Crew Compartment HCR Flashcards
To learn and understand the crew compartment equipment
How many and what categories are the instrument systems divided into?
There are 4
1. Flight Instruments
2. Navigation
3.Propulsion
4. Miscellaneous
What instruments/systems, are included in the flight category?
1.Pitot / Static system
2. Airspeed Indicator
3. Altimeter
4. Turn & Slip Indicator
5. Vertical Speed Indicator.
What instruments are included in the navigation category
Magnetic compass
What instruments are included in the propulsion category
- Dual Tacho (RRPM/NP)
- Gas Producer (Ng)
- Measured Gas Temperature (MGT)
- Engine Oil Temp / Pressure
- Transmission Oil Pressure / Temp indicator
- Fuel Quantity indicator
- Fuel Pressure and Amps Indicator
What instruments are included in the miscellaneous category
- Clock/OAT/Voltmeter
- Engine Hour meter
What material is the static and pitot internal and drain lines made of?
Aluminum
What does the pitot heat switch do?
Activates the heater elements for the pitot and static lines
What is the PRCU and what is the purpose
PRCU is the Pedal Restrictor Control Unit and receives pitot airspeed inputs to control the electrical stop solenoid.
How does the PRCU work
When airspeed is 55 +-5 KIAS or GREATER the
PRCU electrically energises the solenoid which engages a mechanical restrictor and limits the left pedal travel and operates pedal stop caution light.
When airspeed is 55 +- 5 or LESS the PRCU
de-energises the solenoid and spring pressure retracts the mechanical restrictor and left pedal is returned to normal.
How does an electrical failure effect the PRCU
Solenoid is fail safe and restrictor is retracted with full left pedal available.
How does the Air Speed Indicator work
The IAS gauge reads airspeed by measuring the difference between impact air from pitot tube and static air pressure from the static ports.
How does the Altimeter Work
The altimeter pressure reads altitude above MSL when Kollsman window (barometric pressure setting) is adjusted to reflect the current barometric pressure at sea level for that location.
Blocked pitot tube is indicated by what and what are the hazards
If Pitot tube is blocked and drain hole is open then IAS will go to Zero. If both pitot tube and pitot drain is blocked then IAS will remain constant except for change in Altitude will vary due to changing static pressure.
Blocked static vent is indicated by what and what are the hazards
If the static vent is blocked and the pitot unblocked then the ASI reading will be inaccurate with the inaccuracies depending at what altitude the static source was blocked. A blockage of the static source also effets the altimeter and VSI.
Altimeter remains indicating at the altitude where the source was blocked and the VSI will keep reading 0.
How does the turn and slip indicator work?
The turn and slip indicator is a gyroscopic instrument which powers the turn needle by the 28v DC bus through the TURN C/B switch located on the overhead panel - It indicates the rate of turn ie 3deg or 2 min rate of turn when the the needle lines up with the L or R markers indicating left or right turn. It can also indicate a turn greater than or less than a rate 1 turn if not lined up on the L or R markers.
The instrument will also give an indication of a slip or skid in relation to where the tail is in reference to the nose direction of travel.
Describe the NP/NR Tacho gauge
Is a Dual Tacho instrument NR indication is located on the outside scale and NP indication is located on the inside scale. At flight RPM both NR and NP are 100%.
The NP gauge is powered by individual CB located on overhead panel. A NP monopole speed pick up mounted on the engine provides 2 separate signals to the ECU (Electronic Control Unit) One signal is the primary driver of the NP gauge, and is passed through ECU, even when ECU is not powered and the second signal is the primary input to the ECU.
The NR (rotor) side of the gauge is powered by 28v DC bus through its own CB also located on the overhead panel adjacent to the NP C/B.
An NR monopole speed pickup mounted on the MR Transmission lower case provides three separate identical signal outputs of the Rotor RPM.
One signal is sent to the NR circuit of the dual Tacho gauge, one signal is sent to the ECU and the other is sent to the MR RPM switch.
Describe the MGT gauge.
The Measured Gas Temperature indicator displays engine gas temperature between Gas producer turbine and the Power turbine via 4 probes. The MGT gauge is powered by the 28v DC bus through its own CB on the Overhead panel. The MGT gauge can determine and record 2 separate exceedance levels, one for starting and the other for normal operations.
Describe the Engine Oil pressure/Temperature gauge.
The engine oil pressure /temperature indicator displays oil pressure in PSI on the left side of the instrument and oil temperature in degrees C on the right side. This info is displayed on the trend arcs.
The 28v DC bus powers each side of the indicator through their own
CB’s
The engine oil temperature input signal is provided by a thermo-bulb installed on the engine oil tank. A transducer mounted on the forward right side of the engine firewall provides engine oil pressure.
Describe the Transmission Oil pressure/Temperature gauge.
oil pressure is measured in PSI on the left side and oil temperature in deg C on the right side of gauge.
28v DC supplies the gauge through individual CB’s locate on the overhead panel.
Transmission oil temp input signal is provided by a thermo-bulb installed on the transmission oil filter manifold.
Transmission oil pressure PSI indication is provided via a transducer which is mounted on the transmission deck oil manifold.
Describe the Fuel gauge instrument.
The fuel quantity indicator displays TOTAL fuel quantity in pounds from three quantity probes located in the fuel cells. The fuel quantity gauge is powered by 28v DC through its own separate CB.
The fuel Quantity gauge indicates the Total USEABLE fuel in both tanks. If an Aux tank is fitted the quantity is automatically calcualted into the aft tank quantity.
Pressing the FUEL QTY TANK button indicates fuel in the forward tank only.
Describe the Fuel Pressure/Ammeter gauge
The fuel pressure/DC ammeter gauge displays fuel pressure in PSI on the left side and DC current load on the Generator on the right sideof the instrument.
Fuel pressure is measured from a pressure transducer located below the fuel valve and measures the output pressure of both boost pumps.
The ammeter indicates the load in amps that is being supplied to the 28vDC bus by the generator. Each side of the gauge is powered by the 28v DC bus through it’s own CB’s.
describe the clock/OAT and Voltmeter
This is a multifunction indicator which is powered by 28v DC through its own CB. When Batt switch is turned on the gauge should default to Volts mode and displays volts at the bus. The red button toggles between OAT and volts.
The flight time feature FT is activated when the aircraft is in flight, ie weight off gear.
Describe the engine hour meter
The engine hour meter is mounted in the battery compartment and is powered through it’s own C/B. The system is activated when NG is greater than 55% and the aircraft is in flight (ie weight off gear)
What gauges are able to record exceedances/ events? How many exceedances and events can be recorded?
The TQ, MGT & NG gauges are able to record up to 50 events and exceedances