TU-22 Crash

[Astro14]

If you hit the runway at 30 FPS (1800 FPM, easy to achieve if you're trying to correct and get behind a high performance airplane) sink rate, I don't care if the structure is new or old.

It will fail.

It was never designed for that level of stress.

Now, I have no illusions about Russian AF maintenance...but when you see an airplane gain 20 feet of altitude on the bounce, even brand new Boeings wouldn't take that kind of pounding...

A few years ago, ANA permanently damaged a 767-400 on a bounced landing which was nowhere near as bad as this TU-22 landing. It hit at about 10 FPS (600 FPM) and that airplane never flew again.

http://avherald.com/h?article=45173104

Poor approach corrections and they broke the airplane.

Throw in a much less forgiving airplane, snow-obscured runway, and pilots with far less flight time, much higher sink rate than ANA, and yeah, I'm going with pilot error...

I doubt that we will ever get a straight answer from the Russians on this one...

 

[Linctex]

Originally Posted by Astro14
I don't care if the structure is new or old -It will fail.
..
I doubt that we will ever get a straight answer from the Russians on this one...

I'm sure we can agree it was a combination of factors.

My argument is perhaps the plane would no longer be salvageable if it was maintained well - but at least kept in one piece.

I would love to NDI the area where the failure occurred to see what hidden surprises lie within.

 

[Astro14]

Yes - I would be very interested the results of that. Fatigue cracks, corrosion, stress risers, there are so many ways that a 50 year old airplane could have degraded. I doubt it even has a black box recorded to know what the touchdown parameters were...

 

[Cujet]

Originally Posted by Linctex


My argument is perhaps the plane would no longer be salvageable if it was maintained well - but at least kept in one piece.
I would love to NDI the area where the failure occurred to see what hidden surprises lie within.


It's easy to look at the video and believe the airframe could have somehow survived.

However, this beast is nearly 140 feet long. We can use the length of the aircraft as a measurement tool for determining sink rate. Some estimates are as high as 4500 FPM.

[Sarc] Unsubstantiated claim from uncle Boris, who heard from brother Alandr, who heard it from Dmitri who is involved in Russian military aircraft: The G on landing was 5.7, the structural damage restriction on this type was calculated as 3.7G. My personal belief is that the hit was substantially harder than that. When the landing gear bottomed out, the load spiked and the cantilevered nose yielded suddenly.

It looks to me that it took about 2 seconds for the aircraft to descend 140 feet. For an overall sink rate of 70 feet per second or almost 50 MPH. We must remember that a 30mph automotive crash into an immovable object, with standard crumple zones is 20G.

So, even with the flare to stop the sink rate, the hit was extremely hard.

A wild guess on my part, his altimeter setting or altimeter accuracy may have been involved.

 

[Astro14]

Cold weather altimetry is a big consideration...more than folks realize unless they've flown in very cold places...

But the Russians use metric and QFE. So, with QFE (part of why they use it), you simply set the altimeter to the ATIS/published value, and the altimeter reads 0 at field elevation.

This removes most of the cold weather adjustments to altimeter settings.

 

[billt460]

Astro,

As far as hard landings, I always wondered how thick the steel was on the flight deck of an aircraft carrier, right under the arresting cables, where the planes touch down? That Russian wreck reminds me of this one:

 

[Virtus_Probi]

Originally Posted by billt460
Astro,
As far as hard landings, I always wondered how thick the steel was on the flight deck of an aircraft carrier, right under the arresting cables, where the planes touch down? That Russian wreck reminds me of this one:

Wow...you can also see that plane rupturing somewhere towards the middle if you can take your eyes off the tail completely separating. Maybe that airliner wasn't too far off from a total split like we saw with the bomber...

 

[Astro14]

I've never seen that Douglas video, Bill, thanks for sharing that.

What strikes me about that video is that the rate of descent seemed mild compared with the Russian bomber, but camera angle, and other factors can influence how that looks...hard to be certain.

I don't know how thick the steel is on a carrier...it's a couple of inches, at least. Having run on it, it's completely unyielding. It's unyielding when a 54,000# Tomcat hits it, too...

 

[Virtus_Probi]

Another dramatic strategic bomber crash, the truly tragic thing here is that it was 100% preventable...

 

[CT8]

Planes seem to not bounce well.

 

[53' Stude]

Originally Posted by Virtus_Probi
Another dramatic strategic bomber crash, the truly tragic thing here is that it was 100% preventable...



That pilot should have never, ever been in control of any bomber period

 

[Astro14]

Originally Posted by 53' Stude
Originally Posted by Virtus_Probi
Another dramatic strategic bomber crash, the truly tragic thing here is that it was 100% preventable...



That pilot should have never, ever been in control of any bomber period


Agreed.

A history of poor performance, and poor judgement.

This crash was 100% pilot error, he did not fly the approved maneuvers, got slow, lost control.

 

[spasm3]

Originally Posted by Astro14
Originally Posted by 53' Stude
Originally Posted by Virtus_Probi
Another dramatic strategic bomber crash, the truly tragic thing here is that it was 100% preventable...



That pilot should have never, ever been in control of any bomber period


Agreed.

A history of poor performance, and poor judgement.

This crash was 100% pilot error, he did not fly the approved maneuvers, got slow, lost control.


So was that crash a complete loss of lift from slow speed and angle?

 

[Astro14]

Yeah - he stalled the airplane. Simply put.

The crash is a classic case study in a couple of things. First is organizational failure and the second is the effect of load factor on stall speed.

The pilot had a long, egregious history of exceeding parameters while flying. He had come close to crashing before, but because he was the Wing Commander, no one stood up to his poor flying and he was allowed to continue. On this day, he put himself on the schedule to fly the demonstration flight. His history is one of unsafe flaying, with little organizational response to correct it. His history is famous, in aviation safety circles, because it was so blatantly terrible.

The flight was supposed to include some 60 degree bank turns. Now, 60 degrees, done properly in a big airplane, can be done, but the airplane doesn't fly like it does in level flight.

At 60 degrees of bank in level flight, the wings need to generate twice as much lift as they do at 0 degrees of bank. That's because the lift vector (the direction of the lift) is at 60 degrees to vertical, and only half of the lift is countering gravity. So, if your normal stall speed is say, 120 knots, when at 2G, your wing will stall at roughly 145 knots (this varies with wing shape and other factors, but simply, you need more air flowing over the wing for that increase in lift). This is known as an accelerated stall.

Once you stall an airplane wing, roll control is no longer assured. The response varies depending on a bunch of factors, but once you stall the wing, in some airplanes, particularly those that use spoilers for roll control, you get an airplane that rolls the opposite direction from the control input. In other words, you roll left, and the airplane goes right. I don't know a lot about the B-52, but it sure looks like it rolled the opposite direction from the aileron input (you see spoilers up on the right wing, but the airplane rolls left, instead of right, as the controls were positioned). The lift wasn't lost, as much as the Angle of Attack (AOA) was exceeded and the airplane failed to respond to control inputs. IF he had unloaded the airplane (full forward yoke) the AOA would have been reduced, and the roll control restored.

So, as I remember this accident, he overbanked, and was well beyond 60 degrees (and needed a lot more load factor) and stalled it, once stalled, he rolled back to the right, but the airplane rolled left and crashed. HIs overbank was unsafe, but he had done it many, many times before, including coming close to crashing in previous demonstrations.

Pure pilot error.

 

[CT8]

Would greater altitude have given the pilot time and distance to correct the problem. The pilot was showing off?

 

[PimTac]

Originally Posted by CT8
Would greater altitude have given the pilot time and distance to correct the problem. The pilot was showing off?




There were some factors involved. The area he turned towards had a restriction. From Wikipedia;

"The B-52 then began the 360° left turn around the tower starting from about the midfield point of the runway. Located just behind the tower was an area of restricted airspace, reportedly because of a nuclear weapons storage facility."



In the end it was the pilot's error and judgement along with his attitude of being a risk taking flyer. But accidents usually involve a number of holes in the Swiss cheese to line up.

https://en.m.wikipedia.org/wiki/1994_Fairchild_Air_Force_Base_B-52_crash

 

[Shannow]

And the plane can be scaled down and perform exactly as the full size plane....

 

[billt460]

Pretty much the same thing happened in 2010 to a C-17 up in Alaska. They were practicing for an upcoming air show. This video is somehow a goofy, backward mirror image. (Air Force lettering on the plane is backwards). But you can clearly see the result.

 

[Astro14]

Haven't seen that C-17 crash, but yes, it's the same thing - accelerated stall.

And you can see the spoilers up (extended) on the top wing as the airplane continues toward 90 degrees.

When it's past stall, the roll control doesn't exist, and often, with spoilers, the airplane will roll opposite of the control input*.

In that moment, when the pilot knows he's in trouble, and the airplane isn't responding, he's going to respond with instinct - to roll right, you put in more right yoke (even though it doesn't work) and because the ground is approaching, he's going to pull back on the yoke, because as the adrenaline hits his brain, and his frontal cortex is shut down by his amygdala hijacking higher thinking, that's all that he can think of.

It's a fight or flight response. In that moment of fear, his ability to analyze and think has been completely removed.

I promise you that in the first two seconds of the accelerated stall, the airplane could've been saved by an aggressive unload (full forward yoke) followed by rolling input, primarily yoke, but perhaps with just a touch of rudder. With the wing unloaded, at low AOA, roll control is restored and the airplane will respond. Rapidly. With the wings under it (level flight) it can fly at that airspeed and pull out from a shallow dive.

But once this progressed beyond a couple of seconds, the bank angle, nose down pitch, rate of descent, and airspeed were all too far gone to be recoverable. The pilot is crashing, knows he's crashing, knows that this is bad, but is unable to think beyond more of the control inputs that created this problem. With seconds to live, he's unable to think his way out. It's human nature in a stress response.



*I've got some familiarity with this. Above 25 AOA the Tomcat would roll opposite the direction of the stick input...wily Tomcat drivers would use this to their advantage in a fight when very slow. Let's say that you want to roll left in a slow speed fight, you pull back a bit, go right stick (opposite of the direction you want to roll) and feed in left rudder. Off she'll go...to the left...

 

[billt460]

Astro,

Were the variable sweep wings on a F-14 computer controlled? For example, if you were flying slow with the wings extended, and then firewalled the throttles, would the wings automatically sweep back as the airspeed increased? Or did it have to be done manually by the pilot? Or if the opposite happened, and you got too slow with the wings swept back, would they automatically extend?