Cessna 150 Aerobat banks to the left

100hp

Filing Flight Plan
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Jan 2, 2013
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Bill
I have a 1972 Aerobat. On my last flight something happened that now causes it to bank to the left.

It won't fly straight and level without right aileron input. Rudder input doesn't fix the problem.

Any ideas?
 
Maybe its not the plane, but all of that christmas ham you ate? Not to mention the egg nog.


Kidding of course.. I was flying a 152 for awhile that had a 'heavy wing' and looking through the service manual provided instructions on correcting this situation. They involved removing the wing root covers and adjusting the bolts that hold the wing to the airframe. I never did the procedure (obviously this is one best left to an A&P) but I recall cams or some form of adjustment at the wing root bolts. The best guess I can come up with is that one of them is loose and slipped.
 
Have you checked the cable tensions and control surface rigging? Is there any indication it was recently subjected to an over-g condition, say, on a high-g rolling pull-out? Note that the g-loads on the wing in a rolling pull-out can be higher than the g-load indicated on the cockpit accelerometer.
 
From the 152 service manual


ADJUSTMENT (CORRECTING "WING-HEAVY" CONDITION). (Refer to figure 4-1.) If
considerable control wheel pressure is required to keep the wings level in normal flight. a
"wing-heavy" condition exists. To remedy this condition, proceed as follows:
a. Remove wing root fairing strip on "wing-heavy" side of aircraft.
b. Loosen nut (10) and rotate eccentric bushings (8) simultaneously until the bushings
are positioned with the thick sides of the eccentrics up. This will lower the trailing
edge of the wing. and decrease "wing-heaviness" by increasing the angle-ofincidence
of the wing.
CAUTION
Be sure to rotate the eccentric bushings simultaneously.
Rotating them separately will destroy the alignment
between the off-center bolt holes in the bushings, thus
exerting a shearing force on the bolt. with possible
damage to the hole in the wing spar fitting.
 
Have you checked the cable tensions and control surface rigging? Is there any indication it was recently subjected to an over-g condition, say, on a high-g rolling pull-out? Note that the g-loads on the wing in a rolling pull-out can be higher than the g-load indicated on the cockpit accelerometer.

I should have mentioned that my reply was assuming the OP would have said something if he possibly bent or broke something on the previous flight from over stressing.

Make sure a mechanic looks the wings/airframe/cables over thoroughly before trying to solve it with adjustments at the wing attachments or elsewhere. Otherwise you might be putting a band-aid over a serious structural problem.
 
You could also just hang a couple of lead fishing weights from the right side of the wheel! That'll fix it ha
 
Make sure a mechanic looks the wings/airframe/cables over thoroughly before trying to solve it with adjustments at the wing attachments or elsewhere. Otherwise you might be putting a band-aid over a serious structural problem.
Right. That "wing-heavy" procedure from the manual should be looked at only as a last resort after other less drastic causes have been eliminated. It's hard to imagine how an airplane could suddenly have a change in the incidence angle of one wing if it's been flying fine all along unless it were over-g'd, and that would be a serious situation in which simply re-adjusting the wing might just be treating the symptom rather than the disease.
 
The plane has about 6,500 TT. It's no spring chicken.

I haven't been doing any aerobatics or otherwise stressing the plane, other than a little bumpy air.

It was flying fine earlier in the day. Nice smooth air.
 
.. I was flying a 152 for awhile that had a 'heavy wing' and looking through the service manual provided instructions on correcting this situation. They involved removing the wing root covers and adjusting the bolts that hold the wing to the airframe.

This is a procedure to follow after re-installing the wings, it's not something that requires periodic adjustment. In this case the first thing I would do is check that the rudder trim tab and any aileron trim tab, if one is installed, has not been bent out of position. If there is an aileron trim tab it's an indication that the rigging was not done correctly so it should be rechecked.
 
If the airplane's in-flight behavior has changed that dramatically, all at once, I would be VERY concerned about it, and I'd have it gazed at intently by a qualified A&P.

It is possible that something broke, or someone bent a trim tab or something worse. Sudden changes in aircraft behavior are not to be trifled with!
 
If the airplane's in-flight behavior has changed that dramatically, all at once, I would be VERY concerned about it, and I'd have it gazed at intently by a qualified A&P.

It is possible that something broke, or someone bent a trim tab or something worse. Sudden changes in aircraft behavior are not to be trifled with!

:yeahthat:
 
Very slight bends in flaps or ailerons can make a bug difference in rigging. Definitely calls for a careful inspection when a change like that comes on suddenly.
 
Rerigging ailerons will not cure a heavy wing. If you rig one downward, the airflow just exerts upward pressure on it and that force is transmitted through the system and forces the other aileron down a bit.

150s and 152s have no aileron trim tabs.

Wing heaviness is normally adjusted via the aforementioned eccentric bushings. If this heaviness just appeared, something has been damaged or broken. A dented bottom aileron skin can do it. A failing flap roller can do it.

Most common cause is a broken rudder bar return spring. The OP says that rudder doesn't fix it, but I'd like to know if the heaviness is still there when he takes his hands off the yoke and holds the ball centered with the pedals. If the heaviness is gone, one of the springs is broken. It's a really common failure point in the 150/172 series.

Dan
 
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