Two Small Planes Crashed in Alaska. Here’s Why Few Experts Were Surprised.

“The regulations on general aviation have slowly tightened over the years,” said John Cox, a former airline pilot and now a safety consultant.

Mr. Cox and others said it would be premature to suggest that regulations should be changed before it is clear what exactly caused the accident in Alaska. N.T.S.B. officials are currently investigating and the safety board declined to comment. The day was overcast with winds from the southeast at 9 m.p.h.

How common are the cruise flights?

Glacier flights have become a popular add-on for Alaska cruise passengers. On its website, Princess Cruises suggests adding a glacier “flightseeing” trip to your “must-see list.”

The cruise line asks, “Why sightsee when you can flightsee? Flightseeing, also known as flight touring, grants you a bird’s-eye view of the beauty infused into Alaska’s natural landscapes.”

Robert W. Mann, an airline industry consultant in Port Washington, N.Y., said that he was once on a trip similar to the one on Monday and it was easy for him to understand how an accident could happen.

“You’re located on a body of water next to glacial activity, so there’s almost always some low clouds in that area,” he said. “But there’s a lot of pressure to perform because people take these journeys and they pay. I imagine all these things kind of factor together.”

Princess did not return requests for comment, but Brian O’Connor, a spokesman for the company, said in a statement, “All of us at Princess Cruises are deeply saddened by this tragic news and we are extending our full support to the investigating authorities as well as the traveling companions of the guests involved.”

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