3-6. OVERLIMITS INSPECTION. If the airplane has been operated so that any of its components have
exceeded their maximum operational limits, check with the appropriate manufacturer.
3-7. SPECIAL INSPECTIONS. The special inspections given in the following paragraphs, supplement the
scheduled inspections as outlined in the Inspection Report, Table III-I, to include inspection of items which are
required to be examined at intervals not compatible with airframe operating time or airframe inspection intervals.
Typical of this type are:
a. Inspection required because of special conditions or incidents that arise, and because of these conditions or
incidents, an immediate inspection would be required to ensure further safe flight.
b. Inspection of airframe or components on a calendar basis. This type of inspection could often be
accomplished during the nearest scheduled inspection.
c. Specific definitive inspection on engines based strictly upon engine operating time.
d. Those inspections not completely covered in other sections of this manual, but outlined in the Inspection
Report and must be explained in more detail to give a clearer and complete inspection.
3-8. INSPECTION OF EXHAUST SYSTEM. (Refer to Figures 3-1 and 3-2.) The entire exhaust system,
including heat exchange shroud, muffler, muffler baffles, stacks and all exhaust connections must be rigidly
inspected at each 100 hour inspection. The possibility of exhaust system failure increases with use. It is
recommended that the system be checked more carefully as the number of hours increase, therefore inspection at
the 700 hour period, that the exhaust system has been in use, would be more critical than one in the 100 hour
period. The system should also be checked carefully before winter operation when the cabin heat will be in use.
— NOTE —
It is recommended that all PA-28 airplanes be fitted with a new muffler at (or near) the
1000 hour period of which the muffler has been in use.
Removal of the stacks is required for inspection of the muffler baffle. Remove or loosen all exhaust shields,
carburetor and cabin heat muffs, shrouds, heat blankets, etc. as required to permit inspection of the complete
system. Perform the necessary cleaning operations and inspect all external surfaces for dents, cracks and missing
parts. Pay particular attention to welds, clamps, supports and support attachment lugs, slip joints, stack flanges
and gaskets. Inspect internal baffle or diffusers. Any cracks, warpage or severe oxidation are cause for
replacement of the muffler.
If any component is inaccessible for a thorough visual inspection, accomplish one of the following:
a. Accomplish a submerged pressure check of the muffler and exhaust stack at 2 psi air pressure.
b. Conduct a ground test using a carbon monoxide indicator by heading the airplane into the wind, warming
the engine on the ground, advancing the throttle to full static RPM with cabin heat valves open, and taking
readings of the heated air stream inside the cabin at each outlet (including rear seat heat outlet, if installed).
Appropriate sampling procedures applicable to the particular indicator must be followed. If carbon monoxide
concentration exceeds .005 percent or if a dangerous reading is obtained on an indicator not calibrated in
percentages, the muffler must be replaced.
3-9. PROGRAMMED INSPECTION. The programmed inspection was designed to permit the utilization of the
aircraft, by scheduling inspections through the use of a planned inspection schedule. Programmed Inspection
schedules are available from Piper Service Sales P/N 761 831.
PIPER AIRCRAFT
PA-28-161 CADET
AIRPLANE MAINTENANCE MANUAL
Issued: FEBRUARY 28, 1989
I N S P E C T I O N
1D16
