95-10 Pitot-Static System
A. Pitot System Leak Test
CAUTION
Do not apply suction to pitot system or pressure to static system.
1. Open mast fairing per Section 53-22.
2. Refer to Figures 95-1 and 95-2. Seal drain hole in elbow aft of pitot tube with pressure
sensitive tape. Connect a medical syringe, with plunger withdrawn, to pitot tube via
flexible tubing.
3. SLOWLY apply pressure to pitot line by depressing syringe plunger until airspeed indicator
reads 70 knots. Release force on plunger; plunger will remain in place without need to
pinch flexible tubing.
4. Gently tap airspeed indicator glass to remove friction effects.
5. If airspeed indication drops more than 10 knots in one minute, an unacceptable leak is
indicated. SLOWLY release pressure. Locate and repair any leak(s). Retest after any
repairs.
6. Remove tape from pitot tube drain hole and verify airspeed indicator has returned to
zero.
7. Remove test equipment.
B. Static System Leak Test
CAUTION
Airspeed indicator, altimeter, and vertical speed indicator may be
damaged if suction to static line is applied or removed rapidly.
1. Refer to Figures 95-1 and 95-2. Set altimeter to location elevation.
2. Temporarily seal left or right side static opening with pressure sensitive tape. Cover
remaining static port with a suction cup attached to a medical syringe.
3. SLOWLY apply suction to static port by withdrawing syringe plunger until altimeter
indicates 500 feet greater than location elevation. Release force on plunger, wait one
minute, and note any change in altimeter indication.
4. Change of less than 100 feet indication in one minute is acceptable. SLOWLY remove
suction from static port. Locate and repair leak(s) if altimeter indication changes 100 or
more feet in one minute. Retest after any repairs.
5. Remove test equipment.
25 OCT 2010 R66 Maintenance Manual Chapter 95 Instrument System Page 95.3
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