While on a cross-country flight over an area of mountainous terrain near Homer, Alaska, the Cessna 140 pilot noticed a bear near the entrance to a mountain pass. While orbiting over the bear, a strong downdraft emanating from the pass entrance caused the airplane to descend toward the saddle of the mountain pass.
The pilot applied full engine power in an attempt to arrest the descent, but the airplane’s main landing gear wheels ultimately touched down in an area of grass-covered terrain.
The left main wheel subsequently struck a large rock, and the left wing struck the ground, resulting in substantial damage to the left wing and fuselage.
The pilot said that just after the accident, he estimated the surface wind to be from 90° to 140° at 10 knots, with gusts from 15 to 20 knots.
Probable cause: The pilot’s decision to fly at a low altitude in mountainous terrain and weather conditions conducive to downdrafts.
NTSB Identification: ANC15CA051
This July 2015 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
His was a predicted result. Can’t go tooling around at low altitude on the lee side of a mountain pass in gusting wind conditions and not expect something like this. Headwork was definitely lacking. Lucky for him the outcome wasn’t worse.
I suppose the bear had the last laugh
This one is on nature. The pilot did nothing wrong except possibly to be flying an underpowered plane near a canyon.
“The pilot did nothing wrong…” except …
Flying low in a venturi (the lee side of a mountain pass during windy conditions) is a well known high risk tactic even with an O-520 up front.
The pilot reported (in an email to the NTSB investigator, copy in the Docket) that winds were highly variable in flight, ranging from calm to strong winds due to large rocks and rugged terrain. He also said GPS ind speeds were 20-30 kts going into the pass. His estimate of ’10 kts gusting to 15 to 20’ was on the ground at the crash site.
Nature is not to blame…
One of my flying machines is a 65 hp J-3, my day job is flying a large helicopter with over 9000 hp. As different as they are, they have one thing in common, there are places you stay out of!
A good working knowledge of the atmospheric conditions and the terrain you are flying over and what effect it will have on you and your aircraft is a large part of stick and rudder flying.