Piper Arrow PA-28R-201 Pilot Operating Handbook page 199

SECTION 7
DESCRIOPERATION
7.19 VACUUM SYSTEM
regulator is provided in the system to protect the gyros.
A vacuum
valve isset so the normal vacuum reads 4.8 to 5.1 inches of mercury, a setting
which provides sufficient vacuum
Higher settings will damage
unreliable. The regulator islocated behind the instrument panel.
If equipped with the optional auxiliary vacuum
9, Supplement 3, for operationprocedures.
7.21 PITOT-STATIC
supplies both pitot and Static pressure for the airspeed
The system
indicator, altimeterand vertical speed indicator (when installed).
Pitot pressure is picked up by the pitot head on the bottom of the left
wing. An optional heated pitot head, which alleviates problems with icing or
heavy rain, is available. The switch for pitot heat is located on the switch
panel. Static pressure is sensed by button type vents on each side of the aft
fuselage. Push-button type pitot and static drains are located on the lower
leftsidewall of the cockpit.
An alternate static source is available as optional equipment.
control valve islocated below the leftside of the instrument panel. When
valve is set in the alternate position, the altimeter, vertical speed indicator
and airspeed indicator will be using cabin air for static pressure. The storm
and cabin vents must be closed and the cabin heater and defroster
window
must be on during alternatestaticsource operation. The altimeter error is
lessthan 50 feetunless otherwise placarded.
To prevent bugs and water from entering the pitot
the airplane is parked, a cover should be placed over the pitot head. A
partially or completely blocked pitot head will give erratic or zero readings
on the instruments.
During preflight, check to make
cover isremoved.
REPORT:
VB-1612
7-18
HB-PQY, Page: 7-18-(0)
(continued)
to operate allthe gyros at theirrated rpm.
the gyros and with a low setting the gyros will be
SYSTEM
NOTE
Issued: JULY 12, 1995
PA-28R-201, ARROW
system, refer to Section
pressure hole when
sure the pitot
ISSUED:
JULY 12, 1995
The
The
the
7-18