Stone_cold
I thought you yourself stated The reference is the diagram on page stated below.
PRO-NOR-SOP-18-C P 15/18

Agreed: I'm not suggesting flying it in NAV. 3.4nm is the distance to the Fix: equates to 2nm spacing on DW and rolling out on final around 2nm/600ft.

Vilas , maybe I am not being clear , you stated : .

What is your reference for " as corrected for wind " ? The 3sec/100' has no wind coresction .

Stone_cold
You are correct for circling approach there is no correction for wind end of downwind in FCOM. I mixed up with normal circuit because the discussion also stated somewhere the circuit height as 1500ft which is normal circuit height which is corrected for wind abeam landing threshold. The airbus article says only about turning downwind 30 seconds corrected for wind and abeam landing threshold as 3sec/100ft as visual exercise, timings are appx. only and to use ND (for correct placement).

aviate
 

On 15th April 2002, Air China B767 CFIT during circling at Gimae Busan (Pusan) South Korea. Weather was low cloud, 215/17, reduced vis. ILS rwy 36 with RH circle to rwy 18.

47 K tailwind at 2200 ft with assumed tailwind on downwind
Close high terrain north of airfield which was not visible
Circling minima 1100 ft, but crew used 700 ft.
Reduced perspective of the runway from LH seat in right turn
Captain had operated to Gimae 5 previous times, but always straight in approaches.
Air China did not consider this to be a special airport
Crew expected straight in, but there was a runway change due doiwnwind on rwy 36

Note that the circling approach procedure has since been modified with stobe lights for the base turn.

My recommendation would be to study the detail of accidents such as this in preference to spending too much time on an app. A good account can be found at http://flightsafety.org/ap/ap_dec05.pdf

Busan approaches were also designed to TERPS, not PANS-OPS--significant difference in circling areas.

GF

TERPS is mentioned in the link

You're not wrong. The old terps was just ridiculous for circling. Good for a C150, not a jet (although 411A argued til he was blue in the face is was no problem). The new rules aren't much better, methinks.

That prang was a good example of where, if you are forced to do a circle, technology (eg use of Fixes on the ND) could greatly assist SA.

If you want to use technology, in airbus you can use radial in function to the runway threshold and it gives you glide slope guidance from yo yo. But again it's visual manoeuvre.

Circling Approach Awareness
 

The discussion and posts have been interesting.
As I continue to continue to work on the spreadsheet, I've made some adjustments.
It now gives me the bearing and distance to enter three fixes on the downwind leg (FOR AWARENESS ONLY.)

Fix 1: Calculated distance abeam RWY threshold.
Fix 2: Distance from abeam RWY threshold to base turn.
Fix 3: Distance from abeam RWY threshold to limit of PANSOPS protected area.

For 737NG FMS, these fixes can be entered using the RWY fix in the LEGS page.

To do this, a new RWY fix must be created -0.1 back from the RWY fix. e.g. RW05/-0.1. Bearing and distance can then be made from this new fix. The normal RWY fix does not accept bearing and distance.

Comments, questions, and suggestions are welcome.

http://i779.photobucket.com/albums/y...pspttfj11w.png

http://i779.photobucket.com/albums/y...sliqeaa4s.jpeg

I haven't checked your numbers but... the base turn time of 16" is too close. That would roll you out on Final at 200ft-ish. Vilas says Airbus base turn is at 30"... I think even that's a tad close.

For my understanding, what runway are you landing on here?

I've used a timing based on the height to lose from MDA to threshold at 318' per nautical mile at the current GS on downwind. Not adjusted for the change in GS on final.
Runway in spreadsheet is LTFJ. Runway in photo is LTFE. The downwind spacing seems okay.

You need to work backwards from when you have to be Stable ie on-slope (3°) at 500(?)ft. That will define where you roll out of the base turn, then work back to the base turn start point, then the groundspeed on Downwind will define how long you go Downwind for. As mentioned previously, this may mean you fly a level Base turn initially, then start the final descent when intercepting the 3° path, hopefully to roll out at 500ft (or whatever your Stable rule is), on slope. For example, if circling at 1000ft, start down half way round the turn. If circling at 600ft, start as you approach Final.

Yes this makes sense, you don't want to be turning onto final at very low altitudes. I'll rework the calculations based on a 3 degree path from the landing runway. Probably I should use 600 feet to be stable as this approximates lowest OCH above aerodrome elevation.


Airport in spreadsheet is LTAF.

Coupling this topic to those about the dilution of manual flying skills and flight path visual judgement, I hear there are airlines who have grave doubt about the capabilities of even captains to conduct visual finals to runways without GP guidance. To that effect it is only allowed if there is a VNAV constructed path from a minimum 4nm point to the runway. Further, some use airports where a circuit is required to the non-instrument landing runway with PAPI's unreliable or non-existent. A circuit is constructed with FMC WPT's and full LNAV/VNAV guidance to bring you onto a visual finals 'in the slot'. A classic 'children of the magenta line' approach to a circuit arrival. Sad days.
One day there will be an advert for 'Airline Dodo's wanted'.

Hi RAT 5, I agree.

It is sad for those of us who flew before the invention of such aids like FMGCs and pictures on Nav Displays with actual wind and ground speed shown but it would be mad to dismiss them, because using such aids enhance our SA.

However I still believe it should be a basic skills requirement to be able to judge a visual circuit using the view out of the window, backed up with the scale markings on the NAV Rose Display if available and the wind vector information provided.

Making up spread sheets is only inviting other errors in the sheet and / or typos.
Always KISS.

An APP FFS! I was lucky enough to operate in a 737-200 around the south pacific for many years before moving up to LNAV/VNAV flying on big jets, and the 3 seconds per 100 feet above airport elevation after passing the threshold downwind worked every time in the most horrible weather conditions.A small nod to wind effect was often made but the basics were always the same.Stay level until you were more or less heading to the runway then down you go at a nominal 700 fpm, many times with no PAPI etc.Obviously this was generally with sea level ports with not much terrain about, so this is problematic at say BUSAN for example where special procedures are needed to be trained/adhered to.TERPS or PANS OPS not really relevant.What ever has happened to this type of skill............Pete.

How can you calculate your base turn without inputs for your angle of bank and your speed. This will affect your radius and thus your distance flown. Your ROD will be equally affected. It is not a simple task. And throw wind into the mix.

Many years ago I had to calculate the turning radii with different winds to intercept a lat/lon at a time to the second. Even in level flight, it is complex with many variables, and that was clean, level without changing config or speed...

As I said above, manoeuvre into position laterally on downwind, then turn in looking out the window. Reduce or increase the AoB depending on how tight you are. Pull / push sidestick/yoke/throttle as appropriate if you are low or high.

It's a visual manoeuvre, using your eyes and judgement.

If you can't, there's an app for that. It's called the ILS or RNP AR. The button's on the FCU.

I think you guys are being a bit harsh. Precisely what Dadanawa is doing will equip him well for visual circling. CS, you had better work out your expected turn radius beforehand: too close and you could well stall the thing. One can do quite a lot of preparation before doing a base turn, so that the event itself is easy, despite ugly weather. Simply saying "pull/Push" if you don't know what you're doing is going to end in tears.

I will repeat my rider: this is not for LNAV/VNAV use. But arming oneself beforehand is good value IMO. PPPPPP.

An academic interest of the maths and the "perfect" circuit is one thing for a spreadsheet.

Sure, use this information to understand where the FCTM/FCOM figures come from as a starting point but then you modify it by looking out the window.


BTW, the radius doesn't change if the downwind leg is in the same location each time.

People's minds work in different ways.

Some can do maths very easily and use that; others find it easier to fly visually by seat of the pants. I can do mental maths or I can fly, I can't always do both.

I did a similar thing to the OP in that during my ATPL training, I programmed a Psion (remember those?) to work out hold entry and headings etc, for me - given the wind. Of course just before a critical flying test, I dropped my Psion which jogged the batteries and my program was lost !! So I was back to mental maths and ready reckoning. (I passed the test by the way !!)

Nevertheless, I found that my hold program had been very useful to help me explore how things varied with wind, and by changing one parameter I could see how every aspect of the hold changed. Having done this and worked through many examples, I understood the dynamics and I didn't need my hold program again. Later, when I flew basic BAe146s, I got very good at flying holds on the heading bug, just using the seat of my pants. Thanks to the amount of traffic trying to get into Heathrow, I had lots of manual hold practice over Ockham !

So I don't think there is a problem with the OP working out the circling approach in this way. I don't think it means they are trying to fly the perfect circling approach, I think they are just working it out in their mind.

I sat down with a piece of paper and used my remembered school trigonometry one day to work out where the 3s per 100' would actually place me, geographically, relative to the runway. A useful exercise, since I now know roughly where to turn base using visual references without doing any maths as I fly, (and this automatically takes wind into account.)

Good luck D, but don't use your spreadsheet when flying. You will become unstuck one day if you do. Just use it to explore and understand the manoeuvre.

.

Dadanawa, While studying scenarios, by all means look at those that you feel "fit" into the ordinary possibilities, but do not avoid the extraordinary situations. In very high winds, the base turn might need to be commenced prior to reaching abeam the threshold, in order to remain within the circling area during the turn onto final. Timing is irrelevant if compliance results in busting the circling area.
It is no comfort to your widow that remaining within the circling area meant flight through unacceptable weather events like a microburst.
So it is not just a computer app, but aggressive animal survival instincts that can sometimes count.

Very thoughtful post. I'm working on the calculation for the point on the base leg turn to start descent. Calculated in time or bearing from threshold . Will keep you posted. I don't envisage ever using this down low. But it will help with getting the big picture.

How do you drive around an oval shaped roundabout to an exit you can't see? Don't try to calculate your route around L"Etoile in Paris wanting to take the 6th exit from your entry, where you start in the inside lane and need to drift to the outside one in time. After 3 revolutions in rush-hour traffic you throw away the TomTom and decide that dare & cunning works better.

complex subject
 

The complexity of circling can be found in the following links.
Circling Approach Survival Guide | BCA content from Aviation Week
Circling Approach Area