Session 7 at SOAR by Avembsys

                     The session began with a brief explanation about structures in C programming, how they are initialized and used while writing a code in C language. In the previous session we came across the software development life cycle in which there are four phases. Once the analysis phase is approved by the client the developer, before going to the design phase the developer must decide on the software development models such as:
  1. Waterfall model
  2. Spiral model
  3. V-model
                    
                      In the waterfall model, after the completion of each phase, the next phase begins. Here there is no provision for any changes in the previous phase that is completed, hence the second phase onwards, depends upon the success of the previous phase. Thus any failure in the lower phases leads to the failure of the complete software. This is the shortcoming of the waterfall model and is rarely used.
                      Next is the spiral model. In this model the phases are assigned to four different quadrant and the SDLC process is executed in a spiral manner. After the completion of the SDLC process i.e., the initial prototype is shown to the client for approval and further requirements to be enhanced, the process is repeated again and again until all the requirements are fulfilled. This model is used more for a specific product to be developed which has a long life cycle than a software.
                      The final model is the V-model. Here after completing each phase the test case is identified. This model is used for mission critical embedded systems such as bombs and other warfare material. At no point of time is the requirement not tested i.e., at every stage the requirement is tested. We also saw a software requirements specification document(SRSD) for aircraft landing scheduler, which gave us more insight about SDLC.
           
                        The next topic of discussion was about Airports and Airspace, which mainly dealt with the following topics; runways, taxiways, airport signs, lighting systems, controlled airspace, flight information, ATC, radars and landing aids. A runway is a path or area of land prepared for landing and take-off of aircrafts. The runway numbers are generally one-tenth of the magnetic azimuth of the runways heading. The entire horizon is divided into three with the north pole as the zero degree reference. For example a runway numbered 9, it means it is the 90 degree magnetic heading. A runway has two numbers because an aircraft can land from either side of the runway depending upon the direction of the wind i.e., against the direction of the wind. If one side of the runway is numbered 9 the other side will be 27.
                            Then we saw the traffic pattern, i.e., the pattern which the aircraft genarally takes to land or take-off. An entering pattern at 45 degree angle to the midpoint of the downwind is recommended followed by the base leg, final approach, departure leg and crosswind leg. We also saw different types of runways. Taxiways are links between runways and the airport parking areas. We also saw a brief overview of the Instrument landing system(ILS), which guides the aircraft to align itself to the centre of the runway for safe landing. Further details about ILS will be covered in the upcoming sessions.
                              We also saw six different types of airport signs. Each sign gives a certain information to the pilots of an aircraft such as location, direction, destination, runway distance remaining, mandatory information and other important information such as noise sensitive area located south east of runway 9/27.
We also saw the different lighting systems on a runway such as approach light systems, runway edge lights, In-runway lights, taxiway lights, airport beacons, visual approach slope indicator and the precision approach path indicator. Then we saw what is controlled airspace, a brief description of cloud cieling and special airspaces such as prohibited area, restricted areas, warning areas, military operations areas, alert areas and controlled firing areas. Next we had a brief discussion about ATC's, radars, transponder and landing aids. A brief idea about each and how they work. Finally we saw the different ILS categories, i.e., the systems that are used while landing an aircraft based on various factors. For example during bad weather or during zero visibility CAT 3C type of ILS systems are used.
                                  The seventh session at SOAR was very interesting with a lot of project ideas being discussed, but at the same time we aquire a lot of domain knowledge in avioncs and embedded systems.
The sessions are very lively and interactive which makes it less boring. Our techlead is very supportive and approachable with any kind of query or doubt. Looking forward to the next session for more information and ideas in the field of avioncs.                                

Session 6 at SOAR by Avembsys

                    Hello everyone, session 6 at SOAR kickstarted with a brief knowledge of identifying bugs in a program. Our techlead then took over the session. The topic of discussion was about the software  development life cycle(SDLC). The SDLC has the following four phases:
       1. Analysis(10%)
       2. Design(20%)
       3. Development(20%)
       4. Testing(50%)
The percentage in the brackets is an average amount of time required for each phase of the cycle. It may vary from one software to another, i.e., depending on the type of software we are developing.
                   
                    Analysis is the first phase of the SDLC. In this phase it is the job of the developer to identify any problem that coulb be encountered by the software, the feasibility and the requirements.
                    To understand this let us consider the following example. The client who is a banker wants a software for an ATM machine and the developer is required to fulfill his requirement. A business analyst mediates between the two and explains exactly to the developer what he has to do. The developer prepares a questionaire for his client to understand the exact requirement. The developer also has to make sure of the technical, financial and commercial feasibilty of the software. The requirement is a collection of problems and sub-problems. The document of the analysis is sent to the client for approval. Once approved, the next phase of the SDLC is the design.
                 
                     In the design phase, we need to have design goals i.e., what we want to achieve with this design is very essential to have in mind. The first part of the design consists of the high level design. The high level design includes the following; algorithms, flowchart and blocl diagram. The output of a high level design is the high level design document. After this we have the low level design which includes the following; data structure, logic and function. More thought process goes into the design phase, because any flaws here could lead to the failure of the software.
                   
                      The next phase is the development. Here we translate the english language or in other words the design into a C language or any programming language. The code should follow the coding standards and the code should be re-usable i.e., it should be flexible and not rigid. Finally we come to the testing phase which tests the software. If there are any flaws we must go back to the design phase and correct it.With this, the sixth session at SOAR came to a close.

Session 5 at SOAR by Avembsys

                       Hello everyone, session 5 at SOAR bagan at 2 pm. My dear friend Jawad explained the concepts of branching, looping and the importance of precedance of operators. Our techlead then took over the session and we had a brief discussion regarding our project.
                        The main topic of discussion was about AVIONICS which is otherwise known as aviation electronics. It is defined as, all electronics and electromechanical systems and subsystems (hardware and software) installed or attached to an aircraft. Avionics must be integrated in the conceptual design phase in the design of an aircraft.
                         We then discusssed about the avionics system requirements, i.e., safety, mission of the aircraft, life cycle cost and certification. Certification is a major factor in avionics design. Some of the important agencies around the world are the Federal Aviation Administration(FAA) in the United States, Directorate general of civil aviotion in india and others.
                          We then saw a picture of the different avionics placement on a multipurpose aircraft. It consisted of the following; GPS, military IFF(identify friend or foe),microwave landing system, weather radar, glide slope, avionics bay, marker beacon, DMF, VHF 2/military UHF, ATC transponder, TCAS(traffic collision avoidance system), radio altimeter, ELT, TACAN, FM broadcast, live tv, ADF(automatic direction finder), UHF SATCOM, C-band SATCOM and TCAS Dir.
                            The IFF is a critical part of an aircraft. If this does not function, there is a high probability that the aircraft can be shot down while flying over an enemy territory. Another interesting part is the live television at the back end of an aircraft, which is used to see the view outside an aircraft.
                            We then saw a live professional code. The interesting part of the code was how it was written from start to finish, the number of variables used and also the name assigned to any variable. It is important that the name of a variable is unique such that the programmer and the user knows what the variable is actually holding. We also saw the C-coding standards used while writing a professional code.
                              Next we discusssed about the Emergency Location Transmitter(ELT). This subsystem is triggered automatically on high impact or manually. ELT's emit distinctive tones 121.5, 243 and 406Mhz. These frequencies are monitored by search and rescue aircraft and by SASAT-COSTAS satellite. In case of an emergency where a pilot is not able to fly an aircraft, anybody can take over the plane and fly it by tuning it to 121.5Mhz frequency and recieving instructions from the ground.
                              The different regulatory and advisory agencies are as follows, ICAO, FAA, FCC, RTCA, ARINC, SAE, IEEE, JAA, EUROCAE, DGCA UK, DGAC France, DGCA India. The aircraft and its mission  drive the avionics system design. An example of the Avionics systems is the enhanced ground proximity warning system(EGPWS). It provides caution and warning to the pilot about the terrain around the aircraft so that the pilot can take necessary action.
                              The seven modes of EGPWS are as follows:
 MODE 1: excessive descent rate
 MODE 2: excessive closure to terrain
 MODE 3: altitude loss after take off
 MODE 4: unsafe terrain clearance
 MODE 5: excessive glideslope deviation
 MODE 6: advisory callout/bank angle
 MODE 7: windshear alerting

                               Finally discussed about the traffic collision avoidance system(TCAS) which includes traffic and resolution advisories. The TCAS symbols are non-threat traffic, proximity intruder traffic, traffic advisory and resolution advisory. With this another enthralling session came to an end.
                              
                       

Session 4 at SOAR by Avembsys

                   The fourth session was scheduled at 3 pm and we saw the various classification of aircrafts and also analysed a case study on an air disaster that took place on 25th january 1990. The session was of short duration but nevertherless an interesting one.
                    We first discussed about the project that we were assigned to do,
each of us gave our insight of how we intend to progress further and our techlead has guaranteed full support for the same. Then we looked at the evolution of aircrafts, the Ornithopter, the Lighter than aircraft, the Airplane,
the Glider and the Flyer.
                    Aircrafts are classified based on the space in which they operate, i.e., ionosphere, mesosphere, stratosphere and the troposphere. An Aircraft is one which flies from one place on the earth to the other where as a spacecraft flies from one planet to another in the universe. This is the essential difference between the two.
                   Aircrafts are further classified based on the following, propulsion, crew, wings, type of wings, landing mode, engines, number of engines and function. Special types included Reconnaissance, AWACS, microplane, aerial refuelling, vertical takeoff and stealth aircraft. What caught my eye among these is the stealth aircraft which cannot be detected by any radar in the world. It is designed in a manner such that the electromagnetic waves from the radar are scattered away by this aircraft and would fly as though it was invisible. Simple amazing!! but it comes at cost of a whopping two billion dollars.
                    We also saw the skycar and the solo trek XFV solo flying machine and also disscussed about the bermuda triangle where 50 ships and 20 airplanes have crashed due to various factors. We then saw video clip of an air disaster. It was AVIANCA 052 passenger airplane flying from Borgoto to New York.
                    The crash was due to a series of factors. The main factor was due to the mis-communication between the ATC(air traffic control) and the pilots.
The captain of the aircraft was poor in english, hence the co-pilot had to be the mediator between the ATC and the captain. Another reason was the bad weather at the JFK airport, which saw only one runway operating, because of which the air traffic increased. AVIANCA 052 was made to circle around(also called the holding pattern) for more than an hour which caused the fuel load to decrease and crashed due to engine shutdown. The co-pilot also did not declare an emergency, instead he used the word priority which led to further confusion. 85 of the 158 passengers were rescued. ILS called the instrument landing system is a new technology which helps the pilots to align the airplane to the centre of the runway by lateral and vertical guidance.                                          
                           This was the end of another session at SOAR and i look forward for further upcoming sessions.
                    

Session 3 at SOAR by AVEMBSYS

            Avembsys training resumed after a long break and everybody seemed ready to kickstart the session with open ears and mind. The session began with Jawad brushing up a few basics of C programming. He covered topics like data types, identifiers, pointers and command line arguments.
            Our Techlead then took over the session. We first discussed about what is Flight Management System(FMS) and how electromagnetic pulse is used in electronic warfare. An electromagnetic pulse is used in overcoming an enemy assault. The FMS can guide the aircraft's autopilot along the flight plan fed into the system.
            We then looked at the various aerodynamic basics. The core fundamental concepts are based on ninth standard physics such as mass,
weight, force, momentum, moment, couple, density, temperature, viscosity
and pressure.
             Viscosity is the resistance of a fluid being deformed due to pressure.
It increases with speed, an example of which is best understood by keeping your hand outside a moving vehicle, i.e., the viscosity of air increases. Viscosity of liquid decreases with increase in temperature and for gas it increases with increase in temperature. Pressure is the force acting per unit area. An aircraft's airspeed indicator is operated by the static pressure system and the pitot pressure system.
              How does an aircraft fly?
The jet engine sucks the air, forms a small jet of air and rejects it at the back. This provides the thrust required for the aircraft to fly. While take off the lift is achieved by the difference in slope at the top and bottom of the wings, which creates a low pressure on top and high pressure at the bottom of the wing.
We then saw a view of the aircraft which consists of the following, a cockpit, fuselage, spoilers, aileron,flaps,elevator,rudder,vertical and horizontal stabilizer, wing and jet engine.
              Next we discussed about cloudburst. It is a form of precipitation, and is very dangerous for aircrafts to land during a cloudburst. We had a 30 minute lunch session. In the post lunch session we discussed about the projects and were divided into two groups to handle two basic projects. One was based on hardware and software and the other was a software project. I chose to work on the former.
              The project is based on data transmission and reception with two seperate modules using 8051 microcontroller interfaced with an LCD display and a keyboard. Also light sensors are to be used to detect data being transmitted and to send any data to the transmitting module.
              Finally we saw a video of how an aircraft takes off and lands vertically and another video or i must say we saw a documentary of the horrific crash of a french commercial aircraft which took place in the year 1988. We analysed the different causes or reasons for the crash and it gave us a good insight about the different intricate details that has to be taken care before flying an aircraft. With this the 3rd session came to a close. I look forward to gain more knowledge and expertise in this domain.