From the here's-an-accident-report-I-can't-wait-to-read file comes yesterday's report of a Westwind ditching near Norfolk Island, in the western Pacific. As is often the case at a distance, there's not enough detail yet available to illuminate why the Captain decided, after several attempts to land on a runway, to ditch in the water (in darkness) instead. Weather was cited as a controlling factor, but no detail is available yet.
The flight was reportedly carrying a critical patient from Samoa to Melbourne, with a fuel stop on Norfolk Island. To give you an idea of the distance scales in the Pacific, Norfolk Island is 1200 miles northeast of Melbourne and Samoa is 1600 miles east of Norfolk. This is not a region of the world which tolerates short-legged airplanes or poor fuel planning.
To shed at least some light on how this could happen, consider that the Norfolk Island Airport lies at an elevation of 371 feet. So it's easy to imagine how a 200-foot overcast or broken conditions could make for zero-zero conditions at the airport, while below the overcast, visibility over the water could be good. Based on a little Web research, I can't tell if Norfolk has an ILS, but it apparently does have a LAAS-type GPS approach.
Since this seems to be the week for discussing ditching, here's a question: If confronted with the same situationa land airport fully fogged in or open water with good vis, which is the higher survival percentage choice? For piston aircraft during the day, it's almost certainly the water. At night, it creeps me out too much to hazard a guess, frankly.
Some years ago, I studied several hundred ditching events and interviewed some survivors. The conclusion of this research revealed that in piston-engine ditching, the successful egress rate was well into the 90 percent range and the survival rate is nearly as high. It's lower in the open ocean, but still good.
So if you go for the water, chances of survival are nine in 10. I don't have nor could I develop any data comparing the Westwind scenarioa do-or-die zero-zero approach, at night, to a land runway. That one's pretty high up the creep-out scale, too.
If both the water and the land were equally fogged with near zero vis and an ILS were available, I'd take the runway, day or night. The reality is that if you have to and you can bring your A-game, you can fly a Cat I ILS to a little less than 50 feet. Even in the worst of conditions, that should be good enough to permit just enough visual cues to make the landing survivable, if not pretty.
Two mitigating arguments against the otherwise high survivability of the water are its temperature and the prospect of floating in the fog waiting for rescue. On land, you don't have to tread 40-degree water and rescuers in trucks will generally respond faster than boats will.
Either way, it's going to be a near thing. Evidently the Westwind crew got it right, because everyone survived.
FRIDAY A.M. UPDATE: I got an e-mail and a phone call on this accident raising this legitimate question: Wasn't the pilot required to have sufficient fuel to reach a filed alternate? The answer is undoubtedly yes and one presumes the alternate was not the ocean. Unknown is why the alternate wasn't used. As I said, I'm eagerly awaiting the accident investigation findings. This one's going to be interesting.