Forward Slips Part Two

[ShawnC]

Today I got the latest issue of AOPA Flight Training Magizine, I was pleasently surprised to find a rather well written article about Forward slips. It covers the Pro & Cons, and debunks some rather old wifes tales.

I highly suggest that people on both sides of the issue read the article.

BTW: I much prefer the flight training magizine, to the normal AOPA mag, I'm thinking about joining just so I can continue my subcription.

 

[bigD]

That definitely was a good article. I'm a huge fan of the forward slip, and love doing them. It's a shame that a lot of people don't like them. A couple of years ago, the young woman who worked at the front desk of my local FBO was complaining to me about failing her private pilot checkride. Apparently when the examiner failed the engine on downwind, he called her base for her, which put her relatively high on final. Even with the plane dirtied up, she couldn't get it down onto the runway (without risking going off the end), and she took it around. He failed her. Keep in mind that the examiner didn't call her base at midfield or anything - it was at some point after she was abeam the numbers, and this is to a 5,000 foot runway.

So she's a pissed because she thought he brought her in too tight. I asked if she considered a forward slip, and she said, "Well, he didn't tell me to do one, so I figured I wasn't being tested on that. Besides, they feel really strange to me, so I don't like to do them."



I think they're great fun, personally. Although I'm pretty careful about setting up my approach so one isn't necessary if I have skittish passengers with me!

 

[chrisdahut24]

Yeah, FlyChicaga has a good idea. I take them out to the practice area and Just slip it all the way down from one altitude to another. Once they feel comfortable doing it at altitude, and can do it correctly, then I introduce it on landings.
I'm not really too sure what the big deal is about them though. It's the same thing as a side slip except your using more aileron and rudder, and the nose isn't going to be lined up with the runway. But there again, I could certainly understand some anxiety about it: Your putting the plane into the most uncoordinated position possible, at a slow airspeed and closer to stall (spin alert!)- all nice and close to the ground!

 

[DJS]

Slip Sliding Away

I pretty much count on doing a forward slip every time I land at my home field (Crest-S36) at night. You have big old douglas firs all around that you can't see, so you make sure you stay up high until you're certain you're not over trees, then chop power, full flaps, and slip for all your worth.

My CFI made sure I knew how to do them well, and it was on my private checkride (engine out drill, was going for one field, the DE said, nope, can't use that one, use the one closer, so I had to slip in...no sweat).

...Dave

 

[Singlecoil]

It's the same thing as a side slip except your using more aileron and rudder, and the nose isn't going to be lined up with the runway.

There is a great deal of confusion about the difference between the two and probably a lot of different opinions......BUT.....

The main difference is that in a forward slip, you are moving forward through the air mass. In a side slip, you are moving sideways through the airmass.

Some airplanes are certified for side slips, but not forward slips, like the DC-6. Forward slips generally displace the fuel in the tank more than a sideslip, hence the time limit you will see on other airplanes on forward slips (like max 30 seconds.) I'm sure Avbug can provide a more concise answer.

 

[tothelineplz]

Singlecoil is on the right course on this one. May I add that this is an interesting thread which discusses something often glossed over during pilot training.

A side slip and a forward slip are two entirely different tasks/maneuvers.

I'd like to keep this thread active and therefore contribute the following for discussion and maintain the following idea:

The forward slip should be treated as an "emergency pocedure" (unless, of course, you're flying a machine without flaps).

A pilot is not necessarily close to the stall speed when performing this maneuver. In fact, reliance on the ASI during this maneuver can prove to be faulty and not in the best interest of all concerned (depending on which side the slip is performed and the location of the pitot/static components).

Forward slips in the landing configuration (which assumes full flaps for most GA metal) is ill-advised not only because cavitation of the engine driven/electrical (sometimes called auxiliary) fuel pumps and/or disruption of fuel flow to the powerplant, but also for aerodynamic (airflow disruption) reasons beyond the scope of this posting.

I've always taught (from an airmanship standpoint) that a forward slip only becomes necessary as a last resort and primarily results from lack of planning while performing a basic ground reference maneuver called a rectangular course. To intentionally perform a forward slip, as one poster says, "for all your worth" can be a pre-cursor to an NTSB investigation. But, I guess if you're worth more dead than alive then...AEtna, I'm glad I met ya'.

One final comment for this posting...

How often do our CFI's out there teach their students to perform another glossed over maneuver called the "go-around" which becomes necessary when the "last resort" doesn't pan out.

Always leave yourself an out!

BTW...interesting story about the student pilot on her Private Pilot check ride. Reflects poorly on her instructor if you ask me. Perhaps she should ask for a refund for services not rendered?

That is all...

 

[ShawnC]

To the line,
You really need to read the article. Frankly your postion is one of the ones that it addresses.

 

[bigD]

totheline - it's funny to hear your comments regarding the forward slip, considering your high amount of time. That's not to say that you're wrong - I'm interested in hearing from various people what their take is on this. It's just that it's usually the high timers that sit around lamenting the fact that good stick and rudder skills are a lost art, and stuff like the forward slip isn't done much anymore.

I didn't know the intructor of the woman all that well, so I can't vouch for him or his ability to teach. It seemed obvious that the examiner expected her to slip it in - otherwise I don't see why he would have called her base in that situation.

 

[HappyFlying]

I do forwards slips quite often just because they are fun and it tickles the old hangar rats sitting on the bench at the FBO. The non-pilots in the tower get a bit excited sometimes when they see a 150 whizzing over the numbers sideways. Also, I use slips to even out my fuel after I have been parked on a hill. Mostly I'm just goofing off but I do try to keep up my stick and rudder skills.

 

[cvsfly]

Just to add. This is for light planes mostly. Plan accordingly and you don't have to do it at all. Can be upsetting and uncomfortable for passengers.

 

[tothelineplz]

...and I maintain that it is important to be in coordinated flight when below 1000' AGL and most certainly below 500'...

Remember what you teach your students...keep the ball centered or "step on the ball".

Landing Flaps...Safety Check Please...


That is all...

 

[DJS]

Why are they bad?

I went back and read the original thread from this summer, and still haven't figured out why foreward slips are "bad". There are indeed a few "gotchas", and I don't think I'd want to be the passenger in a 767 when the captain decides he's too high and needs to slip.

The 172 (the plane I currently fly) has a recommendation against slips with full flaps, but that's related to a buffet that can be felt as the airflow over the elevator is slightly disrupted. It is disconcerting the first time this happens, but after a bunch of practice, you start to get a feel for it and, as far as I can tell from the POH and my (admittedly somewhat limited) experience, it doesn't lead to any loss of control.

At this point, the slip is a nice tool in my bag given the airplane I currently fly. Yes, a good approach generally means I won't be too high (see my previous post about landing at my particular airport at night, where I intentionally come in a little high). But every now and then, a low hour pilot like me finds themselves a little high on final and 5 seconds of slipping gets me back down to where I want without adding much airspeed.

But if there are true safety issues, I'd certainly like to know about them.

...Dave

 

[carlos]

I was introduced to the forward slip in my flight lesson this morning. It's going to take me a while to get the hang of it (I practically stalled the airplane on one approach!). It's very effective, though, at losing altitude quickly and slowing the airplane up, more so than the flaps it seemed to me. I'm training in a 152. My CFI said that one instance where you might use this technique is if your flaps are inoperative due to an electrical problem (if you have electric flaps, of course), or to lose altitude if you're following someone in on a high final.

I see it as a useful technique to use in the right situation. Like any part of flying it takes some attention to keep it effective and safe. Do it incorrectly, and you could be in bad shape quick, especially on approach. Use it wisely and with care, and you'll be fine, again, like any part of flying. Just my thoughts...

 

[tothelineplz]

I've always taught that full rudder deflection and enough opposite aileron to maintain a ground track parallel to the extended runway centerline when within 500 feet of terra firma is ill-advised.

While performing this maneuver, three things should be considered which correlate with stall/spin awareness. All pilots should ideally understand (working knowlege at a minimum) the follwing prior to performing this maneuver.

1) Adverse Yaw
2) Airflow Dynamics (Stagnation Point/Initial Airflow Separation)
3) Rectangular Courses

There are very limited times this maneuver should be used in real world flying. One of them is powerplant failure when conservation of altitude and airspeed are primary and immediate considerations. More on that in another posting. Another would be to dissipate altitude when the pilot experiences an inflight fire and sees a neon "open" sign on the local tavern immediately below his grief stricken aircraft...but their may be others, can anyone out there think of any?

That is all...

 

[ShawnC]

Rough quotes from the article:

"If slips are so bad, then why does the FAA see fit to spend a considerable amount of the PTS on them. In one case it says that you must be able to land within 400 ft of a selected landing point."

"Yes a slip can depart into a spin if you stall the aircraft, just don't stall the aircraft."

Basiclly if you don't practice slips enough you will lose them as a valuable tool, as such a private pilot should practice it as much as they can, because they may fly monthly if that. Now for commerical pilots both ATP and CPL you should practice it, but never in a fare paying aircraft, but you still need to keep your proficency up.

 

[tothelineplz]

(-23) AT APPROX. 1400 HOURS LOCAL TIME, THE PILOT WAS ACTING AS PIC OF A/C N330JE DURING A TRAINING FLIGHT AT SUNDANCE AIRPORT. THE PILOT WAS DEMONSTRATING A FORWARD SLIP TO LAND ON RUNWAY 17, WHEN ON SHORT FINAL THE SINK RATE SUDDENLY INCREASED RESULTING IN A TAIL LOW HARD LANDING. THE PILOT ADDED POWER BECOMING AIRBORNE AND CHOSE TO RETURN TO WILL ROGERS WORLD AIRPORT. EXAMINATION OF THE A/C REVEALED THAT THE BOTTOM TAIL SKIN AND TAIL TIE DOWN SKID WAS DAMAGED. THE VERTICAL STABILIZER AND RUDDER HAD WRINKLED SKIN AT THE UPPER AND LOWER HINGE POINTS. THE HORIZONTAL STABILIZER LOWER SKINS WERE OIL CANNED.

--------------------------------------------------------------------------------
Detail

Primary Flight Type: INSTRUCTION
Secondary Flight Type: TRAINING
Type of Operation: GENERAL OPERATING RULES
Registration Nbr: 330JE
Total Aboard: 3
Fatalities:
Injuries:
Landing Gear: NONRETRACT TRICYCLE
Aircraft Weight Class: UNDER 12501 LBS
Engine Make:
Engine Model:
Engine Group:
Number of Engines: 1
Engine Type:


--------------------------------------------------------------------------------
Environmental/Operations Info

Primary Flight Conditions: VISUAL FLIGHT RULES
Secondary Flight Conditions:
Wind Direction(deg):
Wind Speed(mph):
Visibility(mi.):
Visibility Restrictions:
Light Condition: DAY
Flight Plan Filed: UNKNOWN
Approach Type:


--------------------------------------------------------------------------------
Pilot In Command

Pilot Certificates: AIRLINE TRANSPORT PILOT FLIGHT INSTRUCTOR
Pilot Rating: AIRPLANE SINGLE, MULTI-ENGINE LAND
Pilot Qualification:
Flight Time Total Hours: 14000
Total in Make/Model: 600
Total in Last 90 days: 120
Total in last 90 days Make/Model:


--------------------------------------------------------------------------------
END REPORT

 

[tothelineplz]

"Unconscious Gear Retraction"? Come on!

NASDAC BRIEF REPORT

--------------------------------------------------------------------------------


--------------------------------------------------------------------------------
GENERAL INFORMATION

Data Source: ACCIDENT AND INCIDENT DATABASE
Report Number: 20010314005239G
Local Date: 14-MAR-01
Local Time:
City: RICHMOND
State: IN
Airport Name: RICHMOND MUNI
Event Type: INCIDENT - GENERAL AVIATION
Mid Air Collision: NOT A MIDAIR


--------------------------------------------------------------------------------
AIRCRAFT INFORMATION

Aircraft Damage: MINOR
Aircraft Make: CESSNA
Aircraft Model: CE-182
Aircraft Series: CE-182-R182
Airframe Hrs: 5633
Operator:

--------------------------------------------------------------------------------
NARRATIVE

(-23) PILOT STATED THAT HE AND A PRIVATE PILOT DEPARTED DAYTON ENROUTE TO RICHMOND TO PRACTICE TAKEOFFS AND LANDINGS. THEY HAD DECIDED TO LEAVE THE LANDING GEAR DOWN WHILE IN THE PATTERN. ^PRIVACY DAT^ A CFII STATED HE HAD UNCONSCIOUSLY RETRACTED THE GEAR AFTER DEPARTURE. ON FINAL APPROACH HE WAS PREDISPOSED TO THINK THE GEAR WAS IN FACT DOWN AS IT DID NOT REGISTER THAT THE GEAR LIGHTS WERE NOT ON. HE HAD A LITTLE EXTRA POWER ON BECAUSE OF THE FORWARD SLIP HE WAS DEMONSTRATING SO THE GEAR HORN NEVER SOUNDED.

--------------------------------------------------------------------------------
Detail

Primary Flight Type: INSTRUCTION
Secondary Flight Type: TRAINING
Type of Operation: GENERAL OPERATING RULES
Registration Nbr: 757YG
Total Aboard: 2
Fatalities:
Injuries:
Landing Gear: RETRACT TRICYCLE
Aircraft Weight Class: UNDER 12501 LBS
Engine Make:
Engine Model:
Engine Group:
Number of Engines: 1
Engine Type:


--------------------------------------------------------------------------------
Environmental/Operations Info

Primary Flight Conditions: VISUAL FLIGHT RULES
Secondary Flight Conditions: WEATHER NOT A FACTOR
Wind Direction(deg):
Wind Speed(mph):
Visibility(mi.):
Visibility Restrictions:
Light Condition: DAY
Flight Plan Filed: UNKNOWN
Approach Type:


--------------------------------------------------------------------------------
Pilot In Command

Pilot Certificates: COMMERCIAL PILOT FLIGHT INSTRUCTOR
Pilot Rating: AIRPLANE SINGLE ENGINE LAND
Pilot Qualification: QUALIFIED
Flight Time Total Hours: 700
Total in Make/Model: 300
Total in Last 90 days: 23
Total in last 90 days Make/Model:


--------------------------------------------------------------------------------
END REPORT

 

[tothelineplz]

(-5) AIRMAN WAS UNDERGOING A FLIGHT INSTRUCTOR CERTIFICATION CHECK RIDE GIVEN BY A DESIGNATED PILOT EXAMINER AND DEMONSTRATING A FORWARD SLIP TO LANDING. DURING THE LANDING FLARE A SCRAPING SOUND WAS HEARD AND BOTH THE AIRMAN AND EXAMINER REALIZED THE LANDING GEAR HAD NOT BEEN LOWERED

Huh? A forward slip with a huge drag device in the well? Now that's airmanship!

 

[tothelineplz]

STUDENT OVERSHOT FINAL AND MADE FORWARD SLIP TO LOSE ALTITUDE. HARD LANDING AND VEERED OFF RUNWAY.


What the heck is a student pilot performing this maneuver for at 26 hours TT? This is an advanced maneuver which requires a thorough understanding prior to perfoming.

 

[tothelineplz]

FAILED A TIMELY RECOVERY FROM A FORWARD SLIP ON SHORT FINAL. RIGHT WING TIP TANK STRUCK THE GROUND

Flight Time Total Hours: 2600
Total in Make/Model: 1500
Total in Last 90 days: 42
Total in last 90 days Make/Model: 42

What is a recovery from a forward slip? In case your last resort didn't work or what?