Moved from the Bolzano thread
what_next wrote:
Caused by one of the most unnecessary accidents in the history of aviation and one of the reasons I still insist that my students be able to fly non-precision approaches on pure raw-data.
Which accident is not unnecessary. But I agree, this one stuck out for many reasons, none of them good.
This accident with those totally unnecessary deaths had me loose faith in a lot of things. None of them have come back, even though today ZRH is reasonably safe with ILS’s on all sides. But politics still dominate safety in many cases.
Mooney_Driver wrote:
Which accident is not unnecessary.
With “unnecessary” I meant “easy to avoid by simply applying very basic flying skills”. At least one of those two pilots could have monitored the approach on instruments but they were both looking outside for lights six miles from touchdown.
Not that there are any necessary accidents, but there are unavoidable ones. Severe unforcast meteorological conditions (like microbursts and windshear outside typical conditions), design deficiencies of the aircraft which only manifest themselves after some time (e.g. De Havilland Comet) and similar.
Mooney_Driver wrote:
An ill designed approach which was an accident waiting to happen if used in such conditions.
That was a bog standard non-precision approach like hundreds everywhere else. I have flown it and I survived, so it can’t have been too difficult… Anyway, a different aircraft was flown into a hill at Zurich during an ILS approach not long before this one – so installing an ILS does not necessarily keep pilots from making mistakes.
Mooney_Driver wrote:
There are plenty [beginner’s slopes] I know in Switzerland,…
Me too, even my all time and forever favorite ski resort (but I have not tried the Rocky Mountains yet) has plenty of easy slopes. Take the cable cars up to the highest point (Kleines Matterhorn, 3883m AMSL – almost FL130) and you can “drive” back down all they way to Zermatt on blue and (easy) red slopes. With the most beautiful view of the whole planet. From Sion where you can leave your plane it is a two hour train ride however. http://www.matterhornparadise.ch/pdf/panoramakarten/panoramakarte_winter.pdf
what_next wrote:
At least one of those two pilots could have monitored the approach on instruments but they were both looking outside for lights six miles from touchdown.
We never really will know what they did. The Captain was apparently intermittedly looking out which is not what he should have been doing at this stage as he commented “we have ground contact” at some stage, which I suppose was out of his left hand window. He could have seen the lights of the villages ahead there, but he almost certainly did not see the runway.
Neither of them reacted to the minimum call of the automated systems nor did they level off at the minimum.
what_next wrote:
That was a bog standard non-precision approach like hundreds everywhere else. I have flown it and I survived, so it can’t have been too difficult…
It was designed to be flown in heavy wind conditions with generally good visibility. That is how it got used. The MAP was very close to the runway and at 2800 ft AMSL so if the runway was seen only approaching the MAP, a safe approach was not possible. Then, shortly before the accident, our minister of transport ordered unilaterally that all approaches at night would have to be flown to this runway unless weather observations demanded the ILS approaches available. Weather that night was marginal to say the least, even though observations taken for the ILS runways indicated it was possible to land. 2 Saab 2000 airplanes managed to land after almost going missed and after taking a sharp dip to the runway after seeing it just before the MAP, which was way too close to the runway to be useful. Even before the crash, there were severe misgivings about the way this approach had been misapropriated on political grounds, the most clear of all was that the use of it violated any sort of best use of equipment and ressources doctrine. That airplane should not have had to use this approach, there was NO reason for it other than the political ambitions of our transport minister, some of which I consider treason. He should have been charged with at the very least manslaughter as a consequence, imho possibly with stronger stuff too.
It also did not help how Crossair’s procedures were. On a NPA they put the go around altitude into the altitude window instead of the level off altitudes and then flew the approaches with VS. Therefore there was no armed altitude at which the airplane would level off.
Clearly, at the end the responsibility and fault lay with the PIC and his FO. (The FO had been a trainee of that captain at a time, which did not help either) . But the pre-conditions were set by political forces.
Following the accident the approach was changed, the MAP was moved back to where the 3° glide to the threshold intercepted 2800 ft. Minimum visibility to use the approach was increased from 2km to 4km. Thankfully, in the mean time the ILS has been comissioned which is a huge improvement not only because there is vertical guidance but also because it is more to the south over less threatening terrain.
what_next wrote:
Anyway, a different aircraft was flown into a hill at Zurich during an ILS approach not long before this one – so installing an ILS does not necessarily keep pilots from making mistakes.
That DC9 crashed because the Crew followed a dead needle into the ground and omitted any form of cross checks DME vs ALT. ILS 1’s glideslope did not work, however there was no flag and the GS needle showed centered. GS 2 indicated correctly. When they intercepted the LOC, the Captain selected both receivers onto the defective No 1 ILS receiver so the airplane entered a standard descent profile but was not following the GS. It started descending way out rather than at the 8 NM point where the GS intercepts the Final Approach altitude. When the FO tried to tell the PIC several times that he was uneasy, he was overruled. Even when the FO commanded “Go Around” shortly before impact and began to execute it, the Captain forcibly stopped him. His last words were “no, no, on glideslope”.
I was on duty that day and experienced the aftermath. One guy I know overflew the crash site in a biz jet and had to divert to Basel after raising the alarm.
Clearly, no ILS will prevent such accidents.
Peter wrote:
Re that DC9 discussion, I wonder if there should be a new thread, because it seems relevant.
Maybe. Both accidents, the Bae146 and the DC9 could have been avoided by checking distance versus altitude. Which is how everybody is trained in every flying school anywhere.
Mooney_Driver wrote:
It also did not help how Crossair’s procedures were. On a NPA they put the go around altitude into the altitude window instead of the level off altitudes and then flew the approaches with VS. Therefore there was no armed altitude at which the airplane would level off.
I have never done it any differently from that, whatever and wherever I was flying. This is not Crossair’s procedure, this is “how it is supposed to be done”.
Mooney_Driver wrote:
It was designed to be flown in heavy wind conditions with generally good visibility.Can you explain what that means? I have never seen approaches specifically designed for heavy wind conditions.
The MAP was very close to the runway and at 2800 ft AMSL so if the runway was seen only approaching the MAP, a safe approach was not possible.That’s the usual placement of the MAPt for non-precision approaches. The fact that you can’t make a safe landing if you get the runway in sight shortly before the MAPt was one of the reasons for CDFA.
I think the referenced post has a “not” missing.
Almost all MAPts, 2D or 3D, are at the threshold these days.
I think the main reason is so that RNAV approaches will continue to give guidance to the numbers, which was part of the discussion @what_next referenced about following the needles even when visual criteria are officially met.
You still go around if you don’t have reference at DA/MDA, of course.
Whatever happened, you couldn’t put the MAPt at the point where the slope intercepted the DA/MDA, because that varies by aircraft category, equipment carried and crew training and qualification.
