Technical data

13773-001
34-10
Page 6 30 Nov 2000
(b) Tape over static air buttons.
(c) Connect hose fitting to alternate static source valve.
(d) Squeeze sphygmomanometer bulb and close check valve to establish a vacuum inside
bulb.
(e) Open alternate static source valve and attach hose to valve.
CAUTION: Do not apply positive pressure with airspeed indicator or vertical speed indi-
cator connected into static system.
(f) Slowly open air bulb check valve until airplane altimeter indicates a 1000-foot increase in
altitude then close check valve to trap suction in system.
(g) While increasing suction and altimeter indicating 1000 feet, ensure that the airspeed indi-
cator shows an increase and the vertical speed indicator shows a climb indication.
(h) Leakage shall not exceed 100 feet of altitude loss as indicated on the altimeter.
(i) Momentarily remove tape from one static air button. There should be a decrease in altim-
eter indication. If no change occurs, the system is blocked and must be repaired prior to
further testing.
Note: If leakage rate exceeds the maximum allowable, check all fittings and hoses
for condition and tightness and repeat leakage test. If leakage rate still
exceeds the maximum allowable, perform the following procedure:
(j) Remove glareshield. (Refer to 25-10)
(k) Disconnect static pressure lines from airspeed indicator, vertical speed indicator, altitude
digitizer, and if applicable, altitude transducer. Use suitable fittings to connect lines
together so altimeter is the only instrument still connected into static pressure system.
(l) Repeat leakage test to ascertain whether the static pressure system or the bypassed
instruments are causing the leakage. If instruments are faulty, repair at an appropriately
rated repair station. If static pressure system is faulty, perform the following procedure to
locate leakage:
CAUTION: Do not apply positive pressure with airspeed indicator or vertical speed indi-
cator connected into static system.
(m) Remove sphygmomanometer assembly and release check valve.
(n) Attach hose to alternate static source valve and slowly apply positive pressure until altim-
eter indicates a 500-foot decrease in altitude. Maintain this altimeter indication while
checking for leaks.
(o) Coat line with a solution of mild soap and water, watching for bubbles to locate leaks.
(p) Tighten leaking connections. Repair or replace defective components.
(q) Reconnect airspeed, vertical speed indicator, altitude digitizer, and if applicable, altitude
transducer. Repeat static system leakage test, and perform pitot system adjustment/test.
(r) Install glareshield. (Refer to 25-10)
Hose Fitting - U.S. Plastics Hose attachment to
valve.
Description P/N or Spec. Supplier Purpose