Moderators: richierich, ua900, PanAm_DC10, hOMSaR

 
Chamonix
Topic Author
Posts: 354
Joined: Sat Mar 05, 2011 1:31 pm

Return To Level:The Anti-Stall Solution

Wed Dec 07, 2011 6:05 pm

The Typhoon which is one of the World's most automated A/C ever has simple solution to stalls.
No input whatsoever,no panick,no worrying about nothing.
A simple RTL "Return To Level" switch which takes care of everything.
This should be made compulsory on every airliner.
RTL feature:
http://typhoon.starstreak.net/Eurofighter/flight-sys.html
"Upon pushing this button, part of the VTAS function set, the aircraft is automatically returned to nose-up, wings level flight with the throttles set at an intermediate position.
 
roseflyer
Posts: 9602
Joined: Fri Feb 13, 2004 9:34 am

RE: Return To Level:The Anti-Stall Solution

Wed Dec 07, 2011 7:03 pm

Boeing airplanes already have stall protection built in via various ways for the mechanically controlled airplanes. 747-8 has a Pitch Augmentation Control System that will automatically move the elevator without pilot input. The 767 has an actuator called a stick nudger that moves that pushes the control column forward to 1 degree nose up attitude when a stall is detected. The 737NG automatically moves the stabilizer to trim the airplane to nose down.

All of these require direct pilot input to counteract. The airplane can still be stalled, but the pilot will be forcing it to. It will automatically try to correct from a stalled condition. The features are also designed not to be overridden electronically by the autopilot or flight computers. They must be overridden by direct pilot command.

In general you do not want a button that when switched takes control away from the pilot. The failure modes to prevent such a system from inadvertantly activating are worse than the protection that it provides. The airplane is already designed to have static stability and in a panic condition the airplane has controls such as those I described earlier so that it will self correct.

AF 447 and XL888 are a cases where such protections, pilot loss of situational awareness, and attitude/speed/etc sensors failing can still bring a plane down. If the inputs to the computer that controls the self leveling protection computer fail, the airplane is in no better with a computer or pilot flying it. If both AOA sensors and pitot static fail and the airplane defaults to direct mode, such a system is not going to help you much. Having built in protections as there are and redundant systems are what prevent accidents like AF 447. Not every failure mode can be designed around as some conditions are deemed to be rare enough not to have design protections. In the case of XL888 they had a failed AOA sensor and when testing the limits of a low speed go around, the fault trees caught up and the pilots lost control.
If you have never designed an airplane part before, let the real designers do the work!
 
lowrider
Posts: 2542
Joined: Wed Jun 30, 2004 3:09 am

RE: Return To Level:The Anti-Stall Solution

Wed Dec 07, 2011 7:55 pm

Or we could just train pilots from the beginning to recognize stalls and how to recover from them, and to not rely on automation. We could even have them do demonstrate the ability to do so on recurring check rides, and emphasize basic airmanship. It is a million dollar solution to a one dollar problem.
Proud OOTSK member
 
Lemmy
Posts: 261
Joined: Fri Dec 10, 2004 8:40 am

RE: Return To Level:The Anti-Stall Solution

Wed Dec 07, 2011 8:26 pm

I think a feature like this is designed to address disorientation moreso than stalls. Even small airplanes like the Cirrus SR-22 have it: http://whycirrus.com/advancements/Cirrus-perspective-cockpit.aspx. They call it the "LVL"button, which does something similar.

But, I wonder how useful this is. If you're disoriented, chances are your inner ear is telling you something (that you believe) and your instruments are telling you something else (that you probably don't believe as much). I think it's a natural reaction to think that something is wrong with the instruments. How likely are you to turn over complete control to a machine that you suspect (correctly or incorrectly) is malfunctioning?
I am a patient boy ...
 
David L
Posts: 8551
Joined: Tue May 18, 1999 2:26 am

RE: Return To Level:The Anti-Stall Solution

Wed Dec 07, 2011 8:54 pm

This looks more like a system for dealing with unusual attitudes and spatial disorientation, particularly when the pilot is aware that spatial awareness has been lost, probably not a bad idea for such an agile combat aircraft. The word "stall" doesn't seem to appear anywhere in the article.

Quoting lowrider (Reply 2):
Or we could just train pilots from the beginning to recognize stalls and how to recover from them, and to not rely on automation

... or, at least to understand the automation. But good luck with that radical idea.   
 
9VSIO
Posts: 654
Joined: Tue Dec 19, 2006 5:00 pm

RE: Return To Level:The Anti-Stall Solution

Thu Dec 08, 2011 2:13 am

Quoting Chamonix (Thread starter):
The Typhoon which is one of the World's most automated A/C ever has simple solution to stalls.

As said, it's not a solution to stalls as stalls aren't related to attitude. You can be stalled, but at the same time be nose up, wings level with throttles set to an intermediate position.
Me: (Lining up on final) I shall now select an aiming point. || Instructor: Well, I hope it's the runway...
 
tdscanuck
Posts: 8573
Joined: Wed Jan 11, 2006 7:25 am

RE: Return To Level:The Anti-Stall Solution

Thu Dec 08, 2011 2:50 am

Quoting Chamonix (Thread starter):
The Typhoon which is one of the World's most automated A/C ever has simple solution to stalls.

They system you describe is not a solution to stalls. In fact, if activated in a stall, it could kill you (eventually, if you didn't realize how stupid what you'd just done actually was).

Quoting Chamonix (Thread starter):
"Upon pushing this button, part of the VTAS function set, the aircraft is automatically returned to nose-up, wings level flight with the throttles set at an intermediate position.

If you're stalled, you usually want nose-down with power. The opposite of what this system does.

Quoting Lemmy (Reply 3):

I think a feature like this is designed to address disorientation moreso than stalls.
Quoting David L (Reply 4):

This looks more like a system for dealing with unusual attitudes and spatial disorientation,

Exactly. This doesn't even apply to modern airliners since, as RoseFlyer nicely described, airliners will return to a stable attitude and speed if you just let go. They effectively have this type of system active all the time and you "activate" it by just letting go of the controls.

In a degraded flight control situation the last time you want to invoke more automation since you have no idea which part is going to be correct when the aircraft tries to return to straight and level...if the IRU is the part that died it could well flip you upside down.

Quoting 9VSIO (Reply 5):
As said, it's not a solution to stalls as stalls aren't related to attitude. You can be stalled, but at the same time be nose up, wings level with throttles set to an intermediate position.

Exactly. Hitting this type of function after a stall would probably result in an accident that looked a whole lot like AF447.

Tom.
 
ThirtyEcho
Posts: 1411
Joined: Tue Jan 01, 2002 1:21 am

RE: Return To Level:The Anti-Stall Solution

Thu Dec 08, 2011 8:34 am

Spin recovery in the British Spitfire was best accomplished by the pilot taking his hand off the stick and placing his feet flat on the floor while increasing power gradually. I tried this in a C152 and it worked perfectly, bringing me out of the spin in about half a turn or so. The airplane had to be held in a spin or it would fly out of it all on its own.

Yes, I am very much in favor of people getting spin recovery training for the PPL.
 
rcair1
Posts: 1147
Joined: Wed Oct 28, 2009 8:39 pm

RE: Return To Level:The Anti-Stall Solution

Thu Dec 08, 2011 3:35 pm

Quoting ThirtyEcho (Reply 7):
Yes, I am very much in favor of people getting spin recovery training for the PPL.

Me too - it was included in my PPL training - though not required. Actually on my first phase check - the check instructor said - gee - you ever spun it? No? Let's do it.

During hood training, my instructor (he could be evil) - snapped us into a spin during a power on stall under the hood. I recovered to discover he had turned the fuel off during my recovery - so just about the time I recovered - the engine stopped.

This was during PPL, not instrument training. He believed in pushing his students a bit....

All this was in a 152...
rcair1

Who is online

Users browsing this forum: No registered users and 118 guests

Popular Searches On Airliners.net

Top Photos of Last:   24 Hours  •  48 Hours  •  7 Days  •  30 Days  •  180 Days  •  365 Days  •  All Time

Military Aircraft Every type from fighters to helicopters from air forces around the globe

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

Night Photos Beautiful shots taken while the sun is below the horizon

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos