When information in this AFM supplement has been included in general revisions of the applicable AFM, the general revisions may be inserted in the applicable AFM, provided the relevant information in the general revision is identical to that in Gulfstream GV/GV-SP AFM Supplement CE51 628M001, Revision A, dated December 20, 2010, and that AFM supplement may be removed.

(3) For Model GV and GV-SP airplanes in which the third fire extinguisher bottle is installed as a spare fire bottle configuration (not connected to the airplane's electrical or fire suppression systems), as defined in the applicable Gulfstream alert customer bulletin identified in table 1 of this AD: Do the actions required by paragraph (g)(3)(i) or (g)(3)(ii) of this AD.

(i) Before further flight, remove the bottle, in accordance with the Accomplishment Instructions of the applicable Gulfstream alert customer bulletin identified in table 1 of this AD.

(ii) Before further flight, revise the limitations section of the applicable Gulfstream AFM specified in table 1 of this AD to include the information in Gulfstream GV/GV-SP AFM Supplement CE51 628M001, Revision A, dated December 20, 2010. This AFM supplement adds restrictions for APU usage. Operate the airplane thereafter according to the limitations in that AFM supplement.

Note 2:

This may be done by inserting a copy of Gulfstream GV/GV-SP AFM Supplement CE51 628M001, Revision A, dated December 20, 2010, in the applicable AFM. When information in this AFM supplement has been included in general revisions of the applicable AFM, the general revisions may be inserted in the applicable AFM, provided the relevant information in the general revision is identical to that in Gulfstream GV/GV-SP AFM Supplement CE51 628M001, Revision A, dated December 20, 2010, and that AFM supplement may be removed.

Credit for Actions Accomplished in Accordance With Previous Service Information

(h) Actions accomplished before the effective date of this AD in accordance with Gulfstream V Alert Customer Bulletin 30 (for Model GV airplanes), dated December 6, 2010, including Gulfstream GV AFM Supplement CE51 628M001, dated November 18, 2010, to the Gulfstream GV AFM; or Gulfstream G550 (for Model GV-SP airplanes) or G500 (for Model GV-SP airplanes) Alert Customer Bulletin 10, both dated December 6, 2010; are acceptable for compliance with the corresponding actions required by paragraph (g) of this AD.

Parts Installation

(i) As of the effective date of this AD, no person may install a third fire extinguisher bottle in the APU fragment impact zone (rotor fragment impact zone) of any airplane.

No Reporting

(j) Although Gulfstream V Alert Customer Bulletin 30A (for Model GV airplanes), Gulfstream G500 Alert Customer Bulletin 10A (for Model GV-SP airplanes), and Gulfstream G550 Alert Customer Bulletin 10A (for Model GV-SP airplanes); all dated December 20, 2010, all including Gulfstream GV/GV-SP AFM Supplement CE51 628M001, Revision A, dated December 20, 2010, to the Gulfstream GV, and GV-SP AFMs; specify to submit certain information to the manufacturer, this AD does not include that requirement.

Special Flight Permit

(k) Special flight permits, as described in Section 21.197 and Section 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199), may be issued to operate the airplane to a location where the requirements of this AD can be accomplished, provided the following conditions are met:

(1) If an airplane is grounded due to a single generator failure, the APU may be operated during a ferry flight, provided no passengers are carried.

(2) Only the minimum required flight crew is allowed on any ferry flight.

Alternative Methods of Compliance (AMOCs)

(l)(1) The Manager, Atlanta 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. In accordance with 14 CFR 39.19, send your request to your principal inspector or local Flight Standards District Office, as appropriate. If sending information directly to the manager of the ACO, send it to the attention of the person identified in the Related Information section of this AD.

(2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/certificate holding district office.

Related Information

(m) For more information about this AD, contact Sanford Proveaux, Aerospace Engineer, Continued Operational Safety and Certificate Management Branch, ACE-102A, FAA, Atlanta Aircraft Certification Office (ACO) 1701 Columbia Avenue, College Park, Georgia 30337; telephone [phone]; fax [phone]; [e-mail].

(n) For service information identified in this AD, contact Gulfstream Aerospace Corporation, Technical Publications Dept., P.O. Box 2206, Savannah, Georgia 31402-2206; telephone [phone]; fax [phone]; e-mail [e-mail]; Internet http://www.gulfstream.com/​product_​support/​technical_​pubs/​pubs/​index.htm. 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.

Issued in Renton, Washington on June 10, 2011.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.