I. INTRODUCTION
This manual provides information for installing the P/N 2042
Gear Alert Landing Gear Warning System on a general aviation
amphibian aircraft. All installation work is to be performed in
accordance with this manual and applicable sections of AC 43.13
- 1B.
II. BASIC OPERATIONS
The Gear Alert System is an electronic device which provides the
pilot of the aircraft with an easily recognizable audible voice
warning if he attempts to make a landing with the landing gear
in the wrong position for either a water landing, or a runway
landing. The system consists of three subassemblies, an
electronic module which is mounted inside the aircraft, and two
switches which mount on the instrument panel. The unit is
interconnected to the existing landing gear position indicating
lights and the existing pitot system. The system functions as
follows: During takeoff, when the aircraft exceeds a preset
speed, the system becomes active. As the aircraft slows to the
landing approach speed, the system will provide a voice message
in the pilots headset. The pilot must then push one of the panel
mounted switches marked “W” for a water landing, or “L” for a
runway landing. The system then checks to determine if the
landing gear is in the proper position for the type of landing
being made. If the landing gear is set correctly, a voice
message will confirm it, if the landing gear is in the incorrect
position for the type of landing, the pilot will hear a second
message in his headset alerting him of the unsafe condition.
Momentarily pushing either switch initiates a self-test
sequence. If the system is O.K, a voice message will be heard.
Pushing and holding either switch for 2 sec. disengages the
system. The amber lights then flash, indicating the system is
disengaged.
WARNING: THE GEAR ALERT IS AN ADVISORY SYSTEM ONLY. IT SHOULD
NOT BE UTILIZED AS THE PRIMARY MEANS OF DETERMINING LANDING GEAR
POSITION THE PILOT SHOULD CONTINUE TO UTILIZE THE NORMAL
OPERATING PROCEDURES, CHECKLISTS, LIGHTS, INDICATORS, ETC. AS
DEFINED IN THE AIRCRAFT FLIGHT MANUAL AS THE PRIMARY INDICATION
OF LANDING GEAR POSITION
III APPLICABILITY
The following is a listing of aircraft approved for installation
of the P/N 2042 Gear Alert System:
Sky Enterprises inc Model RC-3 (Republic Seabee
IV. INSTALLATION INFORMATION
The P/N 2042 Gear Alert System has been designed for
installation in aircraft with different wiring configurations.
The aircraft wiring configuration may require the use of
different cable assemblies Information on the cable
configuration and other installation information is provided in
the following section.
V. CABLE ASSEMBLY MODIFICATION
1. Review the wiring schematic for the particular aircraft that
the system is being installed in. Determine which of the
following configurations applies.
a) If the aircraft is wired so that one side of the gear down
light is grounded, and the gear down limit switch provides power
turning the light on whenever the gear is down, no changes to
the cable are required. Install the system in this aircraft as
shown on FIG A.
b) If the aircraft is wired so that one side of the gear down
light always has power applied, and the down limit switch
supplies a ground, turning the light on when the gear is down,
then it will be necessary to modify the cable as follows
1. Remove the gray plastic cover from the end of the cable
assembly. Locate PIN 1 on the connecter (red wire). PIN 2 will
be empty, followed by PIN 3 with a black wire in it. Leave the
black wire connected to PIN 3, and solder a jumper wire from PIN
2 to PIN 3
2. Inspect the modification to insure there are no solder shorts
between the pins, and that the connections are good.
3. Reassemble the plastic cover to the end of the cable.
4. Install this system in the aircraft as shown on FIG B.
VI. COMPONENT INSTALLATION
1. Locate a place to mount the electronic module in the cockpit.
The unit can be mounted to the front bulkhead, or other aircraft
structure. Choose a location such that the 3/16 inch dia. tubing
on the unit will reach to the pitot pressure line which attaches
to the airspeed indicator. Drill 4 mounting holes using the
template, FIG1, and attach the unit to the aircraft with the
hardware provided as shown on FIG 2.
2. The Gear Alert system “T’s” into the aircraft Pitot pressure
line that goes to the airspeed indicator. Locate the tubing that
runs to the pressure side of the airspeed indicator. Cut the
line, and install a “T” fitting as shown on FIG 3. Attach the
3/16 tubing to the side connection of the “T”. Note: Minimum
bend radius in the tubing should be 1 inch to prevent flattening
the tube. Verify that mounting does not flatten the tube
3. Locate a position on the instrument panel where the 2
switches can be installed. Ideally, the switches should be close
to the gear switch. They can be arranged either horizontally, or
vertically. Refer to FIG 4 for installation information and
proper spacing.
4 install the labels and the switches. Note the switches have
different colored wiring.
This completes the installation of the mechanical equipment.
VII. ELECTRICAL HOOKUP
The Gear Alert System can operate in both 12V or 24V aircraft
systems. Select the proper wiring schematic FIG A, or FIG B for
the installation as defined in section V.
1. The Gear Alert System should be installed on its own separate
1 amp circuit breaker or fuse. Attach the red wire to the 12v or
24v aircraft power buss.
2. Attach the BLACK wire to a good aircraft ground point.
3. Wire the two switches as shown on the schematics, The color
codes on the pre-wired switch match the colors of the main cable
assembly. The 2 orange wires are interchangeable.
4. A 600 ohm audio output is provided (white wire). 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 has an un-switched audio input, the Gear
Alert audio output can be hooked to this point. This will
provide a voice warning directly into the pilots headset and
through the cabin speaker. 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.
5. The system interconnects to the gear up and to the gear down
indicating lights. Select the correct schematic (FIG A or FIG B)
to match the way the gear indicating lights are wired in the
aircraft. The wires must be attached to the correct point in the
wiring as shown on FIG A or FIG B.. One side of the light will
have power or ground continuously, while on the other side of
the light the voltage will change as the gear goes up and down
(light goes on and off). Attach the correct colored wire to the
side of the light that changes voltage as the wheels go up and
down.
6. The P/N 2042 Gear Alert system incorporates an airspeed
activated switch closure that can be used to activate equipment
such as a Hobbs meter, transponder, or other device that
requires a ground signal to activate. Pin 13 on the connecter
(TAN wire) is the switch activation. Whenever the aircraft speed
is above 45 mph, this lead will be grounded. NOTE: It will be
necessary to externally limit the current through this input to
60 ma maximum to prevent damage to it.
7. Attach the gray DB-15 connecter to the electronic module and
secure it with its mounting screws.
8. Bundle and secure all wiring.
VIII. SYSTEM ADJUSTMENTS
An adjustments have been provided to optimize operation of the
Gear Alert system to each aircraft.
1. The speed at which the system will activate when landing can
be adjusted up or down by turning the speed adjusting screw
through the hole on the front panel of the black box. The speed
is setable between 40 mph and 90 mph. The installer should first
determine the airspeed at which at the aircraft will be flying
during the approach, and set the activation to this speed
initially. This adjustment is accomplished as follows: There is
a short VIOLET wire attached to pin 14 in the cable assembly.
Attach a digital volt meter between this VIOLET wire and
aircraft ground. Refer to Fig 5 which is a plot of voltage at
pin 14 vs the activation airspeed. There are 2 adjusting screws
on the front of the electronic module.
The opening closest to the connecter is the
volume adjustment, the opening the furthest away is the speed
adjustment. With power applied to the system, insert a small
screwdriver through the hole in the panel, and turn the speed
control until you read the voltage on the meter that corresponds
to the desired activation speed. Once this adjustment has been
made, insulate the end if the VIOLET wire and secure it in
place. Note: There is a 15 sec. delay between the time the
system recognizes the activation speed and when it actually
starts the warning sequence. This delay was incorporated to
minimize false triggering
2. The headset volume can be adjusted by turning the volume pot
through a hole in the front panel of the black box. Turning the
pot clockwise increases the volume to the headset only.
IX. SYSTEM CHECKOUT AND OPERATION
A .Ground Test
1. Power up the system. The voice must not sound. The amber
lights must not illuminate.
Individually turn on the various electrical devices in the
aircraft. Use the table attached to this procedure as a guide
for performing this test. The acceptance criteria given below
must be met, as each electrical device is activated and then
turned off.
The following criteria must be fully met for each part of this
test.
a) Any false trigger of the Gear Alert at any time constitutes
failure of this test.
c) If any electronic device in the aircraft does not operate
correctly, turn off the Gear Alert and determine if it is the
cause. If the Gear Alert affects the operation of any electronic
device in the aircraft, or if any electronic device in the
aircraft affects the operation of the Gear Alert, that
constitutes failure.
2. Push either test switch and release it. The voice message
“TEST OK, ’ must be heard in the pilots headset, and through the
built in speaker if the system is working. If the test message
fails to function or the volume is inadequate, this constitutes
failure of the test. Repeat this test by pushing the other
switch. The headset volume can be adjusted by turning the volume
pot in the electronic module.
4. Push either switch and hold it for about 2 sec. then release
it. The test message “TEST OK’ should be heard, and when your
finger is released, the amber lights in both switches will flash
alternately indicating that the system is disengaged. Pushing
either switch again will turn the lights off and re-engage the
system. If the test voice does not function, or the amber lights
fail to blink, or the system does not re-engage, the test has
failed.
B. Flight Test
1. Perform a normal takeoff
2. Fly the aircraft at different cruise speeds from maximum
cruise speed to just above approach speed. Tests should include
flight with power changes, climbs, steep turns, etc. Any false
triggering of the Gear Alert at any time constitutes failure of
the test.
3. With the aircraft flying above the activation speed, push
either switch and release it. The voice message “TEST OK” should
be heard at an adequate volume level in the pilots headset, and
through the built in speaker. Repeat by pushing the other
switch. Failure of the voice to sound at an adequate level
constitutes failure of the test.
4. With the landing gear retracted, slow the
aircraft to normal approach speed. The voice message “SELECT
LANDING ......” will be heard continuously in the pilots headset
and through the built in speaker. Push the switch marked W
(water), and the voice message must stop. Accelerate the
aircraft above approach speed, and repeat this test, except this
time push the switch marked L (land). The voice message “CHECK
LANDING GEAR, CHECK LANDING GEAR” will be heard in the pilots
headset and through the built in speaker after the land switch
has been pushed. The voice will continue until either the gear
is extended, or the speed is increased above the approach speed.
Failure to function as described constitutes failure of the
test.
5. With the landing gear extended, slow the aircraft to normal
approach speed. The voice message “SELECT LANDING, ......” will
be heard continuously in the pilots headset and through the
built in speaker. Push the switch marked L (land), and the voice
message must stop. Accelerate the aircraft above approach speed,
and repeat this test, except this time push the switch marked W
(water). The voice message “CHECK LANDING GEAR, CHECK LANDING
GEAR” will be heard in the pilots headset and through the built
in speaker after the W switch has been pushed. The voice will
continue until either the gear is retracted, or the speed is
increased above the approach speed. Failure to function as
described constitutes failure of the test.
6. Individually turn on the various electrical devices in the
aircraft. Use the attached table as a guide. As each device is
activated, verify that its operation is not affected by the Gear
Alert, and that the Gear Alert does not false trigger as the
various electrical devices are turned on. Any false trigger of
the Gear Alert at any time constitutes failure of this test.
X. DOCUMENTATION
1. The installer is responsible for making all logbook entries,
revising weight and balance, and other documentation as
required.
2. Place the aircraft flight manual supplement (AFMS) in the
aircraft.
XI. MATERIALS
The following materials are included in the P/N Gear Alert
assembly. Check all parts before beginning the installation.
1. (1) electronic module assembly P/N 2042-2-1
2. (1) cable assembly P/N 2042-3
3. (1) aircraft flight manual supplement
4. (1) instructions for continued airworthiness
5. (1) installation manual
6. (1) installation kit P/N 2042-10
