Jammed yoke
06-16-2012, 03:46 AM
#1
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Jammed yoke
Hi guys!
Let's say we are flying a small single engine aircraft, we enter a normal left turn and when we reach the bank angle, we are unable to release the yoke back to neutral, it's jammed there. Can we overcome it? Is it a controllable situation if we use full opposite rudder? Can we stop the roll or the aicraft will keep rolling and in a few seconds we gonna crash? In a multi-engine I think you have one more option, that's asymmetric thrust, so it's a little easier to counteract the roll, but what about single engine scenario?
In think it's a barely controllable situation, I didn't find another one like this, maybe jammed yoke in pitch, but you can use the trim opposite way if your elevator is jammed, can you? Or the trim tab is too small to have any effect? And you also have power to pitch up.
If you know scenarios like the one above, I'm really curious to hear them, as I said, I didn't find others to be so close to an out of control sitation.
Thank you very much!
Let's say we are flying a small single engine aircraft, we enter a normal left turn and when we reach the bank angle, we are unable to release the yoke back to neutral, it's jammed there. Can we overcome it? Is it a controllable situation if we use full opposite rudder? Can we stop the roll or the aicraft will keep rolling and in a few seconds we gonna crash? In a multi-engine I think you have one more option, that's asymmetric thrust, so it's a little easier to counteract the roll, but what about single engine scenario?
In think it's a barely controllable situation, I didn't find another one like this, maybe jammed yoke in pitch, but you can use the trim opposite way if your elevator is jammed, can you? Or the trim tab is too small to have any effect? And you also have power to pitch up.
If you know scenarios like the one above, I'm really curious to hear them, as I said, I didn't find others to be so close to an out of control sitation.
Thank you very much!
06-16-2012, 07:36 AM
#2
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Since the rudder extends above the longitudinal axis, it has a bit of effect similar to ailerons, coupled with yawing the outside wing also generates more lift, but it's not terribly effective at this. What would make it more effective would be more speed, unless you're saying the ailerons themselves (not just the yoke) are jammed with a pro-turn input, then I'd imagine it would be very hard to control, if at all. It depends on how "strong" the ailerons are on this particular aircraft vs. the rudder and if you started neutralizing the ailerons prior to reaching the bank angle (most people do).
06-16-2012, 08:04 AM
#3
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Jammed elevator actually has a checklist in several GA aircraft that I've flown (typically just saying use the trim wheel).
Other than requiring some pre-planning, and a great deal of stability (finding and holding a power setting versus chasing), it's totally doable. I've done it for practice with several students.
Other than requiring some pre-planning, and a great deal of stability (finding and holding a power setting versus chasing), it's totally doable. I've done it for practice with several students.
06-16-2012, 08:04 AM
#4
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More details about my dark scenario. I'm thinking about the situation when you just start a normal roll rate turn, so small deflection on yoke, when you realise you can't return it to neutral. The aircraft keeps rolling if you do nothing because the yoke is jammed deflected and ailerons are also deflected because of yoke not being neutral. The single option seems to be opposite rudder pedal and increasing speed to have more rudder effect as you said. It's pretty clear that a big yoke deflection is unrecoverable, but for a small deflection is the rudder effect enough to stop the roll? And after that can it lead to a spin from the cross-controlled attitude harder than in a forward slip?
EDIT: Is the rudder more effective at high speeds or at low speeds? Sorry, but that's not clear for me.
EDIT: Is the rudder more effective at high speeds or at low speeds? Sorry, but that's not clear for me.
Last edited by andrew172; 06-16-2012 at 08:16 AM.
06-16-2012, 09:50 AM
#5
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When you're in a Cirrus, you slam the controls hard (we will die if this doesn't work hard) while stomping on the rudder. That should break through the jam. If that doesn't work, pull the chute.
If you're in other SEL pistons, it's quite possible that something is caught in the pulleys, perhaps a screwdriver or a flashlight, thus slamming the controls hard might snap the screwdriver shaft, or cause enough cable bounce to clear the jam. On older aircraft, a stuck pulley could have caused the cable to thin out, with thicker areas adjacent to the thin area, thus once again, slamming the controls hard could yank the thick area through the jammed pulley.
My friend Barry Schiff has an article about this in one of his books, as well as some video footage floating around. A Cessna 172 can be banked, or bank corrected, by opening and holding doors open. A Piper will yaw and somewhat be convinced to stop turning with the doors. A Cirrus will yaw, and be quite ugly, but does have a little roll and yaw control with the doors.
Pitch-wise, trim works very nice in most aircraft. A Cirrus might have a jammed pitch trim cartridge, so slamming the controls to the stops should clear it.
Don't worry if you crash, the impact will clear up the jam and the NTSB or FAA will blame the crash on the PIC losing control for an undetermined reason.
If you're in other SEL pistons, it's quite possible that something is caught in the pulleys, perhaps a screwdriver or a flashlight, thus slamming the controls hard might snap the screwdriver shaft, or cause enough cable bounce to clear the jam. On older aircraft, a stuck pulley could have caused the cable to thin out, with thicker areas adjacent to the thin area, thus once again, slamming the controls hard could yank the thick area through the jammed pulley.
My friend Barry Schiff has an article about this in one of his books, as well as some video footage floating around. A Cessna 172 can be banked, or bank corrected, by opening and holding doors open. A Piper will yaw and somewhat be convinced to stop turning with the doors. A Cirrus will yaw, and be quite ugly, but does have a little roll and yaw control with the doors.
Pitch-wise, trim works very nice in most aircraft. A Cirrus might have a jammed pitch trim cartridge, so slamming the controls to the stops should clear it.
Don't worry if you crash, the impact will clear up the jam and the NTSB or FAA will blame the crash on the PIC losing control for an undetermined reason.
06-16-2012, 09:57 AM
#6
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Originally Posted by jedinein
When you're in a Cirrus, you slam the controls hard (we will die if this doesn't work hard) while stomping on the rudder. That should break through the jam. If that doesn't work, pull the chute.
If you're in other SEL pistons, it's quite possible that something is caught in the pulleys, perhaps a screwdriver or a flashlight, thus slamming the controls hard might snap the screwdriver shaft, or cause enough cable bounce to clear the jam. On older aircraft, a stuck pulley could have caused the cable to thin out, with thicker areas adjacent to the thin area, thus once again, slamming the controls hard could yank the thick area through the jammed pulley.
My friend Barry Schiff has an article about this in one of his books, as well as some video footage floating around. A Cessna 172 can be banked, or bank corrected, by opening and holding doors open. A Piper will yaw and somewhat be convinced to stop turning with the doors. A Cirrus will yaw, and be quite ugly, but does have a little roll and yaw control with the doors.
Pitch-wise, trim works very nice in most aircraft. A Cirrus might have a jammed pitch trim cartridge, so slamming the controls to the stops should clear it.
Don't worry if you crash, the impact will clear up the jam and the NTSB or FAA will blame the crash on the PIC losing control for an undetermined reason.
If you're in other SEL pistons, it's quite possible that something is caught in the pulleys, perhaps a screwdriver or a flashlight, thus slamming the controls hard might snap the screwdriver shaft, or cause enough cable bounce to clear the jam. On older aircraft, a stuck pulley could have caused the cable to thin out, with thicker areas adjacent to the thin area, thus once again, slamming the controls hard could yank the thick area through the jammed pulley.
My friend Barry Schiff has an article about this in one of his books, as well as some video footage floating around. A Cessna 172 can be banked, or bank corrected, by opening and holding doors open. A Piper will yaw and somewhat be convinced to stop turning with the doors. A Cirrus will yaw, and be quite ugly, but does have a little roll and yaw control with the doors.
Pitch-wise, trim works very nice in most aircraft. A Cirrus might have a jammed pitch trim cartridge, so slamming the controls to the stops should clear it.
Don't worry if you crash, the impact will clear up the jam and the NTSB or FAA will blame the crash on the PIC losing control for an undetermined reason.
USMCFLYR
06-16-2012, 11:12 AM
#7
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Originally Posted by jedinein
When you're in a Cirrus, you slam the controls hard (we will die if this doesn't work hard) while stomping on the rudder. That should break through the jam. If that doesn't work, pull the chute.
06-16-2012, 01:47 PM
#8
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Generally, you can probably fly and land most light SE GA airplanes with one control axis failed and surfaces free-floating, or even jammed neutral or in moderate deflection.
Rudder: Should be easy, use aileron and land straight into the wind.
Elevator: Should be easy, use trim (if the elevator is jammed, then trim may still help but will have a reduced affect in the OPPOSITE direction on most airplanes) . If needed adjust power, airspeed, flaps. In extremis, shift pax/cargo to change CG.
Aileron: More challenging, use rudder. Land straight into the wind. Time permitting adjust pax/cargo lateral distribution and/or fuel balance to level the wings with rudder input to keep the nose straight. As others said, you can try opening doors in extremis.
This is general discussion only, reference you POH/AFM for specific instructions for your airplane.
Rudder: Should be easy, use aileron and land straight into the wind.
Elevator: Should be easy, use trim (if the elevator is jammed, then trim may still help but will have a reduced affect in the OPPOSITE direction on most airplanes) . If needed adjust power, airspeed, flaps. In extremis, shift pax/cargo to change CG.
Aileron: More challenging, use rudder. Land straight into the wind. Time permitting adjust pax/cargo lateral distribution and/or fuel balance to level the wings with rudder input to keep the nose straight. As others said, you can try opening doors in extremis.
This is general discussion only, reference you POH/AFM for specific instructions for your airplane.
06-16-2012, 05:09 PM
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I used to tow gliders in a Cessna Skywagon 185F, a high-performance single engine tailwheel airplane of the mid-1970s weighing about 3,000 pounds. When I did the checkout for this job, my instructor first had me tow several gliders while they did various things such as box wakes and early releases. Then he said go on up to 5,000 AGL and we'll do something. Suddenly at the height said ok, you just post all power and your yoke too, and obviously you are done towing gliders, get us back the ground. He was a veteran Cessna engineer, an experienced engineer and pilot. I thought ok, this fool must know what he is asking for, and surely enough I was amazed to find that I able to steer the 185F all the way to a flare using nothing but rudder pedals. I learned something.
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