Boeing DreamLiner 7E7
Boeing plans for the 21st century, advanced passenger flights that are environmental friendly and innovative in passenger flight manufacturing technology. If Boeing’s plans for the 7E7 Dreamliner come true, air travel will become cleaner for the environment, quieter for those living near airports and more pleasant for passengers.
Boeing will start producing passenger jets with 200-300 capacity from late 2008. Boeing, as the “new steel” of the 21st century is hailing advanced composites. They comprise thin yet incredibly strong sheets of carbon fibers and other non-metallic materials glued together with epoxy resins and baked in giant ovens or autoclaves.
The US aircraft maker says all of these things will flow from the unprecedented use of advanced weight-saving composites and plastics in the 7E7 series. It aims to cut final assembly time of the jets, using large, seamless, rivet free molded parts, from more than four weeks for metal airliners down to three days.
Although composite parts were first used by Airbus 20 years ago, they have never been used as extensively as in the new Boeings, with most of the fuselage, wings and tail made of the miracle materials.
But the design of the 7E7 series and the 62 early orders placed by All Nippon Airways, Air New Zealand, First Choice (UK) and Blue Panorama of Italy are “provisional” meaning as yet incomplete.
Many questions remain unanswered. Is the world ready for jets that pop freshly baked out of an oven? What if should one of them crash and burn.
Australia’s National Airports Emergency Planning Committee has spent several years working on new procedures for composite aircraft accidents for Airservices Australia, which runs the country’s major accident response units as well as its air traffic control system.
The issue for Airservices Australia was the habit of military high-composite aircrafts such as the B-2 stealth bomber or the Black Hawk helicopter to turn into toxic smoke instead of a heap of metal when they crash and burn.
Also, if broken but not burning, advanced composite materials may shatter into potentially lethal contaminants and clouds of light but exceptionally sharp long glassy needles.
Because both its own air force as well as those of visiting allies shares some of Australia’s major airports, the emergency planning committee began reviewing procedures for such accidents well before Boeing announced the Dreamliner project early last year.
Although according to Airservices Australia, there was never any suggestion that the new Boeings or even the giant Airbus A380, which is 23 percent composite in structure, would be banned. Spokesman Richard Dudley stated that they were just determined to understand what different issues might arise in an accident, and do the planning well in advance.
The concerns of the closed sessions of the planning committee in the event of a crash were many, including whether a high proportion of survivors and their rescue workers would die from the longer term effects of inhaling toxic by-products and if there were any proven procedures for effectively decontaminating people exposed to the materials.
It seems there might not be definitive answers until after the jets are in service, even if the worst fears of some experts prove unfounded.
Leith Higgins, director of the Fire and Emergency Services Authority in Western Australia, has been Airservices Australia’s leading adviser on composite materials and has studied them in great detail over the past three years. In his Idea these materials produce horrible little fibers when they break, and that the needles can penetrate right through limbs covered with protective clothing.
They even shatter into very small particles, which can be ingested into the lungs easily and evade the macrophages that help keep them clean from harmful material. On the available research it is yet to prove that composite particles will be as lethal as asbestos as some claimed to be. The trouble with composites, and the reason for devising such elaborate emergency responses, is that no one could prove practically or theoretically, that they will not turn out to be that dangerous.
There are still many unanswered questions. Airservices Australia says its emergency units will drench the site of any high composite aircraft accident with special foam whether or not a fire has broken out. This approach will be to keep any particles on the ground thus containing their spread. This will also apply to survivors and rescue workers.
Personal protection gear resistant to the sharp particles will be issued and closed breathing apparatus will use a molecular filter so fine that it will trap the very fine particles that could pose a serious risk.
The director of the Central Disaster Unit in Sydney, David Cooper, said the policy in the event of such an accident would be to decontaminate any survivors or emergency workers at the site before they were admitted to emergency wards where they might otherwise endanger staff and other patients.
On the plus side, composite engineers say the energy absorbent characteristics of the materials will reduce trauma and improve survival rates in a lower velocity accident such as a bad landing, taxiway collision or even a forced landing in benign circumstances. Metal fuselages break open and rip at comparatively low speeds, but composites recoil or bounce as they absorb much of the energy from a slow blow, and they don’t catch fire as readily either.
These claims are supported by the amazing examples of survival in Grand Prix Formula 1 accidents, where the vehicles today make even more use of composites than a 7E7.