General FAQs

On its release in June 2014, the Jacobson Flare App was available only for the iPad. Version 2.0 was released (March 2020) for the iPad, iPhone and iPod Touch.

The iPad has largely captured the aviation market and is used widely, being approved for the military, airlines and GA. Electronic flight bags (EFB) *, support flight planning, aircraft performance and applications, for ground and in-flight operations.

The Jacobson Flare calculators complement and enhance these EFB applications for in-flight use, providing internet connectivity is available.

 

Good News

However, some later 'silicon screen' versions of MacBook computers can now accept and display the Jacobson Flare ESSENTIAL App.

 

Relax

You do not have to understand the maths to use the Jacobson Flare. The basis is just simple triangulation. The 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. However, the built-in calculators relieve the pilot from even having to bother with a formula.

 

Believe it or not

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 de-mystifies it. Thousands of pilots have noted an immediate improvement in quality and consistency; they now have a visible and quantifiable model.

The Jacobson Flare is based on sound principles, not a loose, non-prescriptive collection of personal opinions, recycled for 100 years.

Myths, legends and misinformation are replaced with a fully defined visual eye path, based on sound mathematical principles.

Let's settle some misconceptions

Some unenlightened people believe David developed a mathematically based theory that he’s attempted to prove in practice. They could not be more mistaken! Here, he responds to that idea:

“The truth is actually the converse: For 20 years, I observed and studied landings. Then I explained those observations, using unassailable, yet simple mathematical principles. The maths are necessary to validate the technique, and to produce a couple of simple formulas. These serve to make ‘The Jacobson Flare’ predictable and useable on our ‘next’ airplane. I haven’t invented anything – I’ve just made a couple of connections."

 

No parlour trick

"The Jacobson Flare is not a parlour trick. It doesn't involve a deck of cards or a pact with the devil. 

It's my considered opinion that pilots who learn to apply Jacobson's techniques can make consistently good landings, provided they know how to configure their aircraft and fly a stable approach at the appropriate airspeed.’ 

‘I'm excited to have a cool, new tool in my teaching toolbox. I can't shake this feeling of a kid in a candy store." 

- John Ewing, Flight Instructor, California, USA

 

Other pilot reactions

"If this was any good, it would have been developed by someone, years ago!" is a lame and unenlightened alternate response. "But we've always done it THIS way", is another. If similar attitudes had prevailed through the rest of aviation, we would not have progressed beyond spruce, wire and fabric structures, unreliable power plants and navigating by DR; we would not have weather radar, GPS, GPWS or TCAS.

The truth is it was developed nearly 40 years ago by Captain David Jacobson, an Australian career flight instructor and airline pilot. Since the original Jacobson Flare Paper, 'Where to Flare' was published in 1987, the multifarious responses by pilots have been insightful, to say the least.

Many pilots have been open-minded, self-aware and honest enough to realise that conventional landing training methods have been inadequate, at the very least. The most common and insightful observation, by a great many pilots celebrating that 'Eureka' moment when they execute another consistently sound landing by applying the Jacobson Flare, is: "This probably what we've all been trying to achieve, without realising!"

These more enlightened pilots understand that the best that generations of flight instructors and flight training organisations have been able to manage is to attempt to describe what they, themselves, do and this loose collection of opinions has been passed down, as fact. This explains why every flight instructor has a different explanation, none of which really explain 'how' to land an airplane. Trial and error is not good enough, when the rest of aviation has grown from the days of World War One.

At best, all conventional landing methods have revolved around opinions, myths and legends that have well and truly passed their use-by dates. They lean heavily on judgment, perception, false information, experience, repetition, personal opinion and an educated guess of vertical height above the landing surface – none of which can be taught. They are inconsistent and unreliable.

Competence comes at some indeterminate time, for each individual pilot and is fallible in differing circumstances. From the dawn of aviation until 1987 there was no definitive, universal landing technique and, even more puzzling, little recognition of the need for one. The silence is deafening.

 

"We've always done it this way!"

The Law of  Primacy in the discipline of education, refers to the way that many people tend to believe implicitly what they are first taught, creating unshakeable views about any given subject. This very much includes any attempt to discuss a different viewpoint on landing training, which the majority of pilots regard as an 'art'.

It has been noted by the author, often during the past 39 years, that when a pilot is presented with an alternative to conventional ideas on landing training, basic defence mechanisms kick in and, sadly, any new idea can be regarded as a personal challenge to their ego. Instead of listening, or reading, or watching and then considering, many pilots tend to become quite defensive, immediately throwing up as many reasons as they can think of, as to why the Jacobson Flare 'cannot work'.

They will argue – from a position of total ignorance in relation to the principles and advantages of the Jacobson Flare – about the wide number of variables that certainly do affect the outcome of all landings (all of which and more are, in fact, embraced, resolved and diminished by the sound principles behind this innovative technique. They are not to know yet that is does work and has always worked, ever since the sound mathematical principles used to explain David's 1965 inspiration were applied.

Incidentally, the 1965 inspiration derived from the 1943 RAF 617 Sqn 'Dambusters' application of simple triangulation to resolve the incredible difficulties of flying at just 18m, yes, 60ft, over dark water at night, in addition to a very basic yet effective bombsight!

 

So, what's so different about the Jacobson Flare?

Essentially, the Jacobson Flare uses a logical, geometric visual 'framework' to guide the pilot through the entire manoeuvre. Since the development of the Jacobson Flare from 1985, pilots are presented with a fully-defined visual eye path, specified by the airplane type – making the landing safe, sure, simple and universal.

Accounting for all – even self-compensating for many – of the variable parameters that distract the attention of pilots away from the 5 essential elements of all landings: Where to aim; How to aim; When to flare; How much to flare; and How fast to flare, the Jacobson Flare explains landings as never before. We know of no flight training manual that answers even one of these elements, let alone all five.

Simply put: Consistently sound landings – in the right place – are obtained through 'flying' a constant-angle final approach to a suitable initial aim point, commencing the flare at an equally-suitable pre-determined visual fix and then executing a 4-second flare through to a new, secondary aim point. That's it. The framework confirms to the pilot exactly what is happening, at every stage dispelling the myths that 'trial and error', 'developing a mental picture' and 'feel' are the only ways to master the landing.

Flown initially at a constant angle, the eye path translates to the classic exponential flare curve that generations of pilots have attempted to execute by judgment alone. The flare is initiated from a visual fix, derived from the cockpit lower visual cut-off angle and the flight path angle, offering a precise and visible model for both student and instructor.

The airplane type/size determines the exact positions of aim points 1 and 2 and the flare initiation point and, on a normal powered approach, is flown using a PATH descent - using the elevators to aim the pilots eye and power/thrust to control airspeed. The technique is equally applicable and adaptable to both light and heavy airplanes, from sailplanes to A380s.

(For those pilots taught that airspeed is controlled with the elevators and rate of descent is controlled with the throttle, the use of elevators to control airspeed, on final approach is more correctly applied to the Non-Normal cases when power/thrust is fixed – or failed – such as in a forced landing. For further explanation, please see FAQ #5, in the FAQs tab.)

 

The Flare Fix

The flare fix determines a longitudinal flare point on the runway centreline (based on the correct conventional flare height) while gradually reducing power/thrust back to idle). The concept of using a longitudinal flare point rather than flare height has two great advantages:

1.  The flare point is visible and therefore easily identified and able to be repeated, consistently; and
2.  Any longitudinal error made in mis-identifying the longitudinal flare point DIMINISHES 20 times, compared with the fact that any error in mis-identifying a conventional vertical flare 'height' COMPOUNDS 20 times. This is due to the fact that the standard approach path angle is 3º - approximately a 1:20 gradient. Overlooked by the entire flight training industry for 100 years, this angle is routinely misrepresented in text books and manuals as approximately 25-30º and this has masked its significance.  Triangles have 3 sides and only 2 were ever utilised. The third (adjacent) side is fully visible as the runway centreline and, on sealed and painted runways, is effectively a calibrated ruler.  The 1:20 tolerance, afforded by utilising a longitudinal flare point, has the great advantage of being so tolerant of error that the technique can be equally applied on unsealed airstrips of grass or gravel, where an estimation of runway segment distance is required.

The Jacobson Flare is comprehensive yet practical, simple to master and extremely effective. Since 1985, it has been adopted in 65 nations by thousands of civil and military pilots of various ages, abilities and experience, in airplane types ranging from sailplanes and single-engine light airplanes to large jet transports. The improvement in confidence, competence and progress of pilots – at all levels – is not only breathtaking: It's measurable.

The Jacobson Flare addresses obvious differences between airplanes but embraces their similarities. It delivers a basic system of flight training that may be adapted as necessary to meet specific requirements. Its universal application is long overdue and the App presents the Jacobson Flare clearly and comprehensively as never before – on both iOS and Android devices.

An expanded version of this FAQ appears in our Blogs tab.

What controls what, on final?

The concept of ‘elevators controlling path angle and power/thrust controlling airspeed’ for normal, powered approaches is not new. Utilisation of the primary effects of the flight controls is essential in achieving a stable approach path in any airplane. This has been widely and wisely practised for decades, by enlightened civil and military aviators, flying visual and instrument approaches.

Using the secondary effects of the flight controls, i.e., ‘elevators controlling airspeed’, is certainly valid when gliding, or on a forced landing caused by partial or total loss of engine power or thrust; and is clearly unavoidable when climbing. These are all cases when power/thrust is at a fixed setting, necessarily.

The dubious concept of ‘power/thrust facilitating rate of descent on a normal, powered approach is very clumsy and unintuitive, especially for student pilots, in light airplanes and is totally ineffective on larger/faster airplanes.

 

So what controls the rate of descent?

The rate of descent on final approach is a function of just two variable factors: flight path angle and groundspeed. Certainly, the variation of power/thrust can facilitate a change in path angle, at a given indicated airspeed, but 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.

 

Other issues

Another critical issue is to consider the two common errors that student pilots (and licensed ones, also) who have been taught this inaccurate 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 things 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 and touchdown points 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, pitching the aeroplane with the elevators to control AIRSPEED, now needs to transfer the purpose of 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.

A further point (apart from greatly improved passenger comfort) is that by flying a stable approach with a more-or-less constant body angle, the lowest angle we can see over the nose of the airplane is also more-or-less constant. This fact is crucial in facilitating the Jacobson Flare's unique visual fix for the initiation of the flare itself - inspired by the 1943 RAF 617 Sqn 'Dambusters'. This stability is responsible for the automatic self-correction of the pre-calculated flare fix for variations in landing flap settings, approach path angles, runway slopes and discounting the height illusions caused by varying runway widths.

“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.” (Mark Santacroce, USA)

Mark was 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.

However, this aspect is only a part of the 'How to aim?' second step in using the Jacobson Flare. All five steps must be applied for this comprehensive approach and landing technique to return consistently fine results.

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

Absolutely! The aim points 1 and 2 and the flare cut-off point are generally visible, in these conditions. However, if faded paint marks or heavy rain (or even snow) make this task difficult, there are options. The lateral axes through selected pairs of runway edge lighting can provide an alternative means to locate these points, longitudinally.

The essential point is this: If the meteorological conditions are suitable for a manual landing, the aim points and flare cut-off point will be visible.

Furthermore, longitudinal runway markings are easier to identify as aim and flare points in rain, than guessing your flare height. In addition, errors made in guessing flare height even with GPWS calls), compounds x 20 times longitudinally, along the runway.

 

Applying the Jacobson Flare to Night Operations

Here is a suggestion to tune your night landings to the same exacting standards as you achieve, by day:

The PAPI aim point comparison calculator, standard in the JF App, can compute the actual PAPI aim point 1*; and

Published runway edge lighting spacing can help locate the appropriate aim and flare cut- off points for the subject aircraft.

* Note: If the destination airfield has no PAPI, then simply ignore the first step, above.

Disclaimer

This is a technical dissertation, intend primarily for more-experienced pilots and to provide an interim supplement to the Jacobson Flare App. Less-experienced pilots are advised to treat the information contained herein, as information, only. Please, do NOT attempt to apply the information, contained herein, if you are a new or yet-to-be user of the Jacobson Flare.

It's generally NOT a good idea to do anything in an airplane, for the very first time! By this, we mean, do it with someone, preferably a flight instructor, who has done it before. Your safety is paramount. So, become proficient at using the Jacobson Flare by day, before attempting to apply it at night.

This information is directed more specifically to pilots of 4-6 place single- and twin-engine-airplanes, below 12,500lb / 5,700Kg MTOW, operating onto runways without glideslope guidance.

Any study or application of this content should not be rushed, if full comprehension is to be achieved.

Pilots of larger airplanes should be able to relate the principles to their current airplane, although the aircraft landing lights generally illuminate the runway fixed distance markings well, which helps to identify both the correct visual aim point 1 and the pre-calculated flare cut-off point for the airplane type. Alternatively, please feel welcome to contact info@jacobsonflare.com for further information.

 

Background

Early in the research and development of the Jacobson Flare, around 1985-87, I was a civilian flight instructor at the RAAF Point Cook Flying Club, in addition to my full-time career as an airline transport pilot – at that time, a DC-9-30 line training captain with Trans-Australia Airlines (TAA)/Australian Airlines.

I am not ex RAAF, myself, but was in the 'right place/right time', from 1983-89), in a more-or-less voluntary capacity.

The following technique was flight-tested and proven, in C150, PA-28 and PA-38 aircraft, on Runway 17 at RAAF Base Williams, at Point Cook -YMPC - a classic  ‘black-hole’ runway, at night, located SW of Melbourne.

When headed away from the lights of Melbourne city, the immense Port Phillip Bay is the black backdrop and, depending on the prevailing conditions. it can be difficult to discern the horizon. The lights of the Melbourne SE shoreline suburbs are not much help, either, when late on final approach for a landing on 17.

There is no T-VASIS, PAPI or ILS glideslope to 'hang your hat on', so it was a 'Mk 1 eyeball' approach. However, this solution proved to work perfectly at YMPC and can be adapted easily to the night situation, at other locations.

Note: If visual glideslope guidance, such as a PAPI system, is available at a particular airfield, then the PAPI aim point comparison calculator (standard in the Jacobson Flare ESSENTIAL App), together with the published runway edge lighting spacing and the following information, can be applied to ascertain and then optimise the actual PAPI aim point 1 and flare cut-off point for the subject aircraft, in night operations.

Let’s take a look at the following standard 5 JF considerations, to re-examine what we use by day and what we can adapt for night landings.

Note: The ft/m conversions have been rounded, for convenience. This makes no practical difference to the landing outcome.

 

The 5 Jacobson Flare Considerations - Applied to Night Operations

 

1. Where to aim?

The JF-suggested visual aim point, for 4-6 place single- and twin-engine-airplanes below 5700Kg MTOW, located at 300ft/90m from the threshold is still ‘King’, to assure approximately 10ft threshold clearance of the main landing gear (MLG). By day it’s the ’top’ of the first centre line mark, past the runway numbers. So it is, normally, by night. Now, the runway edge lighting is a great reference, as you can use the normal (i.e., 90º) axes across the parallel pairs of edge lights, to determine suitable longitudinal references for both the aim point 1 and the flare point.

The standard runway edge lighting spacing is 60m , but a detailed check of this information confirms RAAF Point Cook -YMPC has a non-standard spacing of 85.6m (approx 90m). Like many things in aviation, edge lighting spacing is not as standard as it might be: For example, Australia's busiest GA training aerodromes: Adelaide Parafield YPPF 03L/21R, Brisbane Archerfield YBAF 10L/28R, Melbourne Moorabbin YMMB 13L/31R and 17L/35R and Sydney Bankstown YSBK 11C/29C, have their runway edge lighting spaced at approx 90m intervals, yet Perth Jandakot YPJT 06L/25R and 12/30 has the runway edge lighting spaced at the standard 60m intervals.

Fortunately, these variations are covered by the 1:20 tolerance of the unique longitudinal flare point principle of the Jacobson Flare. This point is explained, below, in 3. When to flare?

Note: In addition, YSBK 11C/29C and YPJT 24R each have 3º PAPIs, with 25ft MEHTs.* (*Minimum Eye Height at Threshold)

By night, the runway threshold is marked by the standard runway threshold green lights.

• At 200ft/60m standard spacing, the 300ft/90m aim point 1 would lie mid-way between the axes of the first and second pairs of edge lights; the flare cut-off point is 100ft/30m back from aim point 1, at 200ft/60m, exactly on the axis of the first row. See the 60m spacing illustration in Fig 1, below:

Fig 1

• At 300ft/90m spacing, aim point 1 would fall exactly on the axis across the first pair of edge lights, at 300ft/90m. However, the flare cut-off point would lie 100ft/30m back from there, at 200ft/60m, unserved by any usable or consistent visual cue at night, except the aircraft landing lights. See the 90m spacing illustration in Fig 2, below:

Fig 2

Having different aim- and flare-point indicator cues at night, for the same actual aim and flare point locations is less than ideal; and you may or may not have the luxury of being able to check the light spacing before you land somewhere. In any case, the quality of this data may not be all that accurate.

So, to keep things simple, consistent and conservative, let’s establish a single, consistent assumption for all aerodromes that you are likely to use at night:

We have established above that, at 200ft/60m standard spacing, the 300ft/90m aim point 1 would lie mid-way between the axes of the first and second pairs of edge lights; the flare cut-off point is 100ft/30m back from aim point 1, at 200ft/60m, exactly on the axis of the first row.

Now, if the spacing was actually 300ft/90m - BUT, we aimed at the same NIGHT aim point 1, mid-way between the axes of the first and second pairs of edge lights, then the ACTUAL aim point 1 location would be located at 450ft/135m, somewhat deeper.

Given that the certified landing distance is factored (increased) by 67%, this is not a practical issue, as long as the approach is flown accurately, within +5/-0kts. See the 90m spacing illustration in Fig 3,  below:

Fig 3

2. How to aim?

No change is needed. Fly the same aim point 1/glare shield relationship as by day, controlled with the elevators and the airspeed controlled with power/thrust - to achieve the essential stable approach path.

Aim point 1, as discussed above, is the mid-point of the imagined axis, longitudinally mid-way between the axes of the first and second pairs of edge lights; in other words, the centre of the black space between the first 4 edge lights.

Now, many pilots find that, at night, things seem to be happening 'faster than by day', as the airplane approaches the runway, on short final. This may be due to our eyes 'zooming-in', like a camera lens, on the pre-dominant object in the pilot's view: the runway shape, outlined by the threshold and edge lighting. The rest of the airfield is often very dark.

It has been found very useful to imagine the airfield as it appears by day, or imagine wearing night-vision goggles, so the visual field more resembles the daylight view: the pilot's eyes don't 'zoom-in' and the approach groundspeed appears more 'normal'.

 

3. When to flare?

This where the 1:20 advantage of a longitudinal flare point assists, greatly. We already know that the flare cut-off point is 100ft/30m back from aim point 1 - for 4-6 place single- and twin-engine-airplanes, below 5700Kg MTOW.

For 200ft/60m spacing, aim point 1, mid-way between the axes of the first and second pairs of edge lights, is perfectly located at 300ft/90m, so the flare point will be located on the axis through the first pair, at 200ft/60m, exactly as by day.

As stated above, if the spacing was 300ft/90m - and we aimed at the same NIGHT aim point 1 cue, mid-way between the axes of the first and second pairs of edge lights then the ACTUAL aim point 1 location would be located at 450ft/135m, somewhat deeper. The correct flare cut-off point for that aim point location would lie 100ft/30m back from there, at 350ft/105m.

However, to be consistent with the 200ft/60m case, we might wish to use the same flare point indicator, namely the axis of the first pair of edge lighting, at 300ft/90m. This would create an actual flare cut-off distance of 150ft/45m: an error of 50ft/15m.

Yes, it’s a little earlier - and correspondingly higher, BUT:

The longitudinal error is 50ft/15m: Applying the 1:20 advantage, (dividing by 20) indicates a diminished vertical error of just 2.5ft/0.75m. This is well within the vertical tolerance of any landing, flared using the conventional 'educated guess' of height.

Speaking of flare point tolerance, it has been found useful to regard the flare point much like a CG, lying within an acceptable range between a forward and an aft limit. This an example of that comparison. Now, at a normal 3-4º approach path angle and flaring over the usual 4-seconds to a new aim point 2, probably at least 2000ft/600m away, or even further, it makes little difference whether you flare at the aft limit, the forward limit, or anywhere in-between: it is relatively insignificant.

Review Figs 1 and 3, above: The edge lighting spacing is different, but we can use the same visual cues for both the aim point 1 and the flare point, for runway edge lighting spacing of 60-90m spacing and the 4-second flare will smooth out the variations in actual flare cut-off distance, between the aim point 1 and the flare point, due to the 1:20 tolerance of using a longitudinal flare cue.

Finally, use EVERY cue at your disposal, including your experienced assessment of vertical flare height, too. Triangles still have three sides! We might as well use all of them.

Airline fleets and other advanced types offer the added advantage of computer-generated call-outs of '100..50.. 40.. 30.. 20.. 10' ft radio altitude ('radalt'), from the ground proximity warning systems (GPWS). However, these are still subject to certain limitations, such as radio interference and the mathematical fact that, on the standard 3º flight path angle, every +/- 1ft vertical error compounds as a longitudinal error of +/- 20ft respectively, along the runway.

 

4. How much to flare?

Again as by day, transition to aim point 2, at the end of the runway lights. For a runway of uniform slope - not necessarily level -  this is the same as used by day: the upwind threshold.

For undulating runways:

Where the landing zone is located on a downhill slope, aim point 2 is relocated to the 'bottom end' of that downhill slope, before the runway becomes more level; geometrically, the flare cue will occur later/lower than the level-runway case. (* See this app Pp 93-95)

Where the landing zone is located on an uphill slope, aim point 2 is relocated to the 'top end', or 'brow' of that uphill slope, before the runway becomes more level; geometrically, the flare cue will occur earlier/higher than the level runway case. (* See this app Pp 93-95)

This technique will assure a more accurate convergence with the landing zone surface in each case.

 

5. How fast to flare?

The usual Jacobson Flare 4-second technique, or maybe stop the flare at 3-3.5 seconds, if the runway has a lot of water on it, to reduce the risk of aquaplaning.

(In a jet transport airplane, aiming at aim point 2, after completing the full, 4-second flare, can result in too-smooth a landing! The main wheels don’t penetrate the water layer and make proper ground contact, so apart from the risk of aquaplaning, the main wheels don’t spin up to about 700rpm and, in some airplane types, the pre-armed auto brakes and auto-spoilers don’t actuate - they actually get 'confused'.)

So, there you go. It’s a bit to digest:  Try drawing it out on some paper, to scale for your airplane; think it through; sit in a chair and visualise the whole thing. And try it, first time, with someone else, preferably a flight instructor, with you, or better still, have a play in a simulator. It may be very beneficial, to prove it to yourself, first.

Use all available cues, including the landing light-illumination of the centreline and fixed distance runway markings and your accumulated experience, (together with the GPWS 'radalt' callouts in larger aircraft), in assessing your height above the runway.

Of the three components to any landing:

1. The initial pilot's eye path to aim point 1;

2. The commencement point of the flare; and

3. The flare, itself, through to the second aim point, usually at the far, upwind threshold:

The first is the most important; second most is the third and the least important is the flare initiation point, so long as it is within that 'range of acceptable flare points/heights' for the airplane type, as discussed above.

Finally, to reiterate, the one aim point 1 - at 1.5 rows of edge lights - and the one flare point - at the first row of edge lights - may be applied for runway edge lighting spacing of 60-90m spacing and the 4-second flare will smooth out the differences. See the generic spacing illustration for 60-90m edge lighting spacing in Fig 4, below:

Fig 4

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 or app preview) 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 just as well, on unsealed surfaces, as it does on a sealed and painted primary airport runway.

The Jacobson Flare ESSENTIAL App explains the Jacobson Flare far better than the earlier papers ever could.

It is more comprehensive than any previous explanation. For this reason, the revised and expanded paper (which David now regards as inadequate, at the most!) is presented for historic reference purposes. The original paper, ‘Where to Flare?’ is available here 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.

Now, the modern The Jacobson Flare ESSENTIAL App for iOS presentation makes for an interesting comparison. At 345 pages, it  squashes that original little paper.

How times have changed!