Aftermath: First There Is a Mountain
As the National Transportation Safety Board explained it:
Given the lack of mechanical deficiencies with the airplane, the absence of any distress communications, and the pilot’s self-induced pressure to get his wife to the airport to avoid missing her flight, it is likely the pilot flew into instrument meteorological conditions while tracking his portable GPS receiver to the wrong destination and subsequently collided with mountainous terrain.
This accident encourages reflection on the nature of mistakes. Everyone makes them; perhaps some people are more aware of their mistakes than others. There have been accidents caused by careless data entry, improper altimeter setting, radio frequencies off by one digit. If it can be done wrong, someone will. Of course, far more mistakes are made that don’t lead to accidents; the vast majority are inconsequential, and so we regard them, and our propensity for them, with indulgence.
Our pilot flew from Juneau to Hoonah just the previous evening and must have made the trip many times before, so he knew the general lay of the land. Why was it necessary at all to use GPS to go 30 miles in a straight line among a host of unambiguous landmarks? But he did; perhaps it seemed convenient, or he wanted an extra layer of assurance, or it was simply for fun.
One defense against navigational mistakes goes by the name of situational awareness. Unfortunately, you can be highly aware of your situation, completely tuned in to the task of flying and yet be operating in some mistaken conception about what that situation actually is. Our pilot probably believed he had everything under control; after all, he had not one but two GPS units, and they agreed with one another.
Something built into our brains inclines us to ignore evidence that conflicts with expectation. In this case, the pilot, having selected, as he believed, the Hoonah-to-Juneau route on his GPS, had a strong, and reasonable, expectation that as long as they showed him to be on that track, he must be in the right place.
Now, cruising at 3,000 feet, he encountered a mountain. He climbed and made a sudden deviation to the left to avoid it. Where had that mountain been when he made the same trip, in the opposite direction, last evening?
Perhaps he said to himself that he must have been slightly north of the straight-line course then, and so this peak had been a few miles off to his left. A glance at the GPS screens would reassure him: There was the course line; there was the mountain. From this point to Juneau, it should all be open water.
Then a second mountain loomed. This was more of a problem. The first mountain could be explained as a slight track error. This one should not exist at all. Things began happening rapidly — too rapidly to allow the pilot to analyze them. The ground was coming up in front of him. It was already too late.
Today, situational awareness is increasingly transferred from a pilot’s brain to his microchips. There is no straightforward protection, other than double- and triple-checking every action against the type of clerical errors we may make in our interactions with digital devices. Two GPS units provide no redundancy if both confirm you in the same mistake. What is needed — and remains available, at least when the terrain is visible and while we still have the VOR network at our disposal — is independent confirmation that we are where we think we are. Visual navigation ought to be a constant cycle of expectation and confirmation: Charts and terrain should come together like two sides of a zipper.
You remember — it’s what we called “pilotage.”
This article is based on the NTSB’s report of the accident and is intended to bring the issues raised to our readers’ attention. It is not intended to judge or to reach any definitive conclusions about the ability or capacity of any person, living or dead, or any aircraft or accessory.