Piper Cherokee Archer II Pilot Operating Handbook page 136

SECTION 7
DESCRJPTION AND OPERATION
7.21 PITOT·STATIC SYSTEM
PIPER AIRCRAFT CORPORATION
PA-28-18I, CHEROKEE ARCHER II
The system supplies both pit at and static pressure for the airspeed indicator, altimeter, and the'
optional vertical speed indicator (Figure 7-17).
Pitot and static pressure are picked up by a pitot head installed on the bottom of the left wing and
carried through pitot and static lines within the wing and fuselage to the gauges on the instrument panel.
An alternate static source is available as optional equipment. The control valve is located below the
left side of the instrument panel. When the 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 window and cabin
vents must be closed and the cabin heater and defroster must be on dUring alternate static source operation.
The altimeter error is less than 50 feet unless otherwise placarded.
Both the pitot and static lines can be drained through separate drain valves located on the left lower
side of the fuselage interior.
A heated pitot head, which alleviates problems with icing and heavy rain, is available as optional
equipment. The switch for the heated pitot head is located on the electrical switch panel to the left of the
right control wheel.
To prevent bugs and water from entering the pitot and static pressure holes, 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.
NOTE
During the preflight, check to make sure the pitot cover is
removed.
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REPORT: VB-790
7-18
ISSUED: JUNE 18, 1976
REVISED: JUL Y12, 1977
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