Q-AFM KEY NOTES Flashcards

Question

Alternate Gear Extension

Answer 1

The landing gear extension INHIBIT switch is installed in the flight compartment ceiling, adjacent to the main LANDING GEAR ALTERNATE RELEASE door. Setting the switch to INHIBIT isolates all hydraulic pressure from the landing gear system. When the main LANDING GEAR ALTERNATE RELEASE door on the flight compartment ceiling is opened, it mechanically opens a bypass valve in the normal hydraulic extension system and gives access to the MAINL/G RELEASE handle. Pulling the handle releases the main landing gear doors and uplocks. The main gear will free fall but may not fully extend. The LANDING GEAR ALTERNATE EXTENSION door, on the flight compartment floor, must then be fully opened giving access to the alternate extension handpump and the NOSE L/G RELEASE handle. Opening the door mechanically operates the MLG alternate selector valve.If the MLG does not reach the down and locked position, the extension pump handle, located behind the co- pilot, is inserted into the pump handle socket and operated to complete main gear extension and subsequent down lock (Figure 6.13-22). Both the LANDING GEAR ALTERNATE EXTENSION door and the MAIN LANDING GEAR ALTERNATE RELEASE door must be left fully open after alternate landing gear extension. When the NOSE L/G RELEASE handle is pulled, the nose gear uplock and doors are released and the nose gear free falls to a down and locked position, assisted by the airflow to a down and locked position. Illumination of the appropriate gear locked down advisory lights (green), in either the primary or alternate panel, is sufficient to conclude that the landing gear is down and locked.

Answer 2

If a fire is detected, the APU automatically shuts down and the fire extinguishing agent is released after 7 seconds. If automatic fire extinguisher discharge fails, the BTL ARM light stays on. The guarded EXTG Switchlight can be pushed to discharge the fire extinguishing agent, if the BTL ARM is on.

Answer 3

The spoilers operate in proportion to, the up going aileron to provide roll control. Turning either the pilot's or copilot's control column, operates the spoilers and ailerons at the same time. The # 1 hydraulic system powers the inboard spoilers and # 2 hydraulic system powers the outboard spoilers (Figure 6.8-21). At airspeeds greater than 170 KIAS, only the inboard spoilers operate, the Flight Control Electronic Control Unit (FCECU) disables the outboard spoilers. At decreasing airspeeds less than 165 KIAS, inboard and outboard spoilers operate. If the outboard spoilers are not disabled above 185 KIAS or activated below 150 KIAS, the SPLR OUTBD caution light turns on.Pushing either SPLR1 or SPLR2 switchlight, inhibits hydraulic pressure to its related spoiler PCU extend ports. This turns on the ROLL SPLR INBD HYD or ROLL SPLR OUTBD HYD caution light. The continuous hold down pressure returns the related spoilers to the down position.

Answer 4

There are 2 lift-dump valves in the inboard spoiler system and 2 in the outboard spoiler system for ground spoiler operations. The lift-dump valves in each spoiler system, are hydraulically in series; both valves mustopen together before the spoilers can extend on the ground. When the lift-dump valves are energized open, hydraulic input commands are sent to the PCUs which fully extend both inboard and outboard spoilers.The lift-dump valves are energized by signals from the FCECU and the Proximity Sensor Electronic Unit (PSEU). For the spoilers to extend on landing, the FCECU and PSEU must receive valid input signals before energizing the lift-dump valves (Figure6.8-22).

Answer 5

The Dash 8-Q400 is powered by two Pratt & Whitney PW150A turboprop engines. Each engine drives a six bladed, constant speed, variable pitch, fully feathering Dowty R408 propeller through the engine gearbox. The powerplant develops 4,580 Shaft Horse Power (SHP) under normal take-off conditions. An automatic uptrim on a manual MTOP rating selection allows either engine, to develop a maximum take-off power of 5071 SHP, for a brief period of time, if an engine failure occurs during take-off.

Answer 6

``` An accessory gearbox mounted on top of the engine is driven by the high pressure compressor rotor NH, and operates: • Oil Pressure and Oil Scavenge Pumps • High Pressure Fuel Pump • Permanent Magnet Alternator (PMA) • DC Starter / Generator ```

Answer 7

The primary source of electrical power for the engine control system is the engine mounted Permanent Magnet Alternator (PMA). The PMA has independent coils that provide electrical power to the individual channels of the FADEC when gas generator speed (NH) is above 20% minimum. The aeroplane essential power busses provide alternate electrical power to the FADEC for engine starting and in the event of a PMA malfunction.

Answer 8

During an engine take-off, an Automatic take-off Power Control System (ATPCS) augments the power of the engine, without pilot intervention, in response to a loss of power of the opposite engine. This function is also referred to as "Uptrim". The working engine's FADEC will respond to the Uptrim signal from the failed engines PEC/AF unit by changing engine rating from NTOP to MTOP. The working ATPCS is armed when both PLAs are "high" and local torque engine is "high". If an engine fails (i.e. engine torque is "low") an Uptrim signal is commanded by the failed engine PEC to theworking engine FADEC. The working engines power is increased 10%. An Uptrim condition is indicated to the pilot by: • the UPTRIM indication on the ED • a change in the engine rating from NTOP to MTOP • a change in the torque bug from NTOP to MTOP

Answer 9

Engine Emergency Power is achieved by advancing the Power Levers above the Rated Power detent position, in the overtravel region. Both the engine control and propeller control systems are affected. In the over travel region, engine power increases linearly from Rated Power to 125% of MTOP, propeller speed increases to 1020 RPM regardless of Condition Lever setting. This speed is latched until Power Levers are returned to the Rated Power detent, or below, and the Condition Levers are selected to MAX/1020, or START/FEATHER or FUEL OFF.

Answer 10

The Torque Limiting Logic in the FADEC prevents engine torque from exceeding a given threshold which is function of PLA and ambient conditions. Generally torque is limited to 35% in reverse, 106% in the forward power range, and 125% in the overtravel range. However, during such events as caused by a spurious feathering of the propeller at high power, the transient overtorque can exceed this steady state threshold. The FADEC uses anticipation in this control loop to rapidly reduce NH to prevent overtorque in exceedance of 135%

Answer 11

Engine starting is accomplished using the STARTER/GENERATOR in conjunction with the ignition and fuel control systems. The STARTER/GENERATOR rotates the High Pressure (NH) compressor through the accessory gearbox, to develop the necessary airflow and engine RPM before fuel is introduced. The start system is armed by selecting the engine to be started on the ENGINE START panel and turned on using the switch. The start sequence is initiated by pressing the START switchlight and selecting the condition lever to the START &FEATHER position at the first indication of NH. Once the start has been initiated, the FADEC controls the starting sequence in the following manner: * When the STARTER/GENERATOR has increased NH speed to 8%, the FADEC commands ignition on and schedules fuel flow as a function of NH, ambient temperature and ambient pressure. * Only one of the two ignitors is turned on (this is to identify any failures in the dual channel ignition system). If the engine does not light-off within 8 seconds of fuel flow being selected on, the FADEC turns on both ignitors, and starts a count towards logging a fault against the faulty igninition. Light-off is defined as anincrease of 20°C in ITT. * When NH is greater than 50%, the ignitor(s) is automatically turned off. * The FADEC controls engine run-up to the requested NH speed or power. During ground starts, to ensure that the engine start does not cause overtemperature, the FADEC has active ITT limiting to reduce the fuel flow if required (below the standard start schedule).

Answer 12

If a jam occurs in a rudder PCU, the corresponding RUD 1 or RUD 2 PUSH OFF switchlight turns on. The illuminated RUD 1 or RUD 2 switchlight must then be pushed to depressurize the affected PCU. The PUSH legend will go out and the OFF legend will remain on as a reminder that the switchlight has been pushed OFF. The # 1 RUD HYD or # 2 RUD HYD caution light will turn on as the PCU is depressurized. The FCECU will reschedule the regulated hydraulic pressure to the operative PCU to maintain the required rudder authority. As directed by paragraph “Rudder Actuator Malfunction” of the AFM - “Abnormal Procedures”, only one RUD PUSH OFF switchlight shall be pushed at a time. If both RUD 1 and RUD 2 PUSH OFF switchlights are pressed inadvertently, the OFF legend will go out, both RUD 1 and RUD 2 PUSH legends will turn on and the previously depressurized PCU will be re-pressurized. This ensures the rudder control system remains powered. Pushing the non-jammed switchlight again turns out both PUSH legends, de-pressurizes the jammed PCU and turns on the appropriate OFF legend on the jammed side. If instead the jammed side switch is pushed, the jammed side RUD PUSH OFF light will turn on while the non-jammed side will be depressurized and its corresponding OFF legend will turn on. When the aircraft is parked on the ground with engines not running, one or both RUD 1 and RUD 2 PUSH OFF switch lights may be illuminated under conditions of strong tailwinds. This is a result of the rudder PCU bungees being compressed when the rudder is moved to one side under the influence of the wind. As soon as hydraulic pressure is available to the PCU following engine start, the rudder will center and the RUD PUSH OFF switchlights will go out.

Answer 13

A Ground Power Unit (GPU) can be connected to the DC external power receptacle (Figure 6.5-18) on the left side of the forward fuselage. The GPU can supply DC power for the airplane EPGDS and for engine starting (Figure 6.5-17). Contractors connecting the main and aux bateries to the main buses are closed automatically upon selection of engine start, as the main and auxiliary batteries assist in the start. The standby battery is diode isolated from the left main, to ensure an acceptable level of voltage on the ESS Busses during the starting process. When the starting process is terminated the power source is still the external power. While DC external power is connected to the airplane, the generators connections to the main buses is inhibited by the EPCU. The main and auxiliary batteries stay connected to the main buses and the standby battery is reconnected. Once the DC EXT PWR switch is turned off after engine start, the generators will come on line if the GEN switches are in the ON position. Both vertical bus ties connecting the main to the secondary buses will remain closed until DC power is available from the TRUs. The EPCU incorporates external DC power protection from too high or too low supply of external DC power voltage. If the external voltage is more than 31+ 0.5 / - 0.75 VDC, or less than 22 ± 1 VDC, an over / under voltage condition will cause the external ground power to stop supplying electrical power to the airplane. If the external power over / under voltage is rectified, the external power source can be reselected by moving the DC EXT PWR switch to OFF and then to EXT PWR.

Answer 14

Pitch control of the airplane is maintained by 2 mechanically controlled and hydraulically powered elevators (Figure 6.8-23). The elevators are attached to the trailing edge of the left and right horizontal stabilizers. The left control column operates the left elevator and the right control column operates the right elevator. However both control columns are connected to each other by the pitch disconnect system so that they both operate together. Fore and aft movement of the pilot's and co-pilot's control columns is transferred through 2 fully independent cable and pulley control circuits to the elevator Power Control Units (PCU). There are 3 identical hydraulic PCUs (outboard, centre and inboard) on each elevator. The outboard and centre PCUs on each elevator are active at all times while the inboard PCU is a standby. The # 1hydraulic system supplies power to the left and right outboard PCUs. The # 2 hydraulic system supplies power to the left and right centre PCUs. The standby # 3 hydraulic system supplies power to the left and right inboard standby PCUs when required. The HYD # 3 ISOL VLV pushbutton on the HYDRAULIC CONTROL panel when pushed, manually activates the inboard PCUs. This will cause the ELEVATOR PRESS caution light to turn on if the # 1 and # 2 hydraulic systems are functioning. The # 3 isolation valve will also activate automatically when # 1 and / or # 2 hydraulic system fails. Pitch trim is accomplished by two pitch trim actuators. The actuators are controlled automatically by the autopilot or manually by the trim switches on the pilot's and co-pilot's control column. Elevator trim position is shown on the elevator trim indicator located on the left side of the centre console. If a mismatch occurs between the left and right elevator an ELEVATOR ASYMMETRY caution light comes on. Elevator position indication is displayed on pilot’s Multi-Function Display (MFD). Gust protection for the elevators is supplied by trapped hydrau- lic fluid within the actuators when the system is depressurized.

Q-AFM KEY NOTES Flashcards

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