Corner Talk: Module 4 Electronics for Category B2 Exams ended yesterday afternoon with a smile on my face. Revision was well-planned, it should not be any problem for this examination. Thanks to the instructor for his patience and dedication in teaching us. Thanks you, Mr Edward. Today is 9th May, public day for the whole Malaysia in conjunction with Wesak's Day. It is a day where all the Buddhism pilgrims celebrate the day where Gautama Buddha achieved enlightenment (Nirvana) under the Buddhism Tree. On that day itself, pilgrims will attend the "Buddha Bathing" ceremony in the temple alongside with recitation of prayers and Buddhism songs. The event usually lasts till in the afternoon with vegetarian lunch in the temple.
Happy Wesak Day!Shiny Water Lily
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Next week, Module 5 Digital Technique for Category B2 will begin; Long module, wide scope with short time of coverage, approximately 2 weeks. So, it will be another hectic month ahead before college term end for semester break in the month of June. Revision during the weekend gives me an opportunity to come across additional knowledge, for example, the Take-Off Warning Circuit.
The main purpose of this Take-Off Warning Circuit is to give an aural and visual warning for the pilots in case the aircraft is in out of standard take-off configuration. A RED color CONFIG light will come on at the main instrument panel, at the same time, a aural warning will be produced to alert the pilots of any out of configuration. So, how this system works? It is quite straight forward ... Follow me step by step :)
The Take-Off Warning Circuit is made up of Logic Gates. Generally, Logic Gates are used to produce the intended outputs by various combination of inputs, commonly known as Logic 1 (HIGH) or Logic 0 (LOW) Logic Gates are came in the form of Transistor-Transistor Logic (TTL) or Complementary Metal-Oxide Semiconductor (CMOS) with the latter being more common nowadays. Two types of gates are involved in this circuit, (i) OR gate and (ii) AND gate. The OR gate will produce an output 1 when one of its input is logic 1. The AND gate will only produce output logic 1 when all of its inputs are logic 1. Remember the rules for these gates ...
Inputs to this system include, the engine throttle, slats position, flaps position, Weight on Wheel (WOW) Switch, Horizontal Stabilizer position and Spoilers position. The following condition occurs during take-off configuration:
Engine throttle (2, Left and Right) pushed to maximun power - Logic 1. The left and right throttle are pushed to maximum power giving logic 1 to OR Gate (1). The resultant outputs is logic 1 which is then inputted into AND gate.
Slats postion to be retracted during take-off. In the retracted position, Logic 0 is produced. Logic 0 is inputted into OR Gate (2) Next, Flaps position should not be more than 25 degrees for take-off. This produces Logic 0 for Flaps < style="color: rgb(153, 51, 153);">Spoilers should be retracted as well for take-off. Logic 0 is produced and inputted to OR Gate (2) The Horizontal Stabilizer should be adjusted to the GREEN band, a position where it gives the best angle of incidence to produce the Lift/Drag ratio for Take-Off. In the GREEN band, a logic 0 is produced and inputted to OR gate (2) Lastly, as the aircraft is yet to take-off, still on the ground, the WOW switch will produce a logic 1 which is inputted to AND Gate. Considering all the settings have been satisfied for take-off; slats retracted, flaps < style="color: rgb(153, 51, 153);">HIGH (Logic 1). So, whenever, the settings are out of the standard take-off configuration, a Logic 1 will be inputted into the OR Gate (2). This output will be fed to the AND Gate, giving an output Logic 1 ( Engine throttle maximum - Logic 1 and WOW Switch on ground- Logic 1) The output Logic 1 from the AND Gate will switch on the Warning Circuit. So, can you see the picture? Trace it down the chains slowly, I believe you will be able to understand it ...
The main purpose of this Take-Off Warning Circuit is to give an aural and visual warning for the pilots in case the aircraft is in out of standard take-off configuration. A RED color CONFIG light will come on at the main instrument panel, at the same time, a aural warning will be produced to alert the pilots of any out of configuration. So, how this system works? It is quite straight forward ... Follow me step by step :)
The Take-Off Warning Circuit is made up of Logic Gates. Generally, Logic Gates are used to produce the intended outputs by various combination of inputs, commonly known as Logic 1 (HIGH) or Logic 0 (LOW) Logic Gates are came in the form of Transistor-Transistor Logic (TTL) or Complementary Metal-Oxide Semiconductor (CMOS) with the latter being more common nowadays. Two types of gates are involved in this circuit, (i) OR gate and (ii) AND gate. The OR gate will produce an output 1 when one of its input is logic 1. The AND gate will only produce output logic 1 when all of its inputs are logic 1. Remember the rules for these gates ...
Inputs to this system include, the engine throttle, slats position, flaps position, Weight on Wheel (WOW) Switch, Horizontal Stabilizer position and Spoilers position. The following condition occurs during take-off configuration:
Engine throttle (2, Left and Right) pushed to maximun power - Logic 1. The left and right throttle are pushed to maximum power giving logic 1 to OR Gate (1). The resultant outputs is logic 1 which is then inputted into AND gate.
Slats postion to be retracted during take-off. In the retracted position, Logic 0 is produced. Logic 0 is inputted into OR Gate (2) Next, Flaps position should not be more than 25 degrees for take-off. This produces Logic 0 for Flaps < style="color: rgb(153, 51, 153);">Spoilers should be retracted as well for take-off. Logic 0 is produced and inputted to OR Gate (2) The Horizontal Stabilizer should be adjusted to the GREEN band, a position where it gives the best angle of incidence to produce the Lift/Drag ratio for Take-Off. In the GREEN band, a logic 0 is produced and inputted to OR gate (2) Lastly, as the aircraft is yet to take-off, still on the ground, the WOW switch will produce a logic 1 which is inputted to AND Gate. Considering all the settings have been satisfied for take-off; slats retracted, flaps < style="color: rgb(153, 51, 153);">HIGH (Logic 1). So, whenever, the settings are out of the standard take-off configuration, a Logic 1 will be inputted into the OR Gate (2). This output will be fed to the AND Gate, giving an output Logic 1 ( Engine throttle maximum - Logic 1 and WOW Switch on ground- Logic 1) The output Logic 1 from the AND Gate will switch on the Warning Circuit. So, can you see the picture? Trace it down the chains slowly, I believe you will be able to understand it ...
The circuit diagramClick on the picture to enlarge ...
Drop me a message anytime
if you wish to know further
about this system,
I will try my best to assist you ...
Happy Wesak Day once again,
Cheers,
KeithK :)
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