Unfortunate example of a classic VMc crash at low level in a twin.

[AdamFrisch]

Well, the video speaks for itself.

Pilot let it get to slow and ran out of rudder and with no altitude left to correct, he was toast. Or maybe he initiated a base turn and got to slow there. Anyway, he should have throttled back on the good engine, or/and kept speed up. Look how fast it rolls when it starts. Tragic.

GMA News: YouScooper captures chilling video of Parañaque plane crash (December 10, 2011) - YouTube

[No RYR for me]

Wow:uhoh: What ever they tell you in the book I was amazed by the speed of this... Any report on how, what, where this happened?

[Ds3]

Happened recently in the Philippines - bit more discussion here:

http://www.pprune.org/rumours-news/471395-13-killed-philippines-plane-crash.html

[peterh337]

Adam - is it known that he was flying assymetric at the time?

I can't tell but it seems equally possible he had an engine failure during slow flight and didn't do anything about it.

[mad_jock]

One engine sounds as if its wasn't very happy backfiring.

Problem is with alot of folk is they think keeping a knackard engine running is helping matters.

If you are down at flight idle alot of the time this is actually creating more drag than if you had shut the thing down. For my type if your under 10-12% torque you are making matters worse flight idle is 2-6%

Of course with additional drag one side that won't give you the expected climb performance or possibly decent drift down performance and also will give you a significant increase in Vmca. Then they are decending not going to make it so pitch up, feed more rudder which creats more drag which makes them pitch up again until they run out of rudder then wham she rolls on her back and in she goes with more airspeed than the books says your safe doing.

[AdamFrisch]

It's hard to know exactly what's going on here, but he seems to turn into the dead/misfiring engine, which at slow speed is not a good idea. Raise the dead, and then proceed to make an approach that will sustain that wing high. In this case, it seems he should have told them he'd do a right circuit to land or gone straight in.

[mad_jock]

I don't think they had any choice in the matter.

You have less than a second to reduce the power on the working engine. It would have been above blue line speed when it happened.

The more power you have in each engine the faster it all happens.

[Jetblu]

Are you sure "above" blue line jock ?

[mad_jock]

Yep your normally Vyse is above Vcma. Maybe blue line is the wrong one as I haven't flown anything with a line for years for me its always V2 and Vyse bugs.

You have more drag on the flight idle engine than if it was feathered which means more yaw with the other one at full chat. This means your Vcma is increased quite dramatically because its worked out with the engine feathered.. The bigger the engines/props the bigger the increase.

[Jetblu]

Yes, that makes sense :ok:

[mmgreve]

Right...you just cured me from ever wanting to get a twin rating.

[AdamFrisch]

As long as you don't get too slow, most twins are pussycats. If an engine quits at altitude or cruise, it's a non event. But down close to Vmca and the ground... In this instance a single would probably have had a safer outcome.

My Vmca is not published, but I tried it recently at altitude and it's around 65-67kts. This is with an unfeathered engine, so potentially slightly lower feathered. I'm guessing around 62kts, maybe. Still, you'd want to keep a good margin above that. My Vyse is 81kts.

Greve - Get a Cessna Skymaster;)

[peterh337]

Right...you just cured me from ever wanting to get a twin rating.

Correct :ok:

Get yourself a TBM850 (http://www.peter2000.co.uk/aviation/tbm850/index.html) :) I was able to fly one "out of the box" with minimal instructor involvement and fly an ILS down to 200ft after the 1.5hr flight.

The catch? You need considerably more dosh than for a typical beaten-up piston twin, although the ongoing operating costs will probably be fairly similar ;)

TBM700 prices are coming down, but they are still way above piston twins.

[AdamFrisch]

Yeah, but even with a TBM850 - would you feel comfortable doing a 4hr leg over water? I wouldn't. But I would in a twin.

If I may offer you, dear sir, the very best aircraft ever built - the Rockwell 695, the last of the twin turbine Commanders....

http://www.flugzeuginfo.net/acimages/695ajetprop1000_marcopianca.jpg

...has a 300kts cruise, a 2100nm range (longest range of any turbine I know of), burning 64gal/hr, can take off and land on any surface. The Dash 10 Garretts have a 5400hr TBO - eat your heart out PT6's, with their puny 2000hr. Not only that, they'll burn less specific fuel per SHP. If you're in a bind they can run on any fuel - diesel or avgas. Try that with a PT6 and they're toast. All this for half the price of a used TBM700. Fantastic aircraft that has true transcontinental capabilities.

[mad_jock]

But... its bloody ugly. ;)

[hum]

But they look great in the air :-)

http://i50.photobucket.com/albums/f318/gerryhum/AC90EISP.jpg

[Pilot DAR]

It's hard to know exactly what's going on here

It often is. It looks to me like during slow flight for whatever reason, the aircraft allowed some left turn. In reaction to a left wing drop, a whole bunch of right aileron was applied (I think I see a lot of right up aileron, as it rolls over). That excess aileron (left down, in particular) serves to aggravate an unrecovered stall to instantly turn into a spin.

I opine that a spin entry will happen with much more abruptness than a roll loss of control resulting from poor flying below Vmca. The below Vmca roll would be recoverable up to a point, with a reduction of power on the high side. An incipient spin entry in that aircraft probably requires a whole turn of recovery effort to get out.

[peterh337]

but even with a TBM850 - would you feel comfortable doing a 4hr leg over water? I wouldn't. But I would in a twin.

That is however an illusion. A SE PT6 is about 5x less likely to go down than a piston twin. But hey we have been here before :)

The other thing is that there are very few 4hr legs over water - unless you are doing an Atlantic run and a pretty direct one. 4hrs is about 1000nm+ at economy cruise.

[Whopity]

My Vmca is not published, but I tried it recently at altitude and it's around 65-67kts. This is with an unfeathered engineVmca is a fixed speed used for certification purposes. It is measured under the following conditions:
Full Power on the live Engine
Failed Engine Windmilling
Critical Engine failed
Flaps in take off position
Undercarriage up
C of G rearmost at MTOW
At Sea Level
If you don't meet those conditions its not VMCA and it doesn't vary.

VMC on the other hand takes into account the element of surprise of a sudden and complete engine failure, with full power on the other engine such that the average skilled pilot can maintain control in straight flight with no more than 5 degrees bank applied towards the live engine.

I don't think that measuring the lowest speed that you can maintain the aircraft straight at altitude is getting close to determining either of these critical speeds.

The film clip is interesting, is the aircraft asymmetric or did it suffer an engine failure in the turn? The rate of roll is more characteristic of a stall that an engine failure in the turn as the base leg power setting would not be sufficient to roll the aircraft so dramatically. If its a stall in the turn, the outcome would not be de-similar in a single. A useful training clip.

[Shaggy Sheep Driver]

Before it turns it seems to have a very low forward speed for the sound of the engine(s) - a 'high power setting' noise. Would this not indicate that the LH engine was probably windmilling (lots of drag) and the RH was at full power, but speed low due the assymetric power and drag?

[421C]

But hey we have been here before
Indeed, after death and taxes, few things are as certain as a PPRUNE thread mentioning a twin attracting your usual anti-twin stuff.

[peterh337]

Tell me honestly and truthfully, 421C, would you rather have a 421C or a TBM850?

:)

Anyway, here is your chance to straighten things out and rubbish singles.

[mad_jock]

I would always get the twin now. But then again i do have way way more hours in them than I do singles.

The PT6 421 thankyou very much.

And its not to say twins are bad but to actually get your poo together with them isn't really done in the 5 hours MEP training. You need to bang away with the single engine work as well and not just once a year for the test.

[421C]

Tell me honestly and truthfully, 421C, would you rather have a 421C or a TBM850?

Of course I'd rather have a TBM850. What a ridiculous question. Why do you transpose every piston twin discussion into the banal and obvious thing that a $3m airplane is superior to any piston twin ever made.

If I said all SEPs were carp, and asked you, honestly, wouldn't you rather have a Citation Mustang or a King Air 250 than a TB20, what point would my question serve?

However, I am not saying that. I like SEPs. I also like MEPs.

[mad_jock]

err a TBM850 isn't a SEP by any stretch of the imagination.

[421C]

...and by no stretch of the imagination was I saying it was?

[mad_jock]

And I wasn't having a go at you.

Just the comparison between a MEP 421C and a turbine single isn't really sporting.

And personally if it was the 421 with PT6's I would go for that instead of the TBM850.

[421C]

sorry, me being slow.

[AdamFrisch]

Gentlemen, gentlemen, you're arguing over all these inferior things like the 421C and the TBM, when all you really should be talking about is the Turbo Commander 695.;):ok:

[mad_jock]

Adam I am sure it has a nice personality but...

Its high wing and bloody ugly.

A certain joke comes to mind about the similarity between fat burds, mopeds and turbo commanders.

[Jetblu]

Aahh you can't beat the 421. The TBM is also rather nice.

The Turbo Commander is ok, but as mad jock says........

[AdamFrisch]

Now, I'm a high wing aficionado so not really objective. But surely, when a high wing sits way behind the cabin like it does on the Commander and many other bigger types, then the one gripe - obscured visibility in a turn - is no longer a factor. So why are people so hot for low wings when all it brings is headaches? Hard to keep clean, belly rashes, prop strikes, painful entry end exit, can't land at fields with high grass on sides, etc, etc. You've just made your life 10 times harder for zero benefit.

I have a social theory in regards to aircraft ownership, and it's firmly tongue in cheek, but with a dollop of truth, me thinks:

Many young private pilots become pilots because they want to impress and be cool (I've certainly met more of those than any other category amongst the younger hopefuls) and I probably - although I'd never admit it - might have belonged to that category myself when I got started.;) You will find that most PPL candidates are normally in the "nerdy" category and presumably might not have had the same pull as the school jock or rock kid in a band with the ladies, so this is in their minds a good way to even the field a bit, firmly ignoring the fact that 99% of the women I've met are;

a) not impressed, and
b) don't want to ride in the damn thing anyway.

One is much more likely to impress another nerdy bloke by mentioning it than ever getting some female admiration out of it. That's my experience, at least. Not that I ever mention it, of course.:rolleyes:;)

Part of this desire to be a ravishing pilot takes the form of being seen as flying in an aircraft that resembles the big iron as much as possible, for maximum admiration. A bit like attaching a Halfords wing to a Corsa, or putting fake carbon fibre weave tape to your wooden Allegro dashboard or building a kit car replica of a Lamborghini. And since most of the big iron is low wing, this is what people like and emulate. Cirrus owes it's entire sale to this very sentiment. They also associate high wing with their days slogging around the circuit in that dog of a 172.

Further evidence - whenever someone comes along this forum asking for what aircraft is best to buy for a given mission bla bla, the answer pretty much always ends up being a C182. Notice the huge resistance to those answers from most of the people that ask that question. Why? Because it doesn't look like a cool, slick airplane. In fact, it looks like a damn C172!

I will now endeavour to start a petition and campaign to stop the racism against high wings! They're airplanes, too!

;):}

[mad_jock]

So why are people so hot for low wings when all it brings is headaches? Hard to keep clean, belly rashes, prop strikes, painful entry end exit, can't land at fields with high grass on sides, etc, etc. You've just made your life 10 times harder for zero benefit.

Sounds like the same excuses a certain FO I have flown with for many years says about his liasons with the local weight watchers club, and he likes plenty of grass on the sides and certainly doesn't mind the older models.

Its a dirty perversion but you can get help for it Adam.

[AdamFrisch]

Sounds like the same excuses a certain FO I have flown with for many years says about his liasons with the local weight watchers club, and he likes plenty of grass on the sides and certainly doesn't mind the older models.

How did you know I liked "grass on the side" on older models?:ok::)