ADDITIONAL ENGINE FAILSAFE
Posted: July 14th, 2016, 11:07 pm
I have put an item in 'Electric Stuff' on our website but to bring it to a wider readership I thought that if it was on this category I would get more feedback;
The CAA requirement laid down in Article242 Air Navigation Order 2009 states that;
(i) Any aircraft with a mass of more than 7Kg must be equipped with a mechanism that will cause the said aircraft to land in the event of disruption to or failure of any its control systems, including the radio link, and any such mechanism is in working order before the said aircraft commences its flight.
The usual application of failsafe settings, as you know, are based around stopping the engine and this is where things can, and do, go wrong.
Preset failsafe can only operate if the receiver in the aircraft is working. The airborne Rx system is subject to many stresses through vibration, hot environment in hot weather, water ingress in English weather and is more likely to fail than any part of the radio link. If the receiver loses its power, broken wires, faulty switches, loose connections, battery malfunction and the like then preset failsafe will not work and your aircraft could go careering on its way at full throttle…..not good!
The device which I put on our LMA forum under ‘Electric Stuff’ is an inexpensive unit for you to construct to include in the aircraft installation providing you are operating a petrol engine with either magneto or battery ignition or a turbine.
This unit will shut down the engine in case of power loss to the receiver thus complying with and completing the CAA requirements.
The application of this Failsafe is mainly aimed at aircraft using only one receiver, over 20Kg models will have dual control systems which will limit any safety problems, nevertheless the Failsafe could still be applied.
One spin-off from the unit for magneto engines is that, providing the Rx is switched off, turning the engine over to prime it can be done without the danger of kickback and bruised
fingers. In either case the engine can only be started with the receiver switched on.
The device will also shut down the engine if the battery voltage falls below 3.8 volts thus giving you the chance to glide the aircraft in before complete battery failure. Current drawn by the module is very low, approx 80 ma. The unit is simple to retrofit to existing installations.
If you are not an electronics ‘dabbler’ I can supply a prebuilt unit complete with wiring for mag or battery engines complete with fitting instructions. Call me on 07831546671 or email sheila.bransfield@btinternet.com
Dave Hayfield LMA 520
The CAA requirement laid down in Article242 Air Navigation Order 2009 states that;
(i) Any aircraft with a mass of more than 7Kg must be equipped with a mechanism that will cause the said aircraft to land in the event of disruption to or failure of any its control systems, including the radio link, and any such mechanism is in working order before the said aircraft commences its flight.
The usual application of failsafe settings, as you know, are based around stopping the engine and this is where things can, and do, go wrong.
Preset failsafe can only operate if the receiver in the aircraft is working. The airborne Rx system is subject to many stresses through vibration, hot environment in hot weather, water ingress in English weather and is more likely to fail than any part of the radio link. If the receiver loses its power, broken wires, faulty switches, loose connections, battery malfunction and the like then preset failsafe will not work and your aircraft could go careering on its way at full throttle…..not good!
The device which I put on our LMA forum under ‘Electric Stuff’ is an inexpensive unit for you to construct to include in the aircraft installation providing you are operating a petrol engine with either magneto or battery ignition or a turbine.
This unit will shut down the engine in case of power loss to the receiver thus complying with and completing the CAA requirements.
The application of this Failsafe is mainly aimed at aircraft using only one receiver, over 20Kg models will have dual control systems which will limit any safety problems, nevertheless the Failsafe could still be applied.
One spin-off from the unit for magneto engines is that, providing the Rx is switched off, turning the engine over to prime it can be done without the danger of kickback and bruised
fingers. In either case the engine can only be started with the receiver switched on.
The device will also shut down the engine if the battery voltage falls below 3.8 volts thus giving you the chance to glide the aircraft in before complete battery failure. Current drawn by the module is very low, approx 80 ma. The unit is simple to retrofit to existing installations.
If you are not an electronics ‘dabbler’ I can supply a prebuilt unit complete with wiring for mag or battery engines complete with fitting instructions. Call me on 07831546671 or email sheila.bransfield@btinternet.com
Dave Hayfield LMA 520