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Fuel pump inertia cutoff switch

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steveg said:
A warning light is for when the condition is present, i.e. your fuel pump is off. With the switch I used, which seems to be very common (and the same as Moss sells), you can use the "NO" pin to run a warning light if the switch is tripped.
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Great idea Steve.... Thanks. That is exactly what I will do!
 
I installed the switch on my rear "seat" heelboard with a box that has two switches, one for each end of my fuel pump. I have two lights only to tell me which half is running. If you have a SU fuel pump, you don't need a light, you can hear the pump, or not.
 
John Turney said:
I installed the switch on my rear "seat" heelboard with a box that has two switches, one for each end of my fuel pump. I have two lights only to tell me which half is running. If you have a SU fuel pump, you don't need a light, you can hear the pump, or not.
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I'm using a dual facet setup with the pumps on rubber isolation mounts. With the engine running, the pumps can't be heard.
 
steveg said:
I'm using a dual facet setup with the pumps on rubber isolation mounts. With the engine running, the pumps can't be heard.
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I can't hear the SUs with the engine running either, but if the engine is running, it won't run long if the fuel pump(s) aren't.
 
Ray Says:
use the tripped switch as an incognito security advantage,

In short, if used as an incognito security device and U want do it but, personally, I see no need.

I agree TOO.​
 
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John Turney said:
I installed the switch on my rear "seat" heelboard with a box that has two switches, one for each end of my fuel pump. I have two lights only to tell me which half is running. If you have a SU fuel pump, you don't need a light, you can hear the pump, or not.
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John - how long have you been running the switch and has it ever deployed?

On a previous car I had a switch deploy on a rough railroad crossing.
 
Maybe germane to this conversation, maybe not: All civilian aircraft in the US--and probably military as well--are required to have an Emergency Locator Transmitter, or ELT, on board. ELTs are radios that transmit a coded 'SOS' signal on emergency frequencies--used to be 121.5MHz but now I think it's 243--if the aircraft encounters significant G-events (i.e. a crash, and sometimes just a hard landing will set them off). ELTs are tested yearly at annual inspections and the batteries are mandated to be replace every couple of years. Presumably, I've never seen a circuit diagram, ELTs have a type of inertia switch to automatically activate the transmitter, but I've read quite a few NTSB accident reports and, often as not, the 'ELT did not activate' (likely explains how aircraft can sometimes disappear without a trace; see: Fossett, Steve).

Just sayin'.
 
That's a nice installation and convenient location Steve. I'm curious to learn if your switch will deploy on bumpy roads. I have yet to install mine but I have some concerns while knocking it about that it may be a little too sensitive. Perhaps I'll wire mine to a buzzer or test light and take it for a drive to see just how trigger happy it is.
 
Bob_Spidell said:
Maybe germane to this conversation, maybe not: All civilian aircraft in the US--and probably military as well--are required to have an Emergency Locator Transmitter, or ELT, on board. ELTs are radios that transmit a coded 'SOS' signal on emergency frequencies--used to be 121.5MHz but now I think it's 243--if the aircraft encounters significant G-events (i.e. a crash, and sometimes just a hard landing will set them off). ELTs are tested yearly at annual inspections and the batteries are mandated to be replace every couple of years. Presumably, I've never seen a circuit diagram, ELTs have a type of inertia switch to automatically activate the transmitter, but I've read quite a few NTSB accident reports and, often as not, the 'ELT did not activate' (likely explains how aircraft can sometimes disappear without a trace; see: Fossett, Steve). Just sayin'.
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Both 121.5 VHF and 243 UHF are the "guard" frequencies that ELTs broadcast on. A landing would have to be really hard - a crash on the runway, essentially - to set it off. It's meant for really catastrophic crashes so that the bodies are easier to locate. Please do not ask me how I know this.
 
You wouldn't think it if you met me but I can be a bit pedantic sometimes. This isn't an aviation forum but the ELT frequency structure changed to 406 mgHz around 2009. I think the military frequency still stands. The satellites no longer relay 121.5 although it is still a vox emergency frequency. When the old ELTs die by attrition they will all be 406 MgHz and they transmit digital data specific to each aircraft that has one. The 406 ELTs and personal locator beacons used by outdoors people and worn on emergency aircrew vests are monitored by the COSPAS/SARSAT international satellites. Interestingly enough this was set up long ago as an international effort, the COSPAS part is actually a Russian acronym. Just sayin'. :tennis:Notwithstanding any reliability issues, I would not fly in the back- country without one.
 
Got the Delphi GT280 pick but wasn't able to extract the connector from the plug. Too bad it doesn't come with three wires.

screenshot.1826.jpg
 
roscoe said:
You wouldn't think it if you met me but I can be a bit pedantic sometimes. This isn't an aviation forum but the ELT frequency structure changed to 406 mgHz around 2009. I think the military frequency still stands. The satellites no longer relay 121.5 although it is still a vox emergency frequency. When the old ELTs die by attrition they will all be 406 MgHz and they transmit digital data specific to each aircraft that has one. The 406 ELTs and personal locator beacons used by outdoors people and worn on emergency aircrew vests are monitored by the COSPAS/SARSAT international satellites. Interestingly enough this was set up long ago as an international effort, the COSPAS part is actually a Russian acronym. Just sayin'. :tennis:Notwithstanding any reliability issues, I would not fly in the back- country without one.
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Thanks for the correction (I've been out of flying for a few years and dropped a bit). If anybody's interested, here's a good source:

https://www.aopa.org/advocacy/aircraft/aircraft-operations/emergency-locator-transmitters
 
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