Lake Gear And Flap LED Modification

Original System

Modified System

   
All of the gear switches are in series - so if a switch fails, or if a gear is not locked, the corresponding light will not illuminate, but there is no indication as to the fault. Each switch has its own dedicated LED.  If a switch is not closed, the LED will not be illuminated and a particular gear can be immediately identified.
If a gear switch were to jam to the "on" position, the pilot would never know and that particular gear position would no longer be monitored. 
If the gear corresponding to a jammed switch were to malfunction, the pilot could have the light on, but the gear in an unsafe situation. (This has happened.  This happened to me!)
If a switch were ever to jam in the "on" position - the corresponding LED would never extinguish.  I.e. in the gear-up position, there would be 3 blue LEDs illuminated, and one of the "down" LEDs would also be illuminated.  The pilot would know right away that there was a fault in the system.  (Instead of waiting until the next annual!)
The colors of the lights are non-intuitive.  For an amphibious plane, gear-up is the desired configuration for a water landing. 
A red light doesn't make sense.
The LED colors have some logic:
 
Function Color Logic
Gear Up Blue Blue Sky, Blue Water
Gear Down Green Land landing - Green Grass
Flaps Up White In the air - White Clouds
Flaps Down Amber Transition - Like traffic lights
Aside from color, the shape and layout of the indicators is identical. 
This allows one to easily confuse which light represents which function.
From a human factors points of view, there are three gear LEDs corresponding to three gear.  There are two flap LEDs corresponding to the two flaps.
A quick look at the LEDs gives an unambiguous interpretation of the information.  
The existing incandescent lamp system draws a lot of power, gets hot, and the bulbs have a limited operating life.
(2 lights on = 660ma, or about 9 watts)
The LEDs draw less power and for all intents and purposes, they will never burn out.
(5 LEDs on = 100mA, or about 1.4 watts)
The original system is dimmable by mechanical irises and each lamp has a test function The system as designed is electronically dimmable and has a test switch which activates all of the LEDs.
Weight of lamp units = 180 grams Weight of LED system = 85 grams
Original wiring. A key feature to this modification is that NO ADDITIONAL wires are required to any of the switches.
Original approval. This modification has been approved by Transport Canada under a Limited STC.