FAQS

with The Jacobson Flare app for iPad  

The Jacobson Flare App is currently available only for the iPad.

The iPad has captured the aviation market and is used widely, being approved for the military, airlines and other GA operators, as an electronic flight bag (EFB), supporting flight planning, aircraft performance and operation and instrument departure and approach applications, for use on the ground and in flight.

The Reference Section, particularly the set of Calculators included within The Jacobson Flare App for iPad, complements and enhances these EFB applications for in-flight use, if desired.

Download The Jacobson Flare App for iPad and add this great resource to your EFB.

You do not have to understand the maths to use the Jacobson Flare, but the basis is just simple triangulation. And illustrations simplify and explain graphically the various aspects, without resorting necessarily to symbols and formulae. They are there, of course, fully defined for those who are curious or want the proof, but the built-in calculators relieve the pilot from even having to bother with a formula.

The Jacobson Flare is NOT some sort of mathematical thesis, which attempts to make life unnecessarily complicated for pilots.

Far from complicating the explanation, it is demystified. Hundreds of thousands of pilots have noted an immediate improvement in quality and consistency, because they now have a visible instructive and quantifiable model, based on sound principles and not a loose, non-descript set of personal opinions, recycled for 100 years. Myths, legends and misinformation is replaced with a fully defined visual eye path, based on sound mathematical principles.

Absolutely! The aim point and flare cut-off point are generally visible, but if faded paint marks or heavy rain (or even snow) make this task difficult, then the axes through suitable pairs of runway edge lighting can provide an alternative means to locate these points.

Even if the actual flare cut-off distance has to be estimated, rather than seen clearly, the 1:20 ratio of the 3° flight path angle ensures that any longitudinal error made is reflected, vertically, by just 1/20th of that error, making the Jacobson Flare 400 times more accurate than methods involving a guess of flare height.

The Jacobson Flare App for iPad explains this point and many others, clearly and simply.

Download The Jacobson Flare App for iPad and check out the simplicity of The Jacobson Flare for yourself.

If you are thinking of learning/refining your technique on sealed and painted runways first, before applying the longitudinal flare cut-off point to unpainted runways or grass or gravel strips, you are on the right track. They could come later, unless your ‘home’ airfield is unsealed grass or gravel. In that case, you could adopt a suitable marker or a transverse axis across a pair of gable markers, or cone markers (see the YPOK Porepunkah video clip in the app) for the flare cut-off point and then physically measure the flare cut-off distance from there, forwards to the aim point 1 position.

There are always some reference marks available, due to the natural contrasts in colour or texture on any runway or airstrip. Here is the important point:

You will read (if you haven’t already) that using the conventional method of guessing a flare height, a 1ft vertical error compounds about 20 times, one way or the other along the runway (1ft high: 20ft long – 1ft low: 20ft short). When we start using a longitudinal flare point on the ground, short of our aim point 1, any error, possibly due to our inaccuracy in assessing that cut-off point distance or a wind gust lifting or dropping the nose slightly (and changing the cockpit lower visual cut-off angle) is reflected, in vertical terms, as only 1/20th of that error.

So instead of a height error compounding 20 times, a longitudinal error REDUCES 20 times, mathematically. That’s why this technique is so tolerant of error and why it is not so critical a problem that the runway is unpainted or is grass or gravel. Even a 100ft error would only make a difference of 5ft, vertically, and it is Improbable that any two pilots would flare within 5ft of each other, using conventional guesswork. That’s why this technique works.

The Jacobson Flare App for iPad explains this point and many others, clearly and simply.

Download The Jacobson Flare App for iPad and check out the simplicity of The Jacobson Flare for yourself.

The concept of ‘elevators controlling path angle and power/thrust controlling airspeed’ is not new. The use of the primary effects of the flight controls is essential in achieving a stable approach path, on visual and instrument approaches in ANY airplane and has been widely used for decades.

Using the secondary effects of the flight controls, ‘elevators controlling airspeed’, with the concept of ‘power/thrust facilitating rate of descent, is valid only when power/thrust is fixed and is ineffective on larger/faster airplanes. The rate of descent on final approach is a function of just two factors: flight path angle and groundspeed. The use of power/thrust facilitates a change in path angle, at a given indicated airspeed. It does not directly control rate of descent. In any case, it is a very second-hand way of flying an approach and offers no stability. A roller coaster flight path is the inevitable result, leading to unstable approaches. This is one of several major reasons for inconsistent and poor quality landings.

Another critical issue is to consider the two common errors that student pilots (and licensed one, also), who have been taught this incorrect method, make frequently:

1. High and fast, on final approach; and/or
2. Low and slow. In each case, the initial response, for a pilot trained to think that the elevators control airspeed will, COMPOUND both problems.

The pilot who is HIGH will pitch UP, making things worse and the pilot who is LOW will pitch DOWN – the LAST thing the pilot should be doing, to resolve each error! A third major issue is that the roller coaster flight path ensures that the threshold crossing height of the aircraft will be totally inconsistent, making landing judgment quite haphazard.

As if all that is not enough of a problem, the situation worsens at a most critical phase: the flare point. A pilot, incorrectly pitching the aeroplane with the elevators to control AIRSPEED, now needs to transfer the use the elevators, to pitch the aircraft to control the FLIGHT PATH ANGLE. What a ridiculous moment to completely redefine the flight path control philosophy! It defies all logic.

“But this is just contrary to the way VFR training is frequently taught. I went through several instrument instructors, and never found one who could adequately explain why we (CFIs) teach aircraft control differently to VFR and IFR students. Your explanation was right on, and satisfied my thirst for that understanding with an easily to implement and repeatable solution.”

You’re dead right – that aspect has long bemused me, also. Why teach the correct method when IFR, and the flawed ‘speed descent’ method when VFR? After all, the airplane doesn’t know the difference between IFR and VFR! But it does know the difference between a powered and a glide approach And that is the arbiter.

The full discussion on this and many other related topics may be found in The Jacobson Flare App for iPad, available on the App Store.

Download The Jacobson Flare App for iPad and check out the simplicity of The Jacobson Flare for yourself

The app explains The Jacobson Flare far better than the earlier papers ever could.
It is more comprehensive than any previous explanation and for this reason the revised and expanded paper (which David now regards as inadequate) is no longer published. However, for historic reference purposes, the original paper, ‘Where to Flare’ is available as a .pdf file.

This original paper was written for the 1987 Australian Aviation Symposium, sponsored jointly by The Institution of Engineers Australia and The Royal Aeronautical Society, following my initial two years of research. The size was limited to just 4 pages and an abstract. By 1999, the original paper had grown to about 17 pages. In 2012, the project to develop The Jacobson Flare App for iPad began.

Download The Jacobson Flare App for iPad and check out the simplicity of The Jacobson Flare for yourself.

Do you want to experience that feeling of satisfaction you get from a beautiful landing more often? 

Read what pilots of all levels have to say about the technique and app here and download The Jacobson Flare for iPad now.