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-   -   Jacobson Flare (https://www.pprune.org/pacific-general-aviation-questions/367354-jacobson-flare.html)

smiling monkey 26th Mar 2009 23:47


Originally Posted by Chimbu chuckles (Post 4815676)
Good grief...who is this dill?

He has quite an impressive biography if you ask me. I'll give it a shot .. BTW, I find this quote interesting;


On September, 2004, a specifically tailored version of the Jacobson Flare was introduced in the Qantas B737 full-flight simulator syllabus for the revised “all-variant” composite conversion for the B737-300/400/800, as the standard training technique.
So do all QF 737 pilots use this technique?

flog 26th Mar 2009 23:48


Originally Posted by gassed_budgie
and you're certainly not going to be looking out of the side window.

Tell that to a Pitts pilot...

Beg Tibs 27th Mar 2009 00:43


So do all QF 737 pilots use this technique?
Hmm...nope, not to my knowledge - I dont even recall it in 737 training to be honest

Lookleft 27th Mar 2009 03:31

I use a technique taught to me by a great Master "Don't think-DO, use the Force let it flow through you". By the time all that has gone through my mind so have the wheels usually!:ok:

Mach E Avelli 27th Mar 2009 06:30

Originally Posted by gassed_budgie
and you're certainly not going to be looking out of the side window.


Many taildraggers do require you to look out the side to successfully land (and taxi). Other quite sophisticated types have a nasty habit of windscreen fogging on descent/approach. Then there is the prospect of ice, heavy rain, delamination etc. obscuring forward vision. Lots of times looking out the side window is about the ONLY way to judge the flare.
And what if landing in 800 metres RVR? You won't even SEE the end of the runway. This is where the half wingspan flare height is quite useful, so to make it easy on myself I always use it, plus the technique of simply looking at the spot that I want the aeroplane to be at when it touches down. Assuming that there is enough visibility, keeping the touchdown point pegged to some constant reference point, be it the centre of the windscreen or somewhere to the side (as in a strong crosswind) helps to arrive at the point - going where you look again.
Hey, if the Jacobsen flare floats your boat, go for it.

-438 28th Mar 2009 00:48

It all comes down to skinning cats.

Captain Sherm 28th Mar 2009 10:03

Now I feel terrible. 8 years on the wonderful 777 and I simply landed it without thinking of Dave J. what an ace I could have been.

Alternatively....what if he's just a self important jerk who has added nothing to aviation except to keep the rest of the world happier by crossing the picket line back and staying home?

I need to study more. I was taught that landing was what you did to keep the passengers happy after you'd passed 200 ft on approach and before you taxied in.

rajsingh0621 5th Sep 2010 15:16

Understand the finals part of Jacobson flare
 
I was having a little trouble understanding the final parts of the Jacobson flare. I would greatly appreciate if you can help with the last few points of your lesson. So after you have passed the cut off point, (approx 90 feet before your aim point for C172), you begin to flare, and then it looks like you're focusing on aim point 2. But now what are you doing in regards to aim point 2 during your flare. Are you trying to slowly bring the nose to touch aim point 2 line of sight? Are you trying to keep the same distance between the nose and the aim point 2? Does your aircraft nose ever go above aim point 2? It also looks like the aim point 2 was closer first & than it moved farther, which you explain that fly your eyes to aim point 2 in 3 to 4 seconds. Can you please elaborate.

Sunfish 5th Sep 2010 21:29

Once your flare point (about 90 feet before the aim point) has disappeared under the aircraft nose, you select your new aim point which in "The Gentle Touch" method of flaring, is described as the centreline at the farther end of the runway. That is where your eyes should be looking as you smoothly reduce power, keep bringing the yoke back as if to try and make the aircraft stretch the glide to that new aim point.

What, in my opinion, Capt. Jacobsen, has done is systematise the visual cues and thus where the pilots eyes and attention should be concentrated on during the each phase of the landing up to wheels on.

When I learned to land, the whole process was taught by the South Park Elves method.

1. Aim point, airspeed, aim point, airspeed.......

2. ?

3. Smoothly apply brakes and taxi to ramp.


I would arrive over the FAA standard tree at the nominated airspeed with no problems. What happened next was a blur; "Touch main wheels first with full back stick and the stall warning sounding", "Don't flare too high", "don't flare too low". Sure, but how?

After a series of especially traumatic arrivals, I was eventually introduced to haptic learning (ie: by feel and do) by a senior instructor who simply stuck a piece of paper over my instruments at about One hundred feet and thereby gave me nothing to look at but what was outside.

I suspect that all of us use Jacobsens technique without realising it, we just learn "the picture' of when to flare by trial and error.

Hope this helps.

PA39 5th Sep 2010 21:47

The jake flare works for some and not for others. i seemed to find that students who worked in an industry where perception of height was essential (crane operators etc) were somehow pretty good at the jake flare.

For the hard gainers i always taught to bring the aircraft to a level attitude and as the speed reduces to graudally adopt a half climb attitude. Didn't lose anyone! :)

VH-XXX 6th Sep 2010 00:34

I've been using the XXX flare for over 10 years now and never had a hard landing or single bounce.

You can read about it in my new book titled "The XXX Flare." Only $19.95 at all good book stores or at your local flying school.


------
On a side note, spoke to a CPL recently whom until about hour 120 of his CPL course used to flare at Moorabbin based on his indicated altitude, at which point he went out for a nav then came back only to find that it was over-reading by around 50 ft so his landing was very hard. I can't believe he made it into his CPL that far and lived.

megle2 16th Nov 2015 22:01

The Jacobson technique gets a gong of sorts in current Aviation Business mag
Many years since this thread had any comment

Ultralights 16th Nov 2015 23:13

seams an awful lot of overthinking a maneuver that all of us just do. not something i would want to show to a student ab initio.

Al E. Vator 17th Nov 2015 04:01

For goodness sake.

This is making something easy complex.

Many years ago there was a book written by Kermode called "Flight Without Formula". No reason why the concepts discussed in that book don't still apply.

This technique, whilst maybe sensible in some context, is typical of what's happening in this industry. It's become bloated by clingons (people and concepts peripheral to the fundamental act of aviating).

...and I can just see Bob Hoover in WWII looking out of the side of a Mustang when landing after combat saying "now what is it again.. 4 times the square root of my wing span divided by the radius of the earth......".

Pull back a bit near the ground. Works every time.

scavenger 17th Nov 2015 10:07

If you had to jump off the first floor to escape a fire, would you look at the ground 1000 m away to break your fall? If you wanted to avoid broken legs, I'd suggest you'd look straight down.

The point of looking at the ground in the landing is to judge the height. Looking straight down in the landing to judge height doesn't work because the ground is blurry due to the forward movement, so you must look further ahead. The point at which the ground ceases to appear to move towards you, and so gains texture, is the correct place to look. This is roughly 50 - 100 m ahead at light aeroplane speeds.

Looking further ahead reduces the accuracy of the judgement of height, just the same as looking straight down. You want the closest point where the eyes can effectively focus to judge the height.

The reason it's harder to judge height above ground at night is that you can't see the ground close to the aeroplane like during the day, but you can still see the end of the runway!

This look at end of runway bull**** is lazy or ignorant instructing. Most people I have challenged on this in their renewals readily admit they don't look there themselves after I point out I can see they're looking closer in the roundout.

Yeah sure, you can teach this end of runway crap and people will learn to land. The brain is very good at compensating, but it will be a slower rate of learning and progression.

pukua 17th Nov 2015 10:32

A kid learning to ride a bike looking at the ground will fall off, a kid looking further ahead will learn how to ride a bike!

PW1830 17th Nov 2015 20:46

Height above the ground is only one part, closure rate just as important -can only be assessed by looking toward end of runway - not necessarily the end.Then there's closure rate of thrust levers to consider to fine tune height and closure rate. There is no magic solution.

The Green Goblin 17th Nov 2015 23:37

It's about using your peripheral vision to judge sink rate and your forward vision to judge flare and drift.

It's just something that can't be taught, it's something you figure out with much encouragement along the way.

Al E. Vator 18th Nov 2015 07:36

"This look at end of runway bull**** is lazy or ignorant instructing".

My goodness I've been doing it wrong all this time!

These Boeings and Airbuses and Cessna's and Douglas's in snow and sandstorms and typhoons must all land themselves. Lucky I've been educated about the error of my ways...

Con Catenator 18th Nov 2015 10:08

If you don't look at the other end of the runway, depth perception tends to be lost and that's a recipe for a hard landing.

Jake's method seems a very complex way to put an aircraft on a runway.

But then again, I have only been doing it for 50 years and still going strong, so I'll stick with what I have been doing if that's OK :ok:


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