Study Guide Questions Flashcards
Recite all the V-speeds from memory.
- VSO (Stall, LDG flaps) ≈ 62 KIAS
- VS1 (Stall, flaps UP) ≈ 69 KIAS
- VMCA (Min control speed) 73–76 KIAS (depending on flap config)
- VR (Rotation speed) ~76 KIAS (Flaps APP short field) or ~80 KIAS (Flaps UP normal)
- VX (Best angle climb, both engines) ≈ 82 KIAS (Flaps APP)
- VY (Best rate climb, both engines) ~85 KIAS (Flaps APP) or 90 KIAS (Flaps UP)
- VYSE (Best single-engine climb, “blue line”) ≈ 85 KIAS
- VFE(APP) (Max flaps APP) = 133 KIAS
- VFE(LDG) (Max flaps LDG) = 113 KIAS
- VLOE / VLE (Max gear extension/extended) = 188 KIAS
- VLOR (Max gear retraction) = 152 KIAS
- VNO (Max structural cruise) = 151 KIAS
- VNE (Never exceed) = 188 KIAS
- VO (Maneuvering) ~112–122 KIAS (weight-dependent)
What material is used to construct the airframe and flight controls?
- Primarily carbon fiber–reinforced plastic (CFRP) and glass fiber–reinforced plastic (GFRP) in a sandwich configuration.
- Fuselage is CFRP semi-monocoque.
- Wings, control surfaces (ailerons, elevator, rudder, flaps) are GFRP/CFRP sandwich.
What is the DA42’s wingspan?
The DA42 NG wingspan is approximately 44.0 ft
How are the ailerons, elevator, and rudder actuated?
- Ailerons and elevator are actuated via push rods (sometimes called control rods).
- Rudder is actuated via cables.
Does the DA42 have elevator and rudder trim?
Yes. Each has a trim tab:
* Elevator: mechanically linked trim tab, adjustable via a trim wheel near the power levers.
* Rudder: adjustable tab via a trim knob or wheel on the center console.
Why is lightning protection required for the DA42?
Because the DA42 is built from composite materials (not inherently conductive like metal), it needs embedded or installed lightning protection (mesh/strips) to safely conduct and dissipate lightning strikes and protect occupants.
What is the elevator friction dampener and why is it needed?
A friction device (sometimes called a dampener) is installed in the elevator control or trim mechanism to reduce unwanted freeplay or “flutter” and to prevent unintended elevator trim movement. It ensures smooth, stable control inputs.
What does the variable elevator backstop do and how is it actuated?
- It limits the maximum elevator-up deflection to about 13° (rather than 15.5°) when both engines’ power levers exceed ~20% power.
- Two microswitches on the power levers signal the system. An electric actuator physically limits elevator travel.
- When you reduce power below ~20% on either engine, the backstop deactivates, restoring the full 15.5° up-elevator.
How many hinges are on each flap?
Each wing flap on the DA42 has multiple hinges. Typically, the AFM notes 6 hinges on the outer portion and 4 on the inner portion for a total of 10 hinges per side. (Different references might show them collectively as 4 or 5 hinges per flap panel, but 10 total per side is common.)
How many doors are there on this aircraft?
- The forward-opening canopy (pilot/copilot)
- Rear passenger door on the left side
- Left nose baggage door
- Right nose baggage door
What makes the flaps extend and retract?
An electric motor (driving a jackscrew or pushrod system) controlled by a three-position flap switch (UP, APP, LDG). When the flap switch is moved, the motor runs until the flaps reach the selected position.
What are the possible flap settings?
- UP (Cruise)
- APP (Approach)
- LDG (Landing)
What flap settings are allowed for takeoff? For landing?
- Takeoff: UP or APP are allowed (APP is commonly used for short-field).
- Landing: LDG is standard for normal landings, though APP can be used if conditions require a flatter approach.
Can the flaps be extended if the electrical system has failed?
No. The flaps depend on the electrically driven flap motor. There is no mechanical backup. If total electrical power is lost, the flaps will remain in their last position.
Describe the stall warning system.
- An electrically powered stall warning switch on the left wing leading edge.
- When nearing the critical angle of attack, it triggers an aural alert in the cockpit.
- There is also a heating element (part of the Pitot/Stall Heat switch) to prevent ice on the sensor.
Describe the landing gear.
- Fully retractable, hydraulically operated tricycle gear.
- Each gear leg has an oleo-pneumatic shock strut.
- Mains retract inboard, nose retracts forward.
- Electric pump pressurizes hydraulic fluid to raise gear; extension is aided by springs.
What makes the landing gear extend and retract?
An electrically powered hydraulic pump supplies hydraulic fluid pressure. The gear selector energizes valves that direct fluid to actuators, raising or lowering the gear.
What is the purpose of the landing gear hydraulic accumulator?
A pressurized container that helps maintain system pressure, preventing continuous pump cycling. It compensates for minor leakage or pressure variations once the gear is up.
How can you test the landing gear indicator lights?
By pressing the “gear test” button (often near the gear selector). All gear indicator lights (three green, one red) should illuminate, and you get the aural warning tone.
What keeps the gear from being retracted while on the ground if the gear selector is set to the UP position?
A squat switch on the nose gear prevents the hydraulic valve from energizing while weight is on the nose gear. If the gear selector is accidentally moved to UP on the ground, the gear stays down.
What three conditions cause the gear warning horn to sound?
- One/both power levers below ~20% power, gear not locked down.
- Flaps set to LDG, gear not locked down.
- Gear handle up on the ground (squat switch logic).
Describe the manual gear extension procedure.
- Reduce speed below 152 KIAS.
- Gear selector to DOWN.
- Pull the Emergency Extension Handle fully out to release hydraulic pressure.
- Let the gear free-fall and lock.
- Leave handle out until after landing.
Describe the brake system.
- Single-disc hydraulic brakes on each main wheel.
- Pilot’s toe pedals control master cylinders.
- Parking brake valve is inline.
- Hydraulic fluid is shared, but each side can optionally have brake pedals.
How do you activate the parking brake?
Press and hold the toe brakes, then pull the parking brake handle (valve) to trap hydraulic pressure. Releasing toe brakes after the valve is locked keeps the brakes engaged.
What is the total usable fuel quantity?
- With main tanks only (2×25 gal): 50 gallons usable.
- With auxiliary tanks as well (2×13.2 gal): additional 26.4 gallons.
- Total = 76.4 US gallons if all four tanks are installed and full.
How many chambers make up each main wing tank? Each auxiliary tank?
- Each main wing tank has three interconnected aluminum chambers.
- Each auxiliary tank (if installed) is a single chamber.
Which tanks have fuel gauges?
Only the main tanks have direct quantity gauges (two capacity probes per tank). The auxiliary tanks do not have direct readouts; instead, an advisory (AUX FUEL E caution) appears if an auxiliary tank is empty.
What grade of fuel is used?
Diesel/Jet fuel:
* JET-A or JET A-1 (ASTM D1655)
* JP-8 or approved equivalents (per the AFM).
Can you feed fuel from the right main tank to the left engine?
Yes. By placing the left engine’s fuel selector to CROSSFEED, the left engine can draw from the right main tank.
How many fuel pumps are there?
- Each engine has two electric low-pressure pumps (4 total).
- Each optional auxiliary tank has one transfer pump (2 more, if installed).
- Plus each engine-driven high-pressure pump.
Commonly we say 6 “electric” pumps (4 low-pressure + 2 aux), plus 2 engi
Why is a fuel cooler required?
Because the AE300 diesel engines return heated fuel to the wing tanks, the system uses a fuel cooler (mounted under each wing) to keep fuel temperature within limits, preventing the tanks from overheating.
Are the main tanks heated? The auxiliary tanks?
No. There is no integral heating for main or auxiliary tanks. The AFM just specifies allowable fuel temperature range (e.g., min –25 °C, max +60 °C). No official “tank heater” system is installed.
Can the engines draw fuel directly from the auxiliary tanks?
No. The engines only draw from the main tanks. The auxiliary tanks each have a transfer pump feeding fuel into the corresponding main tank.
What is PRIST and is its use allowed?
PRIST is an anti-icing (and anti-microbial) fuel additive. The AFM allows it (max ~1500 ppm) in JET A or JET A-1, ideally injected into the fuel stream during fueling rather than poured in the tank.
Where are the aircraft bonding (grounding) locations to be used when fueling?
The left or right engine exhaust pipes are designated as grounding points for static discharge prior to fueling.
Describe the DA42’s engines.
Two Austro Engine AE300 (E4-B) turbocharged diesel engines:
* 4-cylinder, liquid-cooled, common-rail injection, FADEC-controlled.
* Each produces up to ~168 HP (5-min rating) or 152 HP (max continuous) at ~2300 or 2100 prop rpm.
* Reduction gearbox ratio 1:1.69.
Does the G1000 display engine RPM or propeller RPM?
It displays propeller rpm labeled simply as “RPM” on the Engine Indication System (EIS).
What is an ECU (or FADEC)? How many are installed, and how are they powered?
- Each engine has a Full Authority Digital Engine Control (FADEC), called an Electronic Control Unit (ECU).
- Each engine actually has two channels (ECU A and ECU B), so effectively 2 ECUs per engine.
- They are powered by the aircraft electrical system (normally the alternator once the engine is running, or the battery on the ground).
What are the Starter Limitations?
Each start attempt is limited to ~10 seconds. After 3 attempts, a 5-minute cooling period is required. Verify the exact limit in the “Power Plant Limitations” section.
Can the engines continue to run without electrical power?
No. The AE300 diesels rely on their ECU (FADEC) which requires electricity. If both alternators and the battery fail, eventually there’s no power for the ECU, and the engine(s) will stop.
What five things occur when an engine master is turned on?
- Glow plugs energize (if engine is cold).
- ECU powers up and performs self-test.
- Electric governor valve opens.
- Unfeathering accumulator valve opens to supply oil.
- Engine preheat (if required) begins.
What are the engine oil capacity and operating limits?
- Sump capacity ≈ 5 liters (5.3 US qts).
- Recommended minimum is ~4 liters.
- Oil temperature normal range ~50 °C to 135 °C (max 140 °C).
- Oil pressure normal range ~1.5 to ~5.5 bar.
What kind of engine oil does the DA42 use?
Approved multi-grade synthetic or semisynthetic oils meeting ACEA A3/B4 or API CF specs, e.g. “Mobil 1 FS 0W-40” or “SAE 5W-30/40.”
How are the engines cooled?
They are liquid-cooled with a dedicated radiator and thermostat system. Each engine also has a coolant expansion tank and a water/oil heat exchanger.
Where is the coolant level sensor located?
Inside the coolant expansion tank for each engine. If level drops below a threshold, a CAS alert (COOL LVL) triggers.
What do you do if low coolant level and high coolant temperature warnings are both displayed?
- Immediately reduce power on the affected engine.
- Monitor temperature; if it continues rising, be prepared for engine failure.
- Land as soon as practicable (precautionary).
What is the purpose of the intercooler?
It cools the turbocharger’s compressed intake air before it enters the engine, improving density, performance, and efficiency.
Describe the engine fire detection system.
Each engine compartment has an overheat sensor that typically triggers at ~250 °C. A “L/R ENG FIRE” CAS message and an aural warning occur if activated. There is a fire detection test button to verify system integrity.
What is the function of the gearbox?
Each engine drives its propeller via a reduction gearbox (1:1.69 ratio). This allows higher crankshaft RPM than prop RPM. The gearbox also integrates the propeller governor oil circuit.
Describe the propellers.
- Three-blade MT-propellers.
- Wood/composite core with fiber-reinforced plastic sheathing.
- Constant-speed, full-feathering, hydraulically governed.
- An unfeathering accumulator assists re-starts.
How are propeller RPM and blade angle controlled?
A hydraulic governor under the Electronic Control Unit’s authority. Oil pressure adjusts blade pitch to maintain selected RPM. A spring and counterweights drive the blades toward feather if oil pressure is reduced.
What is the CSU and what does it do?
CSU is “Constant Speed Unit,” i.e. the prop governor. It automatically adjusts blade angle to keep a constant prop RPM selected by the ECU/power lever position.
Describe the electrical system voltage, batteries, and sources of power.
- 28 V DC system nominal.
- 24 V main battery (~10 Ah lead-acid).
- Two belt-driven alternators (70A each) on the engines.
- Two small 12 V ECU backup batteries (in series to 24 V).
- External power receptacle for GPU starts.
How would you recognize an alternator failure?
CAS message “L ALTN FAIL” or “R ALTN FAIL,” plus a decreased ammeter reading on that side. Possibly a low voltage alert if the other alternator can’t support the entire system load.
How would you handle an alternator failure?
- Switch OFF the affected alternator.
- Reduce electrical loads.
- Monitor bus voltage on the remaining alternator.
- Land ASAP if both fail (drastically reduce loads and use minimal battery power).
What do the alternator switches do?
They connect or disconnect the alternator field. When ON, the alternator provides power to the main bus. Switching OFF stops the alternator’s output.
How are heat and defrost provided to the cabin?
Engine coolant flows through a heater core (heat exchanger). Cabin and defrost air blow across that core, providing heat. Each engine’s coolant circuit can provide separate heat.
What powers the standby artificial horizon in the event of an electrical system failure?
A dedicated standby instrument battery (often a sealed lead-acid or lithium) that can power the standby horizon for ~1 hour if main power fails.
How many G1000 cooling fans does the DA42 have?
Typically two fans: one behind each display (PFD and MFD). They ensure adequate airflow for internal G1000 components.
Describe the antennae on the DA42.
- Two COM/GPS combined antennae on top of the fuselage (forward = COM1/GPS1, aft = COM2/GPS2).
- Transponder antenna under the belly.
- VOR/LOC/GS whisker or dipole, often on the vertical stab or tail boom.
- Other optional antennas for ADF, DME, etc.
Where are the normal and alternate static sources located?
- Normal static ports: One on each side of the aft fuselage.
- Alternate static source: Inside the cabin, typically under the left side of the instrument panel (cockpit sidewall).
What equipment is required for day VFR? Night VFR? IFR?
- Day VFR: Basic instruments, seat belts, altimeter, airspeed, compass, fuel gauges, engine instruments, etc.
- Night VFR: Day VFR items + position/anticollision lights, instrument lights, landing light (if for hire), adequate electrical power.
- IFR: Night VFR items + IFR-approved navigation, pitot heat, alternate static, heated stall sensor, backup attitude indicator, etc.
How do you handle inoperative equipment?
Follow the KOEL and 14 CFR §91.213. If the item is not required for the intended operation, it can be placarded “INOP” and deactivated. Otherwise, repair or do not dispatch.
What are the maximum takeoff and landing weights?
- Max Takeoff Mass (MTOM): ~1,900 kg (4,189 lb).
- Max Landing Mass: ~1,792 or 1,800 kg (3,950 / 3,968 lb), depending on modifications.
Are maximum landing weight and maximum takeoff weight the same?
No. The max landing weight is typically lower than the max takeoff weight (1,792–1,800 kg vs. 1,900 kg).
What is the zero fuel weight limit?
Commonly 1,700 kg (3,748 lb). Check Section 6 (Mass & Balance) in your specific AFM for the precise approved figure.
What is the combined weight limit for the rear baggage compartments?
Typically 45 kg (99 lb) total, combined. Some AFMs break it down per compartment.
What is VA?
VA (maneuvering speed) is the max speed at which full, abrupt control deflection will not overstress the airplane. For the DA42 NG, it’s about 112–122 KIAS, depending on weight.
What effect does the aircraft’s weight have on VA?
Lower weight = lower VA. Maneuvering speed is lower when the airplane is below max gross weight.
Describe VMC, VY, and VYSE.
- VMC (red radial): Minimum controllable airspeed in a multi-engine with one engine inoperative at max power.
- VY: Best rate-of-climb speed (both engines).
- VYSE (blue line): Best single-engine rate-of-climb speed with one engine inoperative.
Define single-engine service ceiling.
The highest density altitude at which the airplane can maintain a 50 ft/min climb with one engine inoperative (feathered) and the other at max continuous power.
Define maximum operating altitude.
The highest certified pressure altitude for normal operations. For a non-pressurized DA42 NG, typically 18,000 ft (FL180) per the AFM.
Describe the procedure for identifying an engine failure.
- Maintain directional control with rudder.
- “Dead foot, dead engine” (the side without rudder pressure is the failed engine).
- Retard suspected engine’s power lever and confirm no change in performance.
Under what conditions would you try to troubleshoot a failed engine?
- If you have sufficient altitude (commonly ~3,000 ft AGL or more).
- If conditions are stable (no immediate danger).
- No severe mechanical issues (like fire) suspected.
Below that altitude or if conditions are adverse, you typically secure rather than troubleshoot.
Under what conditions would you secure a failed engine?
- If troubleshooting is unsafe or fails to restore power.
- Low altitude or critical flight phase.
- Fire or catastrophic internal issue suspected.
Describe the engine restart procedure.
- Ensure you’re configured for best climb performance (gear/flaps up, pitch Vyse).
- Identify, verify inoperative engine.
- If altitude/time permit, run “Engine Restart” checklist.
- Turn that engine’s master ON; the prop typically windmills and re-lights if not feathered.
- If feathered, use the starter if necessary per AFM.
What factors determine which engine is critical?
In conventional twins (same rotation), the left engine is “critical” due to:
1. P-factor
2. Accelerated slipstream
3. Spiraling slipstream
4. Torque
What are the criteria used to determine VMC?
Per 14 CFR §23.149:
* Critical engine inoperative & windmilling
* Operating engine at max power
* Aft CG (most unfavorable)
* Takeoff config (gear up, flaps T/O)
* Up to 5° bank into operative engine
* Standard sea-level conditions
* ≤ max takeoff weight
What are the DA42 drag factors for wind-milling propeller on the critical engine, landing gear extended, flaps APP, and flaps LDG?
- Windmilling prop on critical engine: ~–300 to –400 fpm
- Gear extended: –300 fpm
- Flaps APP: –400 fpm
- Flaps LDG: –600 fpm
Describe the zero-sideslip configuration.
Use about 2°–5° bank toward the operative engine and apply rudder to keep the fuselage aligned with the relative wind (ball ~half deflection). Minimizes drag, improving single-engine climb.
What is accelerate-stop distance?
Runway length to accelerate on all engines to a decision speed (V1), then abort and stop on the remaining runway. Not required for <6,000 lb, but concept is taught.
What is accelerate-go distance?
Distance to accelerate on all engines to V1, lose the critical engine, then continue takeoff on remaining engine(s) to 35 ft AGL by runway end.
What is a balanced field condition?
A runway length where accelerate-stop distance = accelerate-go distance for a certain weight, runway slope, wind, and density altitude.
What factors affect takeoff and accelerate-stop performance?
- Aircraft weight
- Density altitude (temp/pressure)
- Runway slope/condition
- Wind
- Engine power settings and drag
Describe the takeoff briefing for emergencies.
A standard multi-engine takeoff briefing covers:
* Below VR: Engine failure → abort.
* After VR, runway remaining: Possibly land ahead if feasible.
* After VR, no runway: Pitch for Vyse, identify/verify failed engine, feather if necessary, climb out single-engine, return to land.
