Airfoils; Ice And Rain Protection System Troubleshooting - Piper PA-44-180 SEMINOLE Maintenance Manual

Both the standard two-bladed propeller installation and the optional three bladed propeller installation utilize
single element deicers. When the switch is turned on power is directed through the brush block and slip ring to
all the heating elements on one propeller for approximately 34 seconds. The timer then directs the power to the
other propeller for approximately 34 seconds. This cycle continues until the switch is turned off.
A heated windshield panel can also be installed as a separate item or with any combination of systems. The
installation is controlled by a circuit breaker/ switch on the "control panel" along with the use of a glass panel
imbedded with wire filaments. The panel is mounted to a metal frame and secured by two screws to the fuselage,
on the exterior of the windshield on the pilot's side. The frame is hinged at its base to facilitate cleaning of the
windshield and panel. When not in use, the panel can be removed by removing the two attaching screws and
harness from the fuselage.
The pitot and stall warning heat systems are operated as a single system when they are installed. It should be
noted that although the pitot heat system can be installed in the aircraft by itself, the stall warning heat
combination can only be included if the pitot heat system is also installed. These systems utilize a switch in the
switch cluster on the pilot's side of the instrument panel. Other parts of the systems include a heated pitot head,
heated lift detectors (inner and outer), and two circuit breakers (one for each part of the system).
For seeing and detecting ice at night a wing inspection light can also be included with the systems. The light,
controlled by a switch on the "deice control panel," is mounted to the outboard side of the left nacelle.

AIRFOILS.

Airfoil deicing is performed by the pneumatic deicing system. The system utilizes inflatable boots to clear ice
off the leading edges of the wings, vertical stabilizer, and stabilator.
The boots are of a fabric reinforced rubber construction containing built-in span wise inflation tubes. Attached
to the leading edges of the flight surfaces with adhesive they are connected through the skin by aluminum and/or
flexible rubber air connection stems.
A ply of conductive neoprene is provided on the surface to dissipate static electric charges. These charges, if
allowed to accumulate, would eventually discharge through the boot to the metal skin beneath creating static
interference with radio equipment, and possible punctures in the rubber. Also such static charges would
constitute a temporary fire hazard after each flight.
For operational descriptions refer to the general description at the beginning of this chapter.
TROUBLESHOOTING.
The troubleshooting chart contained herein is based on the premise, except as specified, that the engine driven
pneumatic pumps and the electrical system are operating properly. It is further assumed that the system
components were installed properly.
PIPER AIRCRAFT
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
— Note —
For wiring diagrams (schematics) refer to Chapter 91.
2D6
3 0 - 11 - 0 0
Page 30-02
Revised: May 15, 1989