Read Each Thread and Reply with your thought. The replies must be at least 250 words each. eEach reply must incorporate at least one scholarly citation(s) in APA format. Any sources cited must have be

Read Each Thread and Reply with your thought. The replies must be at least 250 words each. eEach reply must incorporate at least one scholarly citation(s) in APA format. Any sources cited must have been published within the last five years. Acceptable sources include the most current sources you can find which likely means the Internet. Make sure to cite all facts in text.

Thread 1 

At the service center I worked at a few years ago, I had a Lear 60 come in for a bunch of inspections and discrepancies. One of the discrepancies was regarding the windscreen heating system. The write-up was very vague simply stating, “The co-pilots windscreen heat does not work.” Sure enough, I powered the airplane up, and found that the co-pilots windscreen did not heat when the windscreen heat switch was selected on. I also checked the pilots side windscreen and found that it heated appropriately when selected on. Therefore, I had a least isolated it to the co-pilot’s side only, I had completed step 1: define the problem. I then moved to step 2: Collect information regarding the problem. I accessed several components and wiring, and took voltage and continuity readings. I then moved to steps 3 through 7: Analyze the data, determine sufficiency of information, propose a solution, test the solution, and implement the repair (Mostia, 2006).

According to Mostia (2006) “You might propose solutions in the order of the easiest to the most difficult.” Since some components in an aircraft are very difficult to access, this is often the approach I use. If one part is easy to access and check, I will often start there, and work my way up or down the system, depending on my findings. I used that method in this case.

Lear 60’s operate off of a 28-volt direct current electrical system. However, the windscreens have inverters in their system that convert the 28-volt direct current into alternating current. There are two, basically identical windscreen heating systems, one for the co-pilot’s windscreen and one for the pilot’s windscreen. The components of the system include the direct current power supply, coming off a main power buss, a 100-amp fuse located next to the power supply, a relay, a control switch in the cockpit, a 5-amp circuit breaker for the control circuit, an inverter, associated wiring for the direct current side of the system, and wiring that carried the 110-volt alternating current from the inverter up to the windscreen. See the basic diagram I drew up at the bottom of this post for reference.

Effective troubleshooting is both an art and a science. According to McGowan and Coughlin (2016), “The "art" side of troubleshooting includes being a good listener, being observant, taking time to think over information, taking action, opening things up to look at them, and being willing to get dirty to get the job done. The science side includes doing calculations, testing the system, and comparing the results to what was expected in the design”. It is also important to avoid the “shotgun approach” As Mostia (2006) says, “Do not try several solutions at once. This is called the “shotgun approach” and will confuse the issue”. If you approach one problem from several different directions at the same time, you will lose track of what you have learned, and are likely to make mistakes leading to faulty conclusions.

Thread 2

One afternoon, U.S Coast Guard (USCG) 6014 came back from its afternoon patrol with an environmental control system (ECS) discrepancy. The 6014 is an MH-60T helicopter, manufactured by Sikorsky. The ECS is an air-cycle type control system, meaning it uses bleed air from an engine, auxiliary power unit (APU), or external air source to provide cooling for avionics and crew comfort. The air-cycle system in my opinion is easier to maintain and troubleshoot versus its vapor-cycle counterpart.

The ECS consists of an air cycle machine (ACM), water separator, heat exchanger, bleed air ducting, ECS controller, modulating valve, cabin temperature control valve, ECS control panel, and associated valves, sensors, and switches (U.S. G.P.O., 2012, p.163) The ACM is made up of a fan, compressor, and turbine, in which the ACM provides pressure and temperature stages of airflow. The water separator does what you would think, separates moisture from airflow in the final stage before flowing to the air ducts. The heat exchanger is made up of a primary and secondary units, which both are used to provide cooling in the air cycle system. The ECS controller is an electronic module that is essentially the brains, that takes inputs from automatic sensors and control valves to compensate for desired air temperature settings. The modulating valve is what is used to control the flow of the system, which is either “Norm” or “High.” The cabin temperature control valve is used to control cabin/cockpit temperature by mixing hot bleed air with conditioned air from the ACM. The ECS control panel is what houses all the operating controls for system. 

Using the schematic provided by the USCG flight manual, you can follow along with the flow of operation. The system of operation starts with the air flow going from the air source through the modulating valve and then the flow limiting venturi. From there the air splits off and goes to the primary heat exchanger and the cabin temperature control valve. From the primary heat exchanger the airflow is partially cooled, and is sent to the turbine driven compressor of the ACM. The compressor boosts the bleed air pressure and temperature. The output airflow from the compressor is sent to the secondary heat exchanger for additional cooling. Airflow from the secondary heat exchanger is routed to drive the turbine wheel of the ACM. The turbine expands and cools the airflow before it is sent to the water separator. The water separator traps moisture fro the cool air flow. From there the dry cool air flows into the cabin ducting and cools associated equipment/personnel.

This particular discrepancy was that the pilot noticed that the air flow was stuck in “NORM”, and would not go into “HIGH.” The pilot also mentioned that the discrepancy remained whether it was in manual or automatic control. Using the 7-step troubleshooting process found in chapter 4 of our textbook, can you please help me solve it? Remember what Mostia said, “While some argue that troubleshooting is an art, in fact, successful troubleshooting depends more on logic and knowledge” (2006, p. 16) Thanks in advance for the help.