Why don't voice radio communications use FM?

"Emily" wrote in message
...
Mxsmanic wrote:
Peter R. writes:

A leading cause of accidents? Where did you get this statistic?

From the NTSB and several books on the subject.

Guess? If a pilot or controller is not able to comprehend the other
side's
transmission, there is no guess. "Say again?" is the phrase of choice
and
it is used all over the frequencies.

It's routine in linguistics to unconsciously guess. A person
listening to familiar sounds in a familiar context will "fill in the
blanks" for any sounds that cannot be unambiguously distinguished, and
he will do this without thinking. If he guesses wrong, trouble can
result, and accidents have happened in aviation for this reason (the
most famous probably being the one at Tenerife).


Actually, in the Tenerife accident, the only radio problem was caused by
simultaneous radio transmissions by aircraft, NOT a pilot hearing want he
wanted to hear. The tower told the KLM aircraft to stand by at the same
time the Pan Am aircraft transmitted, which resulted in a blocking of both
transmissions. There were many other steps in the accident chain, but
Tenerife was most certainly not caused by a pilot hearing what he wanted
to hear.

Correct, and FM would not have solved any of the problems. At least with AM
the heterodyne lets people know there were multiple simultaneous
transmissions. The capture characteristics of FM do away with this
sometimes useful feature.

Dave Stadt wrote:
"Emily" wrote in message
...
Mxsmanic wrote:
Peter R. writes:

A leading cause of accidents? Where did you get this statistic?
From the NTSB and several books on the subject.

Guess? If a pilot or controller is not able to comprehend the other
side's
transmission, there is no guess. "Say again?" is the phrase of choice
and
it is used all over the frequencies.
It's routine in linguistics to unconsciously guess. A person
listening to familiar sounds in a familiar context will "fill in the
blanks" for any sounds that cannot be unambiguously distinguished, and
he will do this without thinking. If he guesses wrong, trouble can
result, and accidents have happened in aviation for this reason (the
most famous probably being the one at Tenerife).

Actually, in the Tenerife accident, the only radio problem was caused by
simultaneous radio transmissions by aircraft, NOT a pilot hearing want he
wanted to hear. The tower told the KLM aircraft to stand by at the same
time the Pan Am aircraft transmitted, which resulted in a blocking of both
transmissions. There were many other steps in the accident chain, but
Tenerife was most certainly not caused by a pilot hearing what he wanted
to hear.

Correct, and FM would not have solved any of the problems. At least with AM
the heterodyne lets people know there were multiple simultaneous
transmissions. The capture characteristics of FM do away with this
sometimes useful feature.

I think it's very useful. As annoying as it is to have someone out
there with a stuck mic, what would happen if messages were stepped on
and we didn't know it?