Pa-44-180T Air Inlet Filter Housing Inspection And Maintenance; Pa-44-180T Compressor Inlet Duct And Alternate Air Door Inspection - Piper PA-44-180 SEMINOLE Maintenance Manual

PA-44-180T INDUCTION SYSTEM. (Refer to Figure 71-6.)
AFTER ANY REPAIRS TO THE INLET DUCTS, BE
SURE THEY ARE PROPERLY EVA C U ATED TO
PREVENT INGESTION IN COMPRESSOR OR ENGINE.
The induction system for the turbocharged Seminole is similar to that of the standard version only in that it
also takes induction air from the right rear baffle. Air flows into the air box through a flat filter and into the
compressor inlet duct. The compressor inlet duct also incorporates a means of alternate air with a suck in door.
The alternate air door can also be manually operated from the cockpit.
At the front of each engine inlet is a deflector to help prevent turbo bootstrap and give protection against
ice.

PA-44-180T AIR INLET FILTER HOUSING INSPECTION AND MAINTENANCE.

The filter housing is an integral part of the baffling. Repairs to this assembly are limited to standard metal
skin repairs as specified in AC 43.13-1 A. Whenever an inspection is carried out, or the filter is changed, the
housing should be checked for corrosion and cracks. If damage is observed it should be repaired and any holes
sealed. For replacement of the filter refer to chapter on servicing.
MAINTENANCE AND INSPECTION OF PA-44-180T COMPRESSOR INLET DUCT AND ALTER-
NATE AIR DOOR.
For Inspection information refer to Step 2 of the subject paragraph.
1 . The compressor inlet duct is an assembly unto itself, and is supported through connection with the filter
housing and the compressor inlet. Any repairs to the alternate air door or inlet duct should be done
with the assembly removed to prevent foreign object damage to the compressor. Remove the inlet
duct as follows:
A. Remove the top and cowl of the affected engine
B. Disconnect the alternate air door control cable from the actuating lever, and bracket on air duct.
C. Unscrew those clamps retaining the duct to the filter housing and with the aluminum supports
removed, slide the sleeve back over the housing.
D. Loosen the clamp securing the duct to compressor inlet and move the duct out of the support
sleeve.
2. Check the duct for pinholes, excessive corrosion, and cracks, especially at the welds and f l a n g e s .
Check the roller on the door actuating lever for wear and freeness of rotation.
A. Weld all cracks or pinholes that have been discovered. Make sure the surface is smooth on the
inside of the tube.
B. If corrosion is detected,.lightly sand the surface, and properly coat or treat.
3 . To replace the roller on the actuating lever, center punch the rivet and, as accurately as possible to
p r event enlarging the hole, drill out the rivet. Replace the rivet with an appropriate MS20470AD4
rivet.
PIPER AIRCRAFT
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
— CAUTION —
— NOTE —
3E17
71-63-20
Page 71-19
Revised: May 15, 1989