Tweaking the throttle on approach

chris writes:

A good landing starts with a good approach. If you don't get your
approach sorted out you are almost certain to stuff the landing up.

I know. I guess I'm just impatient. I wouldn't be that way in real life, but
in the sim it's often different, as one doesn't always have the time to fly
for a long period, and I like to practice take-offs and landings at tiny
airports as I encounter them.

A good airspeed for crossing the fence is VSo x 1.3. Find out what
your stall speed is, multiply by 1.3 and you have your speed at short
finals. You can add a bit for the early part of the approach, for a
172 you might use 70-80 kt on approach, reducing to 55 kt on short
finals.

Hmm ... well, I've been coming in at around 100 kts, which just happens to be
the full-flaps Vso plus 30%, as you suggest (in the Baron, Vso is 75 kts). So
I guess I haven't been going as fast as I thought. After reading what some
people suggest--that the aircraft should stall as it lands--I thought that
perhaps I was coming in too fast.

Usually I'll stay at right around 100 or so practically to touchdown. As I'm
gliding above the runway I'll reduce power and let the aircraft settle on its
own. It seems to be very smooth. The only disadvantage is that I need a
longer runway. But most runways are more than long enough for my small plane,
so there's no reason to rush down to the ground that I can see.

Whatever light aircraft you fly will be similar, can't speak
for the heavies though.. If you use much more than 80kt on approach
it can be difficult to get rid of the speed while still descending.

I try to come in with a good rate of descent at 100. Then, when I'm close to
the runway and coming into ground effect, I stop the descent, which causes my
airspeed to drop rapidly. As that brings me down, I progressively flare until
the wheels touch.

In heavies it's easier to some extent because the FMC will tell you what speed
to make on the approach. And if you autoland, you just set the MCP for that
speed or slightly above (136 in a lightly loaded 747-400) and it comes out
fine. The main trap with heavies is that you can't change your configuration
at the last minute--you have to be aligned and stable in your approach quite a
distance out, because last minute tweaks can be difficult and dangerous.

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writes:

If not aligned at the threshold in a real plane, you should go around.
You should strive to become aligned with the centerline soon after
turning onto final, and then hold it there. It can be done with
practice. Don't forget you'll need a crab angle to take care of
crosswind.

I'm pretty sure I've seen videos of real pilots (in small aircraft) turning to
align with the runway _after_ the threshold, but I suppose that just because
they do it doesn't make it a smart idea.

Don't try to do both at the same time. Hold power constant, and
adjust pitch with the yoke until you are at your desired airspeed,
then apply trim until you can release the yoke without the pitch
attitude (and therefore, airspeed) changing. Then with the airspeed
stabilized, adjust power to change the rate of descent, small changes
in power won't affect your airspeed.

OK

You need the proper speed for your aircraft. If it's not available in
the Pilot's Operating Handbook, then use an old rule of thumb, set the
airspeed equal to 1.3 times the aircraft's stall speed. Your aircraft
should be slowed to this speed by the time you turn final, and then
hold it precisely at that speed. The normal way to hold airspeed is
by trimming to that speed in pitch.

I'm usually close to 1.3 x Vso, probably just by luck. I'm usually
preoccupied with holding the glide path and I worry about speed a lot less
unless I'm too close to stall speed. My worst experiences on landing have
occurred because I was going too slow and stalled just above the runway, so
that has spooked me into keeping my speed up. But looking at my aircraft I
see that 100 kts is already just about 1.3 x Vso, so I guess I'm not going so
fast after all. I'm usually going 30-40 kts faster on the approach and only
slow to 100 just before crossing the threshold.

In extreme cases I've slipped forward down to the glide path, which works very
well for descending rapidly without going to fast, but my problem there is
getting myself straight and aligned while exiting the slip.

You will not achieve consistent landings until you can fly a
stabilized approach. To do this, you need to discover the numbers for
your aircraft, and then use them. To find them, I suggest you conduct
some experiments in the sim. Set up your aircraft in level flight on
downwind, constant speed, gear down, at 1000 ft AGL, with a medium
power setting. When opposite the numbers, lower your flaps to their
first setting (or 10 deg) and reduce power until you stabilize at a
500 ft/min descent rate with the airspeed at 1.5 times stall speed.
Record the power setting and airspeed. Use those numbers for your
initial descent from the pattern. After 30 seconds, turn base and
lower flaps to the second setting and set pitch for airspeed = 1.4
times stall speed. Then turn final, lower flaps completely, and set
pitch for 1.3 times stall speed. Fly it like this until you hit the
ground. If you land long, then reduce power a little more next time.
If you land short, add a little power next time. Keep iterating until
you zero in on the right numbers.

OK, I'll try that: 1.5, then 1.4, then 1.3. I think I'm pretty close to that
now.

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DR writes:

The benefit of your simulator is that it doesn't destroy the landing
gear on your sloppy landings and that is why it is nothing like real
life.

Actually it does. Sometimes the gear is destroyed (the extreme case),
sometimes it is just damaged, sometimes the damage is subtle and you find out
about it the hard way when it won't lock for the next landing.

It lets you get away with the most terrible landings ...

Not if you are using the add-ons intended for serious simmers, with realism
cranked up. I even damaged a flap once and didn't find out about it until I
encountered a sharp rolling tendency aloft whenever I fully extended the flaps
(that one took a while to figure out, in part because I had trouble believing
that the sim had actually simulated partial damage--but it had).

(It always
says excellent landing to me but that's not what my instructor ever says
-and he's right I'd give myself typically 5-8/10). Based on your
extolling the virtues of MSX I recently got the latest version and tried
it out with the aircraft I'm training on. Basically I'd have to say it
simulates a C172 very poorly and I'd say it's only use is for simulated
instrument flying. Even so, it's response does not mimic my aircraft
near the limits of the flight envelope -it behaves like a flying game
really. Red Bull flying race? What a pile!

Where do you put the realism settings?

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Jim writes:

Excellent advice on all points. Only thing I would add is to use these
steps in basic trainer such as C172 until proficient, as in real life
you must crawl before you can walk. Flying a complex aircraft in
simulation is task intensive and frustrating.

Does a Baron 58 count as complex? It seems easy to fly compared to the big
iron.

I fly mostly the Baron 58 as Dreamfleet's simulation is rigorously accurate,
so it behaves just like the real thing. The C172 seems too easy, so either
this is the world's easiest plane to fly in real life, or the sim is not as
accurate as it could be.

In real life, I'd want to fly the same thing I had flown in the sim, if I
could find a place that would give me instruction in a Baron (a new one, not
one of those WWII relics, but without the G1000 junk).

Be careful not to float or balloon
in ground effect. If you do balloon add a bit of power to stabilize
and cut the throttle again and flare to landing. Hope this helps.

I do seem to glide excessively just before touchdown. I have a phobia about
expensive damage to the gear. I've hardly ever crashed in a way that would
injure me in real life, but I've had a fair number of landings in which the
gear was damaged (on one occasion I damaged flaps as well, not sure how).

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On Mar 6, 6:15 pm, Mxsmanic wrote:
Jim writes:
Excellent advice on all points. Only thing I would add is to use these
steps in basic trainer such as C172 until proficient, as in real life
you must crawl before you can walk. Flying a complex aircraft in
simulation is task intensive and frustrating.

Does a Baron 58 count as complex? It seems easy to fly compared to the big
iron.


It has retractable gear and variable pitch props, means it's complex.
Not to mention multi-engine.

I fly mostly the Baron 58 as Dreamfleet's simulation is rigorously accurate,
so it behaves just like the real thing. The C172 seems too easy, so either
this is the world's easiest plane to fly in real life, or the sim is not as
accurate as it could be.

In real life, I'd want to fly the same thing I had flown in the sim, if I
could find a place that would give me instruction in a Baron (a new one, not
one of those WWII relics, but without the G1000 junk).

You would be very ill-advised to try and start your flight training in
a twin.
There's way too much stuff to cope with when you're trying to learn
how to take off, fly s+l and land..
Best to learn on something small, slow, forgiving, and you can move up
later. I found even going from a C152 to an Archer, I got way behind
the aircraft - too much happening too fast, and the Archer doesn't
have two engines, CSU's or retract. And the difference in cruise is
only 35kt or so, but enough to get me seriously behind the aircraft!!



Be careful not to float or balloon
in ground effect. If you do balloon add a bit of power to stabilize
and cut the throttle again and flare to landing. Hope this helps.

I do seem to glide excessively just before touchdown. I have a phobia about
expensive damage to the gear. I've hardly ever crashed in a way that would
injure me in real life, but I've had a fair number of landings in which the
gear was damaged (on one occasion I damaged flaps as well, not sure how).


If you are floating you are going too fast or trying to hold it off
too long. From reading your earlier post, you identified the VSo of
the Baron as 75. My research came up with 69-72 as stall speeds.
Which makes VSo x1.3 = 89-93kt. You probably don't want to be going
for a full stall landing in a twin, so come in at about 90kt, raise
the nose a bit to flare and let it settle onto the runway. Don't try
and hold it off, that's what a Cessna pilot should do, but probably
not a twin pilot. Just make sure your mains touch before your nose
wheel.
Mind you, I am not a twin pilot so that could all have been
rubbish. :-)

chris wrote:


It has retractable gear and variable pitch props, means it's complex.

And flaps...it has to have flaps.


Not to mention multi-engine.

The number of engines doesn't matter. By the way a twin with two
HP wouldn't be HP either.

Mxsmanic wrote:
writes:

If not aligned at the threshold in a real plane, you should go around.
You should strive to become aligned with the centerline soon after
turning onto final, and then hold it there. It can be done with
practice. Don't forget you'll need a crab angle to take care of
crosswind.

I'm pretty sure I've seen videos of real pilots (in small aircraft) turning to
align with the runway _after_ the threshold, but I suppose that just because
they do it doesn't make it a smart idea.

I may have misunderstood your earlier post about being misaligned when
crossing the threshold. I originally thought you meant that you were
not positioned over the centerline (bad), but maybe you meant that
your airplane's centerline was not parallel to the runway centerline.
If so, then that is not unusual, or bad, but you MUST align before
touchdown. (Use rudder to straighten out, and opposite aileron to
prevent lateral drift)


In extreme cases I've slipped forward down to the glide path, which works very
well for descending rapidly without going to fast, but my problem there is
getting myself straight and aligned while exiting the slip.

Yes, straightening out after a slip seems to be harder in the sim than
in the real plane.

On Mar 5, 11:56 pm, Mxsmanic wrote:
writes:
If not aligned at the threshold in a real plane, you should go around.
You should strive to become aligned with the centerline soon after
turning onto final, and then hold it there. It can be done with
practice. Don't forget you'll need a crab angle to take care of
crosswind.

I'm pretty sure I've seen videos of real pilots (in small aircraft) turning to
align with the runway _after_ the threshold, but I suppose that just because
they do it doesn't make it a smart idea.

When we speak of aligning with the runway, we mean that the _flight
path_ should be straight down the centerline.

This does not necessarily mean (and often doesn't) that the airplane
axis is aligned down its center. Most often you have some kind of
crosswind, and many pilots hold a crab angle (to maintain the flight
path) down almost to the ground, and then "kick it out" (straighten
out) just before touchdown. This is the turning you've seen.

Kev

On 5 Mar 2007 05:11:10 -0800, wrote:

On Mar 4, 12:02 pm, Mxsmanic wrote:

The Baron has a CS prop so I can't watch RPM. I guess I could look at
manifold pressure. However, I've been going mostly by sound to determine how
much power I have applied.

I don't know what CS prop guys do, but in my fixed-pitch prop, I

Depends on how well you know your plane.

always make my initial power reduction based on RPM, I set it to 1500
and then adjust from there, based on the resulting approach. I
suspect that with a CS prop, some initial RPM/Manifold Pressure
combination is selected.

With the Deb my initial power reduction is made well before I'm turned
down wind. I leave the RPM alone at 2400. The idea is to get slowed to
somewhat less than 140 (which is the maximum gear down speed) when I
straighten out and down to about 110 as I pass the end of the runway
outbound. Depending on temperature and particularly density altitude
the power settings can change quite a bit. Note, with the gear up the
glide ratio is about twice that of a 172. With the gear down it's even
steeper than a Cherokee 180 although it and the Cherokee have almost
the same wing loading. With the gear down you can pretty much think
of it as a big, heavy Cherokee that burns a lot of gas and isn't
nearly as forgiving.

In a stabilized pattern, which I seldom fly, I aim for 110 abeam the
numbers outbound, 90 on base and 80 on final slowing to 80 minus 1 MPH
for each 100# under gross. I run *about* 10-15 degrees of flaps down
wind, 20 to 25 on base, and 25 to 30 on final going to the full 40
when either needed or the runway is made.


I have found that flying a normal rectangular pattern in the sim is
significantly more difficult than in real flight. In the real plane,
I compare my actual position to my desired position by frequently
glancing at the desired touchdown point on the runway. I find this
very difficult to do in the sim, I think because of the difficultly in

The view in FSX is very realistic for the 172. OTOH you need a
state-of-the-art system to be able to run it. Development was started
before multi-core and multi-processors were even though of as becoming
popular. Hence it depends on raw horsepower to run things and gets by
with a fair to middlin graphics card. Not a cheap one, but you sure
don't need to go the big bucks for a top end DX-10 graphics card.
Anything much less than a top end machine will leave you CPU bound.
However even with SATA 3 drives it seems to take forever to load.

getting realistic view of the runway from the various legs of the
pattern (?). However, once established on final approach, I think the

I think this is the advantage FSX has over FS9. A flick of the "top
hat" gives you views that look pretty much normal.

sim is quite good in reproducing the sight picture of the approach.
In a light plane, the standard technique is to hold airspeed constant
(usually by trimming to that speed), and then fine tune the flight
path angle with small power adjustments.

But I guess
after a while looking out the window gives me enough clues--as well as
checking instruments, but often I'll adjust power before I see a change in the
instruments.


With the CS prop in the Deb I pretty much use the throttle to adjust
the aiming point and only reference the air speed to make sure it's
not drifting up or down.

The Deb takes a "light touch" on the controls so I set the trim and
then just sort of nudge it here and there.

Bumpy IFR in solid IMC it becomes a two finger control just nudging
the yoke


In a normal approach, started from downwind in the traffic pattern,
once the initial power reduction is made, I make the rest of the
approach mostly without looking at the instruments, except for several
checks of airspeed. The descent to the runway is done visually.
Also, don't forget that in the real plane your attention will be
mostly devoted to looking for and avoiding other aircraft.

Pretty much the same here whether IRL or sim.

I've read about being in a stable configuration on approach and that this is a
Good Thing, but I'm not sure if that applies across the board for all aircraft
and approaches, or just for straight-in approaches, or what. I think it would
be quite a feat to be able to fly a pattern and land without hardly ever
touching the throttles, except perhaps on the kind of windless day that only

I think I remember experiencing those a couple of times IRL.

occurs in simulators. I can get the aircraft into a stable configuration on
approach if the weather is good and I'm coming straight in, but doing it while
flying a pattern seems unattainably difficult at times.

And there in lies another difference between IRL and sim. If I were
flying into a big airport IRL I could pretty much set the power and
let it go, but the touch down point would vary over quite a distance.
As I normally fly into airports with 2500 to 3800 foot runways I don't
have that luxury so although I can fly a rectangular pattern and even
do each segment in the same place repeatedly It required adjustment of
power and flaps. Sometimes even a little slip is called for. :-)) On
really windy days it may call for substantial power on final.

If you want to be realistic in the sim, then you should try to fly the
traffic pattern for most of your visual approaches. (This includes
instrument approaches to small airports in visual conditions; break
off the approach a few miles out and join the pattern normally.) I
agree about the difficulty of setting up a good approach from the
pattern in the sim. You need to find a set of zero-wind numbers that
works for your sim aircraft, e.g., power setting on downwind, initial
power reduction, time until you turn base, position where flaps are
applied, airspeed on final, etc. (Timing your turn to base may work
better for the sim than the real-life technique of waiting for 45
degrees from touchdown point). You may have to find them by trial and
error, but once you have them, they become your starting point for all
subsequent approaches; fly by those numbers, and then make adjustments
for wind, and other factors of the specific situation.

Learn this first with the 172, then work with the bigger stuff.

Once lined up with the end of the runway add about half flaps and come
back on the power. Watch the touchdown zone. (white strips just down
the runway). If they are getting higher in the windshield add enough
power to stop them from moving up. If they are moving down, then
reduce the power. If they are still moving down, go full flaps. If
they are still moving up you are either too high, too fast, or both.
If you aren't going to be able to land in the first third of the
runway go around and try again. A good guide are the VASI lights with
the top ones being red and the bottom being white although IRL a lot
of pilots don't like to come in that shallow.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

On Tue, 06 Mar 2007 16:26:52 -0500, Ron Natalie
wrote:

chris wrote:


It has retractable gear and variable pitch props, means it's complex.

And flaps...it has to have flaps.


Not to mention multi-engine.

The number of engines doesn't matter. By the way a twin with two
HP wouldn't be HP either.
or 200 for that matter. Isn't is still "greater than 200"?


Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com