DHC-6 Twin Otter Flashcards
What is the wing span of the Twin Otter?
65 Feet.
What is the length of the Twin Otter with the Short Nose?
49.6 feet
Where is the Datum located in the Short Nose Variant?
Approximately 6 inches forward of the nose cone fairing.
Where is the Datum located in the Long Nose variant?
Approximately 21 inches aft of the tip of the nose cone fairing
How many Caution lights are located in the Caution Light Panel?
18 Lights (9 per side)
How many Micro Switches are used with the Door Warning Light System?
4 Micro Switches.
Which doors are equipped with Doors Unlocked Micro Switches.
Long Nose Baggage, Aft. Baggage, Right and Left main exit doors
(or air-stair door)
What is the maximum positive “G “loading of the 300 Series?
3.17 Positive.
What is the maximum positive “G“ loading for a 100/200 Twin Otter?
3.21. Positive.
What is the maximum landing weight for the 300 series Otter on floats.
12500 lbs.
What is the maximum negative “G” loading for the 300 Series Otter?
1.5 Negative.
What category of flight operations is the Twin Otter Certified to operate in?
The Normal Category .
Is the Twin Otter capable of doing steep turns of 80 degrees of bank angle?
Perhaps it is, but the Maximum Legal Bank angle is 60 degrees.
Name three major differences on the Three Hundred Series.
Additional Vortex Generators on the Vertical fin, An increase in Allowable
Gross weight, Lowered Positive “G” loading, higher horsepower.
Why is there a Torque Limitation on the -27 powered 100 & 200 Series?
The possibility of the loss of rudder control at maximum power
during single engine operations at low airspeeds.
What is the VMO for the 300 series Otter on floats?
158 Kts. for Wipline Floats. (156 KIAS S.L. wheels)
What is VMC for the 300 series Otter on Floats.
67 Kts. 20 flap. 70 Kts. 10 flap Prop Feathered
64 KIAS wheels.
What is the VP/VB. speed for the Otter on Floats?
135 Kts.
What is VX. For the 300 Otter on Floats?
82 Kts. 87 KIAS wheels.
What is VY for the 300 Otter on Floats?
90 Kts. (wheels 100 Kts).
What is VY. 100 Otter on Floats?
90 Kts (wheels 100 Kts.
What is VFE Flaps 10 300 Otter Floats?
102 Kts. (100 KIAS wheels)
What does the abbreviation VXSE. Stand for?
Velocity Angle Single Engine.
What does the abbreviation VP/VB. stand for?
Velocity Manoeuvring Speed (full and abrupt control deflection).
What does the abbreviation VNE. stand for?
Velocity Never Exceed.
W hat does the abbreviation VYSE stand for?
Velocity Rate Single Engine.
Why is the VP/VB. speed lower than the VNE speed?
To prevent possible structural damage to the aircraft,
when full and abrupt movement of the flight controls are
used, and also to help prevent inadvertent high speed
stall, if encountering gusty wind conditions..
Are the Chip Detector Lights always included with the Caution light Panel?
No, they are an option and sometimes located in front of the co-pilot.
What is the maximum bank angle for normal category.
60 degrees
What could cause the Prop Reset light to illuminate?
Prop. Levers below 91% and or power levers below 75% N.G.
How many RED LIGHTS are located on the Caution Light panel?
There are no RED LIGHTS on the Caution Light panel.
What is your action for any Caution Light Illumination?
Call for the applicable QRH.
If the Aircraft has a Hydraulic Press. Fail light, is it part of the Caution Light System?
No, it is an add-on feature.
You have a failed generator and the buss tie is open, will all the Caution lights work?
No, several Caution Lights are powered from the Opposite Buss.
What Component controls the operation of the hydraulic system?
The pressure switch controls the pump operation.
Does the pressure switch have any effect on the standby hand pump?
No, it has no effect on hand pump operation.
Why is it important to shut off the electric pump if a system leakage is suspected?
To preserve as much fluid as possible for the hand pump operation.
If using the hand pump, is it necessary to pump full system pressure to
operate the flaps?
No, and if a leak is suspected, this would lead to further and more rapid
loss of the remaining fluid.
How much fluid does the hydraulic reservoir contain?
Approximately 2/3 of a U.S. gallon.(just over 2 liters).
What type of hydraulic fluid is used in the system?
Mil. H 5606 (Red in color).
Would any type of fluid work in the Hydraulic System?
Actually ,yes, but other types of fluid would contaminate the system, requiring
Maintenance to do extensive cleaning and component changes.
Could the Hydraulic Fluid tank be accessed in flight, in an emergency situation?
Yes, by lifting the flooring up in the cockpit.
Could the fluid level be checked in flight? And if so by what means?
On some aircraft only. (Dipstick.)
What is the other method used to check fluid level on the ground?
Some aircraft use a sight gauge on the fluid reservoir.
If Hydraulic Fluid were available to the crew, would it be possible to add fluid
In fight to the reservoir?
Yes.
What precaution would have to be taken prior to adding fluid?
Electric pump would need to be turned off, and left off.
What occasion could arise, that Fluid might need to be added in flight?
A choice of a flapless landing on CAP floats, or adding fluid.
Normal operating hydraulic pressure limits on both pre and post mod aircraft?
Approx. 1250 psi. to approx. 1600 psi.
What would be an appropriate action if the Hydraulic System
was noticed to cycling fairly frequently?
Turn off the electric pump.
Which Buss does the hydraulic pump get the power from?
Left hand D.C. Buss.
Which Buss does the hydraulic pump fail light get it’s power from?
Left hand D.C. Buss.
The hydraulic pump circuit breaker has popped in flight is it considered ok to reset it?
No , because the pump may have seized up.
If the flap selector was set to approx 20 degrees, and the flap position indicator
was indicating some other number, would pumping the hand pump result in
any pressure building up on the pressure gauge?
No, there can be no pressure built up until the selector valve and the actual
Flap setting agree.
Is this possible scenario a problem?
(If the flap selector was set to approx 20 degrees, and the flap position indicator
was indicating some other number, would pumping the hand pump result in
any pressure building up on the pressure gauge?)
Not at all. The pressure will start to build when the flap position equal’s the
flap selection. (Provided there is fluid in the system.)
What are the two pressure limits for the two different system pressure relief
valves?
1750 PSI. and 1950 PSI.
What are the two types of brakes that might be installed on a Twin Otter?
Goodyear and Cleveland.
What is the difference between the two types? (of brakes)
The Goodyear brake disc is the floating type, and the Cleveland is
solidly mounted to the wheel assembly.
How is the shock of landing handled on the Twin Otter?
By using two urethane compression blocks, on each main gear and an air
over oil, oleo on the nose, and to some extent, Air pressure in the tires.
Considering the main gear is hinged to the aircraft with two bolts, fore and
aft, what prevents the gear from folding under the aircraft in flight?
The platen center bolt that retains the urethane blocks in place.
What is the tire pressure for the main wheels summer and winter?
38 And 34 PSI of Nitrogen.
What is the normal extension of the Nose oleo?
Approximately 6 to 8 inches.
The Nose gear is steerable how many degrees either side?
60 degrees left or right.
What station of the aircraft is the Nose gear attached too?
Station 60 (forward cockpit bulkhead.)
What is the normal inflation pressure of the Nose Wheel tire?
32 PSI of nitrogen.
How is the Nose Wheel Steering actuated?
Cable and pulleys from the lever in the cockpit.
What provides the motive force for the Nose Wheel Steering?
Pressure from the Aircraft Hydraulic System.
Does the Steering draw pressure from the Brake or the main Accumulator system?
The main Accumulator System.
If the hydraulic system were to start leaking in the brake system could all
Hydraulic pressure be lost?
Yes.
If the leak were only in the Flap/Steering side would all pressure be lost?
No, the Brake system will hold pressure.
Name 4 systems that use aircraft hydraulic pressure to operate?
Brakes, Flaps, Steering, and Ski’s if installed.
Is it possible to operate all hydraulic systems if the electric pump fails?
Yes . Use the manual hand pump.
Is it necessary to pump up full system pressure by hand in order to operate
the various systems ( IE. 1300 /1600 PSI.)?
No, flap and steering systems can selected and pumped as required.
If hydraulic pressure is reading zero and the flaps are selected down on the ground,
will the flaps extend?
Yes, the weight of the flaps will cause them to fully extend.
If direct pumping flaps down in flight, what indication might you see on the gauge?
Pressure fluctuating between 0 and 750 psi until the flaps are at the selected value.
What systems of the aircraft does bleed air operate?
Environmental, de-ice boots, intake deflectors, and autopilot.
What pressure is the bleed air regulated to for the operation of the de-ice boots?
18 PSI.
What is the maximum pressure allowed for the bleed air system?
25 PSI.
What is the time for a complete boot cycle in auto-fast -mode?
1 minute (5-5-3-3 ) 44 seconds off.
What is the time for a complete cycle in auto-slow-mode?
3 minutes 5-5-3-3, then 164 seconds off
If equipped , what do the two blue lights for the tail boots indicate when illuminated?
Only that pressure is available for boot inflation.
Illumination of the pneumatic low pressure light indicates what?
That there is not enough pressure available to inflate the boots.
What is needed for the operation of the optional propeller boots.
Electrical power and oil pressure above 40 PSI.
The Flaps installed on the Otter are called what type?
Full Span Double Slotted Fowler Flaps.
Name the individual Flaps on the Otter.
Inner Fore Flap, Outer Fore Flap and Inner Trailing Flap.
What does a Servo Tab actually do?
It deflects in the Opposite Direction of the Control Surface Movement
to Lessen the Forces Required by the Pilot to move the Control.
What does a Trim Tab actually do?
It is set to a Required Deflection to Remove Control Pressure.
What is the purpose of the Flap-Elevator Inter-Connect Tab?
To Lessen the Pitch-up Moment of the Aircraft when Flaps are Extended.
Which Elevator has the Trim Tab attached?
The Left Hand Elevator.
Which Tab is located on the Upper Portion of the Rudder?
The Rudder Trim Tab.
Which Tab is located on the Right Elevator Assembly?
The Flap Elevator Interconnect Tab.
How many Servo tabs are installed on the Otter.
Three Servo Tabs.
Where are the Servo Tabs located?
Inboard end of each Aileron and the Bottom of the Rudder.
How many Stall Bars need to be installed on the Otter if floats are installed?
Three Stall Bars, one on the Left Wing and two on the Right Wing
What type of mechanism is used to Transmit Control inputs to the Flight
Control Surfaces in the Otter?
Cable and Pulleys.
What method is used transmit Trim Inputs to the Elevator and Rudder.
Cable ,Drum, and Screw-Jacks.
How is the Aileron Trim Actuated?
An Electric Motor installed inside the Left Aileron.
Are the Ailerons attached to the wing?
No, they are attached to the Outboard Fore-Flap.