Aircraft Structures In-course AssignmentGroup (?) Research EssayHistorical Review -Jun JiaFreighter aircraft are either built via mass production or converted from passenger/military aircraft. The method of conversion can be dated back to the early era of commercial aviation, for example, in 1919, American Railway Express used a converted Handley-Page Bomber in an attempt to fly 1,100 pounds( 500kg ) of freight from Washington D.C to Chicago. It wasn’t until after 1945, after WW2, with an abundance of ex-military aircraft (E.g Douglas DC-3, Douglas C-54 Skymaster) that the Air cargo business picked up through converting the unused military aircraft to commercial freighter aircraft.As time passed,other piston engine aircrafts were converted to commercial freighter aircraft. As of 2010, several Douglas DC-6 variants were used as commercial freighter aircraft in Canada. The Lockheed-L’1249 Super Constellation, part of the Lockheed Constellation aircraft family, made for military operations in 1954 and 1955 was short lived and was repurposed for civilian aircrafts.Airframe of the Lockheed-L’1249 was used to build Lockheed-L’1049H the freighter aircraft that “Flying Tiger Line” uses now.In the era of the turboprop engine, two passenger to freighter aircraft stood out. The Lockheed L-188Reasons Behind increasing demand of PTF conversion – Wei KoonCargo transport has a very high demand in the world of transport systems due to it making more money for a transport company than transportation of passengers (Wensween, 2007). Another reason for the increasing rate of conversion from passenger to freighter aircraft is the growth of E-commerce and demand for express delivery services. These industries rely on the movement of time-sensitive and high-value goods like consumer electronics and perishables that require airfreight. Thus, these changes in consumer expectations increase the demand for air -freight and the conversion of passenger planes to freight cargo planes. A specific reason for conversion of aircraft from passenger to freighter is that market conditions favour older generation aircraft due to its availability and also due to the relatively low price of fuel. However, the market is transitioning to a new generation of converted freighters for long term usage, but does not expect growth before 2020 due to the high market value of these new generation aircraft. ( iba 2017 white paper ) An application of PTF conversion is that it extends an aircraft’s economic life by 15-20 years compared to being a passenger aircraft. This is due to normal passenger aircraft having a midlife for up to 25 years, while freighter aircraft have lives up to 35 years and more.However, while it might seem that the benefits of converting to a freighter aircraft far outweigh the cons of doing so, the process of converting a passenger to freighter aircraft is much more complex and expensive than one might think.Firstly, the conversion of an aircraft from passenger to freighter requires a long line of work, such as requiring conversion supplier selection, combining scope of work for conversion and maintenance and fleet standardization with avionics upgrade etc. Also, the time taken for a conversion is typically 3 – 4 months, where an aircraft must be grounded and it earns zero revenue in the time. Furthermore, it is not a cheap procedure, costing around a $ 4 – 6 million dollar investment.