Advanced Aero Safety, Inc.
                                          "LTDS"   "Low Thrust Detector Systems"
                                                               

Maintenance Manual

Supplemental Instructions for Continued Airworthiness
And
 Trouble Shooting Guide for STC SA00804SE
 Low Thrust Detector System  (LTDS

 Advanced Aero Safety, Inc.                                                Contact Advanced Aero Safety, Inc.
Approved: Sherman Hall    Date :_1-15-2001                      for hardcopy of this manual.
Revised: _______________  Date:__________                                 safeaero@camano.net

 I.     Maintenance Manual  Low Thrust Detector System  (LTDS)

FAA approval of STC SA00804SE is based on previous FAA approved data per STC SA1007NW. Detail parts of STC SA00804SE are compatible and may be used to replace detail parts of like part numbers of STC SA1007NW, as long as STC SA1007NW was installed prior to February  5, 2001.

Description:

The systems primary function is to instantly identify the left or right engine if an engine should fail during takeoff or climb. The system also identifies the specific prop control to be used to feather if you have a complete engine failure.  The system functions best at speeds associated with takeoff and landing. 

The "LTDS" is a pneumatic/electrical system that indicates to the pilot a condition of unsymmetrical power.  The engine with the low thrust condition is identified to the pilot by a flashing amber indicator on the instrument panel.  Also a red and amber indicator on the prop control knob identifies the effected engine.  An Aural tone accompanies the flashing indicator for a few pulses.  The system functions by measuring the differential thrust between the left and right  engine.   When power is generated equally there will be no activation of the indicators.  Loss of a significant amount of power on one engine will activate an indicator which identifies to the pilot an unsymmetrical power condition.  The system identifies the engine with the lower power but is not designed to indicate the specific amount of power loss. 

THE SYSTEM CONSISTS OF THE FOLLOWING FIVE COMPONENTS

1.  SENSOR:       A pressure sensor (pitot) is mounted on the nacelle in the slipstream of each engine.  The sensors are provided with a heating element to remove frost or ice.
2.  CONTROL UNIT:      Pressure sending unit that translates the pressure into electrical            control knob a red and amber light.
4.  AURAL INDICATOR :      The first few indicator flashes are accomplished by an aural pulsed tone.
5.  SWITCH:         An “on/off” switch for (LTDS) System and sensor heat.

SYSTEM OPERATION:  See the FAA approved Airplane Flight Manual Supplement

 SERVICE:  (Required equipment for service.)

A water monometer or a calibrated pitot static checking device.

II     MAINTENANCE INSTRUCTIONS   (see wiring schematic 101-1100)

A.    ANNUAL INSPECTION:  No other inspections required.  [Brackets indicate corrective action]
a.      Visually inspect condition of pneumatic lines to the sensor in the engine cowling area.  [Replace any damaged lines or fittings.]
b.     Check operation of sensor pitot heat by turning switch on for  30 seconds and cautiously checking to see if sensor is hot to the touch.  [Replace if not working.]
c.      Conduct a  satisfactory ground or flight function test per this manual.  This function test may be conducted by the owner or operator.

B.    TROUBLE SHOOTING GUIDE:         [Brackets indicate corrective action]
*  Identifies the most common problem areas that may be looked at first.  It may be cost efficient to start by sending the “Control Unit” in for a bench check and adjustment.  This gives a better starting point to find a problem.

e.     No indication regardless of pressure on either sensor. 
1.     Check power source:  circuit breaker or fuse.  [Replace if defective.]
2.     * Check switch:  With switch on, check for power at the red wire, at the switch and the Control unit.  [Replace if defective.]
3.     Open circuit in Control unit:  [Return unit to manufacturer or repair.]

f.      System Activates in flight continuously on one side.
1.     Check black box for leaks:  [Return unit to manufacturer or repair.]
2.     Check both pneumatic lines for leaks or blockage:  [Repair leak with RTV Silicone or replace line.]  Look for kinked line, over tight tie-rap or clamp. [Route and clamp line properly.]
3.     Check both sensors for blockage.  [Disconnect from black box and blow out lines from inside aircraft.  Clean drain hole in sensor with .020 dia. wire.]  (Caution do not damage heating element)
4.     Check for water or moisture in pneumatic line.  [Disconnect black box and blow through lines with air.  Check to see if moisture comes out of pitot sensors.  Route lines so moisture is not trapped in engine compartment.]

g.     System activates continuously  on ground with both engines off
1.     * Black box damaged  by over pressure.  "Blowing into pitot by mouth can damage unit".  [Replace if defective.]
2.     Obstruction in sensor, line pinched or kinked closed.  Bend radius too sharp, or clamps too tight.  [Clean sensor and route lines properly.]

 h. System erratic:  System activates for no apparent reason. 
        (Ground run up between flights is not consistent.)

1.     Water or moisture in lines.  [Disconnect from black box and blow out lines from inside aircraft.  Cover pitot sensors when washing aircraft.  Turn on heat when in moisture.  Assure line routing from pitot sensor is higher and angles slightly up to prevent moisture.  Assure drain hole in sensor is clear.]  * Assure heating element is working.   (21 ohm 24V)  (5.6 ohm 12V)  [Replace if defective.]  * Check sensor (pitot) alignment per installation drawing.  [Adjust if required.]

Some cowling installed landing lights have created turbulence in front of the sensor and caused erratic operation.  Contact Advanced Aero Safety for correct sensor location.  Use FAA approved installation drawing for sensor location. 

C.   TESTING OF INDICATOR LIGHTS:

Indicator lights are L.E.D. (Light Emitting Diodes) and can be checked with a 1 &1/2 volt battery.  Higher voltage or a long test may cause burn out of the light.

1.     Left panel and left prop, amber indicator:           Blue wire (-) ground       Black wire (+) D.C.

2.      Right panel and right prop, amber indicator:      Yellow wire (-) ground    Black wire (+) D.C.

3.     Left prop knob, red indicator:                             Blue wire (+) D.C.        Black wire (-) ground

4.     Right prop knob, red indicator:                          Yellow wire (+) D.C.     Black wire (-) ground 

D.   REMOVAL AND REPLACEMENT:

a.      A certificated mechanic may perform any item in this maintenance manual and if satisfactory, approve the appliance (LTDS) and aircraft for return to service.  The procedures in this manual are considered minor in nature and can be accomplished by a certified mechanic without any specialized equipment.  This manual is the maintenance instructions for the Low Thrust Detector System and is approved by the manufacturer, Advanced Aero Safety, Inc.  FAA approved detail drawings may also be used for more detail instructions.

       1.     Remove and replace any lines or fittings.
2.     Remove and replace any indicator or sensor.  Also a new L.E.D. light may be replaced in the housing if care is taken in soldering the new light in the same manner as the light that was removed.
3.     Adjust the switches in the black box to the proper airspeed setting in this guide, or replace any switch or manifold  as required.  Parts may be obtained from Advanced Aero Safety, Inc.
4.     Remove and replace the 1/2 amp fuse in the black box with the same or equivalent fuse.
5.     A satisfactory ground function test must be completed before returning the appliance to service after any maintenance on the (LTDS).

        E.    Return to service approval:  Sample log book entry.

        F.              IN FLIGHT DEMONSTRATION OR FUNCTION TEST

                            "note airspeed, MP ,RPM during test"
1.     At a safe altitude, slow aircraft to vyse blue line, (or a safe approach speed), extend landing gear and adjust power for level flight.
(props high RPM)
2.     Retard one throttle:  "maintain aircraft speed and direction" an amber flashing Low Thrust warning for the specific engine and prop should be identified.  A pulsing tone will accompany only the first few flashes of the indicator.
3.     Increase power on the engine with power, until an alternating red and amber indication is seen on the prop control.  This will be the indication in event of a full power failure.
4.     Repeat for the other engine
5.     Optional Test:   To prevent rapid cooling of engine and less altitude loss. Set up power for level flight, speed at blue line, gear down and props at high RPM.  To activate system, increase power on one side only until amber indicator starts to flash on the low power side,  "note MP & RPM",.  further increase power until red and amber flashing indication on prop control.  On some aircraft you may have to reduce power on the low power side to activate the red flashing indicator. 

            G.     GROUND FUNCTION TEST:  (With engines running) "note  MP & RPM"
                       (It is normal for the indicators to flicker now and then on the ground in high gusty winds.)

1.     Set both engines at the same RPM at idle speed.

2.     Run one engine up until the amber light flashes, note RPM & MP.

3.     Continue adding power until red and amber indication, note RPM & MP.

4.    Repeat with the other engine:  The indication for the left and right should be within 20%.  *Gusty or windy conditions may make this test inaccurate.

                    H.  GROUND TEST:     (Without running engines)

*  CAUTION:  Do not over pressure system or blow into pitot by mouth. 6" of H2O pressure is equal to 110 mph, excessive pressure can upset calibration or damage the control box. 

1.     Attach a water manometer or "pitot static checking device" to the left pitot sensor.  (block the drain hole in pitot with tape)

2.     Apply a pressure very slowly until right amber indicator flashes and an aural tone warning occurs.  Pressure should be 1.2" H2O +/- .2"  (50 MPH or 43.5 Knots +/- 20%)

3.     Continue pressure until alternating red and amber indications on prop control.  Pressure should be 3"  H2O +/- .25"  (79 MPH or 68.5 Knots  +/- 20%)

4.     *  Leak Test:    Continue pressure to 6" H2O and hold without applying additional pressure.  (Maximum acceptable leak is 1' H2O in 60 seconds.  Preferable no leaks.

5.      The above test can be accomplished with the control unit outside the aircraft.  Bench test: Use wiring schematic 101-1100.

I.       Electrical Load:

1.     Low Thrust Detector System on:     24 or 12 volt systems  ½ amp maximum

2.     Sensor (Pitot) heat on:                     24 volt systems = 2.6 amps maximum.
                                                             12 volt systems = 5.0 amps maximum.

3.     System must be protected by a 5 to 10 amp fuse or circuit breaker to protect the wiring.  The control unit has an internal ½ amp fuse that protects the unit.

J.     Limitations:  None
This (LTDS) System has no appreciable effect on the weight, balance, structural strength, reliability, operational characteristics, or other characteristics affecting the airworthiness of the basic aircraft.  See FAA approved Airplane Flight Manual Supplement for operation of the “Low Thrust Detector System.”