Atlas Air 767 down/Texas
This event was going on for 18 seconds. I would assume that one or both pilots had hold of the yoke.
I can't imagine that either did dot push the A/P disconnect on the yoke.
Note: I am assuming there is an A/P disconnect on the yoke as on previous Boeing's.
I can't imagine that either did dot push the A/P disconnect on the yoke.
Note: I am assuming there is an A/P disconnect on the yoke as on previous Boeing's.
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Also, the NTSB release said the throttles went to full power before the pitch over.
I also can't imagine not pulling the throttles and speedbrake lever back with the nose pointed down for whatever reason.
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One of the things that may need to be looked into on this is how the 767 control system responds if the pilot pushes the column while the autopilot is engaged. More recent models recognize pilot intervention via significant controller displacement as time to disconnect the autopilot. On older models the autopilot does not immediately disengage in response to pilot input. There may have been a period of time where both Hal and Row 0 were providing significant control inputs. Learning that the autopilot remained engaged would not necessarily mean that Hal was at fault.
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Ut Sementem Feeceris
??????......er....if I’m pointing down at the ground (let alone 49 degrees down) I’m going to close the throttles, pull the speed brake and pull.....probably the only way you’re going to get any chance of gaining altitude......once you’ve arrested the descent.....
A4 (10,000+ hrs Airbus)
A4 (10,000+ hrs Airbus)
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??????......er....if I’m pointing down at the ground (let alone 49 degrees down) I’m going to close the throttles, pull the speed brake and pull.....probably the only way you’re going to get any chance of gaining altitude......once you’ve arrested the descent.....
A4 (10,000+ hrs Airbus)
A4 (10,000+ hrs Airbus)
putting out the speedbrakes increases your load on the airframe even more, increasing the chance of an inflight breakup.
Ut Sementem Feeceris
I see that.....but accelerating towards the barbers pole (and beyond) also isn’t going to be great for structural integrity! Additionally, it’s dependent upon how much altitude you have to play with......from 20,000 it’s no issue......from 5,000....different scenario. Does the 777/787 have load factor protection like the Airbus? At least you can pull to the limit with out risking structural integrity (if the aircraft (Bus) is in Normal Law). The 767 would obviously require a more nuanced approach to handling.
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From around 2000’ and 500 kts it would be pretty much a 3 G pull-up. Moot point though if something is preventing full pitch-up control inputs.
I Have Control
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Deliberate act possible. Examination of pilots' histories needed.
This possible cause should be evaluated in the same way as a technical issue. Methodically and objectively.
This possible cause should be evaluated in the same way as a technical issue. Methodically and objectively.
Can you explain this statement. How do speedbrakes increases airframe load?
I see that.....but accelerating towards the barbers pole (and beyond) also isn’t going to be great for structural integrity! Additionally, it’s dependent upon how much altitude you have to play with......from 20,000 it’s no issue......from 5,000....different scenario. Does the 777/787 have load factor protection like the Airbus? At least you can pull to the limit with out risking structural integrity (if the aircraft (Bus) is in Normal Law). The 767 would obviously require a more nuanced approach to handling.
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In any case I doubt you'd still be accelerating if you're pulling 2g+ as the drag would be significantly higher
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Yes, there is. The 767 doesn't have "high tech" computer "augmentations." It's a straight-forward, easy airliner to fly. A/T easy to disconnect or override. Autoflight easy to turn off.
They move the lift distribution outboard, so if you're pulling 2g with the speedbrakes out the root bending moment will be higher compared to a 2g manouevre with a clean wing.
In any case I doubt you'd still be accelerating if you're pulling 2g+ as the drag would be significantly higher
In any case I doubt you'd still be accelerating if you're pulling 2g+ as the drag would be significantly higher
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Cornering Speed
Written from a fighter pilot viewpoint. When applying to a transport, there are going to be additional factors to consider such as control hinge moments, wing bending moment, and control system design. (For Airbus FBW, all such decisions have been already made for you.)
With the nose buried downward, and with concern about hitting the ground, you would like to achieve a minimum radius turn, but without tearing the aircraft apart.
The minimum radius turn is generally achieved where max AOA and max allowable G meet on the performance curves.
You can consider using up some of your safety margin when planning what G level to attain. Then look up the performance curves and determine a cornering velocity based upon your most probable gross weight.
Below cornering velocity, you can slightly improve performance by accelerating slightly and pulling into buffet. Above cornering velocity, you must slow down to improve turn performance and meanwhile avoid going beyond your max acceptable G (without a G meter).
Knowing your cornering speed is strictly emergency knowledge and would be used solely to ensure you are not completely out of the ballpark in your pull out efforts.
No doubt, the test pilots and aerodynamics guys can flesh this out better. As I recall, the F-4 cornering velocity was 420 knots. You definitely will not want to be anywhere near that speed when you pull out in your transport.
With the nose buried downward, and with concern about hitting the ground, you would like to achieve a minimum radius turn, but without tearing the aircraft apart.
The minimum radius turn is generally achieved where max AOA and max allowable G meet on the performance curves.
You can consider using up some of your safety margin when planning what G level to attain. Then look up the performance curves and determine a cornering velocity based upon your most probable gross weight.
Below cornering velocity, you can slightly improve performance by accelerating slightly and pulling into buffet. Above cornering velocity, you must slow down to improve turn performance and meanwhile avoid going beyond your max acceptable G (without a G meter).
Knowing your cornering speed is strictly emergency knowledge and would be used solely to ensure you are not completely out of the ballpark in your pull out efforts.
No doubt, the test pilots and aerodynamics guys can flesh this out better. As I recall, the F-4 cornering velocity was 420 knots. You definitely will not want to be anywhere near that speed when you pull out in your transport.
Transport aircraft like the 767 have a reasonably light wing loading relative to fighters. I suspect that at the 230 knots assigned they could generate 3.75G’s. Since there is no where to read G force unless they had recent aerobatic flying that would be very subjective.
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The interesting question would be, how the speed brakes influence the cornering radius pulling out of the dive. However, even here they won't make things worse I would guess.
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Since there is no where to read G force unless they had recent aerobatic flying that would be very subjective.
The most valuable seconds in a dive recovery are the first few seconds. Delay in getting max g on will cost you altitude.
We haven't even discussed what you do when you realize that you were successful and will miss the ground.