I. INTRODUCTION
This manual provides information for installing the P/N 2050 Landing
Gear Warning System on an Experimental category retractable gear
aircraft. All installation work is to be performed in accordance
with this manual.
II. SYSTEM OPERATION
The Landing Gear Warning System is an electronic device which
provides the pilot of a retractable gear experimental category
aircraft with information on the position of the landing gear prior
to a runway landing. The system consists of a small electronic
module, and a panel mounted switch, and it connects to the aircraft
landing gear DOWN position indicating light. The system is activated
by airspeed on takeoff Once the airspeed has exceeded a pre-selected
speed, a light in the panel switch will illuminate indicating that
the system is active. A delay of 15 sec. is built into the unit to
allow for airspeed transients. As the aircraft slows for landing,
the system enters the warning mode. The electronics check the gear
Down position light to determine if the landing gear is down for a
runway landing. If the gear is down, pilot will then hear the
message “GEAR OK” in his headset, and through the built in speaker.
If the gear is not in the correct position, he will hear the message
“CHECK LANDING GEAR, CHECK LANDING GEAR” repeatedly until the gear
is placed in the proper [position, or the airspeed is increased
above the activation speed.
The system incorporates a test function, and the ability to
temporarily disengage operation for slow flight. Pushing the panel
switch in flight or on the ground will initiate a test sequence. If
the electronics are functioning, the voice message “TEST O.K.” will
be heard. If the panel switch is held for 2 sec., the system will be
deactivated. The light in the panel switch will then flash
indicating that the system is deactivated. Pushing the switch again,
re-engages the system and turns the flashing light off.
The system also has optional inputs that allow the installer to hook
up a switch on the flaps and a switch on the throttle. When these
options are used, closing the throttle or lowering the flaps with
the gear up, will produce the warning message.
The voice messages can be heard through the speaker built into the
unit, and directly in the pilots headset. If the aircraft has an
audio panel with an un-switched input, the voice message will also
play through the cabin speaker.
NOTE: THIS IS AN ADVISORY SYSTEM ONLY. IT SHOULD NOT BE UTILIZED AS
THE PRIMARY MEANS OF DETERMINING GEAR POSITION. THE PILOT SHOULD
CONTINUE TO UTILIZE THE NORMAL OPERATING PROCEDURES, CHECKLISTS,
LIGHTS, INDICATORS, ETC. AS THE PRIMARY INDICATION OF GEAR POSITION.
III APPLICABILITY
This system is not FAA approved. It is intended for installation on
Experimental category aircraft only. The aircraft must have the
following minimum requirements for an installation
:
1. 12v or 24v DC power
2. A minimum of one gear down position indicating light, or an
electrical switch which activates when the gear is up and when the
gear is down.
3. An audio panel with an un-switched audio input or a headset jack
for the pilot.
The system is designed to operate with a variety of light and limit
switch wiring configurations. See the attached Installation
Schematics, or contact the manufacturer for installation information
with other wiring schemes.
IV. INSTALLATION INFORMATION
A. Mechanical Installation
1. Locate a place in the aircraft to mount the P/N 2050 electronic
module. The unit can be mounted to the aircraft structure, side
panels etc. Drill 4 mounting holes as shown on Fig 1, and mount the
unit using the hardware provided.
2. Drill a 5/16 dia hole in the instrument panel in a location in
front of and in easy reach of the pilot, and install the P/N 2048-4
Switch assembly. Place the panel label over the hole before
inserting the switch.
3. Attach the 3/16 inch OD (1/8 inch ID) plastic tube on the
electronic module to the pressure line from the pitot tube. Do not
use a bend radius less than 1 inch, and do not crush the tube when
securing it.
B. Electrical Installation
1. Refer to Fig A, or Fig B, for information on the electrical
installation that fits the wiring configuration in your aircraft.
Fig A is the wiring configuration for aircraft that have gear
position indicating lights wired so that power is always applied to
the lights, and the switches then supply a ground to turn the lights
on. Fig B is the wiring configuration for aircraft that have gear
position indicating lights that are wired so that the switches
supply power to the lights to turn them on. The system can also be
used with aircraft that do not have indicating lights, but do have
up and down limit switches on the gear position. Contact the factory
for information on this installation. If you have individual
indicator lights, and wish to hook all of them up, this can be done
also. Contact the factory for information on this configuration.
2. Hook the RED wire to the aircraft power buss through a 1 amp fuse
or circuit breaker. The system works with both 12v and 24v power.
3. Attach the BLACK wire to a good aircraft ground.
4. NOTE: Installations made using Fig B require that a jumper be
installed in the cable connecter. Remove the gray plastic cover from
the cable connecter and solder a jumper from pin 2 to pin 3 in the
connecter. Attach the correct color wire to the gear down lights or
switches as shown on the correct figure. Note: The short VIOLET wire
is for speed calibration
.
5. The system incorporates a standard audio output. The audio output
must be hooked into the aircraft audio system in a way that the
pilot cannot accidentally turn it off. If the aircraft has an audio
panel that incorporates an un-switched audio input, the Gear Alert
audio output should be hooked to this point. This will provide a
voice warning directly into the pilots headset and through the cabin
speaker. Hook the WHITE wire to this un-switched audio input. If the
aircraft does not have an audio panel with an un-switched input,
then the WHITE wire can be hooked directly to the pilots headset
jack.
6. The system can be attached to a switch on the flaps that provides
a ground when the flaps are fully deflected. This switch closure
will provide a second means of activation when landing. This input
can be left unused if desired.
7. The system incorporates an airspeed activated
switch which can be used to activate an external device like a
transponder, a hobbs meter, etc. The system provides a switch
closure, (a ground) at an airspeeds above 40 mph, and opens (turns
off) at speeds below 40 mph.. NOTE: The switch current must be
externally limited to 40 ma.
8. The system can also be attached to a switch on the throttle that
provides a ground when the throttle is closed. This switch closure
will provide an additional means of activation when landing. This
input can be left unused if desired
9. Cut any remaining wires and insulate the ends. Secure all wiring
in place.
V. SYSTEM CHECKOUT AND OPERATION
A. Ground Testing
1. Turn on the master switch. The system must not operate. Push the
panel switch momentarily and release it. The voice message “TEST OK”
must be heard once through the built in speaker and through the
pilots headset. The voice message will also be heard through the
cabin speaker and all headsets in the aircraft if the audio is
attached to an un-switched input in the audio panel. The volume
level of the audio through the cabin speaker and the headsets can be
adjusted by turning a volume control pot in the electronic module.
Clockwise increases volume, CC decreases it. Locate the correct pot
in the electronic module, and using a small screwdriver turn the pot
to change the volume level.
2. Push the panel switch and hold it for about 2 sec. The voice
message “TEST OK” will play. When you release the switch the built
in light will flash indicating that the system has been disengaged
and will not function when landing. Push the switch again
momentarily and release it. The flashing light must go off
indicating that the system has reactivated.
B. Setting the Activation Speed
1. The activation airspeed can be adjusted over a wide range (40 MPH
to 90 MPH) by a pot in the electronic module. Locate the correct pot
in the electronic module, and use a small screwdriver to adjust it.
2. Attach a digital voltmeter between the short VIOLET wire attached
to pin 9 of the connecter and aircraft ground. Using the table of
voltage vs activation speed, adjust the speed control pot to set the
desired system activation speed. NOTE: The activation speed should
be set lower than the normal climb speed to prevent system
activation when climbing. Insulate and secure the short VIOLET wire
when finished.
C. Flight Testing
1. Make a normal takeoff. If the external switch is connected to an
accessory, it should activate at about 40 mph.
2. Increase the airspeed until the yellow light illuminates
indicating that the system is active. Adjust the activation speed if
necessary. Note: The airspeed must be above the activation speed for
about 15 sec before the system becomes active.
3. Decrease airspeed below the activation airspeed with the landing
gear retracted. The voice message “CHECK LANDING GEAR, CHECK LANDING
GEAR” must be heard in the pilots headset and through the built in
speaker. Lower the landing gear and the voice message “GEAR OK” must
be heard, and the amber light must turn off.
4. If the flap switch or the throttle switch options have been
hooked up, their operation should be verified by testing as above .
5. When in flight, push the panel switch momentarily and release it.
The voice message “TEST OK” will be heard once through the built in
speaker and through the pilots headset.
6. Push the panel switch and hold it for about 2 sec. The voice
message “TEST OK” will play. When you release the switch the built
in light will flash indicating that the system has been disengaged
and will not function when landing. Push the switch again
momentarily and release it. The flashing light will go off and a
steady light will be on, indicating that the system has reactivated.
VI. DOCUMENTATION
1. The installer is responsible for all documentation, logbook
entries, revising weight and balance, etc.
2. System weight is 0.7 lb.
