Val d'Anniviers Airplane Crash

[DX Wombat]

Whether a pilot of a Baron is necessarily any more smart than a pilot of a C150 is another matter (probably not, but he ought to be).

Why? It may simply be that the pilot of a Baron had sufficient pots of gold to enable him/her to do the training, whereas that of a C150/152 may not. Possessing the ME qualification doesn't make you any smarter, it just allows you another engine on your aircraft. I certainly don't have the wherewithall to do a ME qualification and I'm definitely not thick. Whatever the cause it is a very sad accident and I agree with stickand rudder that the B52 post is, to put it mildly, tasteless and wholly inappropriate.

[englishal]

Very good point Barcli (expensive mod too).

I do not think you appreciate what a sudden change in AoA to a high negative number will do to your flying.

I've done a fair bit of mountain flying in the USA and had some pretty turbulent encounters at reasonable altitude and have had the plane climbing at 1500 fpm at zero power then "plummeting" at 1500 fpm at full power climb. The last time as my flying buddy said to me "we got the sh*t kicked out of us" and it was one flight that I was glad was over. It was exceedingly hard work. I think had the wind been strong then it could have been a factor, but Barcli's point is a very good one....

[SkyHawk-N]

15-20 kts shouldn't give too many problems around mountains,

20kts is plenty strong enough to cause problems around mountains, 20kts = 2,000fpm descent, not to mention the rotors that winds of that speed can create.

[RatherBeFlying]

Looking at the photos on 20 minutes and the Wikipedia photo of the ridge, you can see that the ridge zigzags horizontally and vertically; so, the winds would be going every whichway. Add the usual venturi effect acceleration as the air mass passes over the ridge top.

The a/c seems to have come to an abrupt halt upon contacting a spur. It's hard to tell from the available photos but it seems the a/c was heading towards a lower point on the ridge. It could have stalled or been caught in a downdraft when the spur got in the way.

[n5296s]

15-20 kts shouldn't give too many problems around mountains

My one rotor experience - which was extremely unpleasant - was in winds of this magnitude, and I was a couple of thousand feet above the highest point of the ridge. Luckily the horizontal extent of the rotor was fairly small and I flew through it before it smacked me into the ground - which by this point was a lot further down on the leeward side of the ridge.

The absence of forward airspeed in this incident is really strange. It is SO hard to get an airplane to stop! About the only ways I know are a hammerhead (stall turn) and a flat spin. But there is no apparent rotational deformation of the airframe either, as you'd expect if it was in a flat spin. (No idea how fast a Baron would turn in a flat spin but the Pitts is going round about once per second).

[IO540]

The absence of forward airspeed in this incident is really strange. It is SO hard to get an airplane to stop! About the only ways I know are a hammerhead (stall turn) and a flat spin. But there is no apparent rotational deformation of the airframe either, as you'd expect if it was in a flat spin. (No idea how fast a Baron would turn in a flat spin but the Pitts is going round about once per second).

I agree. No way a downdraught could have achieved this, IMHO. There is suitable terrain nearby but not that nearby.

Obviously it is possible to hit the ground with zero forward speed. What you do is a steep climb, to a stall, and then let the plane do a tailslide back down, and if you are really good you should be able to arrange to hit the ground in a flat orientation if you get it just right. Your VS will be pretty high at the moment of impact however - as clearly was in this case, with the wing spars thoroughly wrapped around the ridge.

I just don't think this pilot was doing that...

The domed roof deformation and the ejected seats must have been an oxygen cylinder explosion. Was this a turbo aircraft? Most of those have an installed steel cylinder of a fair size.

[S-Works]

I don't think it was an O2 explosion. There is no burning and the O2 if fitted on the Barron is behind the rear bulkhead. The rear of the aircraft is pretty intact.

[IO540]

What would have ejected the two seats then, in a sideways direction?

Could have been a portable o2 bottle.

O2 doesn't burn anyway.

[S-Works]

I am not sure what threw the loaded seats out, possibly the sheer force of impact. But I am not sure it was O2 related either.

You are quite correct, O2 does not burn, however it is an accelerant and will supporting burning through adbiatic compression and expansion. The rupture of a cylinder would leave high speed gas escaping though a jagged tear which would in most causes be enough to complete all three sides of the fire triangle. I have yet to see an O2 explosion that did not result in ignition of combustibles.

Not saying youbare wrong and it could not happen, I just don't think the damage matches a gas cylinder explosion.

[Pace]

I agree. No way a downdraught could have achieved this

10540

I have posted this incident in PPRuNe before but will post it again.
I used to Fly an owner in a seneca five twin single pilot to Malaga.
On one occasion in the summer it was over 40 Degrees C at madrid.

Aircraft was on auto at FL120 ahead were two storm cells and I requested a heading change to take a clear piece of air between the two cells.

All of a sudden I could not believe my eyes as the airspeed shot from 150 kts IAS to 70 kts IAS in a flash.

I disconnected the auto pushed the nose over and went for full power.

Nothing happened! The aircraft felt as if it had flown into a vacuum airspeed hovering on 70 kts, column forward, full power and going down like a lift at 3000 fpm.

Having lost a few thousand feet the aircraft came alive and I flew out of whatever I had flown into.

I had experienced down draughts before but nothing like this!!!!
Madrid were giving winds of light and variable!

Dont discount or presume anything.

Pace

[englishal]

Maybe there is a big rock under the aircraft which protruded into the cabin. Perhaps the aeroplane back has just been broken by the force? I'm sure if there was O2 onboard that the cylinder went, so that is a reasonable argument.

To me it looks like the aeroplane has fallen flat onto the ridge, slightly nose low as there is seemingly no trail of debris, apart from *maybe* some prop marks from the left engine in the snow just behind the engine.

I doubt a down draft has done this due to the weather conditions at the time (besides a helo has landed there shortly afterwards). Rotors can destroy aeroplanes of course, but I am skeptical about this in this instance due to several things: it was a local aeroplane so I'd assume the pilot had mountain knowledge (was this a charter flight?) and the reported weather wasn't too onerus at the time.

[Maoraigh1]

Horizontal gust equal to airspeed leads initially to overspeed. When pilot gets speed under control, his ground speed is zero. Wind changes. Aircraft stalls. Air has less inertia than aircraft. ??????

[IO540]

Aircraft was on auto at FL120 ahead were two storm cells

With a CB, sure. But there was no convective wx at the time. Not a spot on the radar.

Maybe there is a big rock under the aircraft which protruded into the cabin

I thought that too but the sideways view shows an empty cockpit. The same pic shows the roof curved upwards, and pretty well stretched, with the supports ripped off.

It's possible it was just the impact, at say -10000fpm (100kt) VS, but I don't quite get the physics which would eject seats and occupants in different directions, with the roof intact and in place afterwards.

When pilot gets speed under control, his ground speed is zero

Sure, but where would this come from? The MSLP chart shows nothing significant. You are looking at a 100-150kt wind.

This is the most bizzare accident I have ever come across.

[FlyingKiwi_73]

An ex gliding instructor of mine (Bob Vickers from Lasham if anybody knowshim) told me about a flight in the Rift Valley, where they were in the middle of the valley encounering some mild sink, went the VSI went off the stop in the going down direction (possibly 2000fpm) wings on said glider were very much in the 'U' shape and bob was wondering whether there was a bottom. Very near the valley floor lift returned and they staggered back, i believe it was a Nimbus.

This was a clear blue day. no CB.

[Pace]

I have 150 hrs on the 55. My initial multi engine on one then flew for a company in one. Beautiful handling, benign stall. Couple of things to consider ?
The non turbo version (most) had an engine out ceiling of around 7500 feet.
I don't buy the exploding oxygen cylinder as only the turbo versions had fitted oxygen so it was either a mobile bottle or none or the aircraft was a turbo (not many made)
Had such a cylinder exploded at altitude there would have been a lot more damage. This looks like impact damage with the ground ?
I have flown twins over the alps and even in good weather you can get odd areas of downdraghts.
There could have been an aft C of G stall aft C of G spin. Control failure ? A whole host of possibilities on their own or as an accumulation.
Oxygen bottle ? I doubt it

Pace

[englishal]

I think IO meant the O2 exploded on impact with the ground, ejecting the pax.

[IO540]

Yes.

I agree the boot area looks OK; if it was an o2 cylinder it may have been a portable one. A lot of pilots carry o2; maybe not many in the UK but they do in places where they have to fly higher. I've been using it since 2003.

[S-Works]

WhIch makes it even less likely to have been been an O2 cylinder letting go. A portable unit would need the impact energy passing to it which would only happen if solidly fixed to the airframe. If it bounced around the cabin on impact it would be unlikely to burst. These things are incredibly strong.

I think the O2 thing is a red herring. I suspect more sheer impact force.

[vanHorck]

I agree that from the impact site and the limited pictures we have it is an enigma both regarding the apparent lack of forward speed as well as the distribution of debris (ie seats).


Let's hope the preliminary report will shed some light on this, so if someone comes across it, please let us know.

Some questions I have

Does anybody know (as opposed to suspect) the amount of damage an exploding O2 bottle would do?

Or would a protruding rock (perhaps a little away from the final resting place) rip of the nose and in the course of this energy absorption reduce the forward speed such that the plane just drops down wit more downward speed than forward speed?

The seems to be a little fire damage to the front possibly due to impact fire, but is it possible they had an electric fire and the pilot elected to attempt a stall crash landing against the ridge, not unlike our Biggles friend on the golf course and failed to time the stall and impact moment?

[Pace]

Does anybody know (as opposed to suspect) the amount of damage an exploding O2 bottle would do?

Van

My hobby is scuba diving! the compressed air bottles are pressurised to 2000 ibs per sq inch and I have seen some big blunders with bottles falling a few feet onto hard conrete.

They are like aviation bottles tested and internally inspected for corrosion and contamination but have a large margin for safety built in.

It is possible but unlikely that this had anything to do with an exploding oxygen bottle. Why have one if you have a full aircraft of PAX who would also need oxygen?

This incident could have involved engine failure or double engine failure either man made or running out of fuel?

Remember the Baron 55 is a quirky aircraft with all the levers (throttle,prop, and mixture painted black so easy to confuse.
Its more likely he ran out of fuel and as you said tried to pan it onto a mountain side but then why a mountain side why not just take to the valley no matter how rough the base of the valley looks?

Its all guesswork by all of us.

Pace