The Flaps Let Go

[N1478D]

This morning with a fairly loud noise, the flaps came back up about half way during a slip. Tried to reapply them on short final and only the first and second notch would hold. On the ground, of course, they held fine. Would the flap handle assembly be the first place to look

[Joe West]

Joe,

The force applied to the latch mechanism is directly proportional to the degree of flaps used... higher flap settings = more force applied. I don't have a parts book in front of me, but my guess would be that the tang which locks the flaps in place is worn, or, perhaps the release button is hung up causing the tang to be in a slightly retracted position allowing it to slip in higher flap settings. I guess to answer your question, Yes, check the flap handle assembly.

Kind Regards,

Joe West
N4338B

This morning with a fairly loud noise, the flaps came back up about half way during a slip. Tried to reapply them on short final and only the first and second notch would hold. On the ground, of course, they held fine. Would the flap handle assembly be the first place to look

[Rudy Mantel]

Joe, not to belabor the point, but slipping a Cessna with flaps down is not recommended. The flalps can blanket out the rudder-
Hope you can easily fix the mechanical problem- you definitely don't want your flaps to suddenly retract when close to the ground!
Rudy

[N1478D]

Joe, not to belabor the point, but slipping a Cessna with flaps down is not recommended. The flalps can blanket out the rudder-
Hope you can easily fix the mechanical problem- you definitely don't want your flaps to suddenly retract when close to the ground!
Rudy

Hi Rudy, hope your foot does not hurt
I believe in the A model it is alright to slip with full flaps. They are much smaller than the B, and are not suppose to blanket out the tail feathers.
Have looked thru both of my parts catalogs and am having trouble locating the part number for the stationary part that the handle assembly ratchets on. When I removed the flap cover, the rivits holding the suspect assembly are loose and it is this stationary part that appears to be either worn, or the movement allowed by the loose rivits is the problem. In my original model 170A catalog the part is not even depicted. In my 170 Series Parts Catalog there is a picture of the part on page 28 fiqure 15 - fuselage assembly complete, but no part number assigned to it.

[GAHorn]

figure 17, pg 29, of the 170A parts catalog dipicts the latch, item 23, pn 0425121 and the latch assy, pn 0425122. Although it doesn't show it, I believe there should be a ratchet item 23 locks onto, which is likely repairable in the field. The latch is probably sliding off of the ratchet due to wear and I'm guessing a file might dress it up?
Does it work fine except when slipping?

NOTE: In later years it has been discovered that the latching mechanism of the flap handle incorporates bushings/rivets which wear and allow the flaps to release....and in worst-cases.....fail to retract. This has caused at least one fatality )in a Cessna 180) at Boeing Field. If the reader will continue to search these forums, he/she will find further discussions which better-depict this , and offer solutions to this problem.

See also: http://www.cessna170.org/forums/viewtop ... f=6&t=2231

[N1478D]

figure 17, pg 29, of the 170A parts catalog dipicts the latch, item 23, pn 0425121 and the latch assy, pn 0425122. Although it doesn't show it, I believe there should be a ratchet item 23 locks onto, which is likely repairable in the field. The latch is probably sliding off of the ratchet due to wear and I'm guessing a file might dress it up?
Does it work fine except when slipping?

No, in the hangar, a slight force with my hand will move the flap handle off of the ratchet that is not identified in the parts catalog, so it's not just in slips, it's not working period. What I have not been able to determine yet is if it is a file to dress it up, loose rivits, or too worn to be fixed situation.
The rachet part has spacers on both sides to position it in the center of the bracket. Does anyone know if the ratchet part is suppose to be fixed, or is movement allowed As the flap handle is raised the angle that the catch addresses the ratchet changes, wondering if the ratchet is designed to move a little bit, or is it suppose to be secured tight

[N1478D]

This might be isolated, but it would not hurt during an inspection to inspect the condition of the rivits holding the ratchet assembly in place. On mine, the rivits worked loose allowing the machined part with indents we are calling a ratchet to move which allows the part on the flap handle to move off of the indent. The rachet is suppose to be held tight by the rivits, an inspection could be done without removing the plate which slides down the flap handle - shine a light down into the flap handle opening as you move the flap handle up and observe the ratchet, if it is moving at all you need to replace the rivits.