80-19-01 PIPER AIRCRAFT CORPORATION: Amendment 39-3908. Applies to Model PA-28R-180 serial numbers 28R-30002 through 28R-7130013; Model PA-28R-200 serial numbers 28R-35001 through 28R-7635545; PA-28R-201 serial numbers 28R-7737001 through 28R-7837317; and PA-28RT-201 serial numbers 28R-7918001 through 28R-8018088 airplanes certificated in all categories. \n\n\tCompliance required within the next 50 hours time in service after the effective date of this AD unless already accomplished. \n\n\tTo prevent possible leakage of carbon monoxide into the cabin, accomplish the following: \n\n\t(a)\tRemove upper and lower engine cowling. \n\n\t(b)\tRemove and discard clips on muffler shroud end plates shown on Figure 1. \n\n\t(c)\tInspect for movement between the muffler shroud end plates and the muffler pipes. \n\n\t(d)\tIf there is no relative movement, the muffler assembly is acceptable and no modification is necessary. \n\n\t(e)\tIf relative movement is observed, accomplish the following: \n\n\t\t(1)\tRemove and disassemble the muffler and shroud assembly from the engine and inspect all parts for wear and cracking. Repair or replace as necessary. \n\n\tNOTE: During the inspection required inn (1), direct particular attention to the muffler shroud end plates and the mating area of contact on the muffler tubes. \n\n\t\t(2)\tRework the end plates to provide a 0.030 inch minimum gap between the plates after assembly as shown in Figures 1 and 2. \n\n\t\t(3)\tSlot the two 0.141 inch holes in the top of the shroud assembly to allow the screws to be installed without causing deformation of the shroud skin. \n\n\t\t(4)\tInstall the two screws holding the shroud assembly on the bottom side of the muffler prior to installing the strap clamps but do not tighten until the top screws are in place. \n\n\t\t(5)\tInstall the strap clamps, tightening to a torque of 25 to 30-inch pounds. \n\n\t\t(6)\tInstall and tighten the two top screws then tighten the bottom screws. \n\n\t\t(7)\tInspect the muffler and shroud assembly for tightness. If relative motion still exists between the muffler pipes and the muffler shroud end plates, repeat steps (1) through (6) until any relative motion is eliminated. \n\n\t\t(8)\tReinstall the muffler assembly in the aircraft using new exhaust gaskets, Lycoming part number 65321, and torque exhaust stack nuts to 120 to 170-inch pounds. \n\n\t(f)\tMake an appropriate maintenance record entry. \n\n\tAn equivalent method of compliance may be approved by the Chief, Engineering and Manufacturing Branch, Federal Aviation Administration, Southern Region. \n\n\tNOTE: Piper Service Bulletin No. 691, dated August 6, 1980, pertains to this subject. \n\n\tThis amendment becomes effective September 12, 1980. \n\n\n\n\nFIGURE 1 AD \n80-19-01 \n\n\n\n\nFIGURE 2 \nAD 80-19-01