Planned CFIT?

[Starbear]

Bart

VOR X 13, the suffix X means it is a circling approach (it can be any suffix: A, B, C,....)

I have to confess, I never knew that, about the suffixes I mean. I thought I had been around a long time too. rather embarrassing

1120 at 4.5 DME is a 3.2 degree slope, that is no problem.

I agree it is not as steep as I first thought as I was using 4.5 D =2.8nm to threshold but I see now it is 3.1 as first stated by BOAC,apologies.

These discussions are without doubt an example of the huge benefits of sites like these.

[BOAC]

Seconded. A useful discussion - and polite too. A rarity these days here.

[point8six]

SEZ rwy 13 requires careful planning, not only in how the approach to a visual conclusion will be flown, but the fact that as a destination it requires " island reserve fuel". In other words, if the weather is marginal, the alternate is at least 2 hours away. If the weather is indeed marginal in terms of cloudbase and surface wind, then it is a difficult decision to make, whether or not to 'press on' or divert from a reasonable altitude. If the approach is to be attempted in such conditions, then it needs precise flying and I would suggest the possibilty that GPWS warnings are triggered when 'going visual' and inadvertently increasing the RoD to slot into the rather dim PAPIS. At that time, the aircraft is pointing more at the cliff immediately south of the runway.

[alf5071h]

… the possibility that GPWS warnings are triggered when 'going visual' and inadvertently increasing the RoD

I assume that the onboard equipment is “Enhanced GPWS”. If so, then an alternative is that the ‘look ahead’ function could detect the hill as the turn is made towards it. If this is truly a nuisance warning, then Honeywell, when provided with aircraft type and example alerts (downloadable from the EGPWS box), may be able to adjust the terrain database whilst still maintaining a safe warning boundary.

There have been several EGPWS incidents involving the types of misinterpretation or misjudgement indicated in this thread – except that they occurred in flight with much higher safety risk. The statistics involving unwarranted alerts also suggests that there could be many more incidents involving these problems, except that they may not be reported or investigated.
With EGPWS there is no such thing as a false warning – there is always a reason for it. Always react to a warning by climbing to a safe altitude; then and only then consider the reasons for the alert, don’t assume - check.
So that the industry may learn, as above, submit an incident report, download the EGPWS data, investigate, and publish the results. In my experience Honeywell have always been most receptive to helping in these processes.

I hope that an operator to SEZ will submit a safety report on the poor chart format; it should be changed.
I suggest that any other approach chart showing similar problems be listed in this forum. Please only post the identifier with a link – not a picture; I still used dial-up internet, and then at half speed!

[OzExpat]

I still used dial-up internet, and then at half speed!

Me too alf. The problem is, however, that the specific problems with an approach are usually best seen with a picture. A verbal description just can't do it the same justice without being an overly long post detailing location and nature of obstacles as well as tracks and altitudes.

I have the same problem as you but accept the problems associated with the extra download time, for the sake of seeing the picture. One picture is still worth a thousand words and, as my internet access is probably the most costly in the world (not to mention least reliable!), the picture is also worth a thousand sheckels... or something.

[reynoldsno1]

B763 in landing configuration, on speed and check list completed. A/P on leaves 2500ft at SEY11d in V/S rate 700 ft/min down to 1120 ft. Backed by GPS the fellow is accurately tracking on R324 inbound.
At SEY8.5 passing 1600ft “Terrain Pull Up Terrain” GPWS warning and another one bites the dust!!!!!

Stuff up - the chart quite clearly shows the OCA is 1760 ft to D6.5. This procedure is definitely not a straight-in approach, nor is it circling really. A "cloudbreak" or "point-in-space" procedure is normally prescribed to enable IFR aircraft to establish visual reference for VFR flight to the aerodrome. They most definitely are not stabilised approaches, and trying to fly or code them using the FMS/FD is going to create more problems than solutions.

[alf5071h]

OzExpat, the charts could be linked, which enables download in quite periods or when reading other threads in Pprune.

I don’t have the plates for the following, but I would be interested if there have been any changes.

1. Ajaccio; see the link and incident report - ‘Ajaccio near CFIT’ and the graphic below.

2. Gibraltar, where the radar to visual procedure has no published missed approach in the event of loss of visual contact after the turn, and a procedure that enables ATC to reduce the intensity of the strobe lights when visual contact is called.

[OzExpat]

the charts could be linked, which enables download in quite periods or when reading other threads in Pprune.

Sounds fair to me.

Ajaccio; see the link and incident report - ‘Ajaccio near CFIT’ and the graphic below.

I tried to download it but the file was corrupted - probably because of the slow linespeed. I can't afford to try that download again but the graphic reveals a most interesting approach for sure!

[planoramix]

Dear Reynoldsno1

I agree with Your statement but then, what of the depicted level flight from SEY 6.5 to SEY 4.4?
Is it not strange for the 1760ft OCH to appear lower than the supposedly 1120ft minima at SEY 4.5?


The Jeppesen chart appears to have all the required "vital" informations relative to the instrument portion, looks like another approach altogether, hence:

Can an unsafe approach plate make it into the destinations binder?

Considering that the approach plate has been withdrawn 11 days after first appearance ....................................


-----------------
more notams limiting use of approach plates in SEZ have been issued, apparently GPWS achitecture was not taken into consideration by the artist.

[BOAC]

While I agree the vertical profile appears to have been drawn by a lunatic, I do not see the plate as 'unsafe'. Anyone who launches in there, seeing a terrain envelope of 2500' on the approach and 4000' just right of centreline and is not aware, prepared and briefed for the terrain on the chart....................? To then dive straight down towards (presumably?) 1120' with no apparent terrain awareness defies belief.

Of course there will be possible EGPWS issues, especially if you turn towards finals from MAP, but again, terrain in sight - expected, prepared and briefed? Not very different to FNC in that respect. I would not expect any GPWS warnings (apart from a possible 'Terrain') during a correctly flown inbound descent.

Again, surely each operator will have a specific brief for such a destination? Was there one for that 763?

[reynoldsno1]

I agree with Your statement but then, what of the depicted level flight from SEY 6.5 to SEY 4.4?
Is it not strange for the 1760ft OCH to appear lower than the supposedly 1120ft minima at SEY 4.5?

It doesn't actually - the shaded portions (very faint) represent the OCA. The profile depiction is diabolical, and doesn't really represent anything - I suspect they didn't really know what to do. The JEPP depiction is better, but follows the dive and drive principle.

A 5% descent gradient (300ft/NM) to 1120ft does not work as you will be 1720 ft at D6.5 - IMHO would have been better to publish a 5.2% gradient (3 deg/320ft/NM)) profile back from 1120ft at D4.5 (and publish the descent angle) - 1760ft @ D6.5 and 2880ft @ D10.0 - with a distance/procedure advisory altitude table to match, or the procedure altitudes at the relevant distances, or both!

Be careful out there....

[bookworm]

The profile depiction is diabolical

I think you're being overly generous. The devil plays fairer than that.

Not only are the 1760 and 1120 numbers depicted at the wrong end of the segment, but the profile appears to descend from 11d. No level is given for the FAF. That makes it even more plausible that the 1760 number is the minimum height at the 10d FAF rather than at the 6.5d SDF as is really the case.

[Jumbo Driver]

Apologies for my late arrival to this thread - a fascinating discussion, which I confess I have only just come across.

My recollections are of early (1972-on) trips to Seychelles (SEZ) in the VC10, very soon after the new airport at Mahé was opened. As the VC10 was not equipped with GPWS in those days, a "straight-in" approach to R/W 13 over the hills was often used. This certainly was exciting but of course had to cease with the introduction of GPWS. Does anyone else recall these "fun" arrivals?

Originally Posted by point8six

Landed many times on SEZ rwy 13 -(since 1978). Mostly either visual, arriving from the west, or from the south via a published circling approach, breaking off from the Rwy 31 ILS at 1120ft. into a left-hand circuit with published VOR radials and DMEs. The difficulty in lining up occurs with a strong SE wind due to rotors from the cliff to the south of the runway and strong downdrafts.

I agree; many of my later landings would involve this break-off from ILS or VOR/DME instrument approach to 31, followed by the published visual LH circuit (night or day) round St Anne's island, with VOR / DME checks.

Originally Posted by point8six

A "fun" approach in a large aircraft along with JFK -Carnasie 13 and the old Hong Kong (Kai Tak) IGS 13

Yes, these were indeed all "fun" approaches. Incidentally, I have often thought it strange that all these "curved" approaches were also all, quite co-incidentally, on to a Runway 13 ... ?


JD