AD 98-02-05 Airworthiness Directives; Cessna Aircraft Company Model 172R Airplanes

Makes named: cessna. Models named: 172R. Read the applicability below — it usually turns on serial or part numbers too.

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.

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