DA42 Flashcards
DA42 NG dimensions (span, length)
- span:13.42m
- lenght:8.56
DA42 mass (empty, MTOW, MAX RAMP, MZFW, MLW)
BEM: 1450 kg
MTOW: 1900KG
MAX RAMP: +8KG
MZFW: 1765kg
MLW: 1805KG
max baggage load ( nose, standard compartment)
nose: 30kg
standard compartment: 45kg
typical fuel weight (JETA1, DIESEL kh/ltr)
JET A1= 0.8kg/ltr
diesel= 0.84kg/ltr
VNO (max structural cruising speed)
151kts
VNE (never exceed speed in smooth air)
188kts
V0 (operating maneuvering speed)
(dont make abrupt or full control surface movement above this speed)
1700kg, 1800kg, >1800kg
V0- 1700 kg- 112kts
V0- 1800 kg- 119kts
V0- >1800 kg- 122kts
VYSE (blue line speed)
85kts
VS0 (stall speed in landing config)
62kts
VS1 ( 1g Stall speed)
69kts
VMCA FLAPS UP (minimum control speed airborne)
76kts
VMCA FLAPS APP ( minimum control speed airborne)
73kts
VFE (APP) (max flaps extended speed)
133kts
VFE (LDG) (max flaps extended speed)
113kts
Vloe extension (max landing gear operating speed)
188kts
Vlor retraction (max landing gear operating speed)
152 kts
Vle (max landing gear extended speed)
188kts
Vref FLAPS UP (approach speed)
86kts
Vref FLAPS APP (approach speed)
84kts
Vref FLAPS LDG (approach speed)
84kts
white arc speeds (operating range flaps extended)
62-113kts
green arc speeds (normal operating range)
69-151kts
yellow arc speeds ( caution range only in smooth air)
151-188kts
DA42 Powerplant description
- 2 E4B austro-engines
- inline 4 cylinder, liquid cooled, 4 stroke diesel engines
- common rail, direction injection
- reduction gear
- dual digital engine control
- turbo charger
- torsion vibration damper isolates engine from prop
DA42 RPM limitations ( max takeoff, max continuous, max overspeed)
max takeoff- 2300 rpm, 5mins, 100%
max continuous- 2100 rpm, 92%
max overspeed- 2500 rpm, max 20 secs
DA42 oil pressure, quantity, consumption, temperature)
oil pressure: 2.5-6 bar
quantity: 5-7 Litres
consumption: 0.1 ltrs/hr
temperature: -30 to +140
DA42 coolant temp (min at startup, min full load, max)
min startup: -30
min full load: + 60
max: 105
DA42 fuel temp and pressure
Temp min: -30
Temp max: +60
pressure min: 4 bar
pressure max: 7 bar
DA42 fuel quantity (total + usable in main tanks, aux tanks)
total main: 2 x 26 USGAL
usable main: 2 x 25 USGAL
total aux: 2 x 13.7 USGAL
useable aux: 2 x 13.2 USGAL
max permissible unbalance between LH and RH tank
5 USGAL
describe the fuel system
- 4 fuel tanks; 76USGAL usable Jet A
- 2 main tanks; 25 USG usable each
- 2 aux tanks: 13USG usable each
- main tanks made of aluminium and composed of 3 chambers joined by rubber hoses
- aux tanks made of aluminium with baffles on the inside to prevent rapid fuel movement
how much does jet fuel weigh at standard temperature?
7.01 lbs @15 degrees
what temperature does JET A freeze
-40
describe the main fuel tanks and their components
- main tanks aluminium,: 3 chambers joined by rubber hoses
- fuel quantity probes in inner and outer chambers
- outer chamber: fuel filler, PRV, check valve (tank vent), fuel level shutoff switch (stops aux transfer pump when tank full)
- inner chamber: fuel temp sensor, low level fuel sensor, fuel supply and return connections
how do the low level fuel sensors work
- float based; float drops with decreasing fuel
- at 3 to 4 USG float operates a microswitch activating the low fuel indication on the cockpit
why should the engines not be shutoff by moving fuel selectors to off
causes damage to high pressure fuel pump
with fuel selector in the on position, what is the flow of fuel
- low pressure engine driven pump draws fuel from main tank , through fuel filter and then to the high pressure pump which feeds the common rail injection system
with the fuel selector in the Xfeed position, what is the flow of fuel
- moving fuel selector to xfeed disables flow to and from associated tank
-engine pump takes fuel from opposite tank - returned fuel is supplied back to the tank from which it was taken
- fuel will flow through the cooler from which it was taken
if the RH engine has failed, how do you get fuel from the right tank
- set left fuel selector to Xfeed
why is a fuel cooler necessary on this aircraft
- fuel is compressed to a high pressure thus heated
- excess fuel not used in the common rail injection system needs to be cooled to prevent it turning into vapor, causing vapor lock
how do you use fuel from the AUX tanks
- turn on AUX transfer pumps; transfers fuel to the main tanks via the main fuel return line after the fuel cooler
- fuel passes through the fuel filter, then aux fuel pump then pressure check valve
- pump shuts off when fuel level too low or main tank full
how fast do the AUX fuel transfer pumps transfer fuel
1GAL per minute
how do you know when AUX tanks have finished transferring
- caution on PFD: “L/R AUX FUEL E”
- transfer pump must be turned off now
-will take about 13 minutes
how much fuel is supplied to the engine and how much is actually burned
- 20 USGAL/hr fed to high pressure pump
- approx 7USGAL/hr actually consumed
what happens to excess fuel not consumed
- approx 13 gallons per hour routed through fuel cooler back to main tank inboard section
how many fuel pumps are there
- 6
- 1 LP engine driven pump per side: supplies fuel to engine
-1 High pressure pump per side: provides pressure to common rail - 1 aux pump per side: transfers fuel from aux fuel tank to main
describe fuel flow when the right fuel selector is set to ON
- right engines low pressure engine driven pump draws fuel from the right tank through a fuel filter then feeds fuel to a high pressure pump
- high pressure fuel is then delivered to a fuel injector located in each cylinder
- excess fuel from the common rail is routed through the fuel cooler and then back into the right main tank
describe the fuel flow when the right selector is set to X-feed
- right engines low pressure pump draws fuel from the left main tank through the left tanks fuel filter then feeds the fuel through the high pressure pump
- excess fuel from common rail is routed through the left ide cooler then back into the left main tank
how can aux fuel be consumed and when is aux pump switched off automatically?
- aux fuel can only be transferred to the main tank on the same side using the aux transfer pump
- initiated in 2 steps: 1st half when main tank 17 USG or less
2nd half when main tank 17 USG or less
aux pump switched off automatically when:
- main tank full
- aux tank empty
what happens if aux transfer pumps are turned on but the main tanks are already full
- a shutoff sensor on the outboard segment of the main tank deactivates the aux transfer pump until there is sufficient room in the main tank for transfer to occur
is fuel in the aux tank heated
- no; fuel is returned only to the main tanks not the aux tanks
what kind of fuel can you use in the aux tanks
JET A only
are there fuel gauges in the aux tanks
no
can you use JET A with the additive PRIST
yes
describe the electrical system of a DA42
- 28 V DC system
- powered by two 28 V 70 amp engine driven alternators mounted on left side of each engine
- main battery: 24 V 13.6 Ah battery. battery relay is controlled with electric master switch on instrument panel
- non rechargeable battery: provides emergency power to STBY AI and panel floodlight (1.5hr)
- each alternator has alternator control unit which monitors and controls its output
- under normal conditions, alternator voltage is shown on the voltmeter
- ECU backup battery: two 12V backup batteries provide 30 mins of engine operation in case of complete electrical failure
what is the HOT BAT BUS used for
pilot map / reading light
what does the LH main bus supply
- PFD, ADC, AHRS, COM1, GPS/NAV1, transponder, engine instruments, pitot heating, oxygen system, gear control, gear warning, map light, flood light, taxi light, anticol lights
What does the RH main bus supply
- avionics bus, mfd, horizon, starter control, flap system, avionic/CDU cooling fan, stall warning, autopilot warning, landing light, nav lights, instrument lights
what does the avionics bus supply
- com2, gps/nav2, audio panel, autopilot, data link, wx500, ADF, DME, weather radar
purpose of the electrical master
- connects BAT BUS to BAT (BAT BUS powers L/R MAIN BUS)
- enables alternator switches
purpose of L/R alternator switch
- connects L/R alternator to L/R main bus
(in normal ops, alternator switches are always on)
purpose of L/R engine master
- enables starter activation
- connects L/R ECU (A+B) to L/R ECU BUS
- provides power for “GLOW” and unfeathering accumulator
- connects L/R alternator field to the ECU backup battery
capacity of the ice protection system (max, usable and minimum for dispatched)
- max: 31.5 litres (8.3 USG)
- usable: 30 litres (7.9 USG)
- minimum for dispatch: 22 litres
what are the two means of FPD (freezing point depressant)
- spray nozzles ( windshield, propeller)
propeller: -feeding into a “slinger ring”
-feeder tube to leading edge - porous skin panels
what are the anti-icing fluids used
Glycol Based Fluid
-AL5 and Aeroshell compound 7
what system powers the anti-icing system
- electrically powered from the LH MAIN BUS
what provides engine and airframe anti-ice protection
- provided by 2 electric pumps that feed fluid through filters to proportion units located in each engine nacelle and tail of the aircraft
what do proportion units do
- regulate flow of fluid to porous panels attached to leading edge of wings, horizontal stabiliser, fin and slinger rings at each propeller
what do porous panels do
weep fluid over the airframe leading edge surfaces
what force spreads anticing fluid on the prop
centrifugal forces
do the airframe, prop and windshield utilise the same deicing system
- no airframe and propeller are grouped together
- windshield deicing is a seperate system and operates independently
- all systems draw fluid from a common tank
how long does airframe anticing last with NORM, HIGH and MAX and what pumps operate
- NORM: 2hr 30min (both pumps simultaneously cycled on/off by 30sec ON, 90 OFF)
- HIGH: 1 hr ( only the selected main pump runs continuously)
- MAX: 30 min (both pumps simultaneously for 2 minutes)
NORM, HIGH, MAX colours and fluid cycling duration
NORM: lower white light only (cycled 30secs ON, 90 secs OFF)
HIGH: centre amber light only (continuous fluid flow)
MAX: BOTH (top¢re) amber lights
how many fluid filters are installed in the nose compartment and what is their purpose
- 2; prevent proportioning units from fouling
how many low and high pressure sensors are there in the airframe ice protection system and whats their purpose
- 3 Low pressure sensors: detect system malfunctions
- 1 High pressure sensor: activates indication when cartridges need replacing
summary of how the airframe/prop ice protection works
- active main pump feeds deicing fluid through filters to the proportioning units in each engine nacelle and horizontal and vertical tail
- proportioning units regulate flow to porous panels and propeller slinger rings via capillaries
-nozzles and slinger rings on propeller: nozzle sprays fluid onto the slinger ring mounted on the spinner backplate which is then distributed to the prop blades via centrifugal force
what does the windshield ice protetction system consist of and how does it operate
- 2 windshield deicing pumps installed in the nose compartment
- 1 deicing fluid spraybar for the canopy
- active windshield deicing pump suppies fluid to the spraybar
-1 deicing pump is operative at a time; switch in the cockpit selects the active pump (1 or 2); second installed for redundancy
does the windshield deicing system spray fluid continuously
- no; activated for 5 seconds by operating a push button
when is deicing fluid considered to be low
below 10 litres
what is the minimum operating temperature for the ice protection system
minus 30 degrees
what defines icing conditions
- visually detect ice
- visible moisture and OAT is +3 degrees or below
can you use autopilot during icing conditions
- Yes but disconnect every 10-15 mins to detect out of trim conditions
can you operate FLAPS LDG in icing conditions
- no: flaps ldg prohibited in icing conditions or with residual ice
- intentional 1 eng operation under known or forecast icing conditions is prohibited
what performance class is the DA42
- propeller driven, mopsc max 9, weight <5700kg
- PERFORMANCE CLASS B
max demonstrated x wind component DA42 (UP, APP, icing conditions)
flaps UP: 25kts
flaps APP: 20 kts
icing: 20kts
describe the landing gear of the DA2 and how hydraulic power is provided
- hydraulically operated fully retractable tricycle landing gear
- hydraulic pressure provided by an electrically powered hydraulic pump, activated by a pressure switch when required pressure is too low
- electrically actuated hydraulic valves, which are operated with the gear selector switch provide the required hydraulic pressure for the movement of landing gear
describe the movement of the landing gear when retracted
-main wheels retract inboard into the centre wing
- nose wheel retracts fwd into the nose section
what is the purpose of the squat switch on the landing gear
- prevents retraction on the ground
how long does gear extension take
6-10 seconds
what is the LH squat switch responsible for
- on ground landing gear protection
what is the RH squat switch responsible for
- stall warning heating
- engine preglow
- ECU test
- TAS voice warning
what keeps the landing gear in a retracted position
- hydraulic pressure on the actuators
- one actuator is fitted to each landing gear assembly
- a pressurized gas container acts as an accumulator which keeps system pressure constant and prevents continual starting and stopping of hydraulic pump
what assists the hydraulic system in gear extension
- springs assist in gear extension and locking the gear in down position
- after gear is down and downlock hooks engage, springs maintain force on each hook to keep it locked until its release by hydraulic pressure
what do green and red lights signify on landing gear
- green: gear down and locked
- red: gear neither down or up
when would you get the landing gear aural warning
- GEAR UP and
- one power lever below 20% or flaps LDG
how would you emergency operate the landing gear
- gear held hydraulically thus emergency operation by
-FREEFALL BY RELEASING HYDRAULIC PRESSURE
Nosewheel steering: rudder pedal turning allowance and differential braking allowance
- rudder pedal; 30 degrees either side of centre
- differential braking: 52 degrees
- on retraction the nose wheel is automatically centred and the steering linkage disengaged to reduce rudder pedal loads
describe how the hydraulic brakes operate
- main wheels fitted with hydraulic disc brakes operated by toe pedals fitted to the rudder pedals
- hydraulic fluid for brake operation is independent to the hydraulic retraction system
- stored in 2 resevoirs fitted to the co pilots brake pedal actuators
describe the oxygen system
- continuous flow system
- operation upto 18,000ft
- oxygen cylinder pressure: max 1800 PSI at 21 degrees
- 4 cannulas plus 1 mask
how are the ailerons and elevators actuated
push rods
how are the flaps acuated
electrically by push rods
how are the rudder actuated
cables
how are both the rudder and elevator trim acuated
via bowden cables
describe the variable elevator stop
- normal elevator up deflection; 15.5 degrees
- limited to 13 degrees up when both power levers above 20% (approach power setting)
- reason: with full elevator deflection in case of stalling the handling qualities and stall characteristics are degraded
- preflight check of this device mandatory!
- “STICK LIMIT” caution when variable stop not in proper postion
ECU basics
- ECU voter switches
- 3 position switches
- normally in auto
- working ECU automatically selected according to operating hours in case of malfunction
describe the propeller of the DA42 ( prop type, how is prop pitch set, how governor is operated etc)
- 3 blade wooden propeller
- constant speed, feathering
- prop pitch set by ECU via an electro mechanical actuator on the governor
- governor operated by gearbox oil: oil pressure up=pitch down= rpm up
oil pressure down= pitch up= rpm down
when does the prop feather
- feathering by “Engine Master OFF” if rpm above 1300
- feathers when gear oil pressure is lost
- if rpm below 1300 rpm: prop pitch remains above high pitch lock
how does unfeathering with an unfeathering accumulator occur
- by oil pressure from accumulator when engine master is on
how does unfeathering without an unfeathering accumulator occur
- by building up system oil pressure when cranking the starter
what are the max engine restart altitudes and when shouldnt you attempt a restart
- 18,000 for immediate restart
-10,000 for restart within 2 minutes - no restart attempt if shutdown more than 2 mins
starter limitation: normal operation on ground (time and cool down time)
- max 10 seconds
- 60 seconds cool down time
starter limitation: restarting in the air (time, cool down time and max attempts)
- max 5 seconds
- 30 secs cool down time
- max 3 attempts
