[Federal Register Volume 60, Number 160 (Friday, August 18, 1995)]
[Proposed Rules]
[Pages 43089-43091]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-20505]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95-NM-56-AD]


Airworthiness Directives; Cessna Model 441, 500, 550, and 560 
Series 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 Cessna Model 441, 500, 
550, and 560 series 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 October 16, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 95-NM-56-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, Inc., Controls and Accessories, 1110 North 
Oracle Road, Tucson, Arizona 85737-9588. 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 

[[Page 43090]]
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-56-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-56-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. Cracking in 
the poppets of the outflow/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 March 9, 1995, the FAA issued a proposed rule (Docket 94-NM-211-
AD, 60 FR 14231, March 16, 1995), applicable to certain Learjet Model 
24, 25, 31, 35, 36, and 55 series airplanes and Learjet Model 28 and 29 
airplanes, to address the unsafe condition described previously. The 
outflow/safety valves installed on these airplanes are similar to the 
valves installed on Cessna Model 441, 500, 550, and 560 series 
airplanes. Therefore, the FAA has determined that the latter airplane 
models also are subject to the unsafe condition described previously. -
    The FAA has reviewed and approved the following Allied Signal 
Aerospace Service Bulletins: -
    1. Service Bulletin 103576-21-4054, dated January 30, 1995 (for 
Cessna Model 441 series airplanes); -
    2. Service Bulletin 103576-21-4056, dated January 30, 1995 (for 
Cessna Model 500 and 550 series airplanes); and
    3. Service Bulletin 103648-21-4055, dated January 30, 1995 (for 
Cessna Model 560 series airplanes).
    These service bulletins describe procedures for replacement of 
certain discrepant outflow/safety valves with serviceable valves.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this 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.
    As a result of recent communications with the Air Transport 
Association (ATA) of America, the FAA has learned that, in general, 
some operators may misunderstand the legal effect of AD's on airplanes 
that are identified in the applicability provision of the AD, but that 
have been altered or repaired in the area addressed by the AD. The FAA 
points out that all airplanes identified in the applicability provision 
of an AD are legally subject to the AD. If an airplane has been altered 
or repaired in the affected area in such a way as to affect compliance 
with the AD, the owner or operator is required to obtain FAA approval 
for an alternative method of compliance with the AD, in accordance with 
the paragraph of each AD that provides for such approvals. A note has 
been included in this notice to clarify this long-standing requirement.
    There are approximately 150 Cessna Model 441, 500, 550, and 560 
series airplanes of the affected design in the worldwide fleet. The FAA 
estimates that 120 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. Based on these figures, the total cost 
impact of the inspection requirement of this proposal on U.S. operators 
is estimated to be $86,400, or $720 per airplane. However, the 
manufacturer has advised that it will provide replacement parts at no 
cost to the operator and will reimburse operators for the labor costs 
of the required removal and replacement.
    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 U.S.C. 106(g), 40101, 40113, 44701.

Sec. 39.13  [Amended]

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

Cessna Aircraft Company: Docket 95-NM-56-AD.

    Applicability: Model 441, 500, 550, and 560 series airplanes; 
equipped with Allied Signal outflow/safety valves; as identified in 
Allied Signal Aerospace Service Bulletins 103576-21-4054, 103576-21-
4056, and 103648-21-4055, all dated January 30, 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 use the authority 
provided in paragraph (c) of this AD to request approval from the 
FAA. This approval may address either no action, if the current 
configuration eliminates the unsafe condition; or different actions 
necessary to address the unsafe condition described in 

[[Page 43091]]
this AD. Such a request should include an assessment of the effect of 
the changed configuration on the unsafe condition addressed by this 
AD. In no case does the presence of any modification, alteration, or 
repair remove any airplane from the applicability of this AD.

    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 103576-21-4054 (for Model 441 series 
airplanes), 103576-21-4056 (for Model 500 and 550 series airplanes), 
or 103648-21-4055 (for Model 560 series airplanes), all dated 
January 30, 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 103576-21-
4054 (for Model 441 series airplanes), 103576-21-4056 (for Model 500 
and 550 series airplanes), or 103648-21-4055 (for Model 560 series 
airplanes), all dated January 30, 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 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 August 14, 1995.

S.R. Miller,

Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.

[FR Doc. 95-20505 Filed 8-17-95; 8:45 am]

BILLING CODE 4910-13-U