NTSB Says a Downdraft Killed Steve Fossett

jd writes "The National Transportation Safety Board has now released the text of its examination (full narrative available) into the crash of Steve Fossett's aircraft on Sept 3rd, 2007. It concludes that downdrafts were the likely cause of the crash, dragging the plane into the mountain with such force that, even at full power, it would have been impossible to escape the collision. Pilots experienced in the area report that those winds can rip the wings off aircraft; and Mark Twain remarked that they could roll up a tin house 'like sheet music.' One must wonder why such a skilled aviator was taking a gamble with such hostile conditions, given that he was looking for a flat stretch of land to race cars on, but that is one mystery we shall probably never know the answer to."

Comments

One must wonder ...

[qoncept]

One must wonder ...

...how pilots experienced in the area and are still alive know that these downdrafts can rip the wings off an airplane?

Re:One must wonder ...

[Sir_Lewk]

Perhaps they've seen wreckage where it was evident that's what happened.

Re:One must wonder ...

[maxume]

Are those two things mutually exclusive?

Perhaps experienced pilots in the area, who have seen such wreckage, choose not to fly when the weather indicates such winds are likely.

Re:One must wonder ...

[vertinox]

...how pilots experienced in the area and are still alive know that these downdrafts can rip the wings off an airplane?

Experienced pilots experienced the phenomena by experiencing the event from a safe distance because they were experienced.

Re:One must wonder ...

[DoofusOfDeath]

One must wonder ...

...how pilots experienced in the area and are still alive know that these downdrafts can rip the wings off an airplane?

Yes, it's odd. Almost as though they can somehow communicate amongst themselves or even read NTSB reports.

Yes... this definitely is something we need to understand better.

Re:One must wonder ...

[JWSmythe]

    In searching for Fossett, they found numerous unreported or otherwise undocumented crashed planes. More than likely, any aviator who said that they "knew" it could happen were witnesses to another plane crashing, helped with the search and rescue of a fellow aviator, or simply accounted for the forces and the strength of small aircraft.

    I had discussed this with some people who are very experienced aviators, and they all came to the same conclusion. It was most likely wind that brought him down. The second guess would be a mechanical failure and attempted crash landing. They ranked the second one way behind the first.

    If I read the NTSB review correctly, his altimeter was reading above the mountain peaks, but adjusted for current temp and pressure that would put him a bit lower than them, which should have been ok. They lost radar contact with him approx 1km from the crash site. In that time, he went about 1km (obviously) and a dropped a few thousand feet.

    The report does state that the entire plane was present at the accident site. Well, except for the burnt off parts. They indicate the wingtip lights were present, which would imply the wing came down with the plane. If they had broken off, they would have likely been found at a different location.

    I'm sure he did everything he could. Sometimes that's just not enough, even for people who are really good. :(

NTSB is wrong

[Em Emalb]

Sudden deceleration is what killed him.

Um, obvious speculation?

[Chris Burke]

One must wonder why such a skilled aviator was taking a gamble with such hostile conditions, given that he was looking for a flat stretch of land to race cars on, but that is one mystery we shall probably never know the answer to.

I wondered, but in about a second I came up with this: An adventurer and thrill-seeker, in the course of looking for a place for future thrill-seeking, decided to seek some thrills?

Sure it's just idle speculation... but based on what little I know of the man, taking gambles with danger while tooling around alone in his private plane sounds exactly like something he would do. It makes enough sense for me, at least.

Mountain Wave Action

[Nobo]

The proper term for what they're describing is a mountain wave or wave action. http://en.wikipedia.org/wiki/Lee_wave contains a good description of the effect.

Mountain waves can be felt in small piston powered aircraft even flying significantly above the tops of the mountains, even several thousand feet above the peaks on either side of the valley you're crossing.

If you're holding altitude, you see that you speed up when you're crossing falling terrain and slow down when you're crossing rising terrain -- because as you cross the rising terrain, you're in the downdraft and so to maintain altitude, your airplane "feels" like it has to climb to stay at the same altitude in the falling air. Climbing requires additional power over simple cruise flight, or you slow down.

I've seen airspeed of an aircraft that should cruise at 150 knots, range from 90-180 knots, depending on whether you're on the uphill or downhill side of the wave. In severe conditions, you just cant' maintain altitude without slowing down too much, and you have to vary altitude to ride the waves.

It can be a scary experience knowing you don't have enough power to out-climb the wave -- That's the reason that you typically fly significantly higher in the mountains, even with good visibility -- You're not worried about hitting the mountains because you can't see them, you're worried about getting sucked by these waves and not having enough altitude to ride them out.

Re:Mountain Wave Action

[smellsofbikes]

Mountain flying is technically challenging -- as challenging for an experienced pilot, as just flying is for a person who doesn't know how to fly. There are a lot of things you do when you train in mountain flying to minimize your risk, but if you're in a small piston-engined plane, there are a lot of places where you just don' t know what the best plan is, so you have to make a quick decision and hope you were right.
First off: fly down valleys, not up them. That's not always possible, though: you sort of have to fly up one valley to go over the pass and fly down the next. Another is you don't fly up the middle of a valley. You fly up one side, so that you have room to make a quick turn if you find that you're in a narrow bit of the valley and you need to get out. But here's the tradeoff: there are sometimes strong upslope/downslope winds along the valley sides, so by preserving your ability to turn, you might run into an intense downdraft. (Generally, winds are faster, the higher you go, but in valley conditions, downslope winds known as foehn or scirroco winds tend to be intense right around the valley itself, particularly if you're flying up an old glacial valley with hanging valleys intersecting it: there are these big cold air currents flowing down them just like water would and pouring down into the main valley.)
Likewise, once you're in a downdraft you have to make some hard decisions. You pull the nose up to best angle of climb, full power, and you hold it. What if you're aiming right towards a big rock? If you turn, your stall speed increases, and you're already fairly close to stall speed, so you have to weigh reducing your angle of climb (which in a microburst or downdraft means increasing your speed towards the ground) to make the turn, vs. trying to ride out your current heading and hoping you'll miss that big object. You don't know, a priori, which one is going to work. Maybe you'll break out of the downdraft. Maybe it's worse over there where you're about to turn. That's where skill, experience, and lots and lots of luck come into play.
Where I live, sometimes the clouds from the mountain waves are visible in long rows at over 25,000 feet elevation, in lines for a hundred miles downwind of the mountains themselves, and every one of those is strong enough to shake a plane like a ragdoll. A B-52 bomber had its vertical tail ripped off and lost part of a wing in clear air turbulence 5000 feet above the nearest mountain.

Re:SO uh, when did Mark Twain have a plane?

[JaneTheIgnorantSlut]

Just thought I'd ask.. me thinks Mark Twain died before the aircraft age.

Reports of his death were greatly exaggerated.

Re:Insulting summary

[AB3A]

To someone who isn't an experienced pilot, it isn't obvious. But you should know that it is a significant part of the training for all private pilots.

I've been licensed for more than 20 years as a private pilot. I've taken mountain flying instruction. I've flown around and over the Rocky Mountains. This hazard is a simple issue of flight planning.

I know exactly what performance my aircraft is capable of, as should every pilot who sits in the left seat. I read reports of the winds aloft. I set personal minimums for what I'm willing to fly in. I know, for example, that if the winds aloft at 3000' are approaching 30 knots, that I can expect significant turbulence and down-drafts from the Appalachian mountain chain for up to 100 miles East. I might fly in those conditions if I'm going Eastward. However, if the winds aloft are 35 knots or greater at 3000, I know I'm staying on the ground.

It's not that I can't handle those situations; I can and I have. My goal is to have a reserve in case the forecast is wrong. I've seen blown forecasts more times than I care to think about.

Steve Fossett had a momentary lapse of judgment. It happens to the best of us. Every year, people crash while flying around mountains and canyons from exactly the same damned thing that bit him. There is little room for error when flying in the mountains. Each flight should include a careful evaluation of local and regional weather conditions, terrain, and aircraft performance. Yeah, there are people who launch in to the blue without checking this stuff. Most of the time, they survive without incident.

Those who don't do adequate flight planning in this terrain are accidents waiting to happen.