Hi everyone,

On the Cessna 172 that I'm flying, the right wing seems to be slightly lower than the left one. Does anyone know why? Hope you guys will have an answer for it! Thank you!!

If you're in level flight, the wings are level.

If you're flying straight, the choices are
- level wings
-OR-
- you have some yaw (rudder) and the wings are unlevel to compensate.

jppilot97 wrote:

Hi everyone,

On the Cessna 172 that I'm flying, the right wing seems to be slightly lower than the left one. Does anyone know why? Hope you guys will have an answer for it! Thank you!!

Is there a passenger beside you?

What do you mean by "slightly lower"? Flying right wing heavy? Physically "as in the left wing comes up to your eyes, but the right up to your nose" lower, when on the ground?

Check the tire pressure, or ask which of the other students locked up the brake and put a flat spot on the tire.

Did you check the fuel in each wing? The right wing may have a lot more fuel than the left wing causing an imbalance.

jppilot97 wrote:

Hi everyone,

On the Cessna 172 that I'm flying, the right wing seems to be slightly lower than the left one. Does anyone know why? Hope you guys will have an answer for it! Thank you!!

On the ground?
In the air?

I once had a B737 with a similar snag, captain reported left wing low in flight. After carefully inspecting both wings, I found that the r/h trailing edge flap inboard sailboat fairing was 5mm lower than it's opposite number and a quick re-rigging solved the problem, so check the flaps for correct rigging.

Many, many years ago I few a new C150 back from the factory to KVNY. We discovered the factory had left a bucking bar out near the wing tip. Don;t recall any wing heavy moments though:)

jppilot97 wrote:

On the Cessna 172 that I'm flying, the right wing seems to be slightly lower than the left one. Does anyone know why?

Maybe you're banking to the right?

Sorry, had to get that in.

A 172 does not have rudder trim, IIRC, so, I suspect the rudder is a bit out of rig. Check that by applying enough aileron to level the wings, watch the ball and a mechanic can re-rig or, more Lille twist the little tab on the rudder.

GF

As an aircraft maintenance engineer and a Cessna 172 owner I'm curious to know the answer as well.

Is it wing low while on the ground or flying?

Ground...
Are the tire pressures the same? Start with the simple stuff.
Are the tires themselves the same size and type? I highly doubt they'd be different but in theory it could happen.
Is there more fuel on one side than the other? I'm pretty sure the fuel gauge in my rusty 1989 pickup is far and away more accurate than any Cessna I've flown in (though in fairness they should be set to be accurate on the empty side, and where I fly there isn't a ton of runway choices if things go sideways so I like to bring lots of "if I bring it I won't need it" gas), so get up on the wing and check with a dipstick, which should be part of any pre-flight check anyway.

In the air...
Again a fuel imbalance maybe?
Are the wings rigged correctly? Cessna wings do have adjustment so if it "flies crooked" or "one wing heavy" the wing angles can be tweaked slightly to make it fly straighter.
Is the airframe straight? Could be slightly bent from previous incidences and/or repairs.
How about the tail and rudder? The rudder may require some rigging adjustment, or also many 172s have a manually adjustable on the ground trim tab on the rudder. The 172 I fly has a 180hp engine in place of the original 150hp engine but with that trim tab bent over to compensate it still wants to fly pretty straight (actually requires less right rudder than some of the stock 172s around here) so I know they work.

Hey everyone,

Sorry about the late reply! I really appreciate all your comments in regard to my question! I’ve actually asked my instructor about it. The reason why the right wing is lower than the left is because the manufacturer designed it to counteract with the torque effect that the propeller creates. When at full power during takeoff, the plane tends to go to the left. Therefore, with a higher left wing, the angle of attack becomes greater which helps counteract with the torque effect. This kind of makes sense, but it’s just what my instructor thinks!

Well, looks like JPPilot is either satisfied with answers or just disappeared. Would be interesting to see what caused him to perceive one wing as being low. Was it an actual problem, or a matter of perception? JPPilot, come back and tell us what happened after all.

When I worked at a repair station, I’ve adjusted the control cables on many Cessna single engine airplanes.

The OP didn’t specify it this condition exists while in-flight or on the ground, if on the ground a previous poster did a pretty good job on visually checking the airframe.

What I found back then when the owners complained that the airplane didn’t fly straight and level were common problems like the control cables not tensioned properly.

A common problem with control cables is that they tend to stretch with time so they occasionally have to be re-tensioned. On high wing 100 series Cessna’s the ailerons are controlled by 3 cables, one from the control column to the left aileron, one from the control column to the right aileron and a cable that runs from one aileron across the top of the fuselage to the other aileron. This cable is called the aileron balance cable and the tension is set on this cable, this is after making sure the ailerons themselves are adjusted properly.

To do a fast ground check to see if the ailerons are adjusted properly, I would tape a piece of wood long enough to span across the 4 vertical hand grips of the 2 control wheels and tape it down so all 4 hand grips are firmly touching the wood, by doing this it makes sure the control wheels are locked in exactly in the same position. Then I would visibly check the outboard end of each aileron to see if they lined up with the wing tip, and also check to see if there is any play in the aileron cables by trying to move each aileron up and down. If the ailerons don’t line up with the wing tip or there is movement in the ailerons, then they need to be adjusted and re-tensioned.

One note, if there are press to talk switches mounted on the top of the handgrips, tape the wood along the bottom of the control wheels, just make sure both control wheels are in exactly the same position.

Another time I found a problem when the customer complained the airplane would not fly straight and level and the problem was in the rudder cables, the rudder cables have centering springs, one on each rudder cable located under the control column by the rudder pedal bars, someone in the past had changed one of the springs to a much stronger spring, maybe to try and correct the slight yawing problem and this caused the rudder to pull to one side. After I replaced both springs, they should be replaced as pairs to make sure they have the same force and adjusted the rudder cables, the airplane flew straight and level again.

If these checks do show any problem, I do not advise anyone to attempt to adjust the cables, take it to a certified repair shop or have an A&P mechanic do the work, to properly tension the cables a special device called a tensionmeter is required, the tension can not be set by eye or feel alone.

JetStar

jppilot97 wrote:

Hey everyone,

Sorry about the late reply! I really appreciate all your comments in regard to my question! I’ve actually asked my instructor about it. The reason why the right wing is lower than the left is because the manufacturer designed it to counteract with the torque effect that the propeller creates. When at full power during takeoff, the plane tends to go to the left. Therefore, with a higher left wing, the angle of attack becomes greater which helps counteract with the torque effect. This kind of makes sense, but it’s just what my instructor thinks!

Aaah...no.

Cessna did not place one wing lower to counteract torque, p-factor, asymmetric thrust, or other factors. Cessna did offset the vertical stabilizer slightly. Rigging on the Cessna 172 is the same on both wings, with the same incidence set, and the same dihedral relative to the fuselage, same control deflection, etc. If the airplane is flying wing low in flight, this is either a pilot or a rigging or a trim issue, or possibly any combination thereof, and if it's sitting wing low on the ground, it could be a gear issue, structural problem, tire inflation problem, or simply indicate that there have been a lot of hard landings by students in that airplane. Cessna doesn't build them that way.

Later models of the 172 came with rudder trim, while earlier ones did not.

I know of one light airplane that sits a bit left wing low after the person flying it (not me!) landed a little hard and bent a gear leg up a bit.

Still going strong 15 years later...

This is a 'no Sh*t' factory experience.

I was a liaison engineer for a 6-place [small] cabin class aircraft [won't mention the company].

The ground crew and the test pilots swore something was 'off' with the aircraft... seemed to be twisted in one direction making the same 'wing-low' both on the ground and in the air. Drove everyone 'nuts' that serviced and flew it... even though it appeared to fly smoothly and with no particular trim issues. It was awaiting release for customer delivery except the guys 'couldn't release it' in good conscience. So I was sent to the delivery center to evaluate it.

When I examined the acft it was maddening... I had the 'same' 'wing-low' visual/perception experience.

After walking around it and examining the obvious... it caught me as 'odd' the longitudinal rivet lines [for fore-aft stiffeners/longerons] seemed 'low on one-side' and 'high on the opposites side'... as related to the lower edges of the window panes. So I carefully measured the differences on this acft... about ~0.70-difference... and then went to look at the same features on another 'normal' acft. Measurements for the normal acft were less than 0.060 TOTAL. OH GOD.

I went back to the factory, fuselage assy area... and realized that the upper crown skins with the Pax window belt were installed 'blank'... and then a large fiberglass router-tool was lowered into position over the crown skin and the window-cutouts [and mounting fastener holes] were transferred to the installed skin. Sure-as-heck, I discovered that the mechanics had to hand-adjust the window-cutout tool for optimum/balanced/equal position on the crown-skin side-to-side/fore-aft... otherwise the router-tool could be miss-positioned up-to 0.50[+/-] either side of centerline.... and about 0.25[+/-] fore-aft.

When I briefed managers that the aircraft was 'normal' EXCEPT for the miss-positioning of the Pax windows cutouts, the solution was obvious/painful/necessary: remove and replace the upper crown skin with a new skin that had properly positioned window cutouts. I can't remember if the managers decided to replace only the crown-skin and re-rout/drill the window-cutouts and fastener holes in-place... or if they replaced most of the upper cabin structure that included several critical structural elements [doublers, frames, longerons, etc] that had the windows in-proper position.

jppilot97 wrote:

Hey everyone,

Sorry about the late reply! I really appreciate all your comments in regard to my question! I’ve actually asked my instructor about it. The reason why the right wing is lower than the left is because the manufacturer designed it to counteract with the torque effect that the propeller creates. When at full power during takeoff, the plane tends to go to the left. Therefore, with a higher left wing, the angle of attack becomes greater which helps counteract with the torque effect. This kind of makes sense, but it’s just what my instructor thinks!

As have others, you should seek a new instructor as his/her explanation is "homegrown theory of flight". I can't answer your question as I don't really understand what you're asking. Suffice it to say, an instructor that gives a BS answer is not one you want to follow to flight test.

jppilot97 wrote:

Hey everyone,

Sorry about the late reply! I really appreciate all your comments in regard to my question! I’ve actually asked my instructor about it. The reason why the right wing is lower than the left is because the manufacturer designed it to counteract with the torque effect that the propeller creates. When at full power during takeoff, the plane tends to go to the left. Therefore, with a higher left wing, the angle of attack becomes greater which helps counteract with the torque effect. This kind of makes sense, but it’s just what my instructor thinks!

I don’t understand your original question, and I understand your instructor’s “answer” even less. It’s like a feedback loop of incoherence.

Personally, I think you have better things to be spending your mental energy on while learning to fly, and your instructor sounds like a bit of a dufus. Please re-examine both your priorities and your choice of CFI.

Hi: On Cessna 172, each wing is hold by 2ea bolts, washers and nuts
Check the service Manual for correct torque and, removing longitudinal plates in the wings, near fuselage, have a Mechanic, preferred with an IA to check that torque. If torque is not ok (low) for one bolt-nut, I suggest to replace all bolts-nuts with new one, torque to proper value and check torque again after first flight.
Please do not flight if You can see a incline. If necessary, go to a shop
Rgds

Hi: On Cessna 172, each wing is hold by 2ea bolts, washers and nuts
Check the service Manual for correct torque and, removing longitudinal plates in the wings, near fuselage, have a Mechanic, preferred with an IA to check that torque. If torque is not ok (low) for one bolt-nut, I suggest to replace all bolts-nuts with new one, torque to proper value and check torque again after first flight.
Please do not flight if You can see a incline. If necessary, go to a shop
Rgds

jppilot97 wrote:

Hey everyone,

Sorry about the late reply! I really appreciate all your comments in regard to my question! I’ve actually asked my instructor about it. The reason why the right wing is lower than the left is because the manufacturer designed it to counteract with the torque effect that the propeller creates. When at full power during takeoff, the plane tends to go to the left. Therefore, with a higher left wing, the angle of attack becomes greater which helps counteract with the torque effect. This kind of makes sense, but it’s just what my instructor thinks!

Hi
Sorry, me again.
If You find this information about disbalance in FM or Service Manual, ok. If not, please don’t believe anybody, (even me), ask Cessna, they will answer and THEY KNOW,!

Rgds

So, I see that this discussion is still going on and decided to use the Google machine to find some information. A search of "Cessna 172 Service Manual" turned this up:

http://hhh.gavilan.edu/hspenner/iLearnI ... _pre63.pdf

And, within this piece of classic literature, we find this (on page 4-3 (65)):

4-6.
ADJUSTMENT (CORRECTING "WING-HEAVY" CONDITION).
If considerable control wheel pressure is required to keep
the wings level in normal flight, a wing-heavy condition
exists. To correct wing heaviness:
a. Remove wing fairing strip on the wing-heavy
side of the airplane.
b. Loosen nut and rotate bushings (5) simultane-
ously until the bushings are positioned with the
thick side of the eccentrics up. This will lower the
trailing edge of the wing, and. decrease wing
heaviness by increasing the angle-of-attack of
the wing.

Who knew?

If the airframe has been tweaked or damaged, yes, the correction for truing the aircraft is to adjust wing incidence. I've done it many times. Most mechanics go for the cheap fix, which is to adjust the flap rod out on the heavy side to apply a bit more flap. There are two clevis fittings for the wing attach point with and one top and bottom for the strut. It's not a complicated process, but most solve it by adjusting the flap a little, which isn't really a fix, but more of a patch.

Cessna did not design the airplane, as the original poster's instructor suggested, to have a "wing low" to counter torque, asymmetric thrust, etc.

Anyone who works on Cessna's knew...but apparently no the original poster's instructor, who is making things up.

Apprentice wrote:

Hi: On Cessna 172, each wing is hold by 2ea bolts, washers and nuts
Check the service Manual for correct torque and, removing longitudinal plates in the wings, near fuselage, have a Mechanic, preferred with an IA to check that torque. If torque is not ok (low) for one bolt-nut, I suggest to replace all bolts-nuts with new one, torque to proper value and check torque again after first flight.
Please do not flight if You can see a incline. If necessary, go to a shop
Rgds

??????????????????????????????????????????????!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!???????????????????????????????????????????

What on earth do you think you're talking about, and why are you attempting to give maintenance advice regarding something you know nothing about? This is dangerous. Don't do this.

Hi: I do have formation and practice on Cessna 172’s maintenance. Do You?
Hi: JPilot 97, On Service Manual. Section IV, You will find necessary data..
Recently, We have 1 plane that had to land in the beach do to fuel starvation.
Wing were removed and a/c moved to a shop where a/c was inspected and wing mounted.
On next Annual, no bolts had proper torque. Bolts/nut were checked and replaced with a test flight and torque retest..
Rgds

Apprentice wrote:

Hi: I do have formation and practice on Cessna 172’s maintenance. Do You?

Yes, if you're trying to refer to actual maintenance, inspecting, modifying, overhauling (and operating, instructing in, etc). Several decades worth. And on 120s, 140s, 150s, 152s, 182s, 180s, 185s, 188s, 205s, 206s, 207, 208s, and 210s.

What is "formation on 172's?"

What do you "practice on 172's?"

Longitudinal plates?

High:
When I write in this forum, must of the time I like to discuss with mechanics, since Pilots, use to “Drive” a plane, only.
For “Longitudinal Plates” I refer to plates, 1ea in each wing, to be removed from wing in order to get acces to bolts. They are run in from LE to TE, on the wing root.

Concerning formation and experience, I will display only when I see Your.
Rgds

747Whale wrote:

Apprentice wrote:

Hi: I do have formation and practice on Cessna 172’s maintenance. Do You?

Yes, if you're trying to refer to actual maintenance, inspecting, modifying, overhauling (and operating, instructing in, etc). Several decades worth. And on 120s, 140s, 150s, 152s, 182s, 180s, 185s, 188s, 205s, 206s, 207, 208s, and 210s.

What is "formation on 172's?"

What do you "practice on 172's?"

Longitudinal plates?

I'm pretty sure there is a language difference with our Apprentice. Seek to understand..............

Hi: From 172M SM., section 4, fig 4.1. (Remember to check SM effectivity to Your Plane.)
You will found necessary data about wing installation .
Item 1, Fairing, is what I called as Longitudinal Plate

Out of memory: washers “8”. not always are 3ea installed, and Eccentric Bushes 8 positioning, have also relation which wing position.
Rgds

Agree. I don’t use to check this site looking for fights.
My formation date back to 1978, when I start studying for Commercial Aircraft Maintenance. This type of GA planes were the basis for formation.
My working experience, since 2004, when I became FAA’s IA and start doing annually to a friend’s plane.

N766UA wrote:

jppilot97 wrote:

Hey everyone,

Sorry about the late reply! I really appreciate all your comments in regard to my question! I’ve actually asked my instructor about it. The reason why the right wing is lower than the left is because the manufacturer designed it to counteract with the torque effect that the propeller creates. When at full power during takeoff, the plane tends to go to the left. Therefore, with a higher left wing, the angle of attack becomes greater which helps counteract with the torque effect. This kind of makes sense, but it’s just what my instructor thinks!

I don’t understand your original question, and I understand your instructor’s “answer” even less. It’s like a feedback loop of incoherence.

Personally, I think you have better things to be spending your mental energy on while learning to fly, and your instructor sounds like a bit of a dufus. Please re-examine both your priorities and your choice of CFI.

Check out “Torque Reaction” section (paragraph 2) on page 5-31 on the Aerodynamica of Flight chapter of the Pilots Handbook of Aeronautical Knowledge found here:

https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/phak/media/07_phak_ch5.pdf

If the 172 is one of the “older aircraft” referenced in the handbook your instructors answer sounds about right

No, the instructor's answer is absolutely ridiculous jibberish and completely wrong. Cessna did not build an airplane with one wing low nor design them to be flown that way, or sit on the ground that way, or be rigged or set up that way.

Hi: Some one to help me to find “sección 4 of the Aircraft Maintenance Manual for the 1985 Cessna 172”