Frozen Flaps

I am still familiarizing with a newly acquired 150.
The other day I flew on a chilly evening just above freezing.
I applied flaps in the pattern, and when I landed, the flaps didn't want
to retract
I had earlier exercised the flaps on preflight without problem
and before the plane was put away, the flaps went up OK.

I guessed that the actuator froze up, so it probably needs lube to keep
the water away.... The flap motor fuse checked OK of course...

Any thoughts?

Brian W

brian whatcott wrote:
I am still familiarizing with a newly acquired 150.
The other day I flew on a chilly evening just above freezing.
I applied flaps in the pattern, and when I landed, the flaps didn't want
to retract
I had earlier exercised the flaps on preflight without problem
and before the plane was put away, the flaps went up OK.

I guessed that the actuator froze up, so it probably needs lube to keep
the water away.... The flap motor fuse checked OK of course...

Any thoughts?

Brian W

Brian,

The most common cause of "frozen flaps" in Cessnas like yours are the
limit switches on the flap actuator, rather than the actuator itself. A
judicious application of a heat gun, through the appropriate inspection
panel, will free them up for a while. They are relatively inexpensive
to replace, however, and that's what is needed for a more permanent fix.

Happy Flying!
Scott Skylane

On Dec 13, 3:35 pm, Scott Braddock wrote:

The most common cause of "frozen flaps" in Cessnas like yours are the
limit switches on the flap actuator, rather than the actuator itself. A
judicious application of a heat gun, through the appropriate inspection
panel, will free them up for a while. They are relatively inexpensive
to replace, however, and that's what is needed for a more permanent fix.

Those little microswitches get oil in them from the jackscrew
threads, and the oil draws dust and crud and gunks up the switch
contacts with sludge. In the cold the sludge will congeal and make the
switch's mechanism stick, too. Replacing them is the best thing, and
you want to do it soon. If you had to abort a landing and go around,
the flaps on a 150/152 will hurt the climbout dangerously; there's
just too much drag.

Dan

wrote:
On Dec 13, 3:35 pm, Scott Braddock wrote:

The most common cause of "frozen flaps" in Cessnas like yours are the
limit switches on the flap actuator, rather than the actuator itself. A
judicious application of a heat gun, through the appropriate inspection
panel, will free them up for a while. They are relatively inexpensive
to replace, however, and that's what is needed for a more permanent fix.

Those little microswitches get oil in them from the jackscrew
threads, and the oil draws dust and crud and gunks up the switch
contacts with sludge. In the cold the sludge will congeal and make the
switch's mechanism stick, too. Replacing them is the best thing, and
you want to do it soon. If you had to abort a landing and go around,
the flaps on a 150/152 will hurt the climbout dangerously; there's
just too much drag.

Dan


Thanks to Scott and Dan for the insightful hints on flap limit switches.


Brian W

brian whatcott wrote:
I am still familiarizing with a newly acquired 150.
The other day I flew on a chilly evening just above freezing.
I applied flaps in the pattern, and when I landed, the flaps didn't want
to retract
I had earlier exercised the flaps on preflight without problem
and before the plane was put away, the flaps went up OK.

I guessed that the actuator froze up, so it probably needs lube to keep
the water away.... The flap motor fuse checked OK of course...

Any thoughts?

Brian W

When I had the Skyhawk and cleaning of relube of the jack screw for the
flaps was mandatory at annual. Has this been done? Or the motor can be
wearing out. the track on the flap rollers needs lubrication also.

--

Regards, Ross
C-172F 180HP
Sold
KSWI

Ross wrote:

When I had the Skyhawk and cleaning of relube of the jack screw for the
flaps was mandatory at annual. Has this been done? Or the motor can be
wearing out. the track on the flap rollers needs lubrication also.

Good question. I don't see a record of the jackscrew lube on the last
annual - but I haven't looked for it either....

Thanks

Brian W

"brian whatcott" wrote in message
...
I am still familiarizing with a newly acquired 150.
The other day I flew on a chilly evening just above freezing.
I applied flaps in the pattern, and when I landed, the flaps didn't
want to retract
I had earlier exercised the flaps on preflight without problem
and before the plane was put away, the flaps went up OK.

I guessed that the actuator froze up, so it probably needs lube to
keep the water away.... The flap motor fuse checked OK of course...

Any thoughts?

Brian W


Hi Brian

Just thought I'd pass this along. You probably know all this
anyway but.....
I've never had a problem with the flaps on my Cessna 150F but I use
the
standard 10 downwind, 20 on base and keep it on 20 on final until I'm
close
enough to the numbers to check for deer, runway is clear etc before I
use the
30 flap setting and only if I need 30 which is rare. I know my C150
will fly with
20 degrees of flap. With 20 I can arrest the descent and climb out.
When doing T & G's always put your two eyes on the flaps to verify
they have gone back up before
lifting off the ground. May not seem like it but you have plenty of
time while accelerating. Just a quick glane out both sides. If one
doesn't look right
stay on the ground and shut it down. You don't want one flap handing
down on
climb out. Winter can cause unusal problems such as a piece of ice
getting
someplace it doesn't belong.

Just a few thoughts to pass along to all that read this newsgroup...

Terry N6401F

Terry wrote:

Hi Brian

Just thought I'd pass this along. You probably know all this
anyway but.....
I've never had a problem with the flaps on my Cessna 150F but I use
the
standard 10 downwind, 20 on base and keep it on 20 on final until I'm
close
enough to the numbers to check for deer, runway is clear etc before I
use the
30 flap setting and only if I need 30 which is rare. I know my C150
will fly with
20 degrees of flap. With 20 I can arrest the descent and climb out.
When doing T & G's always put your two eyes on the flaps to verify
they have gone back up before
lifting off the ground. May not seem like it but you have plenty of
time while accelerating. Just a quick glane out both sides. If one
doesn't look right
stay on the ground and shut it down. You don't want one flap handing
down on
climb out. Winter can cause unusal problems such as a piece of ice
getting
someplace it doesn't belong.

Just a few thoughts to pass along to all that read this newsgroup...

Terry N6401F


Sounds good to me. I want to set about 15 deg flaps for landing,
having seen what 40 years of landings do to a tail tie down eye bolt -
its lower surface is about 40% its original thickness....
About deer: I hear some unicom chatter from a field 30 miles down the road:
* take care for the deer inside the fence line
* Those aren't deer they're hogs.
* There are deer AND hogs.

Which reminded me of the intelligence from the homeowner where I keep a
horse:
"deer are becoming a nuisance so the does are open every hunting dasy.
And I know a man at Dallas who will purchase live wild hogs - he fattens
them for the top drawer restaurant market as wild boar: which they are,
essentially...."

Brian W

"Terry" wrote
I know my C150 will fly with 20 degrees of flap.
With 20 I can arrest the descent and climb out.

In fact Terry, FAR Part 23 requires that your aircraft and all of the
Cessna 150/152/172 series be able to execute a go-around at the maximum
flap setting at the maximum TOGW. This requirement is what actually sets
the maximum TOGW for these aircraft.
Several years back, Cessna was able to raise the Maximum TOGW of the C-
172 by 100 lbs by simply removing the 40 degree flap setting.

Section 23.77: Balked landing.
(a) Each normal, utility, and acrobatic category reciprocating engine-
powered airplane at 6,000 pounds or less maximum weight must be able to
maintain a steady gradient of climb at sea level of at least 3.3 percent
with-

(1) Takeoff power on each engine;

(2) The landing gear extended;

(3) The wing flaps in the landing position, except that if the flaps may
safely be retracted in two seconds or less without loss of altitude and
without sudden changes of angle of attack, they may be retracted; and

(4) A climb speed equal to VREF, as defined in 23.73(a).


Bob Moore, ATP CFI
PanAm (retired)

"Robert Moore" wrote in message
5.247...
"Terry" wrote
I know my C150 will fly with 20 degrees of flap.
With 20 I can arrest the descent and climb out.

In fact Terry, FAR Part 23 requires that your aircraft and all of
the
Cessna 150/152/172 series be able to execute a go-around at the
maximum
flap setting at the maximum TOGW. This requirement is what actually
sets
the maximum TOGW for these aircraft.
Several years back, Cessna was able to raise the Maximum TOGW of the
C-
172 by 100 lbs by simply removing the 40 degree flap setting.

Section 23.77: Balked landing.
(a) Each normal, utility, and acrobatic category reciprocating
engine-
powered airplane at 6,000 pounds or less maximum weight must be able
to
maintain a steady gradient of climb at sea level of at least 3.3
percent
with-

(1) Takeoff power on each engine;

(2) The landing gear extended;

(3) The wing flaps in the landing position, except that if the flaps
may
safely be retracted in two seconds or less without loss of altitude
and
without sudden changes of angle of attack, they may be retracted;
and

(4) A climb speed equal to VREF, as defined in 23.73(a).


Bob Moore, ATP CFI
PanAm (retired)


Hi Bob

Your correct in every aspect. I know what my airplane is capable of
at or near gross. I know that I can climb at 30 degrees of flaps but
not the 40 degrees that my C150 has. I was just trying to put some
general guidelines into winter flying with an underpowered 100hp
engine. I don't know if a new student or experience pilot such as
yourself is reading this newsgroup. Have a nice Holiday Bob.

Terry N6401F