The quest to determine the fate of Lion Air Flight 610 took a step forward this month when investigators finally discovered the plane’s second black box following a two-month search, Indonesia’s Transportation Safety Committee announced. The Boeing 737 MAX 8 went down on October 29, losing contact with air traffic control just 13 minutes after taking off from Jakarta, crashing into the Java Sea and killing all 189 people aboard. Investigators currently believe the crash was caused by a new automated flight control system, which was designed to prevent stalling by automatically correcting the angle between the plane’s wing and the oncoming air flow, but instead fed false data to the flight computer that forced the craft’s nose down. The new black box contains the voice cockpit recorder, which will hopefully shed additional light on the causes of the crash.
As the tragedy of Lion Air Flight 610 illustrates, even a small mistake in aerospace design can have deadly consequences. Aerospace is a no-failure industry, where the precision of every part counts, no matter how small. Here’s a look at some small parts that play a major role in aircraft performance and safety.
O-rings
One small but vital component of today’s aircraft is the rubber seal known as the o-ring. Originally developed to seal piston cylinders in electric streetcars, the o-ring was quickly adapted for use in hydraulic systems in aircraft during World War II. Today, o-rings serve important functions in many parts of aircraft, including engines, wing flaps, landing gear and brakes. O-ring seals designed for aircraft are made from specialized materials such as Viton, which has a wide range of temperature resistance from -13 degrees F to 446F, as well as strong chemical resistance, making it suitable for use in airplane engines.
While o-rings are small, their impact on aircraft performance can be enormous. For instance, after Eastern Airlines Flight 855 had to make an emergency landing in Miami on the way to the Bahamas, it turned out that the mechanic had failed to install o-rings in the engine’s magnetic chip detector, used to detect early signs of engine failure by attracting metal chips that have broken off from engine parts. Without the o-rings, oil seeped out of the engine during the flight, nearly causing a catastrophe.
Spark plugs
Another basic but critical component of aircraft design is the spark plug. Like car engines, aircraft engines rely on devices to deliver electrical current from the vehicle’s ignition system to engine’s combustion chamber. When airplanes were first invented in the early 1900s, small planes initially used spark plugs adapted from automobile engines. Soon, specialized aviation spark plugs were developed specifically for use in aircraft engines.
Because spark plugs play such a key role in starting up aircraft engines, when they don’t work correctly, the impact can be dramatic. For example, Continental Motors aircraft engines have recently suffered incidents of pre-ignition suspected to be caused by damaged spark plug insulators. Pre-ignition can be one of the most damaging combustion processes an engine experiences, generating enough heat to melt pistons and rings.
Fasteners
One of the most important but most easily overlooked components of aircraft design is the many fasteners that go into holding a plane together. Fasteners include items such as rivets, screws, bolts, nuts and clamps. Half of the millions of parts used to build a single aircraft are typically varieties of fasteners, making fasteners among the most vital structural components of an airplane.
Since fasters play such a key role in aircraft structure, their failure can cause significant damage. For instance, an Air Force Boeing RC-135 reconnaissance aircraft suffered major fire damage caused by a loose retaining nut, CNN reports. The nut was supposed to be connecting a metal oxygen tube to a junction fitting, and when it came loose, it triggered an oxygen leak, causing the aircraft to catch fire. Fortunately, the plane skidded to a stop on the runway before taking off, and all crew members escaped safely, but the fire cost $62.4 million in damage.
O-rings, spark plugs and fasteners are small parts that are easy to take for granted, but their functioning is crucial for aircraft performance and safety. Installing these parts correctly and maintaining them properly is a prerequisite for efficient, accident-free air travel.
Photograph by Danilo Bueno