[Federal Register Volume 63, Number 24 (Thursday, February 5, 1998)]
[Rules and Regulations]
[Pages 5879-5881]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-2774]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-CE-06-AD; Amendment 39-10306; AD 98-02-05]
RIN 2120-AA64


Airworthiness Directives; Cessna Aircraft Company Model 172R 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This document publishes in the Federal Register an amendment 
adopting Airworthiness Directive (AD) 98-02-05, which was sent 
previously to all known U.S. owners and operators of Cessna Aircraft 
Company (Cessna) Model 172R airplanes. This AD requires de-activating 
the cabin heating system until the engine exhaust muffler can be 
replaced, and fabricating and installing a placard within the pilot's 
clear view, using \1/8\-inch letters with the following words: ``CABIN 
HEATER INOPERATIVE.'' Inadequate or failed weldments that are leaking 
exhaust gas (including carbon monoxide) from the muffler into the 
airplane's cabin and cockpit area prompted this action. The actions 
specified by this AD are intended to prevent carbon monoxide gas from 
entering the airplane's cabin heating system and cabin, which, if not 
corrected, could result in passenger and pilot injury with consequent 
loss of control of the airplane.

DATES: Effective February 23, 1998, to all persons except those to whom 
it was made immediately effective by priority letter AD 98-02-05, 
issued January 9, 1998, which contained the requirements of this 
amendment.
    Comments for inclusion in the Rules Docket must be received on or 
before March 30, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Central Region, Office of the Regional Counsel, 
Attention: Rules Docket 98-CE-06-AD, Room 1558, 601 E. 12th Street, 
Kansas City, Missouri 64106.

FOR FURTHER INFORMATION CONTACT: Mr. Paul Pendleton, Aerospace 
Engineer, Wichita Aircraft Certification Office, 1801 Airport Road, Rm. 
100, Mid-Continent Airport, Wichita, Kansas, 67209, telephone (316) 
946-4143; facsimile (316) 946-4407.

SUPPLEMENTARY INFORMATION:

[[Page 5880]]

Discussion

    On January 9, 1998, the FAA issued priority letter AD 98-02-05, 
which applies to Cessna Model 172R airplanes (serial numbers 17280001 
through 17280305). That AD resulted from a quality control problem with 
Aeroquip engine exhaust mufflers installed on certain Cessna Model 172R 
airplanes. Cessna recently notified the FAA that the Aeroquip muffler, 
part number (P/N) 00624-NH4000011-10 71379 0554011-2, is installed in 
approximately 250 Cessna Model 172R airplanes. Cessna has determined, 
through pressure testing, that approximately 5 out of the 25 tested 
mufflers manufactured by Aeroquip are leaking. These inadequate or 
failed weldments will permit exhaust gas (including carbon monoxide) 
leakage from the muffler, and consequently into the airplane's cabin 
and cockpit area. This condition, if not corrected, could result in 
passenger and pilot injury with consequent loss of control of the 
airplane.

The FAA's Determination and Explanation of the AD

    Since an unsafe condition has been identified that is likely to 
exist or develop in other Cessna Model 172R airplanes of the same type 
design, the FAA issued priority letter AD 98-02-05 to prevent carbon 
monoxide gas from entering the airplane's cabin heating system and 
cabin, which, if not corrected, could result in passenger and pilot 
injury with consequent loss of control of the airplane.
    The AD requires de-activating the cabin heating system, and 
fabricating and installing a placard within the pilot's clear view, 
using \1/8\-inch letters with the following words: ``CABIN HEATER 
INOPERATIVE'' prior to further flight.
    This AD also requires replacing the Aeroquip engine exhaust muffler 
(P/N 00624-NH4000011-10 71379 0554011-2). If replacement parts are not 
available, the airplane may continue operation with the heating system 
de-activated for a period not to exceed 6 calendar months after the 
effective date of this AD.

Determination of the Effective Date of the AD

    Since it was found that immediate corrective action was required, 
notice and opportunity for prior public comment thereon were 
impracticable and contrary to the public interest, and good cause 
existed to make the AD effective immediately by individual letters 
issued on January 9, 1998, to all known U.S. operators of Cessna Model 
172R airplanes with serial numbers 17280001 through 17280305. These 
conditions still exist, and the AD is hereby published in the Federal 
Register as an amendment to section 39.13 of the Federal Aviation 
Regulations (14 CFR 39.13) to make it effective as to all persons.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting immediate flight safety and, thus, was not 
preceded by notice and opportunity to comment, comments are invited on 
this rule. Interested persons are invited to comment on this rule by 
submitting such written data, views, or arguments as they may desire. 
Communications should 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 will be considered, 
and this rule may be amended in light of the comments received. Factual 
information that supports the commenter's ideas and suggestions is 
extremely helpful in evaluating the effectiveness of the AD action and 
determining whether additional rulemaking action would be needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the 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 that 
summarizes each FAA-public contact concerned with the substance of this 
AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket No. 98-CE-06-AD.'' The postcard will be date stamped and 
returned to the commenter.

Regulatory Impact

    The regulations adopted herein will 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 final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and is not a ``significant regulatory action'' 
under Executive Order 12866. It has been determined further that this 
action involves an emergency regulation under DOT Regulatory Policies 
and Procedures (44 FR 11034, February 26, 1979). If it is determined 
that this emergency regulation otherwise would be significant under DOT 
Regulatory Policies and Procedures, a final regulatory evaluation will 
be prepared and placed in the Rules Docket. A copy of it, if filed, may 
be obtained from 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.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 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), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding a new airworthiness directive 
(AD) to read as follows:

98-02-05  Cessna Aircraft Company: Amendment 39-10306; Docket No. 
98-CE-06-AD.

    Applicability: Model 172R airplanes (serial numbers 17280001 
through 17280305), certificated in any category, that are equipped 
with an Aeroquip engine exhaust muffler (part number 00624-
NH4000011-10 71379 0554011-2).

    Note 1: The letters ``PT'' or ``PTT'' stamped on the right-hand 
external ring that supports the muffler cabin heater shroud indicate 
that Cessna has built or re-built the part. Parts marked in this 
manner are not Aeroquip parts.
    Note 2: 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 (h) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or

[[Page 5881]]

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 in the body of this AD, unless 
already accomplished.
    To prevent carbon monoxide gas from entering the airplane's 
cabin heating system and cabin, which, if not corrected, could 
result in passenger and pilot injury with consequent loss of control 
of the airplane, accomplish the following:
    (a) Prior to further flight after the effective date of this AD, 
de-activate the cabin heating system by ensuring that the valve 
mechanism is functional, and that the cabin heat valve lever is 
safety wired in the down ``off'' position.
    (b) Prior to further flight after the effective date of this AD, 
fabricate and install a placard near the cabin heat control knob, 
within the pilot's clear view, using at least \1/8\-inch letters 
with the following words:

``CABIN HEATER INOPERATIVE''

    (c) Within the next 50 hours time-in-service (TIS) after the 
effective date of this AD, replace the engine exhaust muffler with a 
muffler having one of the following part numbers (P/N) in accordance 
with the appropriate Cessna maintenance manual:

00624-NH4000011-10 71379 0554011-2-PTT, or
0554011-2, or
0554011-6, or
an FAA-approved equivalent part number.

    Note 3: P/N 0554011-2 will have ``PT'' stamped on the right-hand 
external ring that supports the muffler; and, P/N 0554011-6 may have 
``PT'' stamped on the right-hand external ring.

    (d) If parts are not available for the replacement required in 
paragraph (c) of this AD, the airplane may continue to be operated 
for a period not to exceed 6 calendar months from the effective date 
of this AD, provided the cabin heating system remains de-activated.
    (e) The cabin heating system may be re-activated and the placard 
required in paragraph (b) of this AD may be removed, once the 
muffler is replaced in accordance with this AD.
    (f) Upon the effective date of this AD, no person may install 
any Aeroquip engine exhaust muffler, P/N 00624-NH4000011-10 71379 
0554011-2, on any Cessna Model 172R airplane.
    (g) 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, provided the 
airplane cabin heater system is not used during that flight.
    (h) An alternative method of compliance or adjustment of the 
compliance time that provides an equivalent level of safety may be 
approved by the Manager, Wichita Aircraft Certification Office, 1801 
Airport Road, Rm. 100, Mid-Continent Airport, Wichita, Kansas, 
67209. The request shall be forwarded through an appropriate FAA 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Wichita Aircraft Certification Office.

    Note 4: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Wichita Aircraft Certification Office.
    (i) Copies of this document may be inspected at the FAA, Central 
Region, Office of the Regional Counsel, Room 1558, 601 E. 12th 
Street, Kansas City, Missouri.
    (j) This amendment (39-10306) becomes effective on February 23, 
1998, to all persons except those persons to whom it was made 
immediately effective by priority letter AD 98-02-05, issued January 
9, 1998, which contained the requirements of this amendment.

    Issued in Kansas City, Missouri, on January 28, 1998.
Terry L. Chasteen,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-2774 Filed 2-4-98; 8:45 am]
BILLING CODE 4910-13-U