Piper PA-32R-301T SARATOGA S Maintenance Manual Download

Page: 408 / 956

ICE AND RAIN PROTECTION (Cont.)

B. Description and Operation (cont.)

Propeller deice system, which can be installed by itself or included in a package with others of ice

protection system, is designed for both two- and three-bladed propeller installations. Each propeller

deice system consists of an electrically heated deicer bonded to each propeller blade, slip ring assembly

with brush block assembly to transfer electrical power to rotating deicers, a timer, an ammeter, a control

switch-circuit breaker, shunt, together with wiring harnesses to complete circuit. Power is drawn from

aircraft electrical system.
To conserve electrical power current is cycled to deicer heaters at timed intervals rather than

continuously. Each has two separate heaters; one for outer half and one for inner half. By heating all

outer or inner heaters, rotational balance is held during deicing. Current is drawn from airplane

electrical system through switch, ammeter and timer. Timer successively delivers current via slip ring

and brush block arrangement to (Phase 1) outer heaters on propeller and then inner heaters on propeller.

Timer energizes each of these phases in turn for about 30 seconds and then repeats cycle as long as

control switch is on. See cycle sequence. (Refer to Figures 8 and 9.) System may be used continuously

inflight if needed.

– NOTE –

Heating may begin at any phase in cycle depending on timer
position when switch was turned off from previous use.

Deicers contain special heater wires protected by fabric plies and by oil and abrasion-resistant rubber.

Side of deicer cemented to propeller has a dull finish whereas air side finish is glossy. Each deicer has

separate lead for inboard and a third lead which is a common ground. These leads are so marked. An

unmarked ground can be identified by using an ohmmeter across three possible pairs of leads. One pair

will show twice resistance of other pairs. Latter are hot leads and lead excluded from pair that shows

twice resistance of other pairs is ground lead.
To transfer electrical power to rotating deicer, a brush block assembly is mounted to engine or similar

stationary member and has brushes which are spring loaded to press against revolving slip rings. Slip

ring assembly is provided as a slip ring gear assembly which replaces original starter ring gear of

engine.
Timer is a sealed unit. If found inoperative, it must be replaced as an assembly - no field repairs are

authorized.
Ammeter is designed for each particular system and it is therefore important that correct replacement

part number be used if replacement should be required. In event of low aircraft battery voltage (very

possible in ground check), ammeter reading will be lower than at full voltage. Provided ammeter

needle reads in shaded range on scale, (full aircraft voltage) current flow is considered as normal.
A heated windshield panel can also be installed as a separate item or with any combination of systems.

Piper PA-32R-301T SARATOGA S, Maintenance Manual

Search results

Summary of Contents for PA-32R-301T SARATOGA S

Reviews:

Related manuals for PA-32R-301T SARATOGA S

Brands by name

Popular brands