Here's a cautionary tale....
I was searching for some examples of the dangers involved in flying low over featureless terrain. I came across these examples on the NTSB site. I suspect the company involved decided that no RadAlt was a false economy.
http://www.ntsb.gov/NTSB/brief.asp?e...12X19659&key=1 The certificated commercial helicopter pilot, with five passengers aboard, was attempting to return to the Juneau International Airport after completion of an ice field sightseeing tour flight.
During a gradual descent, over a large, featureless, and snow-covered ice field.... Guess the rest??
Followed by...
http://www.ntsb.gov/NTSB/brief.asp?e...12X19666&key=1 The commercial helicopter pilot, with one passenger aboard, was conducting a search for an overdue company helicopter. While searching the upper portion of a glacial ice field.......
And then;
http://www.ntsb.gov/NTSB/brief.asp?e...12X19667&key=1 The commercial helicopter pilot, with one passenger aboard, was en route from Petersburg to Juneau, when he was requested to join a search for an overdue company helicopter
(N6007S). He said that just after entering the search area........