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WIZZ AIR Skiathos vid

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WIZZ AIR Skiathos vid

Old 13th Aug 2022, 14:31
  #141 (permalink)  
 
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Originally Posted by topgas
Image from 2013, as the Greek Govt have helpfully pixelated all their airports in current views. Looks like the piano keys have been moved. Yellow line is 300m
See earlier posts with AIP runway data: 01 (formerly 02) has a 58 m displaced threshold, which matches those "phantom" piano keys.

So presumably at one point in time it didn't, although historical GE imagery is inconclusive.

Edit: painted-out original piano keys more clearly visible here:

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Old 13th Aug 2022, 14:38
  #142 (permalink)  
 
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I note from the above picture that the aiming point is the first marker and, I assume, 500ft past the threshold, half the usual length. Does that mean that the correct threshold crossing height would be 25ft instead of 50ft?
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Old 13th Aug 2022, 14:45
  #143 (permalink)  
 
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Confusious,
1-4
But I doubt that posting a link to Pprune would have the desired (any) effect !
Also, with sceptical demeanour, what hope of action; any past histories of similar issues.

“… but it wasn't a mistake not to have executed a Go-Around”.
but your quote ‘mistake’ is constructed with hindsight; is that a mistake …

The professional core of this thread appears to conclude that the operation is safe without intervention (my conclusion without further justification).

So why are some operations experiencing such variability in TCH at this airport
N.B. previous long video of many approach and landings.
Back to # 102. Upslope, visual approach, oversea, PAPI, and # 142

For info; ‘A Study of Normal Operational Landing Performance on Subsonic, Civil, Narrow-Body Jet Aircraft During Instrument Landing System Approaches’, DOT/FAA/AR-07/7

Chart of ‘estimated’ TCH from precision approach landing measurements.
A sample ≈ 1% of total.

Caution; datum ref not known. wheel ht, ILS deviation at 50ft RA, or cg.
probably ILS - RA thus wheel ht would be less, cf touch down.



Last edited by safetypee; 13th Aug 2022 at 15:06.
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Old 13th Aug 2022, 15:06
  #144 (permalink)  
 
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But I doubt that posting a link to PPRuNe would have the desired (any) effect !
Also, with sceptical demeanour, what hope of action; any past histories of similar issues.

I don't have a desired effect and don't believe that there is a course of action required. As said in a previous post, normal approaches don't attract YouTube videos and media attention. Also posted previously by Down Three Greens was evidence that the performance numbers stack up.

I assumed from your comment about an App for filing reports that you wanted to, hence the links. Perhaps that was another 'mistake'. 🤔
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Old 13th Aug 2022, 15:08
  #145 (permalink)  

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Originally Posted by Doors to Automatic
I note from the above picture that the aiming point is the first marker and, I assume, 500ft past the threshold, half the usual length. Does that mean that the correct threshold crossing height would be 25ft instead of 50ft?
That means the confusion on how to use the aim point markers is still prevalent.

You don't. They are rarely painted where you need them.
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Old 13th Aug 2022, 15:46
  #146 (permalink)  
 
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Originally Posted by AirportPlanner1
Possibly worth saying there’s airlines and crews that have been operating into JSI for years without a hitch. Wizz come along and within a couple of months they’ve managed to get themselves mainstream news coverage, a viral video and long thread on here.

Mass tourism at current levels won’t be sustained if people are flown into Volos with a coach and ferry transfer. More so for those that transfer on to Skopelos. In turn the island’s fragile economy tanks. Politically closing or restricting JSI is a non-starter. Discussing it is a waste of time.
No publicity is bad publicity or so I was told

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Old 13th Aug 2022, 16:02
  #147 (permalink)  
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Originally Posted by safetypee
Confusious,
1-4
But I doubt that posting a link to Pprune would have the desired (any) effect !
Also, with sceptical demeanour, what hope of action; any past histories of similar issues.

“… but it wasn't a mistake not to have executed a Go-Around”.
but your quote ‘mistake’ is constructed with hindsight; is that a mistake …

The professional core of this thread appears to conclude that the operation is safe without intervention (my conclusion without further justification).

So why are some operations experiencing such variability in TCH at this airport
N.B. previous long video of many approach and landings.
Back to # 102. Upslope, visual approach, oversea, PAPI, and # 142

For info; ‘A Study of Normal Operational Landing Performance on Subsonic, Civil, Narrow-Body Jet Aircraft During Instrument Landing System Approaches’, DOT/FAA/AR-07/7

Chart of ‘estimated’ TCH from precision approach landing measurements.
A sample ≈ 1% of total.

Caution; datum ref not known. wheel ht, ILS deviation at 50ft RA, or cg.
probably ILS - RA thus wheel ht would be less, cf touch down.



Was an interesting study. It used an estimate of the the flight path down low based on the D/S deviation which has some issues, but at least the methodology was retained for all cases. The G/S signal is not a linear transmission in close, it has a scallop from ground plane effects that is factored into the siting and calibration of the aid. works fine out at 200' normally, (except where there is any anomaly that affects the ground plane, thinking flooding of a plain out at midfield, was a habit at U-tapao in the wet. The cues to the bus assist in reducing speed variability, which helps with touchdown dispersion, however the vertical distribution is tighter on the B737 than the bus. The approach attitude and body lengths in the study would give some effects there.

If the CEOs want the guys to operate into these airfield, then give them good HUD's, a dialled in desired FPA and a live FPV gives a much more accurate finals and minimises the spread of the touchdowns. The collimated displays are great, but lightweight and effective HUDs are available if there is a desire to reduce the need for the cone of shame.


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Old 13th Aug 2022, 16:29
  #148 (permalink)  
 
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Confusious; touché

fdr
If the CEOs want the guys to operate into these airfield, then give them good HUD's, …

HUD has many positive attributes, but why install expensive new systems without first understanding the issue; and - is there a problem requiring that type of solution.
Fix the PAPI; required flt path vs flt path required; ground to air (PAPI) or air to ground (HUD).
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Old 13th Aug 2022, 19:48
  #149 (permalink)  
 
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Originally Posted by Confusious
Absolutely correct, and in a lot of airlines this would be a 'chat with no tea and biscuits' event. I can't believe how all the spotters stayed put!
It seems that, with a 1600m runway, it's tea and biscuits any way you try to land there. If they flew at 50ft over the threshold, they would have made a "high speed at runway end event"..
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Old 13th Aug 2022, 19:58
  #150 (permalink)  
 
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Originally Posted by CVividasku
It seems that, with a 1600m runway, it's tea and biscuits any way you try to land there. If they flew at 50ft over the threshold, they would have made a "high speed at runway end"..
​​​​​
How could 50' over the threshold lead to a high speed event?

Last edited by Confusious; 13th Aug 2022 at 20:16.
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Old 13th Aug 2022, 20:16
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Originally Posted by Confusious
Originally Posted by CVividasku
It seems that, with a 1600m runway, it's tea and biscuits any way you try to land there. If they flew at 50ft over the threshold, they would have made a "high speed at runway end

How could 50' over the threshold lead to a high speed event?
The margin are very low.
Touch down slighly further than the 300m mark, or fail to fully and immediately apply the max manual braking and full reversers, the opposite end of the runway will come at you very quickly.
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Old 13th Aug 2022, 21:10
  #152 (permalink)  
 
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Originally Posted by CVividasku
The margin are very low.
Touch down slighly further than the 300m mark, or fail to fully and immediately apply the max manual braking and full reversers, the opposite end of the runway will come at you very quickly.
So, if your flying technique into Skiathos is to cross the threshold lower than 50', then what is your target height at the threshold and what height do you start the flare?
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Old 13th Aug 2022, 21:18
  #153 (permalink)  
 
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Originally Posted by CVividasku
The margin are very low.
Touch down slighly further than the 300m mark, or fail to fully and immediately apply the max manual braking and full reversers, the opposite end of the runway will come at you very quickly.
Nope. You will stop comfortably with config full, auto brake medium and normal reverse in the A321. Just don't try to grease it.

Plenty of examples of how it should be done can be found here.
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Old 13th Aug 2022, 22:40
  #154 (permalink)  
 
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Plenty of examples of how it should be done can be found here.
And none of them crosses the threshold at 50 ft. There was a beautiful one by Ryanair in pissing rain. Touchdown point similar to the Wizzair but they didn't drag themselves in like Wizz.

Saying that you should land the same way regardless of runway is too easy of an answer. If the runway is short, contaminated and the plane is heavy there is good reason to choose a visual aiming point short of the "normal" touchdown point. Whatever "normal" is, because the PAPI in Munich takes you to a different touchdown point than the PAPI at Skiathos.
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Old 14th Aug 2022, 06:48
  #155 (permalink)  
 
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Originally Posted by 172_driver

If the runway is short, contaminated and the plane is heavy there is good reason to choose a visual aiming point short of the "normal" touchdown point.
Can this sage advice be found in your OM-A? Does your training department advocate these techniques?
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Old 14th Aug 2022, 07:07
  #156 (permalink)  

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Originally Posted by 172_driver
Whatever "normal" is, because the PAPI in Munich takes you to a different touchdown point than the PAPI at Skiathos.
There may be other threads on professional pilots forums (somewhere?), trying to explain why the aiming point for an AFM-compliant landing is independent of the PAPIs due to their varying location. Cue in the name: Approach Indicator.

Just saying. If only someone drew a meme for it, easier to remeber.



​​​

Last edited by FlightDetent; 14th Aug 2022 at 13:15.
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Old 14th Aug 2022, 08:40
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Can this sage advice be found in your OM-A? Does your training department advocate these techniques?
Not found in the OM-A. Not sure landing technique is described at all in the OM-A but in more operational documents, such as FCTM.
The training department condones free thinking and risk mitigation. When then the situation so warrants, you are not confined to a narrow tunnel of operating practices.

There may be other threads on professional pilots forums (somewhere?), trying to explain why the aiming pint for an AFM-compliant landing is independent of the PAPIs due to their varying location. Cue in the name: Approach Indicator.
What I think you're getting at is reachig AFM landing data?
Where my opinion deviates from others' opinion seems to be only one way of landing and always cross the threshold at 50 ft. It may be in part semantics, as the landing maneuver will look similar in profile view regardless where the trajectory will take you (and where the RA starts to shout). The amining point markers at Skiathos is about 150 m from the threshold. Runways with a length above 2400 m (is it?) has the aiming point markers at 450 m past the threshold. The threshold crossing heights can't be the same, if your objective is to land at the aiming point. The performance in-flight calculations for Actual Landing Distance from 50 ft doesn't care about the runway length. By going for the makers at Skiathos, you've earned yourself a couple of hundred meters compared to the performance figures, but you haven't crossed the threshold at 50 ft.

The video above shows many good (and similar looking) landings at Skiathos with touch downs at or near the aiming point markers. What they all have in common is the threshold crossing is a lot lower than landings at longer (and maybe wider) runways.
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Old 14th Aug 2022, 08:41
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Originally Posted by 172_driver
Saying that you should land the same way regardless of runway is too easy of an answer. If the runway is short, contaminated and the plane is heavy there is good reason to choose a visual aiming point short of the "normal" touchdown point.
I’m pretty sure your landing performance is calculated based on a normal technique, and not aiming for the piano keys. And if the (these days factored) numbers say you can make it, why apply a different technique and expose yourself (and your passengers) to additional risks?
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Old 14th Aug 2022, 09:10
  #159 (permalink)  
 
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The discussion on PAPI, #142 onwards is intriguing; as is the continuing views of ‘normal’.

Adding to the PAPI issue, is the setting of the angular change between white and red, which adjusts the sensitivity of the aid; e.g. crossing the road 3R 1W - a ‘minor’ (unseen) transgression is a small height difference on a ‘tight’ setting, but a larger height difference on a ‘wide’ setting. Not forgetting that this relates to the height of the cockpit, and not the wheel height judged by video.



If aiming to land at the normal touchdown point is safe, then why advise to aim short of normal on a ‘wet’ runway, if it is ‘less safe’, (increase undershoot risk vs perceived increased risk in landing distance for a wet runway). ‘Wet’ is one view, ‘contaminated’ another, but not the same.
This is another SOP double bind; the procedure makers move responsibility down to the crew - no right answer, except by judged outcome.

Where does the perception that risk is increased on wet runways come from; the published landing distances show adequate margin.

[One view is that wet runways landing distances do not always have equivalent distance margins as for dry - a view which I subscribe to, debatable elsewhere - , but not requiring a change in aiming point.]
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Old 14th Aug 2022, 09:19
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What I would say is, have a look at where the touchdown aiming point markers are in the runway, then tell me how low you have to be to get those in the right place in the windscreen?
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