Re: Flight AA77 on 9/11: Nuova analisi FDR conferma official path di A77
Inviato da UN_post il 25/1/2011 21:18:56
Citazione:
http://www.explainthatstuff.com/how-altimeters-work.html
How does a radio altimeter work? Radio altimeters don't suffer this problem. They're simpler and work in a similar way to radar (the system planes, ships, and other vehicles use to navigate): they just fire a beam of radio waves down from the plane and wait for the reflections to return. Since radio waves travel at the speed of light (300,000km or 186,000 miles each second), it takes only a few hundredths of a second for a radio beam to make the 20,000-meter or so round trip to Earth's surface and back. The plane times the beam and calculates its altitude in kilometers by multiplying the time in seconds by 150,000 (that's 300,000 divided by two: don't forget the beam has travelled twice as far as its own altitude going to the ground and back again). Radar altimeters are much quicker and more precise than pressure instruments and are widely used in high-speed airplanes or ones that need to fly at particularly low altitudes, such as jet fighters.
Rob, almeno sinora, non ha fatto niente di tutto questo ma si sta limitando a ripetere che Frank Legge ha commesso molti errori e che il Radio Altimetro non era affidabile a quelle velocità.
http://www.explainthatstuff.com/how-altimeters-work.html
How does a radio altimeter work? Radio altimeters don't suffer this problem. They're simpler and work in a similar way to radar (the system planes, ships, and other vehicles use to navigate): they just fire a beam of radio waves down from the plane and wait for the reflections to return. Since radio waves travel at the speed of light (300,000km or 186,000 miles each second), it takes only a few hundredths of a second for a radio beam to make the 20,000-meter or so round trip to Earth's surface and back. The plane times the beam and calculates its altitude in kilometers by multiplying the time in seconds by 150,000 (that's 300,000 divided by two: don't forget the beam has travelled twice as far as its own altitude going to the ground and back again). Radar altimeters are much quicker and more precise than pressure instruments and are widely used in high-speed airplanes or ones that need to fly at particularly low altitudes, such as jet fighters.
Messaggio orinale: https://old.luogocomune.net/site/newbb/viewtopic.php?forum=3&topic_id=6116&post_id=183996