East of Desolation — Jack Higgins

CAPE DESOLATION, GREENLAND--The wreckage of a private airplane is discovered high up in the icy desert. The pilot listed in the log and the body found near the plane are not the same. Charter pilot Joe Martin is hired by the pilot's widow and insurance company to fly them through deadly terrain to the site of the crash...

But Martin doesn't trust the widow or the agents. Because the widow isn't mourning. And the agents aren't afraid of dying. And when a fortune in emeralds is found--and lost--near the wreckage, Martin realizes he has no idea who he is working for. Suddenly, the natural dangers that loomed so darkly are nothing compared to the human malice on Cape Desolation...