Cessna Flap

[QJB]

Can anyone provide an insight:

I've been noticing for a lot of small Cessnas (152, 172), when I do the pre-flight inspection and push on the flap on each wing, one side seems to have a significant amount of give compared to the other. I assume this is something to do with the mechanism. Can anyone clear this up for me. Not really a concern, just interested.

J

[ACARS]

Hi

Do you really push the flaps on a cessna 152 / 172 during pre flight? I was never taught this in my primary training. I thought they should be placed in the down position for the pre flight so that you can inspect the rod/fitting mechanism?

[QJB]

That's how I was taught, its probably useful to know that they are locked in place so that they aren't pushed up in flight resulting in flap retraction or asymmetric flap.

[bearfoil]

I think nothing about control surfaces should be sloppy, especially if there is a difference between L and R. I too was shown to drop full flaps during pre flight, and check the play as deployed. Don't forget to practice flapless landings!!

rgds bear

[Old Fella]

It is not uncommon to find movement in the flaps on the Cessna aircraft. It is usually due to wear in the flap track/flap rollers and if you are concerned that it may be excessive bring it to the notice of the operator or write it up.

[subsonicsubic]

In all the 152s and 172s I fly have a good deal of movement when the flaps are fully extended. when checking the flap, I can easilly move the trailing edge +/- in excess of an inch or so.

I consider this normal however these aircraft are all well worn examples.


Best,

SSS

[bingofuel]

If something is well worn, a good engineer will overhaul or replace it back to original manufacturers specifications. If you are concerned enough to post here, why not ask an engineer if it is within allowed tolerances?

[Karl Bamforth]

IIRC
The left hand flap is driven direct by a motor, the right hand is operated by a cable.
As a result it is not unusual to find more movement in the right hand side than the left.

[W2k]

I haven't flown a Cessna yet but on our 70's-80's vintage PA28's it's part of our pre-flight to push the flaps to check for movement when in the fully extended position. Rarely is there more than 1 cm (.2 inches) of movement on the trailing edge. Then again the flaps on the PA28 are a rather simple "bicycle chain" style setup so I would not anticipate much sloppiness unless something was in dire need of servicing.

[Old Fella]

W2k The flaps on the Cessna 152 are totally different to those on the PA-28. The Cessna uses a Fowler type slotted flap in that they initially move more 'aft' than 'down' on initial movement to 10 degrees, which effectively increases the wing area, and then move progressively more 'down' than 'aft' as the profile of the flap tracks dictate to 30 degrees. The PA-28 on the other hand is a hinged slotted type flap which simply moves from a flap up to flap down position with no aft movement, thus no increase in wing area.

[LeadSled]

Folks,
Interestingly, many flap tracks as replacement parts from Cessna, when measured, are the equivalent of on the limit or beyond the wear limit.
If you are replacing worn 172 etc., flap tracks, get the ones from J&R Aerospace at Moorabbin, they will be right in size and last for years.
Tootle pip!!

[SeldomFixit]

As Karl said - one side is direct drive and the other isn't - relative movement being different is exactly what you should feel - having had mine apart I can vouch for it :ok:

[411A]

Then...when you get to the twin Cessna flap design, cable tensions, chain adjustment, micro switches galore, four flap sections, rod ends, bell cranks, torque links, etc...all must be in alignment, and adjusted properly, in conformity with the maintenance and service manual.
Figure eight hours mechanic time, at the minimum.
However, when completed, the system is very reliable and trouble-free.
No 'floopy flap', either.:yuk:

[barit1]

I was taught to gently push all surfaces to check for flex, slop, etc. Also hold the wingtip with both hands, & shake gently to check for undue flex, rattles, etc.