By Jonny Lupsha, Wondrium Staff Writer
Boeing has chosen to ground all of its 737 Max airplanes, BBC News reported Thursday, March 14. The decision follows reports that recent satellite data shows similarities between the Ethiopian Airlines crash March 10 and another fatal crash in Indonesia last October. It’s a tragic misstep in the evolution of aircraft design.
Aviation has come a long way since wood-framed planes and the Wright brothers. From propellers to turbines and from biplanes to space shuttles, humanity has left the ground and reached for the stars for well over a century. Despite the heart-breaking loss of life that sometimes accompanies commercial airliners, passenger jets are still a giant stride in our advancement of flight. Let’s look at some other specifics in the history of aviation.
Combating Hypoxia with Pressurized Cabins
The external air pressure at the cruising altitude for a commercial flight is only about 25 percent of the air pressure at sea level. Breathing that low level of air causes the human body to suffer from hypoxia, a condition in which the body’s tissues become starved of oxygen. To prevent this from occurring, the cabins of modern aircraft are sealed and they circulate oxygen with a pressure that’s still lower than normal for most people but high enough to maintain a healthy traveling condition. “Your experience inside the cabin is like visiting a high-altitude city like Denver, Santa Fe, or Mexico City,” said Dr. James W. Gregory, Professor of Mechanical and Aerospace Engineering at The Ohio State University.
“The first planes with a pressurized cabin were a modified U.S. Army Air Corps plane in 1937, the Boeing B-29 Superfortress long-range bomber in 1939, and the Boeing 307 Stratoliner in 1940—a passenger plane that flew at 20,000 feet,” Dr. Gregory said. “These days, airliners can cruise at 35,000 to 40,000 feet.” This pre-World War II innovation significantly increased the maximum flying height of both military and commercial air travel.
High Strength and Light Weight
Since the dawn of aviation, aeronautical engineers and aircraft designers have struggled to reduce the weight of an airplane while maintaining its strength and structural integrity. This lofty goal led to the development of aluminum alloys in the early 20th century. Heating and combining metals into alloys first began in Germany. “It resulted in an early alloy termed duralumin in 1909, which transformed airship aircraft structural design and helped jumpstart the creation of the first monocoque planes,” Dr. Gregory said.
The Lockheed-Martin SR-71 Blackbird, a Cold War-era spy plane, required a material that was not only lightweight and durable, but could withstand high temperatures. Dr. Gregory explained that it necessitated the use of titanium in its production, and although the Blackbird was often used to spy on the USSR, most of its titanium was, ironically, obtained from the Soviet Union. Many aircraft in the 21st century use composite materials in their structures—for example, a combination of a carbon fiber weave and aluminum.
By regularly testing and refining the materials and engineering used in flight, aircraft designers can develop safer airplanes for commercial, private, and military use. Ideally, tragedies like the Ethiopian Airlines crash will become rarer in the future. For now, Boeing taking the initiative to ground its entire fleet of 737 Max aircraft is the safest bet in the wake of this disaster.
Dr. James W. Gregory contributed to this article. Dr. Gregory is Professor of Mechanical and Aerospace Engineering at The Ohio State University. He received a bachelor of science degree in Aerospace Engineering from Georgia Tech and a doctorate in Aeronautics and Astronautics from Purdue University.