Session 7 at SOAR by AVEMBSYS

                                  The SDLC has four phases namely Analysis,Design,Development and testing .After each phase the product under development is sent to the client for approval.The client at this stage can request for change(RFC).These changes should be incorporated and then tested.Once Analysis phase is over,its output is a SRSD(Software Requirement Specification Document) which is sent to the client for approval.
                                   The different software development models use are:

1. Waterfall Model
2. Spiral Model
3. V Model

Waterfall Model
               The waterfall model is so called because of the cascade from one phase to another.In this model the following phase should not start until the previous phase has finished.The problems with the analysis phase are identified in the design phase and problems with design phase are identified in the development phase and so on.
Advantages:

• Provides certainity
• Documentation is provided at each phase

Disadvantages:

• Difficult to respond to changing customer needs.

Spiral Model
              Rather than representing the SLDC phases in a sequence this model allows backtracking from one phase to another.Each spiral represents a single phase.The number of spirals shows the level of development.

V Model
               This model is used for machine critical embedded systems.At each phase of the SDLC the corresponding test cases are identified and noted.After the testing phase each of these test cases are tested.At every stage the client requirements are tested.


Then we discussed about the SRS(software requirements specification) for aircraft landing schedules and high level design document.
Airports and Airspace
The airport consists of:

1. Runways-the path where aircrafts run,to takeoff and land.It may be paved or unpaved.The runways are numbered using the magnetic heading.The default is the North Pole.Nmae of the runway is one-tenth of the magnetic heading.Every runway has two numbers.

Standard traffic pattern:

• Downwind leg
• Base leg
• Final approach
• Departure leg
• Crossing leg

The windsock is used to determine the direction of flow of wind.
     2.Taxiway-These are the links between runways and the airport parking areas.
     3.Airport Signs-There are six basic types of signs

• Mandatory
• Location
• Destination
• Direction
• Information
• Runway distance remaining

    4.Lighting systems

• Approach light systems
• Runway edge systems
• In runway lighting
• Taxiway lighting
• Airport beacon
• Visual Approach Slope Indicator(VASI)
• Precision Approach Path Indicator(PAPI)

     5.Controlled airspace

• Class A
• Class B
• Class C
• Class D
• Class E
• Uncontrolled airspace:Class G

Special Airspace

• Prohibited area
• Restricted area
• Warning area
• Military operations areas
• Alert areas
• Controlled firing area

ILS Categories

• Precision

        Cat 1
        Cat 2
        Cat 3:Cat 3A,Cat 3B,Cat 3C

• Non-precision

Session 6 at SOAR by AVEMBSYS

                                           The topic of discussion in the sixth session was the SDLC i.e the Software Development Life Cycle.This cycle consists of four phases:

1. Analysis Phase
2. Design Phase
3. Development Phase
4. Testing Phase

The percentage of time and resources  each of these phases require is as follows:
Analysis Phase-10%

Design Phase-20%

Development Phase-20%

Testing Phase-50%


Analysis Phase
This phase consists of:

• Finding the problem
• Feasibility- It can be of two types: Technical Feasibility and Financial Feasibility.Technical Feasibility means that the technical limitations should be considered and Financial Feasibility makes sure that the resources available are considered.

The analysis phase consists of analyzing the problem and defining the requirements.
Design Phase
This phase consists of:

• Top Level Design(system level design)- Here algorithms,flowcharts and block diagrams are used.
• Low Level Design(detailed design)-Here data structures,logic and functions are used.

The output of this phase is either a HLDD(high level design documentation) or the LDD(low level design documentation).

Development Phase
Here the documentation is translated into any one of the programming languages by a programmer.

Testing Phase
Here the product is tested against a list of test cases.These test cases are based on the client requirements.
                             This session was very helpful in knowing the importance of the SDLC as SDLC is very important in all aspects of engineering.

Session 5 at SOAR by AVEMBSYS

               Session five began with an introduction to Avionics.The term Avionics is derived from Aviation Electronics.It consists of all electronic and electromechanical systems and subsystems(hardware and software) installed in an aircraft or attached to it.Avionics must be integrated in the conceptual design phase in the design of an aircraft.Aircrafts can be further classified as:

• Aircraft with ejection.eg:Civil Aircraft(probability of catastrophic failure<10-9/flight hour).
• Aircraft with ejection.eg:Fighter Aircraft(probability of catastrophic failure<10-7/flight hour).

                 The following are the basic principles:

1. Safety of an aircraft.
2. Mission of an aircraft.
3. Life Cycle Cost/Cost of Ownership.
4. Certification.

[note:
 FAA(Federal Aviation Administration) does the certification of aircrafts for the US.
 DGCA(Director General of Civil Aviation) does the certification for India.
 CEMILAC(Center for Military Airworthiness Certification) for military aircraft certification.]
                   The military IFF(Identify Friend or Foe) sends a code.Commercial aircrafts flying over a particular country's airspace send codes,which the radars fixed on the ground,catch.If the aircraft is not a civil aircraft(i.e if the IFF code does not match) the aircraft is shot considering it to be an enemy aircraft.These IFF codes are standard codes and cannot be manipulated easily.
                    The Avionics System consists of the following:Weather Radar,Glide Slope,Marker Beacon,DME(Distance Measuring Equipment),ATC Transponder(transmitter and receiver),TCAS,Radio Altimeter,VHF or UHF,FM Broadcast(communication between two pilots),ADF(Automatic Direction Finder),UHF Satcom(Satellite communication).
                    The next topic to be discussed was about navigation.Under navigation you have Absolute Navigation System,Dead Reckoning Navigation System and Mapping Navigation System(most widely
used).The various type of controls are:

• Flight Control
• Engine Control(electronic control of engine thrust).eg:FADEC which stands for Full Control Digital Engine Control System.
• Flight Management eg:FMS which stores th co-ordinates of the en route way points and calculates the steering signals to fly towards them(4D Navigation).
• Subsystem Monitoring and Control(faults in all subsystems are displayed).
• Collision Avoidance(predicts impending collisions with other aircrafts).eg:TCAS and EGPWS.                     

                   There are four types of data that is handled:

1. Fresh and valid data.(this is the data that is used)
2. Fresh but invalid data.(not to be considered)
3. Stale but valid data.(new data is read every 50ms).
4. Stale and invalid data.(useless data).

The next term discussed was the ELT(Emergency Location Transmitter).This is triggered automatically on high-g(high gravity).ELT's emit distinctive tones on 121.5,234,406 MHz.The 121.5MHz is the emergengy frequency.When tuned to this frequency,the ATC instructions can be heard.
                  For military aircrafts the Avionics Systems are different.Namely:

• Radar,Infrared and other Target Sensors.
• Weapon Management(Fire control and Stores management).
• Electronic Counter Measures.(ACAX)
• Mission Planning.(preflight mission planning)
• Formation Flight.

The Regulatory and Advisory Agencies are:

• ICAO-International Civil Aviation Organization,Canada.
• FAA-Federal Aviation Administration,USA
• FCC-Federal Communication Commission
• RTC-Requirements and Technical in aviation
• ARINC-Aeronautical Radio Incorporated
• SAE-Society for Automotive Engineers
• IEEE-Institution on Electrical and Electronic Engineers
• JAA-European Joint Aviation Authorities
• EUROCAE-European Organization for Civil Aviation Equipment
• DGCA UK,DGCA-Director General of Civil Aviation

The term EGPWS stands for Enhanced Ground Proximity Warning System.This system provides caution and warning to the pilot about terrain around the aircraft so that pilot can take necessary action.There are seven modes:

1. Excessive Descent Rate
2. Excessive Closure to terrain
3. Altitude loss after takeoff
4. Unsafe terrain clearence
5. Excessive glideslope deviation
6. Advisory Callout/Backangle
7. Wind Shear Alerting

The next system discussed was the TCAS(Traffic Collision Avoidance System).It has two types of alerts:

• Traffic Advisories(TAs)-assist pilot in the visual search for intruder aircrafts.
• Resolution Advisories(RAs)-resolve potential mid-air collisions.

Session 4 at SOAR by AVEMBSYS

               The fourth session commenced with a detailed discussion about aircrafts and their various classifications.
                The early aircrafts were the Ornithopter(Leornado Da Vinci,1500),Lighter than Air-Craft(Fransesco de Lana,1670),Airplane(George Cayley's Model,1804),Glider(Otto,1896).The Flyer by the Wright Brothers was the first powered,sustained and controlled flight(1903).The aircrafts are further classified based on the following:

• Based on the space they operate in:

1. Spacecrafts
2. Aircrafts

• Based on propulsion:

1. Propelled(Airplanes)
2. Unpropelled(Airships/Gliders)

• Based on crew:

1. Manned
2. Un-manned(UAV/RPV)

• Based on wings:

1. Fixed Wings
2. Rotary Wings

• Based on type of winds:

1. Monoplane
2. Bi-plane
3. Tri-plane

• Based on landing mode:

1. Sea
2. Land
3. Amphibian

• Based on engines:

1. Propeller
2. Turbofan
3. Turboprop

• Based on number of engines:

1. Single
2. Twin
3. Multiple

• Based on function:

1. Fighter(F-16)
2. Bomber(Jaguar)
3. Transport(IL-76Gajraj)

• Special types:

1. Reconnoissance
2. Microplane
3. AWACS(Airborne Warning and Controlled System)
4. Aerial Refueling
5. Vertical Takeoff
6. Stealth
7. Aircraft Carriers
8. Voyager
9. Skycar
10. Solo Flying Machine

                          The next thing that was shown to us was a crash video of the Avianca Flight 052.The reason this video was shown to us was to comprehend the communication between the pilot and the ATC(Air Traffic Controller).The crash occured due to many of the following reasons.The first reason was that the pilot was not very fluent with his English and could not clearly understand what the co-pilot was trying to convey to him.The second reason was that when the co-pilot mentioned to the ATC that the flight was running on low fuel,this information was not transferred to the subsequent ATC's.The third reason was that an emergency was not declared by the flight crew.Instead the word priority was used for a priority landing.If these reasons would have been taken care of,then this crash could have been prevented.
                           The last topic to be discussed was the ILS(Instrument Landing System).There are two things that need to be taken care of during the landing of an aircraft,the lateral guidance and the vertical guidance.The airplane on landing should be exactly at the center of the runway.This alignment should be done at a distance of 10kms.The lateral and vertical guidance is maintained by the ILS antennae located on either sides of the runway.These antennae emit radiofrequency waves of 90MHz and 121MHz and help the aircraft in landing.
                           This session enlightened us about the important role played by an ATC in the landing of an aircraft and also brought into light the different technologies used to make sure the aircraft is during its flight and on landing.

Session 3 at SOAR by AVEMBSYS

                      The third session held by Avembsys was our actual venture into the Aerospace field.We were given a brief introduction on the classification of aircrafts.We discussed about the various aspects of Aerodynamics and terms related to it,some of which I was hearing for the first time.We discussed topics like Electronic Warfare and EMP(Electromagnetic Pulse).Terms like Static Pressure,Stagnation Pressure,Standard Sea-Level Conditions,Aircraft Attitude,Center of Gravity,Angle of Attack,Stall Speed,etc were also discussed.
                      We then learnt about the different externally visible parts of an aircraft and how each of these parts are integrated to form an aircraft as a whole.The following parts were discussed in detail:

• Cockpit
• Fuselage
• Jet Engine
• Wing
• Elevator
• Rudder
• Spoiler
• Aileron
• Slats

                   The parts of an aircraft wing and its functionality was taught in great detail.The role of a wing in the lift of an aircraft was also discussed.A video of a crash that included the first computerized control system for an aircraft,Airbus 320 was shown along with the investigation and report details.
                   The session ended with a discussion on the probable project topics.I found this session more interesting as compared to the last two sessions as it gave me a deeper insight into the Aerodynamics field as a whole and opened doors to a great field,I had not known much about!

Session 2 -> " Almost Right is 100% Wrong "

The second session was fun.We first learnt about the basics of embedded systems and then a video clip was shown to us and we were asked to identify the different embedded systems.We were also shown many interesting videos of mid-air collisions and the 10 most scariest landings.
              What I found most interesting was the crab landing  piolets do during cross winds.It was simply amazing!This was the first time i did not feel sleepy in a class. We are told that we will be visiting the AVEMBSYS office this Monday.Looking forward to that.

Session 1 at SOAR by AVEMBSYS

Finally created a blog for myself!!!:)All thanks to AVEMBSYS!!AVEMBSYS is a company where I,along with a few of my college mates,are being trained for our final year projects.Not only is AVEMBSYS going to help us complete our projects,it is also going to impart us knowledge in the field of avionics!We have completed two sessions as of now.The first session was an introduction to basic C programming concepts.A few students also shared their project ideas and we discussed the feasibility of those projects.Of all the project ideas,I liked Santoshini's idea the most.A very noble idea indeed!!!!