DIBO wrote: ↑03 Feb 2019, 17:23
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The TUI spokesperson certainly did not wait for an official analysis to comment on TV on the circumstances & causes and even a 'structural' contributing factor, the misleading layout in that corner of the apron. And on that point, I have to agree. Maybe a dozen (slightly) similar mistakes where made in the past couple of years. But the cases I remember were in the opposite direction (from twy A1 to the apron) towards the GA parking, by small GA aircraft, where it was a total non-event to correct the taxi direction (seldom a full 180-turn was needed). So although these were total non-events, it indicates that there was a mistake waiting to happen. I hope airport management will take some actions now. Better late than never.
And the mistake of yesterday, did not have to lead to this minor incident. The theoretical 21.4m minimum rwy width to make a 180-turn, was in ideal conditions within the limit of the 29m width of the old heli-platform. Darkness, rain, poorly lit corner of the apron, without marshaling assistance, clearly were not ideal conditions.
And they almost made it, just a few extra square meters of concrete was all they needed. Must be frustrating....
I fully agree with you.
Unfortunately the blame will go straight to where it too often goes in such case and indeed one can claim they shouldn’t have attempted to make a 180 on that stretch of TWY when they realized the dead-end.
The width of the helipad is 29m but the TWY stub is only 19m wide. The min RWY width for a U-turn is when you can align your outer main gear to “kiss” the pavement edge before swinging and it couldn’t be done here.
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Also, if I’m not mistaken there is no tiller wheel for ground steering from the RHS seat. That didn’t help to make full use of the pavement available for a left turn with the driver in the left hand seat.
But, my perception is that once again an airport did not act pre-emptively. The poor taxiway system layout made this a mistake waiting to happen indeed.
It seems they were parked on stand 113, powering out in direction of that lighting pole alongside the SV museum building north of their position. You then leave the (well) lit apron and start manoeuvring into the dark. As we all know, e.g. by entering/leaving a tunnel, human eye does need time to dark adapt, from photopic/mesopic to scotopic vision.
ATIS gave light rain, wind from 360 at 6. This is in the pilot’s left frontal sector initially then, further into the turn to leave the apron, on her/his left side (window).
TWY A is equipped with green centreline lights. They were supposed to be energized and probably were, although some airports switch them On only in LVP or foul Wx.
Anyhow, these lights are directional and have a rather narrow beam. After the main turn to his right, when he could have possibly seen the first light on the centreline of TWY A1, the pilot was 80m away from it at an angle of about 45° with the light axis. This is beyond the light beam coverage. The second C/L light is 15m further away.
TWY A is also equipped with edge lights
as well as TWY F in the background. All these are omnidirectional lights, projecting blue light all around which creates what we call a “
sea of blue” making it sometimes difficult to determine where the pavement really is that these lights delineate.
So after turning right you know you will soon need to bear left onto TWY A, and a piece of wet pavement reflecting under the floodlighting invites to do just that : turn left, …. onto that TWY stub.
Vision just starting to dark adapt, cockpit windows blurred by the rain, green centreline light(s) hardly visible if at all, sea of blue, …. what else do you need for this to happen?
Now, did the airport do something wrong? Nothing that you can take them to court.
Could they do it better? Yes, for sure.
I keep on hammering this for 20 years : You may feel doing it well by putting a label “Open here” on your box, but don’t blame your customer if he doesn’t because he may have seen the box … from the unmarked side.
The two guys/gals in front are professionals and had no intention to make the news but the trap was in place.
I feel sorry for them.
H.A.