Aftermath: First There Is a Mountain
The 77-year-old, 8,000 hour pilot-owner of a Cessna 182, accompanied by his wife, flew from Anchorage to Juneau, Alaska, on a July afternoon. The couple was in the process of moving to Hoonah, about 31 nm west-southwest of Juneau; the ostensible purpose of this trip was to position the 182 there before the start of winter. The pilot’s wife intended to return to Anchorage, but the 505 nm IFR trip took longer than expected, and her Alaska Airlines flight was taxiing out when they arrived. She rebooked for the following morning, and the couple then flew over to Hoonah for the night.
Her flight back to Anchorage was to depart at 7:28 a.m. At 6:43 a.m., the local controller at Juneau received a call from the pilot, reporting 10 miles southwest for landing. The controller told him to report four miles out. A moment later, a faint ELT signal was picked up in the tower and also at the Juneau Flight Service Station.
Delayed by worsening weather, searchers located the wreckage of the 182 the next day in mountainous terrain a few miles south of the Juneau International Airport (PAJN). The airplane had struck the descending side of a ridge on Douglas Island, coming to rest on a rock ledge at the 3,100-foot level. The impact was sufficiently violent that the engine, propeller and nosewheel broke away from the airframe and tumbled 900 feet down into the valley below.
Juneau lies amid a jumble of islands, inlets, channels, fjords and peaks. The climate tends toward cloudy and wet; Ketchikan, a little farther south, enjoys between 12 and 13 feet of rain a year. On the day of the accident, however, the weather was not bad: Hoonah was reporting 10 miles visibility under a 3,500-foot overcast with calm winds; Juneau was five miles, 2,800 broken and 3,600 overcast. The mountains south of Juneau were misty and obscured.
Douglas Island lies directly south of Juneau. The peaks in its center rise to 3,350 feet. A straight line from Hoonah to the Juneau airport just misses the northern shore of Douglas Island but crosses a 1,200-foot ridge on the Mansfield Peninsula, halfway between Hoonah and Juneau.
The pilot carried two handheld Garmin GPS units, a 195 and a 495. Neither was badly damaged in the crash, and accident investigators were able to download position and altitude logs of the fatal trip from both.
The ground track was not perfectly straight, but it was straight enough to suggest an airplane being hand-flown along a GPS course. Curiously, the course was not that from Hoonah to the Juneau airport; instead, it pointed toward Juneau Harbor Seaplane Base (5Z1), six miles southeast of the airport. One of the GPS units contained a previously stored program for a flight from Hoonah to the seaplane base; it seemed probable the pilot somehow selected it by mistake.
Six miles is a small difference, but when the total distance to be flown is only 31 miles, the angular error is 13 degrees, and in the mountainous terrain surrounding Juneau it had the effect of putting obstacles in the pilot’s way that ought not to have been there. The first was a 3,300-foot peak on the Mansfield Peninsula. The previous evening that ridge had been several miles to his left as he flew from Juneau to Hoonah; now, strangely, it was right in his way, and he had to swerve, and climb 600 feet, to avoid it.
Nine miles farther along, he should have had Juneau in sight; his groundspeed was 125 knots and he had been airborne for 15 minutes. He had already called to report that he was 10 miles southwest — a figure that actually reflected the GPS-reported distance from the seaplane base. But now he encountered another oddity: a second ridge where there should have been none at all.
He may have been flying in mist just below the overcast or between layers. The illumination was fair; the Alaskan summer sun had been up for two hours. He was level at 2,800 feet but then started to climb. Judging from the altitudes in the GPS log, which were recorded 10 times per minute, he must have been surprised by the steepness of the ridge because, after several seconds of climbing gradually at 89 knots groundspeed, the 182 suddenly shot upward from 3,166 feet to 3,583 feet at 2,000 fpm, while its groundspeed dropped from 101 to 34 knots.
It cleared the ridge but crashed a short distance past it. Perhaps it stalled; five seconds after the 34-knot point, one more entry was made in the GPS log, with a groundspeed of 41 knots.