Lake Gear And Flap LED Modification |
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Original System |
Modified System |
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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:
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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. |
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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) |
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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. |