FREQUENTLY ASKED QUESTIONS

FAQ #1 Is the Jacobson Flare Paper still available as a .pdf?

FAQ #2 Is the Jacobson Flare app available for Android devices?

FAQ #3 Can I download the app to my Mac or PC computer?

FAQ #4 It looks complicated – I won’t understand the maths!

FAQ #5 Does the Jacobson Flare work on unmarked grass or gravel airstrips?

FAQ #6 Does the Jacobson Flare work at night or in rain?

FAQ #7 “I was taught that airspeed is controlled with the elevators and rate of descent is controlled with the throttle. Is this not correct?”


FAQ #1 Is the Jacobson Flare Paper still available as a .pdf?
I wrote the original paper, ‘Where to Flare’, 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. The paper grew to about 17 pages, by 1999.

In 2012, I began the project to develop the Jacobson Flare App for iPad. Launched recently, in July 2014, this is the equivalent of a 370-page treatise, comprising about 130 pages of text and 240 pages of illustrations and diagrams and including 6 video clips (demonstrating the one technique applied to the C172, B737-400, B777-300ER and the A380) and 5 interactive calculators. Further details are available on www.jacobsonflare.com .

The original paper certainly highlighted my longitudinal ‘flare fix’, based on a pre-calculated supplementary point on the runway centreline, short of the aim point; however, the new app offers much more than that. To land any airplane consistently well, on any runway or airstrip, a pilot must know the answers to the following questions:

1. Where to aim?

2. How to aim?

3. When to commence the flare?

4. How much to flare?

5. How fast to flare? (The flare rate.)

The app explains all of these topics and more, far better than the earlier papers ever could.

Clearly, it is more comprehensive than any previous explanation and for this reason the revised and expanded paper (which I now regard as inadequate) is no longer published. However, for historic reference purposes, the original paper, ‘Where to Flare’ is available as a .pdf file.

Click to view

We have kept the cost of the Jacobson Flare App for the iPad to a minimum, so that student pilots can afford it. They will save a lot more than the purchase price in training hours, as they will no longer have to struggle with the trial and error methods dating back to the end of World War One, in 1918.


FAQ #2 Is the Jacobson Flare app available for Android devices?

We do have plans to offer an Android version at some point; however, the Android platform is quite diverse in screen size and aspect ratio, in comparison with the iPad.

Apart from the additional cost of production we are advised that, currently, an Android version of our app would not be as fully functional and user friendly as the iPad version and currently is not cost-effective.

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, especially the five Calculators included within the Jacobson Flare App for the iPad, complements and enhances these EFB applications.

For those who do not yet own one, the Apple (on-line) Store doe offer superseded or refurbished iPads of various sizes and capacities, with new screens, batteries and warranty, for substantially reduced prices.


FAQ #3 Can I download the app to my Mac or PC computer?

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 the iPad, complements and enhances these EFB applications for in-flight use, if desired.

The Jacobson Flare App is currently available only for the iPad for these reasons and to protect copyright on our original material and design.

For those who do not yet own one, the Apple (on-line) Store doe offer superseded or refurbished iPads of various sizes and capacities, with new screens, batteries and warranty, for substantially reduced prices.


FAQ #4 It looks complicated – I won’t understand the maths!

A misconception, made by some uninformed pilots, is that the Jacobson Flare is some sort of mathematical thesis, which attempts to make life unnecessarily complicated for pilots. They couldn’t be more mistaken. It is the plethora of legends, myths and misinformation that have complicated the landing for decades.

The truth is that I observed landings for twenty years and then I explained. I actually applied the technique on DC-9-30’s and a wide range of light aircraft for two years before developing the mathematical solutions, which are necessary to prove and explain the technique and provide the means to calculate aim point and flare cut-off point positions for the next airplane – the one we have yet to fly. The maths facilitate the universal application to any fixed-wing airplane and provide a quantified, predictable and consistent flare point, assisting greatly in developing both ‘judgment’ and confidence.

One does not have to understand the maths to use the Jacobson Flare, but the basis is just simple triangulation. There is nothing more challenging than long-established pilot navigation techniques. The 1 in 60 rule is utilised to advantage and diagrams and illustrations serve to 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.

Far from complicating the explanation, it is demystified. Hundreds 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..

Now that the manoeuvre is fully understood pilot confidence just soars.

‘This has the elegant simplicity of the safety pin!’ – Glen Adamson, – Captain DC-9, 1987
‘Simple Unassailable Aerodynamic Logic’ – John Chesterfield AM MRAeS


FAQ #5 Does the Jacobson Flare work on unmarked grass or gravel airstrips?

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 (like I did in 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 is 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 doubtful that any two pilots would flare within 5ft of each other, using conventional guesswork. That’s why this works.

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


FAQ #6 Does the Jacobson Flare work at night or in rain?

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 the iPad explains this point and many others, clearly and simply.


FAQ #7 “I was taught that airspeed is controlled with the elevators and rate of descent is controlled with the throttle. Is this not correct?”

DJ: The concept of ‘elevators controlling path angle and power/thrust controlling airspeed’ is not new…I was introduced to it in 1965, thankfully. 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 ‘power/thrust facillitating rate of descent’ *, is valid only when power/thrust is fixed and is ineffective on larger/faster airplanes. 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.
(* the rate of descent is a function of just two factors: flight path angle and groundspeed. The use of power/thrust facillitates 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.)

“But this is just contrary to the way VFR training is normally 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.”

DJ: 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.