Short vs Soft Field Takeoff and Landings

"Matt Whiting" wrote in message
...

What is obnoxious about pointing someone to a source of information
related to their question? I assumed the OP doesn't frequent this forum
and thus had no way to know that his topic of interest was covered in some
detail not that long ago. What is your problem today?

Matt

AFAIK, the OP is a very frequent poster here and over at r.a.s.

The points he raised were on topic, relavant and worth discussing.

He didn't, per se, ask a question that needed *an* answer. He tossed out
some scenarios and asked the pilot population how they handle them and if
they train for them.

How dare OS&B interupt the stream of other crap that seems to have utterly
derailed this newsgroup of late and bring up anything related to flying?

The Nerve...

;O)

Jay B

"Ol Shy & Bashful" wrote in message
ups.com...
What is a soft field? Sand, gravel, grass, mud, water (rainfall), snow?
What about a hard surface with 6" of fresh snow?

All of the above, and none of the above. The big problem is that there's no
quantifiable way to identify a "soft field", especially as it pertains to
any advice the POH might give on soft field operations. Some soft field may
be a LOT softer than whatever the aircraft designers had in mind.

IMHO, anything that isn't clearly the same as the nominal soft field being
described in the POH (assuming it gives performance numbers for a soft field
at all), one really needs to make sure there's some reliable reference with
which to compare results during the takeoff run, well before you reach the
point of no return. Of course, this means you also have experience on a
nominal soft field, so that you *can* compare.

Short could be a 9000'
runway that the snowplow cleared a swath of 25' and the thing broke
down after about 1500' of runway. ??? Ok.........

Yup...1500' runway. At least it's been plowed.

A short field takeoff nearly always assumes a 50' obstacle and directs
the technique in that direction.

As a student, I used to wonder where these 50' obstacles were. Now that
I've been flying for awhile, I realize that lots of trees are WAY higher
than 50'. Here in the Pacific Northwest, mature evergreens are easily 100'
high, old ones can be even higher. At one relatively short airport around
here, there are 100' trees off the north end of the runway, sitting on a
rise in terrain that itself is probably a good 30-40'.

Well, what about a short field that is
pointed over a lake, or the ocean? No obstacle to contend with.??

An unlandable surface is an "obstacle" in its own sense. Vx will keep you
closer to the airport surface in case of a need for a landing, but of course
Vy is what will get you to altitude the fastest (giving you enough height to
make an emergency landing more likely to be successful).

That said, if you're taking off over water, there's a pretty good chance
that one could at least land near the shoreline, or even on a beach, if the
engine goes out. It would all depend on the exact nature of the terrain and
shoreline.

How about a short/soft/obstacle with a good crosswind? Not hard to
conjure up....landing on a curving beach??
Landing with a short and potentially soft field....technique change?

IMHO, short and soft field as a combination is best to be avoided by most
pilots in most planes.

Conversely, if on a soft field, one may find it useful to redefine "short
field". That is, whereas 1500' might be short on a hard surface, one might
consider a 3000-4000' runway to be a "short field" if the surface is very
soft. With a surface soft enough, it may be that *no* amount of length is
sufficient...there will just be too much drag to get off the ground.

IMHO, when you have short and soft (however you define it), soft needs to
trump short, unless you don't expect to have to take off again. If the
runway is too short for that, you need a different place to land.

Add an obstacle...?
when is the last time you got out there and really checked to see what
the (your) aircraft is capable of with your present state of
proficiency?

At least once a year. I'd like to think that if the insurance company
didn't require it, I'd do it anyway. I do often practice short field and
soft field techniques even when on my own, so in practice it's usually at
least a few times a year.

And yes, I agree...one ought to be current on short field techniques. One
can avoid landing in a soft field when you want to take off again, but as
you say...any emergency landing may well require short field techniques. At
the very least, the concept of landing with as little forward speed as
possible is practically always going to be of concern in an emergency
landing.

Pete

Good things in my favor - Only two on board & the Xwind was from the
right. If I had been heavier or if it had been from the left, I would
have lost it for sure.

That's the part I don't get. Probably something to do with the right
rudder you use to counteract P-factor?

Jose
--
"Never trust anything that can think for itself, if you can't see where
it keeps its brain." (chapter 10 of book 3 - Harry Potter).
for Email, make the obvious change in the address.

On Wed, 15 Nov 2006 20:32:37 -0800, Peter Duniho wrote:
Some soft field may be a LOT softer than whatever the aircraft designers
had in mind.

A soft field is when you can be stopped and apply full power, but your
aircraft will not move... grin

If the wheels sink down to the point where the wheel farings are resting
on the ground, it's past the point of being a soft field and you should
start considering floats... While I was waiting on a hangar space to open
up at one time, I was stuck parking my plane outside... One of my neighbor
planes discovered that armadillos tunneling underneath your wheels is not
a good thing... His aircraft was resting on the wheel pants after the
armadillo's tunnel had collapsed under his wheels...

"Jose" wrote in message
m...
That's the part I don't get. Probably something to do with the right
rudder you use to counteract P-factor?

Jose

Exactly, and it can make a big difference in a Cessna 185, that has big "P"
factor and also a gyroscopic left turning tendency when the tail come up on
takeoff. Makes a HUGE difference on floats.

Take off and land with a right crosswind if possible. Goes for all GA
airplanes with CC rotation.
(seen from front)

Karl
"Curator" N185KG

As much as I use CoPilot (thank you Laurie & Paul) there's another
package for the Palm OS, DSSTop. It has a number of pages that you define
the characteristics of both the aircraft and the environment.

(No, I'm not a shill for DSS products, I just like using a couple of
them)

Acutal weight
Altitude (yes, DA)
OAT
Humidity or dewpoint
headwind or runway direction & wind info
Runway slope

Then the interesting stuff
runway composition
paved, turf, short grass, tall grass, soft/mud/snow and what %
Then you add a safety factor (e.g. 5%, 10% and so on)

The result is an estimated takeoff distance, rate of climb,
and so on.

It helps.

As for the example of a 9000 ft. runway where only 1500 ft has been
plowed, to me that's a 1500 ft. runway unless I'm on skis or balloon
tires.

"T o d d P a t t i s t" wrote in message
...
Peter, do you see this post from me twice? I see two
copies, but I'm sure I only posted once.

I only saw it once. Sounds like a newsreader or server burp on your side.

On 15 Nov 2006 06:51:09 -0800, "Ol Shy & Bashful"
wrote:

In an attempt to get the board back on track with aviation
subjects...Of late I have been doing curriculum directed training for
soft and short field ops. What strikes me is the absolute limited
thinking on the subject as far as the books and available study
courses. For example......
What is a soft field? Sand, gravel, grass, mud, water (rainfall), snow?
What about a hard surface with 6" of fresh snow? Short could be a 9000'
runway that the snowplow cleared a swath of 25' and the thing broke
down after about 1500' of runway. ??? Ok.........

I doubt any description is going to be all inclusive and your
experience is far greater than mine but:

There are short fields and short field take offs. They don't always go
together.

Think of it this way. A short filed is anything that requires a short
field technique. Some fields that are short are of a nature to
prevent short field take offs. IE soft. In that case is the soft
field technique good enough to get in and out?

A short field takeoff nearly always assumes a 50' obstacle and directs
the technique in that direction. Well, what about a short field that is
pointed over a lake, or the ocean? No obstacle to contend with.??

I see that as one very big obstacle. How many pilots are going to be
comfortable, or willing to fly out over a lake or ocean in ground
effect. I'd be climbing for all the plane was capable of. I have no
problem at all doing a short field over a cliff, but I have a big
problem doing it over water. Over the years I've done very few short
field take offs and landings that didn't have at least a 50 foot
obstacle such as trees or power lines.

I saw the results of a high, hot, humid, and heavy take off. The
pilots and plane survived but portions of the plane needed a bit of
"ironing". The pilot admitted that had it not been for the pilot in
the right seat telling him to keep the nose down they'd have never
cleared the trees. As it was they shortened them a bit and brought
home a few branches. However they did survive even if they removed the
nav lights from both wing tips. :-)) They tell me that some where in
the upper peninsula of Michigan there are two large trees sporting nav
lights. You can cut it much thinner than that.

Short field take offs consist of two distinct phases. The take off and
the climb. The take of part is the same whether there is an obstacle
or not. In a tricycle gear equipped plane it's: Flaps as specified in
POH. Brakes locked and full power if possible, Controls and trim
neutral, accelerate with no back pressure except to keep the plane
straight and level to Vx or Vx - 5. Climb at Vx until obstacle is
cleared be it a 3 foot fence or 50 foot tree. Then climb at Vy.

So regardless of what kind of field the first phase is the same except
for cross wind corrections..

Curved beach. That's unlikely to be pavement so unless the wet sand
is really hard and smooth you are going to have to resort to soft
field technique which would be a good idea for safety. Those planes
stop real quick when the nose gear digs in.

How about a short/soft/obstacle with a good crosswind? Not hard to
conjure up....landing on a curving beach??

Which do you want, short field or soft field take off. As my old
instructor used to say...you can't do both. The two techniques are
the anthisis (sp? my spell checker choked on this one) of each other.

Soft field is a rolling into position, high drag configuration that
will use more distance to get over much of any thing compared to a
short field take off.

Soft Field: Nose gear off as soon as possible, hold off and let plane
accelerate and lift off by itself. Stay in ground effect to Vy. (this
could be Vx if the pilot is careful of the transition) This is usually
rolling into position with full up elevator and applying power. Ease
off on the elevator as soon as the nose gear lifts off and hold the
gear off with up elevator.

BTW in the Deb and F-33 you need to lower the nose as soon as it lifts
off, or it'll settle right back on and never lift off again. There is
very little leeway between not lowering it enough and having it settle
or lowering it too much and touching down on the nose gear.

The two techniques can be combined, but not without sacrificing the
best of both. You can not safely use the short field take off
technique on many soft fields in a tricycle gear aircraft without
running the danger of digging in the nose gear.

As one instructor said: Mains are strong for landing. Nose gear is
fragile and expensive for steering during taxi.

BTW I did have the chance to convert a normal take off to a short
field on that big *long* 27 at Osh. It was hot, humid, and windy. We
were loaded to gross for the conditions. Acelleration was anemic but
we were doing well until the wind did an abrupt switch from 270 to 180
at 30 knots. On a good day I'm good for 25 knots. The Deb's cross wind
limit is 25 knots on a cooler day. And there we were. Not enough
aileron for correction although there was enough rudder to holdit
straight. Unfortunately the wind was skidding us sideways.. I hauled
it off in ground effect and fortunately the mains did not touch back
down. We slewed a good 45 degrees. The north 40 looked like a prarie
dog town with all the heads popping up. We cleared the overpass by
about 100 feet.

BTW the tri-motor was on final behind us. He thanked the tower and
said they were going to opt for Pioneer Field. That was the day the
big thunderstorms came through and uprooted some tie downs in the
antique/classic camping area and parked some planes on top of others.

It was so hot it didn't get comfortable until we were crossing Lake
Michigan at 8000 East Bound. ATC asked if we'd take the non cardinal
altitude for traffic avoidance. As I reacall there was almost 10
degrees difference between 7,000 and 8,000. What ever it was it was
noticeable. Man, but we had a tail wind. Mad it home in about 45 to 50
minutes when it's usually 1:15 to 1:20.
Landing with a short and potentially soft field....technique change?
Add an obstacle...?
when is the last time you got out there and really checked to see what
the (your) aircraft is capable of with your present state of

Almost every time I go out by myself.

proficiency? Don't think it important? If you don't think so, you have
never been faced with an actual emergency and few options for a landing
spot.

Had a for real, complete engine failure on take off. I'd practiced so
many times my body went on auto pilot. I'd done all the important
stuff before I had to even think about it.

What about precision landings? Done any lately? If not, WHY NOT? Have
you checked the book to see what the numbers are and gone out to see if

Landed with the nose gear on one side of the tape and the mains on the
other. Almost a perfect split. Then I had my ego busted. Nuther Bo
pilot came along and cut the tape with his mains as he set the plane
down right on the tape.

When he missed the tape by 11 inches in a 172 he went to get his Bo
grumbling, "I can do better than that". Two other people also did 11
inches in the same 172. They were the Bo pilot's daughter and her boy
friend.

you can match them? Have you ever read the fine print to qualify the

I can normally beat them. Note the normally as I haven't been flying
as much lately so I'm not that proficient at present. Having been
there I'm quite conscious of any slip in proficiency.

Short field...Steep, power by the numbers, short round out, plant the
mains, let the nose down immediately, get on the brakes and haul back
on the yoke. Aerodynamic breaking works very well and will shorten
the roll far more than trying to raise the flaps (Except in a Cherokee
with manual flaps)

conditions for either takeoff or landing? Don't forget,THE LARGE PRINT
GIVETH and the small print taketh away.......

What small print? It's all large print in my POH:-)) Particularly the
warnings about W&B and density altitude. There's a whole section on
runway materials and how they affect both landing and take off
distances. I particularly like the warning that a 17% increase in
touch down speed translates into a 36% increase in ground roll and
ground roll is normally about 30% of the square of the landing speed.
That's something to think about for those who like to add "a little
extra".

I'm still a low timer at 1300 hours and I still like to practice
maneuvers. (Probably why so few like to rid along when I go out to
practice) I think about that little extra every time I'm out doing a
few take offs and landings. I see Cherokees and Cessnas using 2/3 of
the 3800 foot runway while I'm using about 1200' in the Deb without
having to get on the brakes.

Hope this stirs some discussion.
Rocky aka Ol Shy & Bashful 23,000+ hrs and going strong after 70

Awh, come on. You could have at least thrown in a circle to land prior
to said short or soft field landings:-)) That way you can make the
final a bit steeper.
Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com