Piper Aircraft Corporation Malibu Mirage PA-46-350P, Airplane Maintenance Manual

Page: 707 / 1956

PAGE 1
Feb 28/07
30-60-00
3J19
PIPER AIRCRAFT, INC.
PA-46-350P, MALIBU MIRAGE
MAINTENANCE MANUAL
PROPELLERS
1. Propeller Heat System
A. Description and Operation
The Goodrich Corporation propeller heat system installed on this airplane uses single element
deice boots. In this system each deicer has one electrothermal heating element. When the PROP
HEAT switch is turned ON, the timer directs power through the modular brush assembly and slip
ring to all the heating elements on the propeller for approximately 90 seconds. The timer then
switches power off for approximately 90 seconds (see Figure 1 and 91-30-60). This cycle will
continue as long as the PROP HEAT switch is in the ON position
except in S/N’s 4636132 and up .
In S/N’s 4636132 and up , the PROP HEAT system employs a Moritz timer and a squat switch relay
to create a ground test mode which interrupts power to the boots after an initial 30-45 seconds as
long as the squat switch indicates weight on the wheels. During the 30-45 second test cycle, the
PROP HEAT switch will flash at a fast rate and the ship’s ammeter will show an increase. In flight,
the PROP HEAT switch flashes at a slow rate during the 90 second off cycle and is continuously
illuminated during the 90 second ON cycle.
The propeller heat system consists of the following:
In S/N’s 4636001 thru 4636131 : electrically heated deicers bonded to the propeller blades; slip ring
assemblies connected to the propeller hub to distribute power to the propeller deicers; a modular
brush assembly which transfers electrical power to the rotating slip rings; a timer to cycle power to
the deicers; a propeller heat ammeter to indicate that the system is functioning correctly; an external
ammeter shunt, a manual ON-OFF switch; and a circuit breaker.
In S/N’s 4636132 and up : electrically heated deicers bonded to the propeller blades; slip ring
assemblies connected to the propeller hub to distribute power to the propeller deicers; a modular
brush assembly which transfers electrical power to the rotating slip rings; when equipped with the
optional composite 3-blade propeller only - a metal oxide varistor (MOV) module to protect the
propeller; a timer to cycle power to the deicers; an LED equipped manual ON-OFF switch; a circuit
breaker; and a squat switch relay.
Prop Heat Cycle Sequence
Figure 1