Using a slip to lose altitude during a landing should you use flaps.?

Question

Using a slip to lose altitude during a landing should you use flaps.?

Answer 1

The Cessna 172 is placarded "Avoid slips with flaps extended."

Now we know something about somebody, don't we!

It's okay in other airplanes.  Check the pilot's operating handbook, and always be familiar with all placards in the cockpit.

The airplane that I fly on pretty blue days doesn't have flaps; that's what I recommend.

Answer 2

Flaps will help you loose altitude faster when slipping, but it can give you problems because of the steepness of the approach it creates.  For aircraft with flaps you should be able to establish a fairly steep approach depending on your power setting and airspeed without slipping.  I make a fairly steep approach in the 172 with full flaps (40), 55-60 knots, and 1500RPM and have never needed to slip.

However, slips are good for adjusting your approach because if you find you have slipped too much and are undershooting, you can simply stop slipping.  Not the same for flaps.

For the 172, it says "AVOID slips with flaps" on the placard and in the POH, not they are prohibited.

In the amplified procedures it says: "Steep slips should be avoided with flap settings greater than 20 degrees due to a slight tendancy for the elevator to oscillate under certain combinations of airspeed, sideslip angle, and center of gravity loadings."

I don't know of any other aircraft that has specific slip limitations in relationship to flap use.

Answer 3

There is a place card against it in some aircraft. I think they are worried about fuel delivery when the tanks are almost dry. I will slip and flap as I see fit.  Having said this remember do what the "manual" says.

Answer 4

Generally No. In many light aircraft, doing this with full flaps can cause damage to the fuselage. They woudl place a warning to that effect in the aircraft operating manual.

Doing it with partial flaps may be allowable but with caution. Full deflection of controls may not be wise.

Answer 5

Always Check the POH for the aircraft you are flying.

My instructor [who has 30+yrs of flying experience] has told me that if flaps are used while slipping, it may cause ineffectiveness of the rudder since the extended flaps sweeps off the air that is suppose to reach the rudder area.

But you always check the POH.

Answer 6

NO!

Answer 7

In general, if you have flaps available, having to do a slip to lose altitude or descend steeply shows poor planning and / or judgement on the landing approach. That said, there are still times (very few) where a forward slip with flaps can be useful and is adviseable, such as on an engine-out dead-stick approach where it is better to be a little high than too low. It is worth practicing for this reason. It is also worth practicing just so you know what your airplane is capable of. However, as mentioned by others, slips are prohibited in some airplanes if the flaps are down, particularly full flaps. Check the flight manual for prohibitions.  The potential for structural damage is very seldom the reason. It is more often that the rudder could get blanketed with turbulent air from the flap on the wing-down side, rendering it less effective. Should a stall occur, you may not have enough rudder control to stop a spin from developing.

Answer 8

yes better deceleration used one two days ago with a slight crosswind , use those rudders!

Answer 9

You can slip to a landing.w/out flaps  I have done it many times in a Piper PA-12 Super Cruiser.....it has NO flaps!!! check your POH!!!!

Answer 10

Check the airplane flight manual.  Some planes prohibit intentional forward slips to landing with flaps.  Other planes don't have any limitations against them.

If there is no limitation against it, yes, use flaps if they are available.  Flaps should be your first option to lose altitude.

A forward slip to landing isn't really a normal procedure, but it's useful if the flaps fail, if you need to make an unusually steep approach over obstacles, or if you need to lose altitude during a forced landing (no engine power available).  If you are making a "normal" approach and didn't plan the forward slip ahead of time, your best option is to go around and try again.  You can use a forward slip if you are on a long final and have a lot of distance to re-establish yourself, but don't try to salvage a landing out of a bad approach.

Answer 11

Rudder not effective during a slip?  Wait, doesn't a slip require rudder?  .... and if it is not effective .. .then ... is it a slip?

Lots of answers ... very few 'authorities'.  Including "avoid slips while using flaps" in a C 172.  That does NOT say prohibited!  The result is buffeting, but not 'uncontrollability'.