6.
Plug off the portable pressure bench.

2. Checking the air tightness in the static pressure circuit
1.
Plug the portable pressure bench to the manifold intake.

2.
Apply a de-pressure corresponding to an altimeter reading increasing of about 20 000ft. Limit the applied de-pressure to the value of 200 mph read by the air speed indicator, if this is the first value reached.

3.
Check the vertical speed indicator to make sure that the pressure drop does not fall below the maximum allowed value.

4.
Set the source to the above-mentioned value.

5.
After a minute, the reading variation on the altimeter and vertical speed indicator should be below 30% of the original reading.

2. Remedying of possible failures: 
1. Airspeed indicator  
Problem/Probable causes  Solutions 
Airspeed indicator does not read:      
-clogged static or manifold pressure  -check the pipes and unclog if necessary. 
intake ports or throttled pipes.  -repair or replace the faulty pipe after 
-inadequate connection of manifold  checking the connection air tightness. 

S.C. AEROSTAR  S.A.
FESTIVAL R40S
BACAU - ROMANIA
   AIRPLANE MAINTENANCE MANUAL
pipe to manifold intake.
Airspeed indicator reads erroneously:

-air losses in the static or manifold
-repair or replace any damaged pipes. pressure pipes.
-replace the airspeed indicator with a good
-damaged airspeed indicator
one, checking its reading; if still mechanism.
malfunctioning after the test, replace the airspeed indicator.
     2.Vertical speed indicator
Possible causes  Solutions 
Vertical speed indicator does not read:       - clogged, cracked or broken static pressure pipe.  - check the pipe and unclog, repair or replace it. -check the air tightness at connections. 
  Vertical speed indicator reads  -check the pipe for clogging, and unclog,       
erroneously:  - replace the vertical speed indicator with a 
- partially clogged static pressure pipe.  good one, checking its reading 
- broken diaphragm of manometer  - if the indicator still proves to be faulty 
capsule.  after the test, replace it. 
- needle does not read zero in stationary  - bring the needle to zero when the aircraft 
mode.  is parked on ground. 
  Vacillating needle:  -check the pipe for clogging and unclog,        
- partially clogged static pressure pipe  - check the pipes and their connections; 
- air losses at the static pressure pipe.  repair and replace, as the case may be.  
　
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