Systems and Limitations Flashcards
Engines
Lycoming
Horizontally Opposed
Air Cooled
Normally Aspirated
Direct Drive
4-Cylinder
Carburated
180 horsepower at 2700 RPM
Left Engine: O-360 (clockwise)
Right Engine: LO-360 (Counter)
Oil
The engines use a wet-sump pressure type oil system with a maximum of 8 qts. and a minimum of 5 qts.
Propellers
Hartzell, 76 inch diameter, constant speed, full feathering, 2-bladed propellers.
Propeller Positioning
Springs and dome air pressure, aided by counterweights move the blades to high pitch (feathered) position
Engine oil under governor-boosted oil pressure moves the blades to the low pitch, high RPM position.
a feathered blade edge on into the wind.
What do the propeller controls in the cockpit allow the pilot to do
The propeller controls in the cockpit allow the pilot to select the governor’s RPM range.
What does the prop governor do?
Propeller RPM is controlled by the engine driven propeller governor which regulates oil pressure in the hub
Engine oil under governor-boosted oil pressure moves the blades to the low pitch, high RPM position
What if the propeller rotates faster than 700-800 rpm
The blades have centrifugal lock pins that retract into the blade bases. When the propeller is rotating faster than 700-800 RPM, these pins will remain in the blade bases and allow the propeller to move into the feather position.
What if the propeller rotates below 700-800 RPM
The blades have centrifugal lock pins that retract into the blade bases
Below 700-800 RPM, the pins will spring out preventing the blades from feathering. This is why the blades don’t feather on engine shutdown on the ground.
What if I feathered and shut down the wrong engine??
Unfeathering accumulator
Nitrogen pressurized accumulators take the props out of feather when controls are brought full forward
What is the important thing to remember about unfeathering accumulators?
The important thing to remember is that these are a one-shot deal. If they are used and the blades don’t come out of feather, they can’t be used again until the engine has been restarted.
How does the unfeathering accumulator work?
Unfeathering accumulators store oil from the engine to use for forcing the propellers out of the feather position
They build pressure by means of the engine oil pumps
Fuel type and capacity total and unusable and tabs
100 Green and 100LL Blue av gas 103 gallons total and 100 usable
51.5g total per wing tank 50g usable per side
Tab 30g total 28.5g usable
Tab 40g total 38.5g usable
Fuel selector arrangement
On
Crossfeed
Off
Fuel system
Selector - The fuel system uses an “ON-CROSSFEED-OFF” selector arrangement located on the lower center floor panel
Fuel Pumps - There are two engine-driven and two electrically-driven auxiliary fuel pumps. The electric pumps are used for engine start, takeoff, landing, and fuel selector changes. Each tank feeds its respective engine.
Crossfeed - Fuel cannot be transferred from tank to tank; however, either tank may feed both engines in crossfeed mode. The fuel crossfeed system is to be used during emergency conditions in level flight only.
Sumps
There are a total of 8 fuel sumps: 4 per side. 1 sump for each tank, 1 sump for each engine strainer, 2 for each crossfeed line.
Pressure System
Two engine-driven, dry pressure pumps supply air pressure to drive the attitude and directional gyro instruments, and autopilot (if installed). The pumps are interconnected to form a single system. Check valves will automatically close if either pump fails to ensure continued operation.
Flaps
Wing flaps are operated by an electric motor located under the right rear passenger seat and connected via torque tubes which operate worm gears to extend or retract the flaps.
Landing Gear
The Duchess is equipped with a retractable tricycle landing gear that is hydraulically actuated
Has an electrically driven hydraulic pump
Has a hydraulic system terminating in a hydraulic actuator assembly mounted in each wheel well
Landing gear up and down position
The gear is held in the up position by a hydraulic pressure of 1250-1550 psi
It remains in the down and locked position using an over-center brace and springs.
Landing Gear Hydraulic pump
The hydraulic pump is equipped with a time delay that will disengage it after 30 seconds of continuous operation.
Gear Warning Horn activation
The aircraft is equipped with a gear warning horn that will activate under the following conditions:
- Gear is not in the down and locked position when throttles are reduced below a setting to sustain flight.
- Gear is not in the down and locked position with flaps extended below 16°.
- Gear handle is in the up position on the ground.
How do you prevent gear retraction on the ground
Gear retraction on the ground is prevented by a pressure safety switch located in the pitot system to deactivate the pump circuit when airspeed is below 59-63 KIAS. (Gear warning systems are no replacement for proper checklist usage and should not be relied upon to prevent an inadvertent gear up.
What if the landing gear doesn’t come down?
The gear system is equipped with a hydraulic bypass valve located beneath the floor panel in front of the pilot.
How does the hydraulic bypass valve work?
By turning the valve counter clockwise 90°, hydraulic pressure will release and allow the gear to free fall to the down and locked position. This can only be done with an airspeed below 100 KIAS and the emergency checklist should be used. In the event that hydraulic pressure is lost, the gear will free fall to the down and locked position.
