[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

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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