Technical data

13773-001
34-10
Page 330 Nov 2000
3. MAINTENANCE PRACTICES
A. Pitot Tube Assembly (See Figure 34-101)
(1) Removal - Pitot Tube Assembly
(a) Ensure BAT 1, BAT 2, and AVIONICS master switches are in off position.
(b) Pull PITOT HEAT circuit breaker.
(c) Remove left wing tip. (Refer to 57-20)
(d) Identify and disconnect pitot line at low point on connector projecting from top of pitot
bracket. Cap off connector.
(e) Remove attaching screws securing pitot tube assembly to bracket, disconnect pitot heat
electrical connector, and remove pitot tube.
(f) Remove attaching screws securing pitot tube bracket to rib and remove bracket.
(2) Installation - Pitot Assembly
(a) Align mounting holes on pitot tube bracket with screw holes in rib and install screws.
(b) Slide pitot tube assembly into bracket, connect pitot heat electrical connector, and connect
pitot line.
(c) Install attaching screws securing pitot tube to bracket.
(d) Perform pitot system leakage test. (Refer to 34-10)
(e) Install left wing tip. (Refer to 57-20)
(f) Reset PITOT HEAT circuit breaker.
(3) Inspection/Check - Purging the Pitot System
Pitot system lines must be kept clear and connections tight. A water trap and plug, located at the
low point of the pitot system directly behind the center console and underneath the cabin floor, is
used to trap and then drain water from the system. However, moisture may collect at other
points of the system. To purge the static system, proceed as follows:
(a) Remove glareshield. (Refer to 25-10)
(b) Disconnect pitot line at airspeed indicator and cap off airspeed indicator.
CAUTION: Never blow air through the line toward the instruments. To do so will seri-
ously damage the instruments.
Pointer vibrates. Excessive vibration caused by
loose mounting screws.
Tighten mounting screws.
Excessive tube vibration. Tighten clamps and connections.
Trouble - Altimeter Probable Cause Remedy
Excess scale error. Improper calibration adjustment. Replace instrument.
Excessive pointer oscillation. Defective instrument. Replace or repair instrument.
High reading. Static system leak. Inspect static system. (Refer to
34-10)
Difficult to turn setting knob. Wrong or lack of lubrication. Replace or repair instrument.
Cracked or loose cover glass. Excessive vibration caused by
loose mounting screws.
Tighten mounting screws.
Trouble - Pitot Static Probable Cause Remedy