What is aircraft shock wave?
Shock waves are formed when a pressure front moves at supersonic speeds and pushes on the surrounding air. The sound wave is heard as the familiar “thud” or “thump” of a sonic boom, commonly created by the supersonic flight of aircraft.
What are the possible effects of excessive noise exposure on the hearing thresholds of aviation workers?
Ear pain: May occur during exposure to a 130 dB noise. Eardrum rupture: May occur during exposure to a 140 dB) noise. Temporary hearing impairment. Unprotected exposure to loud, steady noise over 90 dB for a short time, even several hours, may cause hearing impairment.
What is airframe fatigue?
Fatigue is a common occurrence among all metal airframes. Due to the repeated flight cycles and frequent use, the metal elements of planes become weakened over time, and they will eventually require attention and repair. This weakness manifests in cracks, which are microscopic at first.
What is the name of the shock wave at the front of the aircraft?
Sonic boom is an impulsive noise similar to thunder. It is caused by an object moving faster than sound — about 750 miles per hour at sea level. An aircraft traveling through the atmosphere continuously produces air-pressure waves similar to the water waves caused by a ship’s bow.
What happens across a shock wave?
Across a shock wave, the static pressure, temperature, and gas density increases almost instantaneously. The Mach number and speed of the flow also decrease across a shock wave. If the shock wave is perpendicular to the flow direction it is called a normal shock.
What are the key effects of aircraft noise?
It can cause community annoyance, disrupt sleep, adversely affect academic performance of children, and could increase the risk for cardiovascular disease of people living in the vicinity of airports. In some airports, noise constrains air traffic growth.
What are the health problems associated with noise from aircraft?
Scientists have raised concerns about the health effects of aircraft noise for two main reasons: There are studies that link excess noise exposure to increased stress levels; Some studies suggest that chronic stress might lead to an increased risk of high blood pressure (hypertension) and heart disease for some people.
What causes metal fatigue in aircraft?
Metal fatigue occurs when continuous stress leads to the accumulation of small cracks, causing metal to weaken. In a late-night news conference, the NTSB said that one of the engine’s 24 fan blades was missing. The blade had separated where it attached to the hub, where there was evidence of metal fatigue.
What is aircraft metal fatigue?
Aviation metal fatigue describes the effect of cyclical pressure and stress on metal parts. It’s particularly dangerous for aircraft since much of the aviation today involves at least 1-2 human lives on board in addition to any cargo.
What is Mach trimmer?
A Mach trimmer is a device which varies the pitch trim automatically as a function of Mach number to oppose Mach tuck and maintain level flight.