What does an alternate static source valve?
Alternate static source valve. A valve in the instrument static air system that supplies reference air pressure to the altimeter, airspeed indicator, and vertical speed indicator if the normal static pickup should become clogged or iced over.
What is alternate static?
An alternate static source is provided in some aircraft to provide static pressure should the primary static source become blocked. Due to the venturi effect of the air flowing around the fuselage, the air pressure inside the flight deck is lower than the exterior pressure.
How does the pitot-static system work?
The pitot-static system of instruments uses the principle of air pressure gradient. It works by measuring pressures or pressure differences and using these values to assess the speed and altitude. The static pressure is used in all measurements, while the pitot pressure is used only to determine airspeed.
What is the most relied on indicator when flying by instruments?
The term “vertical speed indicator” or “VSI” is most often used for the instrument when it is installed in a powered aircraft. The term “variometer” is most often used when the instrument is installed in a glider or sailplane.
Why is alternate static lower pressure?
Flight deck static pressure is lower than outside static pressure. The reason for this error with alternate static source is that the air flowing around the airframe creates a slight vacuum inside the airframe, thereby lowering the barometric pressure and generating erroneous readings in the pitot-static system.
Where is the alternate static port located?
Explanation: An alternative static port is located inside the cabin of the aircraft. The alternate port acts as a backup, in case the external static port(s) are blocked.
What 3 instruments work on the pitot static system?
So, there is three flight instruments that ultimately use this pitot-static system – the airspeed indicator, the altimeter, and the vertical speed indicator.
Can you fly without an attitude indicator?
No. Just the removal maintenance needs to be signed off and the inop indicator shown removed per 91.213. As long as you verified it’s not needed for flight you should be ready to go.
Where is the alternate static source valve on an airplane?
Alternate static source valve is installed on the instrument panel to use when the external static source is not in operation. On airplanes with an autopilot, there is a tube that connects the autopilot to a static port on the left side of the airplane at FS 117.25.
How does the pitot system work on a Cessna 172R?
PITOT/STATIC SYSTEM. Pitot system supplies ram air pressure to ASI. Static system connects the VSI, altimeter, and ASI to atmospheric pressure through plastic tubing connected to a static port. Static line sump is installed at the source button to collect condensation in the static system.
Where is the static port on an airplane?
On airplanes with an autopilot, there is a tube that connects the autopilot to a static port on the left side of the airplane at FS 117.25. This part of the pitot/static system is not connected to the other parts of the pitot/static system.