Systems Guide

Aerosoft
Twin Otter E
XTENDED
Systems
Vol
2
2-1-15
19 November 2013
roll the aircraft further left. If the horizontal bar is displaced above the aircraft symbol then the pilot should
increase pitch. Perfectly flown the horizontal and vertical bar should form a cross at the middle of the aircraft
symbol in the ADI.
Note that in IAS mode the horizontal bar indicates whether you fly too slow or too fast rather than required
pitch.
UNITED INSTRUMENTS 5506L ALTITUDE ALERTER
The AP-106 is also connected to United Instruments 5506L Altitude Alerter. The alerter can be set to a desired
altitude and will give an audible warning when within 1000 ft of the set value. A light will be lit when between
1000 and 200 ft from the set value. There are 3 buttons and lights associated with the Altitude Alerter and AP.
MDA: (Minimum Descend Altitude): Is used for non-precision approaches, like VOR/DME or Localizer
only approaches, where the Altitude Alerter should be set to the minimum descend altitude and the
MDA button pressed. Once the aircraft descends to the set MDA, the AP will level out and maintain
the set altitude in order to prevent from descending below MDA. If MDA is engaged and the
Glideslope is being captured, MDA will turn off, since the approach is deemed a precision (full ILS)
approach.
G/A: The Go around button is used when executing a Go Around. Pressing the G/A button will
disengage the AP and set the vertical FD bar for a 8° climb.
ALT ALRT: Will automatically level out the aircraft once it has reached the set altitude when the AP is
in either "Manual" or IAS mode.
When NAV mode is used for tracking a VOR radial and the signals disappears when near vertical to the station,
then "DED REC" mode will be indicated for "Deduced reckoning". In this mode the AP memorizes the heading
present when the signal was lost and will maintain it until past the station where the signal will be received
again. Note that using the autopilot to acquire an exact altitude, as set on the Altitude Alerter, the ALT button
should not be used. The ALT button simply levels the aircraft at the altitude present when the ALT button was
pressed. To acquire a selected altitude on the Altitude Alerter use either IAS mode or Autopilot manual vertical
mode (Autopilot on, but with IAS, ALT and APPR unselected).
GARMIN GNS530 GPS
The GPS used in the twin Otter
extended is based on the
default FSX GPS 500, but has
been tweaked to resemble the
Garmin GNS530, which also
includes the Com1 and Nav1
radios as well as DME readouts
and current radial on which the
aircraft is situated. For the GPS
part please refer to the FSX
description of its use, found in
FSX's build-in Learning centre.
On the left and lower part of
the GPS the following functions
can be found: