Pitot Static System - PDF

WELCOME TO PITOT & STATIC SYSTEM 1 At the end of this lesson, student will be able to:PITOT STATIC SYSTEM 1. Describe the layout and function of a Pitot Static system. 2. List the external and internal components connected to the Pitot Static system. 3....

WELCOME TO PITOT & STATIC SYSTEM 1 At the end of this lesson, student will be able to:PITOT STATIC SYSTEM 1. Describe the layout and function of a Pitot Static system. 2. List the external and internal components connected to the Pitot Static system. 3. Locate and identify the external and internal components of a Pitot Static system. 4. Explain the functional principle of a  PITOT STATIC SYSTEM What is a Pitot Static System? A Pitot Static system consists of 2 interrelated systems : 1.Pitot System. he pitot system of2.Static System. an aircraft senses the total pressur created by forward motion of the aircraft through the ram air effect. The Static system senses the static pressure of the atmosphere surrounding the aircraft. The pressure created by the forward motion of the aircraft and the atmospheric pressure is called Total pressure.  PITOT STATIC SYSTEM Pitot pressure also called : Impact pressure or Dynamic pressure. Pitot pressure is caused by movement of the aircraft through the air, or movement of the air relative to the aircraft. This pressure is sensed by the Pitot tube. Static Pressure: Static pressure is the pressure of air at rest. This pressure is sensed by a Static tube or Static vent is that of still air. Both of these pressures are sensed and measured in terms of: Speed Altitude Rate of change of altitude  INFORMATIONS PROVIDED BY PITOT STATIC SYSTEM Altitude = 15,000 ft. (AGL) Speed of the aircraft Altitude increases Altitude = 10,000 ft. (AGL) Rate of Change of altitude Altitude = Ground level  LIST OF COMPONENTS of PITOT STATIC SYSTEM External Components Pitot Static tube or probe Pipelines –Pitot and Static Drain valves – Pitot and Static Internal Components 3 Primary flight instrument Indicators Air speed indicator Altimeter Vertical Speed  indicator some complex systems have a selector valve for the alternate static pressure source. To indicate the speed of the aircraft To indicate the altitude of the aircraft To indicate the rate of change of altitude Fig 1 PITOT STATIC SYSTEM AIRCRAFT INSTRUMENT PANEL Fig 2 COMPLEX PITOT STATIC SYSTEM  P RH RH static 2 pitot port tube S S Drain valve 1 2 Airspeed Indicator Copilot Vertical Speed Drain valve Indicator Altimeter Copilot Copilot Alternate Static Altimeter pressure selector pilot Vertical Speed Indicator pilot Drain valve VNO Warning Airspeed light Indicator pilot Airspeed switch Drain valve S S LH 1 2 P pitot LH static 1 tube port Figure 4 PITOT STATIC SYSTEM, Block Diagram ALTITUDE Vs PRESSURE Vs TEMPERATURE STRATOSPHERE (Height: 36,089 Feet) (Temperature : - 56.5˚C) As the height increases temperature decreases at a rate of 2˚C every 1,000 feet of altitude from sea level. MSL (Mean sea level ) = 0 Feet  INFORMATION FROM INTERNET EXPLORER Pitot-static related disasters 1 December 1974-Northwest Orient Airlines Flight 6231, a Boeing 727, crashes northwest of John F. Kennedy International Airport during climb en route to Buffalo Niagara International Airport because of blockage of the Electrical heating element of the Pitot-Static system is fitted within the probe head. Fig 3 Typical Heating Circuit Arrangements  The power supply to the heater is controlled by a switch in the cockpit.  Alternate pressure sources If failure of the primary pitot-static pressure source should occur, e.g complete icing up of a pressure head due to a failed heater circuit, a standby system may be installed in aircraft, where alternate sources can be selected. ALTERNATE STATIC PRESURE SOURCE  Pitot Static Tube/Probe A source of input of a Pitot and Static pressure to the Flight Instrument Indicators A PitotStatic tube is used to measure the difference between Total pressure and Static pressure The difference is called `Dynamic Pressure’  Pitot Static Tube/Probe The typical pitot static probe consists of the following main parts:  heating element  static slots  pitot tube connection (coded P)  static tube connection (coded S)  electrical connection  drain holes  mounting flange.  Pitot Static Tube/Probe It consists of 2 tubes: The inner tube has an open front and senses the pitot pressure. The outer tube has slots radially cut along its length and senses the static pressure.  Pitot Static Tube/Probe Located at a part of the aircraft which is free from turbulent air flow. AIRCRAFT PITOTSTA INSTRUME TIC NTS Pitot Static Tube/Probe SYSTEM AIRCRAFT PITOTSTA TIC INSTRUME NTS Pitot Static Tubes SYSTEM  Water Drain Valves Purpose - To drain water, which has entered by condensation, from the system. Located at the lowest part of the system to facilitate better accumulation and easy drainage of water. Failure to drain water may lead to inaccurate indications, breakage of pipelines and lead up to aircraft disaster  INFORMATION FROM INTERNET EXPLORER Pitot-static related disasters 6 February 1996—Birgenair Flight 301 crashes shortly after takeoff due to the pitot tube being blocked and causing the system to provide incorrect airspeed data. 2 October 1996—AeroPeru Flight 603 crashes because of blockage of the static ports. The static ports on the left side of the aircraft had been taped over while the aircraft was being waxed and cleaned. After the job, the tape was not removed. 24 I&I PS Pitot Static Pipelines Instrument panel Pitot Static Drain traps/holes tube Pipelines of a pitot static system are manufactured from aluminium or stainless steel. The pipelines are of different diameters; Pitot pipelines are 5/16 inch and Static pipelines are 3/8 inch. I&I PS The chosen diameter of pipelines is related to the distance from the pressure sources to the instruments in order to eliminate pressure drop and time lag. Pitot and Static tubing in aircraft are identified by Coding and Marking `P’ and `S’ Figure 8 Marking of Pitot Static System Pipes I&I PS INTERNATIONAL CIVIL AVIATION ORGANISATION (ICAO) ICAO standard conditions at sea level is 1,013.2 hPa or 29.92 inch Hg or 14.7 psi). hPa = hectopascal, Hg = mercury, psi = pound per square inch I&I PS Functional Principle of the Pitot Static System I&I PS PITOT STATIC SYSTEM Pressu re switch es Flight Instrume Air Data Automatic Navigati nts Unit Flight on Indicator component Control I&I PS Maintenance of a Pitot Static System In order to ensure that all instruments read correctly, SENSE and LEAK Check/ Test must be carried out on a Pitot Static system in accordance with the relevant servicing schedules, when; - a pitot or static connection is damaged or broken. - the pitot or static connection is disturbed. After replacement of the pipeline, all the total pitot static system instruments must be checked Aircraft is considered serviceable only after Sense and Leak Test and Independent Check has been carried out on the Pitot Static System. I&I PS Safety Precautions hotttttttt t!  Overall Check 1. What is Pitot pressure? 2. What is Static pressure? 3. State the list of components of Pitot Static System 4. State the external components of Pitot Static System 5. State the internal components of Pitot Static System 6. What are the Barometric components of Pitot Static System? 7. Where is the Heating Element of Pitot Static System fitted? 8. What is the purpose of Alternate Pressure Sources? 9. What is a Differential Pressure of Pitot Static Systems? 10. Where is the best location to fit Pitot Static Tube/Probe? 11. What is the purpose of Heating Element? 12. What is the purpose of Drain Valve?  Summary 1. Where is the location of Drain Valve? 2. What are the sizes of Pitot and Static pipelines? 3. What is Dynamic pressure? 4. Under ICAO, what are the Standard Atmosphere at MSL? 5. State the Functional Principal of Pitot Static System 6. When we need to do Sense and Leak Check? 7. What precaution/s to be observed on Pitot Static System when the aircraft is on ground? 8. State, the systems or components that uses information from Pitot Static System? Be familiar with the diagram The End of Pitot Static System The next subject is on Barometric Instruments