Control surface hardover

[Starman170]

I guess it's the same case mentioned above.

John Pugliese recently experienced an elevator hinge bolt fail, and he was barely able to handle
it.

Isn't it?

[GAHorn]

That is correct..same event. But it's not an isolated case...it has occurred in other aircraft.
Other types of failures have also occurred...for example, ice has bridged across stabilizers and
counter balance weights of controls and locked them....then the pilot has broken the control free,
only to discover the control blocked out of position by the icicles.
Anyway, I doubt a discussion forum such as this wil prove to be much value as an aerodynamics
design course for emergency training.
And I doubt too many closed cockpit gliders have the ability to accomodate much weight shifting
to overcome greatly displaced flight controls in an emergency.
Good luck with your seminar.

[Starman170]

Other types of failures have also occurred...for example, ice has bridged across stabilizers and
counter balance weights of controls and locked them....then the pilot has broken the control free,
only to discover the control blocked out of position by the icicles.

Quite interesting. I haven't thought such a thing. It seems like you have great experience about these kind of troubles I'm interested in. I assure you it's not useless.

Anyway, I doubt a discussion forum such as this wil prove to be much value as an aerodynamics
design course for emergency training.

I assure you it's not useless. I really appreciate your help. Could you please detaliate what would be that course?

And I doubt too many closed cockpit gliders have the ability to accomodate much weight shifting
to overcome greatly displaced flight controls in an emergency.
Good luck with your seminar.

As you can see, I try to figure out that is unlikely that controls will be greatly displaced if the pilot haven't use large deflections before the jam occured. I think you won't be able to overcome greatly displaced flight controls even with all remaining controls in case the affected surface is greatly displaced. So, shifting CG might help a bit to have a little more authority to raise the nose for a more favorable landing attitude or so, but I certainly agree it wouldn't be enough.

[hilltop170]

You would still have trim (if installed) but it would act reversed with jambed control surfaces.

[CF-HEW]

I knew a flight instructor who died practicing spins with a student. They were in a Cessna 152 and the rudder jammed fully deflected. The rudder stop was not properly aligned and latched on to the rudder. No amount of force on the opposite rudder would release it and they couldn't power out of it either. They ended up in a flat spin and landed in 15 feet of water. Both survived the impact but the instructor drowned.

[GAHorn]

I knew a flight instructor who died practicing spins with a student. They were in a Cessna 152 and the rudder jammed fully deflected. The rudder stop was not properly aligned and latched on to the rudder. No amount of force on the opposite rudder would release it and they couldn't power out of it either. They ended up in a flat spin and landed in 15 feet of water. Both survived the impact but the instructor drowned.

There is an AD note about C-150/152 rudder stops failing in such a fashion. It applies only to swept-tail aircraft, however. The straight-vertical tails do not apply, if I recall correctly.

[GAHorn]

I knew a flight instructor who died practicing spins with a student. They were in a Cessna 152 and the rudder jammed fully deflected. The rudder stop was not properly aligned and latched on to the rudder. No amount of force on the opposite rudder would release it and they couldn't power out of it either. They ended up in a flat spin and landed in 15 feet of water. Both survived the impact but the instructor drowned.

There is an AD note about C-150/152 rudder stops failing in such a fashion. It applies only to swept-tail aircraft, however. The straight-vertical tails do not apply, if I recall correctly.

[Poncho73]

Starman170

Go to the NTSB site and read the Galloping Ghost accident report - Sept 2011 Reno- there is a great study on flutter and aerodynamic loads, I witnessed that accident and saw flutter first hand.

The TSBC web site has the C-152 accident report on the jammed rudder control - that's a good read for you as well.

Research the 748 accident in Carp Ontario in the late 1980's, aerodynamic jam of the roll control system and subsequent loss of the aircraft.

Also read the TSBC accident report of the BD5J aerodynamic asymmetry flap linkage failure - Ottawa Ontario.

There have been numerous aircraft accidents and incidents where flight controls have departed aircraft, jammed, incurred stiffness, broken away, cable failures, tab failures and so on and some events have resulted in accident and incidents. I my experience as an accident investigator I have seen elevator balance weight bolts migrate out and jam surfaces, cable breakage, rehydrated deice/anti fuild jamming unpowered control surfaces on so on....the list is endless

As far as our 170 flight control systems - like another Cessna, an uncommanded jamming of a flight control surface would be unlikely. If the aircraft is mechanically sound and correctly rigged it would be almost impossible, IMO, to aerodynamically jam a normal control surface. Now if your looking for failure scenario's to jam something, that is a completely different ball park, and a slippery slope to discuss, - unless you are very versed in the field. Make sure you read up on the stuff I mentioned above. Good luck with your conference discussion.