Transcription
On August 4th, 2012, this video made it to the internet. What you're about to witness is a plane crash as it was experienced from the right seat inside the cockpit. The accident took place on Saturday, June 30th, 2012.
At the time of this report, information was preliminary and subject to change, but some had been collected by the NTSB. The aircraft is a Stinson model 108-35, generally a 165 horsepower single-engine, high-wing, propeller-driven aircraft capable of carrying four plus full fuel and light baggage. But an aircraft's performance is dependent, among other things, on the density of the air it moves through.
The aircraft appears to be operating from Bruce Meadows air strip, a 5,000 ft long dirt and grass air strip situated at an elevation of 6,370 ft, surrounded by 8,000 and 9,000 ft mountain peaks near the town of Stanley, Idaho. And that may be important. Watch what happens here.
What you just saw was the aircraft skipping off the ground after having previously become airborne only after a prolonged ground run. The aircraft seems unwilling to climb. We will not speculate as to the cause of the crash, but it may nonetheless provide a good example of what pilots call a high-density altitude takeoff. Cold, low-altitude air is more dense; it's thicker than air found found at higher altitudes and/or higher temperatures. Moisture in the air, humidity, displaces air molecules and also acts to thin the air.
For the pilot of a propeller-driven aircraft, thick air has its benefits. It gives the surfaces of the aircraft, the wings and propeller, more to push against, as it were. It gives a naturally aspirated, non-turbocharged engine more air molecules to mix with fuel, and that results in higher power output.
Relevant to what you're seeing here, the NTSB has collected air data including barometric pressure, temperature, and moisture for the accident's location on the day of the crash. The figures show that while the aircraft was physically located at an elevation of 6,370 ft, the air around it was as thin as that found at 9,167 ft on a standard day. In other words, compared with a cooler day at a lower altitude, the engine of this aircraft had less air to mix with fuel; it put out less power, while the propeller moved less air and produced less thrust. Meanwhile, the wings produced less lift for any given speed over the ground.
In practice, that means the aircraft needed more land to get to speed and more speed to create lift, all the while working with less available power. It means it was harder for the aircraft to start to fly. Assuming that the pilot was attempting to climb, this particular aircraft appears strained at best and unwilling at worst. Whatever the cause, this was the result.
All four men involved in this accident walked away. Early reports state that the pilot suffered the worst injury, including a broken jaw. Shown in slow motion, you can get a sense of how the airframe absorbed energy. Each impact with a tree lessens the amount of energy left for the final impact with the ground. The occupants were lucky. Once over the trees, there was very little the pilot could do. If faced with low air speed and rising terrain, a turn was out of the question at that point. Riding it in might have been their best and only option.
I'm Glenn Pew for AV web.com. Thanks for watching.