News Analysis: Air India Learns: Composite Aircraft Advertised “Lightweight” Is ‘Stealthy’; “Fuel Saving” Is ‘Cloaked’ since “Manufacturing” may be at odds with “Marketing” where it involves Commercial Airline Manufacturers.
Beyond the varied inherent problems in Carbon/Carbon Composites (as ‘Rain in the Plane’), there is also the problem of strength to highly stressed areas of an aircraft such as the “Wing Box” where it merges into the fuselage. Other areas such as the wing interfaces (hard points) with engine pylon nacelles may require additional support for strength. The list goes on and on.
Where strengthening is required, ‘Doublers’ made of Carbon/Carbon Composite can be fabricated. In many cases, Stainless Steel or Titanium is required for maximum strength. ALL of the ‘Doublers’ add weight; much more than many ‘Marketeers’ will admit to customers.
Fuel burn increases occur, with the added weight of structural enforcements, subsequently added in production. The vaunted: “5%”, “6%”, “10%”, “12%”, or “15%” Fuel Savings, touted by some airframes, is an illusion in many cases.
Since Carbon/Carbon Composite Construction FOR COMMERCIAL AIRCRAFT, is with a very short history, it is likely such aircraft can be expected to be written off in a much SHORTER LIFE SPAN. Metal aircraft have decades of life-span confirmation. They are not subject to deterioration from Solar Ray degradation of the metals (as are the adhesives used in Carbon/Carbon Construction). Furthermore de-lamination of the plies (due to stressing over time) weakens the fabrication significantly.
The Ethiopian Airlines Battery Fire, which was widely disseminated in the press, demonstrates another shortcoming of Composites: Heat. Allegedly, the Airframe rebuilt, in purported secrecy, the area that was damaged. “Why the concealment?” many airlines ask.
Lastly, Composites do not dent; they fracture when hit. Any Landing Gear Failures will demonstrate the “Shattered Egg Shell Principle” as Composite Aircraft Fuselages hit runways.
From a Manufacturing perspective: If an Airline wants Longevity, Reliability, and Safety (LRS), Metal Constructions cannot be beat; a long History demonstrates this simple fact.
Alleged “Light-Weight” Construction is an also-ran in the ‘LRS’ Evaluation of Airline Aircraft to Purchase.
What materials may be suitable for Warfare Environment “Expendable” Military Aircraft is not necessarily the best for the travelling public in Commercial Airliners.