Slip approach landings

[SportCubJim]

Just a questions?

About how low do you slip your plane before you feel the need to align?

For me at about 50 feet I feel the need to get aligned and stabilized for flair and touch down.

[Jim Stewart]

50 feet works for me and my CTSW.

[3Dreaming]

It's mostly what you are OK with, but sometimes it depends on the airplane. A T-Craft will pick up a little speed as you straighten it out and then float down the runway, so I will keep the slip in right until I'm ready to touch down. The Sport Cub has a bunch of drag, so the speed is not much of a problem. Tom

[bryancobb]

Most training programs where persons OTHER THAN THE OWNER are flying the aircraft, spell out that alignment with the runway should be maintained below 50'.

That tells me that anything below that is "COWBOYING IT."

[KSCessnaDriver]

Most training programs where persons OTHER THAN THE OWNER are flying the aircraft, spell out that alignment with the runway should be maintained below 50'.

That tells me that anything below that is "COWBOYING IT."

Really? I've never, ever ever seen that in a rental agreement, and I've flown at quite a few number of FBOs/Flight schools around the country.

[drseti]

Altitude limits in a forward slip depend largely upon whether your airplane is a high or a low wing configuration. My SportStar has an ugly scrape under the right wingtip, where a former student (of the previous owner's not mine) scraped it on the runway. There's a matching scrape in the lower right corner of the right aileron, where that too contacted the pavement when same former student realized his or her mistake (just after hearing the scraping sound, I imagine), and slapped the stick to the left, lowering the right aileron while trying to raise that right wing off the tarmac. The wing in this plane is very close to the ground; slips to a crosswind landing are ill-advised.

A good rule of thumb is to kick out the slip when within a wingspan of the ground.

[rfane]

Are we talking forward slips to lose altitude, or side slips for crosswinds? Or are we confused about crabbing into a crosswind, and what altitude to get rid of the crab and put in a side slip?

Side slips for crosswind correction can be kept in all the way to the ground. If you have nose wheel steering, you need to neutralize the rudder before you set the nose wheel down. CFI's should be training their students to be able to land on the upwind main gear, while keeping the side slip in.

High wing planes typically will allow you to land with higher crosswinds than low wing planes like the SportStar, due to wing clearance.

The wing in this plane is very close to the ground; slips to a crosswind landing are ill-advised.

A good rule of thumb is to kick out the slip when within a wingspan of the ground.

Paul,
How are you then maintaining wind correction until you touch down?



Forward slips for loosing altitude should be gotten out of at a safe enough height to:

1. Stabilize airspeed and set up for the landing. That may include enough altitude to get into a side slip for crosswind correction.

2. Get the aircraft aligned with the forward direction the aircraft is going, in order not to side load the landing gear. Notice that I did not say aligned with the runway, as that may not be the actual direction the aircraft is going. Ideally, you will have the aircraft on the runway centerline, and travelling straight down it, but there may be crosswinds, you might be out of practice, or you might be in an emergency situation that doesn't include a runway centerline.

3. Hit your target in an emergency landing situation. If the engine quits in a place where your options are limited, you might need to set it down in a very tight spot, such as a small field, park, golf course fairway, etc. Trees, houses or other buildings, powerlines, etc., might be involved. In that case you might need to hold the slip almost to the ground in order to hit your spot.

[FastEddieB]

A good rule of thumb is to kick out the slip when within a wingspan of the ground.

I would agree with that sentiment (of drseti and others).

Here's a video of a trip around the pattern in my Sky Arrow:

http://www.youtube.com/watch?v=sjlU_JlvDIQ

For the final approach you can fast-forward to about 4:40.

Its hard to see (I have a headset-mounted camera here, and the camera is looking where I'm looking), but I always slip down to the runway when I have the trees made. And, like drseti, I "kick out" the forward slip once I begin my roundout - about one wingspan above the ground.

[drseti]

Are we talking forward slips to lose altitude, or side slips for crosswinds?

Fair question, Roger. I was talking here about crosswind correction, but perhaps that's not what the initial post was about.

Paul,
How are you then maintaining wind correction until you touch down?

In a very low wing design like the SportStar, I teach tracking the centerline in a crab, and then working the nose to straight down the runway just before touchdown. Of course, that last-minute maneuver is tricky, and takes practice, but it's probably safer to touch down slightly canted than it is to scrape a wingtip on the runway.

Also, bear in mind that some LSAs have very low demonstrated crosswind components. In the SportStar, the spec is only 10 kts. Part of that is because of the limited ground clearance of the wingtip. You can usually slip a high-wing design much closer to the ground without clearance problems, so the x-wind spec is likely more liberal.

Hit your target in an emergency landing situation. If the engine quits in a place where your options are limited, you might need to set it down in a very tight spot, such as a small field, park, golf course fairway, etc. Trees, houses or other buildings, powerlines, etc., might be involved. In that case you might need to hold the slip almost to the ground in order to hit your spot.

This is a different situation, and what you say is entirely correct. But, don't forget that, in some planes, your flaps will do a better job of getting you down safely than will a slip. The SportStar, for example, has a very effective split flap, with 50 degrees available. Also, consider that some planes prohibit (or recommend against) slips with flaps extended beyond a certain point. Check your AOI. The point is, this is an emergency maneuver which you should practice with an instructor who knows that particular plane. And emergency maneuvers are just that -- non-standard procedures to be learned, and then used when needed.

[pitfield]

I trained on a Sportstar and would argue that it doesn't have sufficient rudder authority to slip really well. I now fly a Ran S-7 and can slip perhaps twice as effectively as with the Sportstar. I much prefer to come in with surplus altitude and use a slip to get me down, even with full flaps (my 3rd notch is only 33 degrees). The most important metric in aggressive slipping (IMHO) is airspeed control; it doesn't do you any good to slip like mad, straighten out, and then have to bleed excess energy for hundreds of feet. I will defer to others with more experience, but I'd suggest that slipping is a critical skill to effective altitude management on final, and even more important in the event of an emergency in which you're confronting an abbreviated landing area.

[ibgarrett]

Just from my experience in training in a Sportstar I was able to do some great slips to landing. The main trick was to have full flaps in and I had all the rudder control that I needed.

At least that was my experience...