DA42 Twin Star

Aircraft Systems
Part I

DA42 Systems
 Outline
n Airframe n Propeller
n Flight Controls n Electric
n Stall Warning
n Landing gear
n Heating & Ventilation
n Engines and n Ice Protection System
associated systems n Performance Charts
n Fire Protection n Operating Limitations
n Fuel

DA42 Systems
Airframe

DA42 Systems
 Airframe
n Fuselage
n Semi monocoque molded construction
n Carbon Fibre Reinforced Plastic (CFRP) half-shells
for skin (includes vertical stabilizer)
n Glass Fibre Reinforced Plastic (GFRP) frames and
webs for strength and stiffness
n ‘Centre wing’ bolted to fuselage
n Mountings for wings, engine nacelles and landing
gear

DA42 Systems
 Airframe
n Wings
n Front & rear spar; top shell and bottom shell
n Principally sandwich construction; aluminium
fuel tank in each wing
n Horizontal Stabilizer
n Top & Bottom shells of GFRP; front & rear
spars

DA42 Systems
 Lightning Protection
nNecessary due to
composite
construction
nAll metal
components are
bonded to the
lightning conductors
naluminium alloy
tubes (nose to tail,
wingtip to wingtip)
and strips / braids

DA42 Systems
 Questions?

n For You:
n What material(s) is the DA42 constructed
with?
n Why is a lightning protection system
necessary on the DA42?

DA42 Systems
Flight Controls

DA42 Systems
DA42 Systems
 Ailerons
n GFRP / CFRP Sandwich
n Operated through control rods
n 4 hinges secured by a roll pin
n Check for presence and alignment
n Aerodynamic balance
n Located on outboard bottom of aileron
n Must be checked for debris before flight

DA42 Systems
 Flaps
n GFRP / CFRP Sandwich

n 2 section construction
n Outer
n 6 hinges; connects to wing
n Inner
n 4 hinges; connects to center wing

n Fail-safe construction

DA42 Systems
 Flaps
Fail-safe construction

DA42 Systems
 Flaps
n Electrically operated; 3 settings:
n UP (cruise), APP (approach) & LDG (landing)
n 0°, 20°, 42° Respectively
n Flap Position Indicator

DA42 Systems
 Elevator
n GFRP top &
bottom shells

n Operated through
steel push rods

n Trim tab at
trailing edge

DA42 Systems
 Variable elevator stop

n Electrically operated

n Linear actuator
n Acts as a moveable stop

n Limits elevator up movement

n When both engines exceed 20%
and
n Flaps are set to landing

DA42 Systems
 Elevator Trim
n Mechanical & electrical
systems
n Trim Tab & actuator through
trailing edge of elevator
n Two actuating levers
n Left:
n Connects to long flexible
cable that is adjusted by the
pilot
n Right:
n Friction damper
n Prevents fluttering if
mechanical failure of trim
cable

DA42 Systems
 Rudder
n Operated through
cables from rudder
pedal assembly
n Two hinges
n Upper hinge
n One bolt
n Lower hinge
n Is available for visual
inspection

DA42 Systems
 Rudder Trim
n Controlled with a black
wheel in center console

n Flexible cable
n Connects hand wheel to
trim actuator assembly

n Two operating rods

n Connect actuator
assembly to the trim tab
control horn

DA42 Systems
 Questions?

n For You:
n What is the purpose of the elevator stick-
limiter? How does it work?

DA42 Systems
Landing Gear

DA42 Systems
 Landing Gear
n General
n Steering
n Hydraulic Supply & Control
n Extension & Retraction
n Emergency Extension
n Indicating System
n Safety Features
n Brakes
DA42 Systems
 Landing Gear
n General

n Fully
retractable

n Hydraulically
operated,
electrically
powered

DA42 Systems
n Main Gear

n Tubular strut with a trailing

link at the bottom

n Wheel attaches to the

trailing link

n Gas/oil filled damper

attaches to rear of tubular
steel strut and the trailing
link

DA42 Systems
Main Gear

DA42 Systems
 Landing Gear
n Nose Gear
n Steel strut with gas/oil
damper to absorb shock
n Steering obtained by rudder
control system via a steering
linkage
n Steering stops attached to
gear leg limit nosewheel
travel to 30°
n Spring assembly attached to
tubular steel strut centres
gear when deflected

DA42 Systems
n Nose Gear
n Steering stops attached to
gear leg limit nosewheel
travel to 30°
n Spring assembly attached to
tubular steel strut centres
gear when deflected

DA42 Systems
 Hydraulic Supply & Control
n Hydraulic Control Block

n Heart of hydraulic system

n Electric motor
n Hydraulic pump & pressure
switch
n Hydraulic reservoir
n Hydraulic accumulator

n Located rear of aft

cockpit bulkhead, left
side

DA42 Systems
 Landing Gear Operation
n System is always pressurized
n Electrically operated valves provide required
hydraulic pressure to move actuators on each
gear leg
n Main gear retracts inboard into centre wing
n Nose gear retracts forward into nose
n Hydraulic pressure on actuators keep gear
retracted

DA42 Systems
Retraction – Differential Pressure

DA42 Systems
Retraction – Full Pressure

DA42 Systems
Normal Extension

DA42 Systems
 Emergency Extension
n Up to 156 KIAS
n Emergency extension
lever
n Releases hydraulic
pressure to reservoir
n May take 20 seconds

DA42 Systems
Emergency Extension

DA42 Systems
 Emergency Extension

n NOTE: Failure of electrical system causes gear to

automatically extend!

n AFM Notes “gear may slowly extend”

DA42 Systems
 Indicating System
n On instrument panel, next to gear selector
switch

DA42 Systems
 Safety Features
n Squat switch
n Left main gear leg
n Gear warning horn
n Either Power Lever
n Below 25%
n Flap position
n LDG

DA42 Systems
 Questions?
n For you:
n How could you test the function of the gear
warning horn while in-flight?
n What will happen if the gear handle is
selected “UP” while on the ground?
n What is the emergency extension method for
the landing gear?

DA42 Systems
 Brakes
n Two sets of master cylinders
n Pilot & co pilot

n Fluid reservoirs
n Behind co pilot’s rudder pedals

n Operated with toe of rudder pedal

n Each pedal operates the brake for
that main wheel
n Parking brake
n Pull down and pump

DA42 Systems