How to use the PAPI

Hi again,

below you find another „How to“ article. It consists more or less of three parts:

First, I would like to acquaint with a very important visual reference used for landings called „PAPI“:
Precision Approach Path Indicator
The PAPI is a very reliable tool, to fly the right way down the approach path. If you are set on an ILS you will be able to crosscheck your approach with the PAPI, because it will visually indicate to you, if you are on a 3.5 degree glideslope, e.g. at the so called 1.000ft point (I come to that gate a little later). If there is no ILS available, you can still fly a very good approach in VFR conditions with the use of the PAPI.
In reality, it comes either with either 4 or 2 lights in one row. The color of the lights are red and white and it is used on small and large airports, and -off course- also in Infinite Flight.
In IF we have two lights, located left of the runway (see image below):

The logic and the mechanism of this visual system is quite simple: It is a strong white light, that is projected thru a lens. Before the lens, there is a red filter, covering the upper half of the light channel. So the result is a white and a red light (see the two images below):


Your position relative to the PAPI light on the approach decides how you see it…red or white. The combination of the two lights in a row indicates to you, if you are on a 3.5 degree glideslope to the runway touchdown point:

  • Red and White, ….everything ‘s allright
  • White and White, you‘ re too high
  • Red and Red, you are dead



(Attention: in IF it is red and white and not white and red, but that is a marginal detail)

This is how it looks in IF (…pls. forget about the 747 at the threshold, I just needed to move around with the camera

Too high (white and white)

Perfect (red and white)

Too low (red and red)

Please also take particular note of the different shapes of the runway from this distant perspective!! If you are coming in very high and steep, the runway edge lights form something like a christmas tree. To the opposite, if you are too low. Bear this in mind on your next approach. You will soon get a feeling, if it looks right or not.

Now, something about the subject „adherence to procedures“ and the subsequent question of using Infinite Flight as a game or a simulation

I did mention the so called „1.000ft“ point on the radio altimeter! - This particular gate is used as a general CONTINUE / GO AROUND decision point, regardless what the actual decision height, according to the CAT Status in IFR conditions is.

In IF at 1.000ft above ground, if you are not fully configured for landing, which is defined as having

  • gear down,
  • flaps in landing configuration,
  • speedbrake armed,
  • speed at V REF,
  • established on glideslope and on localizer (ILS provided)
    ->… you must go around!!

Why? - because „haste makes waste“ and if you are not established and fully configured at this gate, chances are great, that you are getting in hectic in order to make it, thus forget about something, thus loosing the complete control, the situation will get more dynamic than necessary, increasing the chances to crash or at least (on short rwys) to a balked landing or to overshoot. By the way, runway excursion is almost on top of the real world incidents list!!

So the intention of this rule is, to set a last safety gate with the respective parameters for an approach to decide, continue or go around. In other words, the gate is a slice of swiss cheese (…no I am not kidding:-),
just continue reading.

Folks, this is an important rule, and it is not that easy to comply. Not in the real world, and even more so, not in a flight simulator. Test yourself and try it! - In IF your life is not at stake, there is no fear, no feeling for the speed or the upset situation and besides its a game, its a simulator. You will not end up in the hospital.
Especially in a simulator this notion applies:
Every landing you can walk away from is a good landing;-)

You will always think: I am gonna make it anyay! - And yes, maybe you will make the landing, but not by applying good airmanship, but because you will move your aircraft out of its normal and applicable operation areas) with applying:

  • higher sink rates
  • excessive bank angles
  • throttles in idle
  • use of speedbrakes although flaps are set
  • a nd so on

Bottom line:
In the real world flying does not become safer because of past successes, but because the industry tries harder every day and every flight and the pilots strictly adhere to procedures. (…just between you and me, do you always buckle up, when you start the engine of your car? see what I mean)
So commercial flying is not about interpreting rules individually. The necessary level of safety will only be maintained, if one follows the operating procedures. Off course you should not stop thinking. But do not become creative with regard to procedures, unless you have tried anything else thats in the QRH (Quick Reference Handbook) or OM (Operations Manual).

So,…in Infinite Flight I do the following:
I follow the procedure and go around if I do not comply with my set of rules. Even more so, if I fly in LIVE mode. I do the extra 10 mins before I try to land based on maybe‘s and pure luck. Not to talk about the fact that I know, everybody watching the scene notices I am well out of limits and fly pretty unprofessional;-)!

I am aware, that some of you might think, …what a stupid guy, … its just a game after all.

Well, yes its a game, but then again its also a serious simulation and there are people around who want to practise and „simulate“ the real commercial flying. (see also the article „What‘s the use - Playground server is a circus by jasonroswell“)

I propose the following, so everybody can be happy with what he/she draws out of IF as there is no digital right or wrong:

You use it as a game?
Perfectly fine! – I am serious. Play around in SOLO, there are no rules, boldly go where no one has gone before. Try everything, fly everything. Create your challenges: How about an A380 approach in Aspen?:-)
But,…please accept, that there are also a lot of people who have an interest in simulating flying, air traffic control and, in general, modern commercial aviation. They are right too, and deserve the same respect & tolerance for their interpretation of IF. This means, you have your playground (SOLO) and they have theirs (LIVE). If you are getting lonely in SOLO, try LIVE, but then you have to accept certain rules!

You use it as a simulation?
Well then, this is a totally different set of challenges. You have to familiarize yourself with procedures, do some research, learning and reading …and forget about the freedom of the skies.
Commercial aviation is heavily regulated, so is a commercial aviation simulation.
We must adhere to procedures, as we do in real life business. Flight safety is about flying in bandwidths, gates, envelopes and adherence to procedures. That is true professionalism.

Now, last but not least, the swiss cheese model by the psychologist James Reason

This model of accident causation, likens human system defences to a series of slices of randomly-holed Swiss Cheese arranged vertically and parallel to each other with gaps in-between each slice.


Reason hypothesizes, that most accidents can be traced to one or more of four levels of failure:

  • Organisational influences,
  • Unsafe supervision,
  • Preconditions for unsafe acts (e.g. unestablished approaches) , and
  • The unsafe acts themselves (flying out of the limits).

In the Swiss Cheese model, an organisation’s defences against failures are modelled as a series of barriers (e.g. gates, procedures, checklists), represented as slices of the cheese.
The holes in the cheese slices represent individual weaknesses in individual parts of the system, and are continually varying in size and position in all slices.
The system as a whole produces failures when holes in all of the slices momentarily align, permitting “a trajectory of accident opportunity”, so that a hazard passes through holes in all of the defences, leading to an accident.

In our example, you continue the unstabilized approach at the 1000ft gate, extending speed brakes with flaps full, gear down, throttles in idle, in a desperate move to loose altitude and speed, then you undershoot, pull up, forget about the disengaged autothrottle, stall and crash into the approach lights. This is not a fictional scenario, …It happened in real life!!

So that is why the 1.000ft gate is a slice of a swiss cheese and if you do not follow it, you are flying thru a safety slice, getting closer to an accident.

By the way, unfortunately the Reason model is valid in all fields of our day to day live! - think about it, think ahead!

Thanks for reading! - and as always comments are welcome

Safe landings & see u around



Excellent post, very helpful! Thanks :)


Professional knowledge gained. Look forward to a continuation of this series. I’m compiling your stuff in a QRH. Keep it coming. Regards, Max Sends


Wonderful post. Thanks for sharing this information.

Thanks. Didn’t know about this and honestly wouldn’t have thought it would work in IF.

The PAPi works very well!

The other two aspects (1.000ft gate + reason model) are more or less taking out of the commercial aviation knowledge base.

The first one is a standard procedure and very useful.

The Reason model helps us to make flight and cabin crews ( and the “earthlings” in the offices too ;-)) understand, that flight safety depends on many many factors and is everybody’s every day responsibility. Flight safety starts in the organization, in the corporate culture and not on board. All these aspects form slices of swiss cheese!

Methods like this reduce the risk, and here is another interesting equation covering this subject:

Risk = Threat / Countermeasures

This means, if you have a given threat (e.g. collision with other aircraft) and, as a countermeasure, you install TCAS (traffic collision avoidance system) in all aircraft, you will, as a consequence reduce the risk

Off course one can push this even further: To reduce the threat of an accident a 100%, the countermeasure would be: just do not fly! -> risk =0 :smile:

I just think, some of this knowledge can be applied in IF too, that’s why I share the experience.

Happy landings



While I’m a pilot and have used PAPI and VASI regularly, I haven’t been using the VASI in IF. Now I will, thanks Clip!

This may be an area that the developers can improve the IF experience with all the new pilots on the Playground. Turn up the intensity of the VASI (right now, if you’re using the HUD, it pretty much blocks out the VASI lights until about 300 ft above the runway). and give the ATC a message for the pilot to “… use the VASI”.

I think a lot of the pilots on IF really want to learn how to put that heavy onto the runway nicely and using the VASI/PAPI is a really solid way, with direct feedback, to give those pilots some guidance. VASI/PAPI adherence combined with the correct airspeed will usually result in a good landing. Just gotta learn how to configure the airplane to achieve them.


Did somebody say SWISS cheese?!?

No really, nice tutorial! :smiley:

i forgot to mention:

thre is a callout : “1.000”

so we have an aural alert, almost like a virtual First Officer reminding us to observe the 1000 feet gate

Happy Landings



It aint easy… Practices make perfect.

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Moved to the Tutorials category. Please keep topic titles simple. No need for a whole paragraph. :) makes it easier for people to find and engage the discussion.

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Thanks for the info great artical I am definitely a simer. Any thing that gets me as close to actual flight im all about I have learned so much from this sim. And where else can you talk to real life pilots and they will explain to you how it’s done?

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Dave if you read this again one quick question why is the horizon in the dash always slanted? Always wanted to ask😀

I’m not sure what you mean?

In the picture above the horizon in the dash is banking right. And all the cockpits do it.

You mean the static image of the instrument? No reason. Just is.

I suppose it’s a question for Matt I just was curious. Like an inside joke or something lol

I don’t know for sure, but it’s always looked super awkward to me. I just try to ignore it.

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Yes that’s what I ment have you ever tried to land in that view you have no sense of level 😀

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No way, not without the HUD, it’s distracting otherwise.