Working on my Instrument Panel. Layout is pretty much done, and I have shown it before, now working on labeling and placarding. Several issues have come up. First thing to know is the electrical scheme is AeroElectricConnection Z-14. Circuit protection is by ATC type fuses. CB’s are only used in conjunction with crowbar type over voltage protection from the alternators and ground power. The fuel pumps and ECU for running the engine are powered off of always hot buses.
My panel is to be powder coated flat light grey, all labeling and placards are engraved in the panel then filled with black paint except where I feel a need to accentuate the item with red paint instead. Both colors contrast well with the grey powder coat. All placarded text has an outline.
One of the principles in warning design is to emphasize based upon seriousness and likelihood. So one of the checks is if I have too much or I picked the wrong ones to focus on. Let’s get to the high severity stuff:
Autopilot Disconnect
Electric Cross Feed
Engine Fire
Electrical Fire
Autopilot Disconnect Pushbutton and Pullable Circuit Breaker
I have the pushbutton disconnect switch and pullable circuit breaker to make sure that I can disconnect a runaway servo. Both are planned to be labeled in red to help the pilot find them in a hurry. Wondering about also bordering both controls in red instead of black. How often does a runaway servo happen anyway? Thoughts on this?
Electrical Cross Feed
This function is (per AEC Z-14) combined with starter function on an S700-2-5 switch also called an On-Off-(On) switch. The middle position is not connected to anything. Bottom position is spring loaded to center and for engaging both batteries to crank the engine. Top position will stay, engaging the electrical cross feed to allow running anything in the system, even if the battery and alternator on that set of buses have died. I am thinking the placard is a double black border, black words for STARTER and red for X-FEED to aid the pilot in finding it if he needs something powered by the dead buses.
Engine Fire
Fire in Engine Area is pretty straightforward. Cut off flow of fuel to the fire and do the fastest job you can of getting it on the ground.
In this airplane, turning the fuel selector handle OFF still leaves 9 gallons of gas available to an engine fire. I have in mind a cutoff valve between the header tank and EFI fuel pumps, operated by a cable to a pull handle on the panel. Our local mechanic says I should secure the valve with a single turn of thin brass safety wire to keep that valve open until that engine fire happens. I am planning a red handle on that cable, red lettering, and a red border with the words FUEL SHUT OFF PULL HARD. Sound OK or not?
Just in case the valve does not close or there is already fuel all over the place, I have in mind to shut off the transfer pumps, EFI pumps, and ECU after pulling the Fuel Cutoff handle. These are all OFF in the down position and right in front of the pilot. They are powered from an always hot bus, so we had better turn them off. I was thinking two options:
Since the pumps and ECU are not powered from the Masters, I thought that I should have this spelled out where the pilot is reminded of the unusual procedure every time it is seen… Thoughts on this scheme?
The heat/defog system has an air flow control that should be closed to avoid pumping flame products from the engine compartment into the cabin. Pull to close, like the Fuel Cutoff? Label the close function in red paint? Red border on this placard or black?
Electrical Fire
Placard next to Master Switches in red:
ELEC FIRE CK LIST
TURN OFF MASTERS
IF NO EFFECT
ENGINE FIRE CK LIST
While hitting the Masters will turn off power to about ¾ of the circuits, I thought that the reminder to shut down the remaining electrical sources was in order if that proves to be not enough. Thoughts?
Yeah, I know, Billski is overthinking this stuff again.
Billski
My panel is to be powder coated flat light grey, all labeling and placards are engraved in the panel then filled with black paint except where I feel a need to accentuate the item with red paint instead. Both colors contrast well with the grey powder coat. All placarded text has an outline.
One of the principles in warning design is to emphasize based upon seriousness and likelihood. So one of the checks is if I have too much or I picked the wrong ones to focus on. Let’s get to the high severity stuff:
Autopilot Disconnect
Electric Cross Feed
Engine Fire
Electrical Fire
Autopilot Disconnect Pushbutton and Pullable Circuit Breaker
I have the pushbutton disconnect switch and pullable circuit breaker to make sure that I can disconnect a runaway servo. Both are planned to be labeled in red to help the pilot find them in a hurry. Wondering about also bordering both controls in red instead of black. How often does a runaway servo happen anyway? Thoughts on this?
Electrical Cross Feed
This function is (per AEC Z-14) combined with starter function on an S700-2-5 switch also called an On-Off-(On) switch. The middle position is not connected to anything. Bottom position is spring loaded to center and for engaging both batteries to crank the engine. Top position will stay, engaging the electrical cross feed to allow running anything in the system, even if the battery and alternator on that set of buses have died. I am thinking the placard is a double black border, black words for STARTER and red for X-FEED to aid the pilot in finding it if he needs something powered by the dead buses.
Engine Fire
Fire in Engine Area is pretty straightforward. Cut off flow of fuel to the fire and do the fastest job you can of getting it on the ground.
In this airplane, turning the fuel selector handle OFF still leaves 9 gallons of gas available to an engine fire. I have in mind a cutoff valve between the header tank and EFI fuel pumps, operated by a cable to a pull handle on the panel. Our local mechanic says I should secure the valve with a single turn of thin brass safety wire to keep that valve open until that engine fire happens. I am planning a red handle on that cable, red lettering, and a red border with the words FUEL SHUT OFF PULL HARD. Sound OK or not?
Just in case the valve does not close or there is already fuel all over the place, I have in mind to shut off the transfer pumps, EFI pumps, and ECU after pulling the Fuel Cutoff handle. These are all OFF in the down position and right in front of the pilot. They are powered from an always hot bus, so we had better turn them off. I was thinking two options:
- First is to mark the off positions of these switches in red;
- Second is to placard above the switches in red with:
ENGINE FIRE CK LIST – PULL FUEL CUTOFF
CLOSE ALL VENTS + TURN OFF THESE SWITCHES + EMERGENCY DESCENT
CLOSE ALL VENTS + TURN OFF THESE SWITCHES + EMERGENCY DESCENT
Since the pumps and ECU are not powered from the Masters, I thought that I should have this spelled out where the pilot is reminded of the unusual procedure every time it is seen… Thoughts on this scheme?
The heat/defog system has an air flow control that should be closed to avoid pumping flame products from the engine compartment into the cabin. Pull to close, like the Fuel Cutoff? Label the close function in red paint? Red border on this placard or black?
Electrical Fire
Placard next to Master Switches in red:
ELEC FIRE CK LIST
TURN OFF MASTERS
IF NO EFFECT
ENGINE FIRE CK LIST
While hitting the Masters will turn off power to about ¾ of the circuits, I thought that the reminder to shut down the remaining electrical sources was in order if that proves to be not enough. Thoughts?
Yeah, I know, Billski is overthinking this stuff again.
Billski
