Concerning that a 20 000 hour captain couldn't fly a straight forward VOR approach remaining above the steps. Damn lucky they didn't hit anything. No GPWS with the gear hanging out either.
Looking at the chart, it appears to me to be poorly drawn. The 10 DME point appears to be on the 3 degree profile at 2500 feet. Anyone else see the potential for starting descent at 10 miles instead of 8?
"The aircraft operator’s flight crews were probably not adequately equipped to manage the vertical profile of non-precision approaches in other than autopilot managed mode"
Looking at the chart, it appears to me to be poorly drawn. The 10 DME point appears to be on the 3 degree profile at 2500 feet. Anyone else see the potential for starting descent at 10 miles instead of 8?
There are any number of approaches in Australia that have similar situations where the 3 degree final descent path starts after a DME step. I don't have access to non Australian charts to know whether this is unique to Aus or not.
Looking at my Jepp plate for CG, the shaded step is significantly below the 3 degree path line at this point. Sorry I can't paste it here to show you. Also looks like the scale is wrong - look at the 4000 line versus the 3000 shading in the profile!
Looking at the chart, it appears to me to be poorly drawn. The 10 DME point appears to be on the 3 degree profile at 2500 feet. Anyone else see the potential for starting descent at 10 miles instead of 8?
I think you're misinterpreting the chart.
At 10 DME the DME steps allow for a minimum altitude of 2500' AMSL, which provides terrain/obstacle clearance. However, to be on the 3 degree constant descent approach slope, one would be just a touch over 3000' (Descent from 3000' commencing at 9.6 DME according to Jeppesen Plate 13-2 eff 26Aug10).
The chart at Appendix D doesn't appear to be a Jeppesen chart. Whilst it doesn't give crossing altitudes for all DME, it does give enough for the approach, in my view. I'm not sure what would trigger "starting descent at 10 miles instead of 8".
Agree MW. It does appear to be a poorly depicted chart which looks like it could contribute to a crew initially interpreting descent point from 2500 at 10 dme. The Jepps chart for this approach that I have seems to depict the 3 degree constant descent profile much more clearly. The Jepps chart also has a dme vs alt table for the constant descent profile which helps with profile and support calls.
In any incident there are obviously a number of contributing factors but the chart depicted in the ATSB report is somewhat lacking in my opinion. Possibly a case of 3 degrees flight path angle selected at 10 dme, an error which went unnoticed for a while? There is mention of a new chart issued after these events, I wonder what the changes were?
This is an international airport- where is the ILS? Why did the altitude breaches not alert radar control? On one of these incidents the aircraft was below the steps for up to 6 miles after being vectored for the approach. The only query came from the aerodrome controller if I read this correctly.
This is a real worry seeing as this App is very basic stuff for an NPA. 10nm (9.6 close enuf)starting at 3000', 3 deg's slope it's about the same as any std ILS to a seal lvl drome. If these guys where at 2500' then as long as they where within tracking tolerances laterally you start down 3 deg's FPA just coming up to 8 miles & tick the boxes as you pass each dist/alt step, much like multiple outer marker check heights on an ILS. sheeeeez it doesn't get much simpler than that! Too much automation has numbed the mind as these guys can't think outside the box !
Wally, Not trying to defend anyone - just pointing out possible contributing factors not mentioned by the ATSB. Malaysian crews fly all over the world including many airports not at sea level, and/or with DME's not at the threshold, sometimes not even at the airport! Have you ever done an NPA with the DME behind you on final approach? Not easy, especially after an all nighter. Not having a DME/ALT table is a major oversight on this chart. I know how to read a chart but am pointing out why I feel this error was made. Poor chart design seems to me to be a major factor.
Not sure if it was reported this day, but I was at Bilinga visiting rellies and they did a missed approach in bad weather and managed to fly over the high rises / beach a loooong way away from where the threshold was! There's international airports all over the world that don't necessarily have an ILS. If you're not competent at flying a VOR, why should it be on your licence? Hope anyone who doesn't like VORs aren't sent to JFK!
Last edited by maggotdriver; 11th Feb 2012 at 22:23.
Reason: Grammar
Not having a DME/ALT table is a major oversight on this chart.
I agree that the chart is poorly designed, but it seems to have a DME/ALT table (immediately below the profile). Personally, I find the Jeppesen charts a much better presentation – but I want to make a more important point: an unfamiliar approach needs some preparation; pilots should not be reading an approach chart – for the first time – just prior to (or during!) an approach. Modern chart presentation is greatly improved over early efforts, but they still take some planning: when do I need to configure?; what altitude will I start descent?; what ROD/FPA will I need?; what's the critical step?; is their a step that is on or close to my path, or is the descent clearance pretty much not critical?; what do I expect to see when visual (runway a bit left or right considering final course and wind)?
My answer for the 32 VOR is to dive and drive to 3000', start slowing and configuring from 20 miles DTG to be in landing configuration by 12 miles DTG. Start dialing in a VS of 5 x GS at 9.8 DME. Keep a casual eye on the not-below heights because I know nothing is critical (100-200+ feet clearance over each step). I expect to get visual with the runway slightly to the right with about a 10 degree right turn needed to line-up for landing. I'm looking for a T-VASIS, but with a TCH of 39', I want to be one dot high (in an A330). Simple.
As my flying instructor in the early days once said. a lack of prior planning leads to piss poor performance.
Anyone else see the potential for starting descent at 10 miles instead of 8?
Sort-of. The IAF diamond is quite close to the 2500ft limit caption. But then again, the profile table clearly shows that 3000 is at 9.6 DME, 2480 at 8. Not much 3xDME going on, by the looks of it.
