Use Of Light Alloy Materials In Aircraft Construction Engineering Essay

Q1. Evaluate and Analyse: The use of light alloy materials in aircraft construction. Aircraft construction involves the use of various alloys including titanium alloy, magnesium alloy and aluminium alloy. Titanium alloys are useful in parts of aircraft that need to be of high resistance against heat. This alloy is usually used in turbine engine blades, tail pipe casings, and engine firewalls. The alloy is also preferred more for construction of high speed aircrafts. This alloy has melting point of around 13000 C to 14500 C (Huang, 2004). This alloy is useful for aircrafts that are built for fighting purposes. Cutting of alloys of titanium and magnesium results in generation of; sparking at normal instances. These are not easy to cut down. Therefore, parts of aircraft that need to cut down at any moment in the future, do not make use of these two alloys.

Magnesium alloy is best suited for strengthening of brackets all across the aircrafts, turbine engines for compressor casings, piston engine’s crank cases, and brackets of engine mounting (Anyalebechi, 2005). This alloy melts at a temperature ranging from 7000C to 8000 C and burns at a temperature higher than this (Huang, 2004). Aluminium alloys on the other hand are of quite less melting point and are easy to be cut down. Therefore, these are best suited for aircraft parts that need not be too tough and can be cut down as and when required.

Alloys of magnesium are preferably used in construction of aircraft due to their nature of being light weight resulting in cost reduction on consumption of fuel and air pollution. The stiffness and strength of magnesium alloys is quite lower at the temperature of around 1500 C (Greger et al., 2007; Kielbus et al., 2007; Dobrzanski et al., 2007). These characteristics act in favour of the alloy and raise its demand in the construction work of aircrafts. This alloy is highly acceptable due to its strong nature of material ability leading it in favour of the alloy and increased demand of this material to suit the needs of the industry.

The use of composites in aircraft construction.

Composite materials are quite widely used in today’s times for the construction and development of modern aircrafts. Even these can be used to retrofit to aircrafts that become old. The composites are developed by using MMMF (Also called as Man Made Mineral Fibres) to make it a durable and strong material for construction purpose of aircraft. These materials are more used for construction of wheel bay doors, engine cowlings, cabin floors, and control surface. However, these materials are not good for those who locate around the aircraft during wreckage conditions.

The material of aircraft at certain instances require good ratio between strength and weight, i.e. the ratio has to be high enough (Anyalebechi, 2005). The nature to fabricate satisfies this need for aircraft construction and development. Bonding materials are used for development of these composite materials. Therefore, these are best suited to prepare majority of parts of an aircraft. Because of this reason, composite materials are in huge demand in present days for construction purpose of normal aircrafts. The materials are also durable and because of this nature of durability, the parts of aircraft suit best for these. However, there are situations when there is the need to cut the material while carrying on the construction work. At such instances it becomes important to make use of these materials for parts that are hard enough to keep the aircraft safe against risk situations.

With the change in thermal value of a composite takes place, it generates thermal stress on the body, which is due to the disturbance created. Composites are made up of thin sheets and fibres are stated in lines within the sheet therefore for making use of composite, these shall be in the form of layer (Olsen, 1986). For construction work, aircraft’s ends that need to be constructed by moulding material, composites are well suited. One can also manipulate physical properties of the material by introducing some orientations in between the layers of fibre (Olsen, 1986).

Analyse/Compare the choice of use made in a & b above.

For the construction of an aircraft, it becomes important to focus on the quality of material used. The material used shall be of high strength first of all. This is necessary to ensure that the aircraft is strong enough and can stand well. However, there are chances that the aircraft due to this factor becomes quite heavy and in turn requires huge force to fly it due to high degree of stress over its wings. The tensile strength of devices shall be strong enough in aircraft.

However, at present times the aircraft construction has migrated towards the use of composites of high strength (Wireless News, 2005). At normal instances, graphite composites are used for construction of aircraft wings, which does offer high degree of strength. The density of these composites too is quite high. Therefore, the composite of this type results in quite a well defined value of strength to weight ratio.

Figure 1: Change in coefficient of thermal expansion due to change in temperature.

Source: Huang, 2004

From the above we can note how the increase in temperature affects the value of coefficient of thermal expansion for the composites of aluminium alloys. Higher the temperature of surroundings, higher is the risk of melting of material used for construction work. Therefore, it becomes crucial to use materials based on the need, else there can be chances of accidents for these devices. There are always risks of fire and other accidents in the environment for aircraft industry. Alloys and composites are however, not possible to be used alone for the construction of an aircraft. Depending on the requirement, both of these shall be made use of instead of just depending on either of the materials. Therefore, before the construction to take place, it shall be clear enough in mind to know the requirement and basic needs of each of the parts. In this case, the situation becomes favourable for aircraft resulting in production of a strong and safe aircraft.

It is noted that composites of graphite outperform the value of metal alloys of common nature for constructing any wing. The strength of graphite composite is higher as compared to that of steel too. The stiffness range is quite varied up to the minimum value of AA6061- T6. Therefore, the composite, on comparing with aluminium, has high stiffness. In addition, these composites can even be stiffer as compared to mild steel. Composite materials are therefore a preferred choice in present times due to their high degree of stiffness and strength. These materials can be used in quite a large number of parts of an aircraft resulting in increased demand for construction work of an aircraft, as compared to that of alloys (Anyalebechi, 2005).

Depending on the requirement for construction of any part of the aircraft, it becomes crucial to make use of the material that suits best to the need. Some of the parts of aircraft demand the use of strong material, whereas others do not need high tensile strength. Parts of aircraft such as wings require ability to be safe against high temperature conditions, whereas other parts such as cabin and floor need to be durable enough to make a good quality of aircraft. Therefore, composite materials such as graphite composite are quite suitable for construction of wings while other parts can be made using alloys of aluminium.

Q2. Investigate and Evaluate:

Why the correct identification of aircraft spare parts is critical to the safety of aircraft.

Aircraft carries hundreds of lives at risk in the sky. A minor mistake can result in huge losses of life. Therefore, it becomes quite important to properly evaluate the safety features of aircraft’s spare parts. Fire is amongst the most risky hazard against aircrafts, whether they are for military, civil or commercial purpose. Fire while in flight is considered as 4th highest hazard that arises due to accidents in jet aircrafts (Boeing, 2005). This shows the risk of fire as quite notable ones. FAA (Federal Aviation Administration) had argued that if no proper measure is taken and the rate of occurrence of accidents in aircraft taking place due to fire continue at same rate, the increase in demand of air traffic would further increase death due to fire by 4% annually (Federal Aviation Administration, 2006).

If no proper measures are taken then the risks are probable to increase more and more. Polymer composites reinforced by fibre are increasingly used in today’s scenario and is a serious point of concern, because these composites are more risky against fire. These materials produce heat and smoke, which cause serious damage against livestock. Therefore, it becomes important to properly evaluate the risk features against aircraft and associated fire hazards. Aircraft manufacturing companies take due care for construction of aircrafts with proper safety standards. Aircraft parts at both of its sides may look similar, but there are possibilities that they are a bit different then each other. This can result in high risk of functionality making it unsafe for use.

While building an aircraft, it is important to look at each and every part of aircraft and adopt proper measures for pilot testing of finished aircraft. Construction Company for aircraft shall make sure that right parts are used in construction work. Although there are number of parts of aircraft, ones that are safer are preferred ones. Thus, the parts that are durable in nature shall be the better choice for construction.

In case, risks due to flaws in aircraft spare parts are not identified at the right time, it may result in huge loss of lives. There is huge sensitivity risk in this industry due to the reason that a minor mistake can be quite dangerous for mankind. For evolutionary stages of construction work, it shall be properly taken care of. There should be testing efforts made for individual units of aircraft, as this strategy can help in finding out the mistakes thoroughly.

Studies conducted by Li (1994) long ago also had explored the concept of risk of accidents in aircraft due to one or the other reason in its spare parts. He suggested cohort study as an important method to alloy complete investigation for the aircraft and its associated risks (Li, 1994). Therefore, cohort study shall take place to find out the weaker parts of an aircraft and work towards improvement of these sections. If one finds out any particular region is not of enough potential and strength, steps shall be taken to make it a stronger one with greater tensile strength. At such an instance the use of graphite composite can be a good selection due to high strength of this material.

Also the measures shall be taken to find out the sections of aircraft that are prone to creep down or shrink in high temperature conditions. This can further lead to void of wing’s skin, which is a notable point of worry at all the situations, else there are always the risk of breakage of these materials in the sky due to change in pressure and other conditions of air in that situation. The measures at such instance can lead to a safer stand for the aircraft and therefore would increase the safety of people using these services.

Evaluate an example of a safety incident due to incorrect spares.

Safety has always been an important point of concern for safety of humanity. People living in this technological era are continuously faced with one or the other risk. There are situations when the aircraft parts are not used properly or there are shortcomings in the quality of spare parts used for construction of an aircraft, which result in huge losses. There are also the situations that involve illegal trade of spare parts that cause danger situations.

There has been quite a number of bogus parts usage found in the aircraft industry at various instances. These were fifty two in number during 1991 and increased to more than three hundred by the end of year 1992 (Wolmar, 1993). This represents an increase in risk of aircrafts due to incorrect use of parts for construction work. These faulty parts lead to loss of quality and stiffness of aircraft. Same was the condition that occurred in South West part of USA when

The discussion here is done of crash that happened on 10 July 2006 of Fokker Airplane. This F27 plane production had started since year 1955. Initially the development work was done more for less seating capacity of aircrafts. However, with the passage of time, its strength has increased. The company was doing well in its industry though; the accident that took place in July 2006 completely changed the scenario.

The aircraft was constructed in the year 1964. The airplane flew successfully on 24th January 1964 for the first time in France. This was then sold to “All Nippon AW” and then to TAT and then to PIA. The plane served well till 10 July 2006, when the crash happened. This was the crash that changed the perception of individuals towards the airplanes. People had increasingly feared of using this mode of transport due to its associated risks. This accident was 66th in the world for aircraft industry whereas in Pakistan, 8 accidents took place before this (High Court Bar Association, 2011).

The aircraft F-27 was quite appreciated in Europe due to its economic benefits, however the materials used in its products increased its inherent defects, resulting in a crash finally in the year 2006. Though the aircraft had served well for quite a long duration, the negative results were finally obtained. The manufacturer of this product had to suffer for bankruptcy due to this accident. Anthon Herman Gerard Company located in Holland was bought to an end finally after the accident. The vendor of this aircraft construction company was working on spare parts that were not approved. Because of this step, the life of individuals had to suffer a lot. Thus, the humanity got endangered due to this mistake. Rapid occurrence of accidents had resulted in numerous accidents in Europe because of which the people protested against aircrafts thereon. This lead to introduction of safer aircrafts with assured quality of construction material used.

There had been several problems found in technical operations of the aircrafts. Main issues of concern have always been the use of air safety features and spare parts used in aircraft construction. Therefore it becomes important for engineers constructing aircraft to assure that there is no weak section in the aircraft due to weak quality of materials used. Mentioning the list of important spare parts is not enough, but there shall be due care of the parts used for each of the shelf. This gives greater strength to the aircraft designed. The accident of Fokker aircraft had occurred mainly because of the non usage of genuine spare parts for maintenance and the operations had been carried on by locals instead of using certified engineers and organizations and humanity had to pay for this.