Note that these devices should only be utilized during ground operations when necessary
Leaving them on unnecessarily can cause heat to the point of damage/malfunction
Static Port:
Samples of ambient still-air atmospheric pressure
Normally flush mounted on the side of the aircraft where air is undisturbed
Senses movement of the aircraft through air both horizontally and vertically
Placed in one more places where the air is not disturbed
Some ports are heated
Dual ports remove errors due to slips and skids
Responsible for Airspeed Indicator, Altimeter, and Vertical Speed Indicators
The POH/AFM contains any corrections that must be applied to the airspeed for the various configurations of flaps and landing gear
Alternate Static Source:
On some aircraft, an alternate static air source valve is used for emergencies
If the alternate source is vented inside the airplane, where static pressure is usually lower than outside static pressure, selection of the alternate source may result in the following erroneous instrument indications:
The altimeter reads higher than normal
Indicated airspeed (IAS) reads greater than normal
VSI momentarily shows a climb
Many POHs provide a correction table and aircraft-specific instructions
In any case, the alternate static source is not corrected for non-standard pressure (as it is with an altimeter's Kollsman window)
The use of alternate static sources may impact other instruments that rely on static pressure (i.e., autopilots, TCAS, transponder, etc.)
The use of alternate static sources can also decrease the accuracy beyond the 75 feet recommendation outlined in the Aeronautical Information Manual
Pitot-Static System Anomalies and Malfunctions:
Blockages in the system can cause a variety of errors
To prevent these errors, you must complete a thorough pre-flight
Blockages can occur from FOD, striking an object, insects, and icing
At the altitude where the Pitot tube becomes blocked, the airspeed indicator remains at the existing airspeed and doesn't reflect actual changes in speed
At altitudes above where the Pitot tube became blocked, the ASI displays a higher-than-actual airspeed, increasing steadily as altitude increases
At lower altitudes, the ASI displays a lower-than-actual airspeed, decreasing steadily as altitude decreases
Pitot-Tube Drain Hole Blockage:
Would cause ASI to malfunction
Pitot-Tube and Drain Hole Blocked:
Would cause ASI to malfunction
Static Port Blockage:
Would cause ASI, altimeter, and VSI to malfunction
If in a real emergency, malfunctions can be corrected with alternate air or breaking the glass on a Pitot static instrument (VSI)
If the static ports become blocked, the ASI would still function but could produce inaccurate indications
At the altitude where the blockage occurs, airspeed indications would be normal
At altitudes above which the static ports became blocked, the ASI displays a lower-than-actual airspeed continually decreasing as altitude is increased
At lower altitudes, the ASI displays a higher-than-actual airspeed, increasing steadily as altitude decreases
The trapped pressure in the static system causes the altimeter to remain at the altitude where the blockage occurred
The VSI remains at zero
Pilots should use alternate static sources per the pilot operating handbook
Common Training Aircraft Pitot-Static System Characteristics:
Piper Arrow:
Composed of a heated Pitot tube on the lower left wing
Two static ports are located on each side of the fuselage
Alternate static air (below the pilot control yoke) provides static pressure from inside the cabin
Cessna 172:
Composed of a heated Pitot tube on the lower surface of the left wing
An external static port is located on the lower left side of the forward fuselage
Pitot Tube consists of a heating element, a 5-amp switch/breaker, and associated wiring
Alternate static (below throttle) provides pressure from inside the cabin
Private Pilot (Airplane) Operation of Aircraft Systems Airman Certification Standards:
.
Objective: To determine the applicant exhibits satisfactory knowledge, risk management, and skills associated with safe operation of systems on the airplane provided for the flight test.
Private Pilot (Airplane) Operation of Aircraft Systems Risk Management:
The applicant is able to identify, assess, and mitigate risk associated with:
PA.I.G.R1:
Detection of system malfunctions or failures.
PA.I.G.R2:
Management of a system failure.
PA.I.G.R3:
Monitoring and management of automated systems.
Private Pilot (Airplane) Operation of Aircraft Systems Skills:
The applicant exhibits the skill to:
PA.I.G.S1:
Operate at least three of the systems listed in K1a through K1l appropriately.
PA.I.G.S2:
Complete the appropriate checklist(s).
Private Pilot (Airplane) Systems and Equipment Malfunctions Airman Certification Standards:
Objective: To determine the applicant exhibits satisfactory knowledge, risk management, and skills associated with system and equipment malfunctions appropriate to the airplane provided for the practical test
Causes and remedies for smoke or fire onboard the aircraft.
PA.IX.C.K4:
Any other system specific to the airplane (e.g., supplemental oxygen, deicing).
PA.IX.C.K5:
Inadvertent door or window opening.
Private Pilot (Airplane) Systems and Equipment Malfunctions Risk Management:
The applicant is able to identify, assess, and mitigate risk associated with:
PA.IX.C.R1:
Checklist usage for a system or equipment malfunction.
PA.IX.C.R2:
Distractions, task prioritization, loss of situational awareness, or disorientation.
PA.IX.C.R3:
Undesired aircraft state.
PA.IX.C.R4:
Startle response.
Private Pilot (Airplane) Systems and Equipment Malfunctions Skills:
The applicant exhibits the skill to:
PA.IX.C.S1:
Describe appropriate action for simulated emergencies specified by the evaluator, from at least three of the elements or sub-elements listed in K1 through K5 above.