Airworthiness Directives; Piaggio Model P-180 Airplanes

[Federal Register Volume 61, Number 50 (Wednesday, March 13, 1996)] [Proposed Rules] [Pages 10292-10294] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 96-5944]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95-NM-256-AD]

Airworthiness Directives; Piaggio Model P-180 Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Piaggio Model P-180 airplanes. This proposal would require replacement of outflow/safety valves with serviceable valves. This proposal is prompted by a report of cracking and subsequent failure of outflow safety valves in the pressurization system. The actions specified by the proposed AD are intended to prevent such cracking and subsequent failure of the outflow/safety valves, which could result in rapid decompression of the airplane.

DATES: Comments must be received by April 22, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-103, Attention: Rules Docket No. 95-NM-256-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal holidays. The service information referenced in the proposed rule may be obtained from Allied Signal Aerospace, Technical Publications, Dept. 65-70, P.O. Box 52170, Phoenix, Arizona 85072-2170. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Transport Airplane Directorate, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California.

FOR FURTHER INFORMATION CONTACT: Walter Eierman, Aerospace Engineer, Systems and Equipment Branch, ANM-130L, FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712; telephone (310) 627-5336; fax (310) 627-5210.

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to participate in the making of the proposed rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this notice may be changed in light of the comments received. Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket. Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: ``Comments to Docket Number 95-NM-256-AD.'' The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-103, Attention: Rules Docket No. 95-NM-256-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA has received a report of the failure of a safety valve in the pressurization system on a Learjet Model 31A airplane. Failure of the valve resulted in depressurization of the cabin. Investigation revealed that the poppets of certain outflow/safety valves were cracked. These discrepant valves, including the safety valve installed on the incident airplane, had been manufactured since January 1, 1989. Certain valves manufactured since that date have been found to be susceptible to cracking due to an improper molding process during their manufacture. Cracking in the poppets of the outflow/

[[Page 10293]] safety valves in the pressurization system can result in an open valve with an effective flow area of 4.4 square inches; additionally, the valve may close and remain closed. This condition, if not corrected, could result in cracking and subsequent failure of the airflow/safety valves, which could lead to rapid decompression of the airplane. On September 20, 1995, the FAA issued AD 95-20-03, amendment 39- 9381 (60 FR 51709, October 3, 1995), to address this unsafe condition on certain Learjet Model 24, 25, 28, 29, 31, 35, 36, and 55 series airplanes. Subsequently, on December 5, 1995, the FAA issued AD 95-25- 10, amendment 39-9456, (60 FR 66484, December 22, 1995), to address the unsafe condition on certain Cessna Model 441, 500, 550, and 560 series airplanes. The outflow/safety valves installed on these Cessna and Learjet airplane models are similar to the valves installed on Piaggio Model P-180 series airplanes. Therefore, the FAA has determined that the latter airplane model also is subject to the unsafe condition described previously. The FAA has reviewed and approved Allied Signal Aerospace Service Bulletins 103742-21-4059 (for airplanes equipped with valves having part number 103742) and 103744-21-4060 (for airplanes equipped with valves having part number 103744), both dated March 31, 1995, which describe procedures for replacement of certain discrepant outflow/ safety valves with serviceable valves. This airplane model is manufactured in Italy and is type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design, the proposed AD would require replacement of certain discrepant outflow/ safety valves with serviceable valves. The actions would be required to be accomplished in accordance with the service bulletins described previously. Operators should note that, although the service bulletins recommend accomplishing the replacement within 300 flight hours or six months (after the release of the service bulletins), whichever occurs first, the FAA has determined that an interval of 18 months will address the identified unsafe condition in a timely manner. This proposed compliance time of 18 months was determined to be appropriate in consideration of the safety implications, the average utilization rate of the affected fleet, the practical aspects of accomplishment of the replacement during regular maintenance periods, and the availability of required replacement parts. The FAA estimates that 10 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 12 work hours per airplane to accomplish the proposed actions, and that the average labor rate is $60 per work hour. The parts manufacturer has advised that it will provide replacement parts at no cost to operators. Based on these figures, the cost impact of this proposal on U.S. operators is estimated to be $7,200, or $720 per airplane. The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the proposed requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. The regulations proposed herein would not have substantial direct effects 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. Therefore, in accordance with Executive Order 12612, it is determined that this proposal would not have sufficient federalism implications to warrant the preparation of a Federalism Assessment. For the reasons discussed above, I certify that 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) if promulgated, 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. A copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39--AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 USC 106(g), 40113, 44701.

Sec. 39.13--[Amended]

2. Section 39.13 is amended by adding the following new airworthiness directive:

I.A.M. Rinaldo Piaggio S.P.A.: Docket 95-NM-256-AD.

Applicability: Model P-180 airplanes equipped with Allied Signal outflow/safety valves, as identified in Allied Signal Aerospace Service Bulletins 103742-21-4059 and 103744-21-4060, both dated March 31, 1995, certificated in any category.

Note 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (c) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it. Compliance: Required as indicated, unless accomplished previously. To prevent cracking and subsequent failure of the outflow/safety valves, which would result in rapid decompression of the airplane, accomplish the following: (a) Within 18 months after the effective date of this AD, replace the outflow/safety valve in accordance with Allied Signal Aerospace Service Bulletin 103742-21-4059 (for airplanes equipped with valves having part number 103742), or 103744-21-4060 (for airplanes equipped with valves having part number 103744), both dated March 31, 1995, as applicable. (b) As of the effective date of this AD, no person shall install an outflow/safety valve, having a part number and serial number identified in Allied Signal Aerospace Service Bulletin 103742-21- 4059 (for airplanes equipped with valves having part number 103742) or 103744-21-4060 (for airplanes equipped with valves having part number 103744), both dated March 31, 1995, on any airplane unless that valve is considered to be serviceable in accordance with the applicable service bulletin. (c) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Los Angeles ACO.

Note 2: Information concerning the existence of approved alternative methods of

[[Page 10294]] compliance with this AD, if any, may be obtained from the Los Angeles ACO. (d) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.

Issued in Renton, Washington, on March 7, 1996. Darrell M. Pederson, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 96-5944 Filed 3-12-96; 8:45 am] BILLING CODE 4910-13-U