In 1994, the FAA — hoping to reduce the number of helicopter tour crashes in Hawaii — promulgated a controversial rule that set minimum altitudes for Hawaiian sight seeing flights.

According to an article appearing this spring in Aviation, Space and Environmental Medicine, after the rule went into effect the overall number of helicopter crashes in Hawaii decreased, but the number of crashes resulting from improper VFR flight into instrument conditions increased.  That means fewer overall crashes (especially ocean ditchings), but  more crashes into mountainsides hidden in the clouds. The number of fatal crashes remained the same.

Although its data and methodology may be questionable, the recent report concludes:

the FAA should reconsider the Rule’s clause that established a minimum flying altitude of 1,500 feet, as we know higher altitudes are associated with more cloud cover. 

This conclusion delighted the helicopter industry which opposed the new minimum altitude requirement.  And a possible increase in weather-related accidents was one of the FAA’s concerns from the outset.  Requiring helicopters to maintain more clearance from terrain features, and more altitude to deal with engine failure, makes it harder for them to remain clear of the clouds.  But the report fails to consider the "deviations" the FAA has issued to air tour operators that allow them to fly lower than the established minimums.  Depending on the number of deviations that the FAA issued, it may be unfair to blame the rule for the increased number of mountainside collisions.

It’s a modern day Scylla and Charybdis. (OK, you’ll have to indulge me, my favorite mythical allusion because it’s more accurate than saying "catch-22” or "caught between a rock and a hard place.") Is the danger posed by the close proximity to the terrain more daunting than the unpredictable cloud cover? When it spoke in 1994 the FAA said, “No — higher altitude is safer".