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-   -   11 miles out @ 530 feet AGL (https://www.pprune.org/rumours-news/490907-11-miles-out-530-feet-agl.html)

FlightPathOBN 23rd Jul 2012 17:09

Sorry, but it is a 1000' ROC on initial segment, 2000' ROC if mountainous...
(note the MSA is 4700, indicating a 2000'ROC)

From the instrument procedures handbook...

here is that turn illustrated...


aterpster 23rd Jul 2012 21:01

FlightPathOBN:

You're mixing PANS-OPS and TERPS. The MSA at UIII is PANS-OPS.

The illustration you show is a DME ARC from TERPs with 1,000 feet of ROC, because it is an initial approach segment. Nothing is stated about Designated Mountainous Areas.

You obviously don't work with U.S. TERPs or you would know that initial approach segments are a minimum of 1,000 feet ROC; DMA or not.

Feeder routes are de facto airways with a minimum ROC of 1,000; 2,000 in DMAs.

MSAs are always 1,000 feet im the U.S., because they are not operational altitudes.

FlightPathOBN 23rd Jul 2012 21:06


FBO:

Quote:
Intermediate segments are 500' ROC, and Initial segments are 1000' ROC unless mountainous, then 2000' ROC...
Correct?
Correct as to intermediates. Not correct as to initial approach segments.
you said this...

aterpster 23rd Jul 2012 23:50

FlightPathOBN:

Go look at Page 1 of the 8260-9 for Dillon, Montana, RNAV 35. This airport is in the Western DMA. Note the feeder ROC is 2000, the initial segment ROC is 1000. This is the same for everu 8260-9 for IAPs in the DMAs of the U.S.

https://www.faa.gov/air_traffic/flig...ifp&nasrId=DLN

FlightPathOBN 24th Jul 2012 00:13

Are you high???!

I have stated all along that initial segment ROC's are 1000, and 2000 if mountainous...

you disagreed...

the MSA calculations for PansOps is the same as TERPS..

back to the point.....

why didnt the aircraft get a prox warning, when it was 540 ASBL and on initial?

autoflight 24th Jul 2012 00:41

In approach configuration, the GPWS announcement could be as simple as "too low flap".

safetypee 24th Jul 2012 00:49

FP OBN, are you assuming EGPWS. Isn’t more likely that this airframe had T2CAS ?

aterpster 24th Jul 2012 12:33

FlightPathOBN:


I have stated all along that initial segment ROC's are 1000, and 2000 if mountainous...

you disagreed...
OF course, I disagreed. Here is the FAA worksheet for KDLN RNAV 35. The ROCs shown are standard for a mountainous area: (Or, did the FAA design and complete their work record incorrectly?)

http://i201.photobucket.com/albums/a...AV358260-9.jpg

scrubba 25th Jul 2012 07:27

FMC vs (E)GPWS
 
I think FlightpathOBN is mistaking the source of ground prox warning as coming from the FMC :=, rather than from the purposely independent (E)GPWS :ok:.

There also seems to be a miscommunication :uhoh: about required obstacle clearances for enroute feeder routes in DMAs (2000') and initial approach segments (1000' anywhere).

BOAC 25th Jul 2012 07:54


rather than from the purposely independent (E)GPWS
Indeed, scrubba, but I fear that the 'independence' is being progressively blurred as systems like T2CAS and TAWS or any terrain mapping system become commonplace, deriving information as they do from the FMC.

Apart from 'lost' or some misguided 'dive and drive' approach, does anyone have any idea why they descended before the FAF? The '530' AGL reported puts them at around 2800-3000' QNH at 11.5nm

PJ2 25th Jul 2012 13:18

BOAC;

Apart from 'lost' or some misguided 'dive and drive' approach, does anyone have any idea why they descended before the FAF?
Yes. I provided three separate posts, (here, here and here) on ideas why they descended before the FAF and provided links to two EGPWS documents. I said that I had recently seen this occur once again and gave the reason why it occurred, (glidepath failed to the centered-position - crew followed it). ;)

TAWS (EGPWS) and, I assume T2CAS, have Premature Descent Alerting (PDA) if the aircraft is in the landing configuration but descends below a nominal, internally-generated 3deg glidepath. Inside 12nm, a "Too Low Terrain" warning would not occur until 400ft RA.

http://batcave1.smugmug.com/photos/i...-hDbQ6Bs-M.jpg

BOAC 25th Jul 2012 14:06

Yes, I saw those, but it is the gross discard of the fact that they probably had been looking at a centred GP for a while, and probably had only just rolled out on the LOC I cannot understand. That's where I need the 'theories'.

Incidentally, I wonder if the ANZ crew were 'senior' management? The video showed a fairly relaxed company attitude to the poor approach preparation (described as thorough) and misunderstanding of 'unmonitored'. I would like, as I said earlier, to have seen the NOTAMS for UIII that day too. The first warning flag for the ANZ crew should have been the ILS NOTAM, and a firm DME/GP descent point briefed. Again, the ANZ video casually 'slips' in the fact that no GP intercept crosscheck was made - makes you wonder! Was it even briefed?

Are we really at that low a level of skills?

fantom 25th Jul 2012 14:12


Are we really at that low a level of skills?
How many times have you met a self-sponsored crew for a type rating course and sighed in dispair?

Not everyone has proper training, as you very well know. What is going on the the ME and Asia, I don't like to think about.

BOAC 25th Jul 2012 14:34

Agreed, but rather worryingly I was thinking of ANZ................................

BOAC 25th Jul 2012 14:54


Late descent, poor approach briefing, casual attitude, complacency, non-stabilized rushed approach, poor-to-non-existent CRM, poor monitoring by the PM, some or all of which may have contributing to non-existent altitude awareness, ignoring the information available on the PFD and esp. the ND, and a descent which blew through the FAF altitude.
- probably all those indeed. quite a liturgy.

How does it go? "Learn from others' mistakes before you die from yours"?

PJ2 25th Jul 2012 15:00

BOAC;

That's where I need the 'theories'.
Again, like aspects of AF447, I don't think it's complex or complicated.

Having flown the A320 and the A330 for many years, I can't, for example, accept many of the criticisms of the airplane, (meaning, in the case of AF447, up to the point of stall the A330 was not an elusive, inscrutable, opague machine which would have hid things from knowledgeable and disciplined pilots, (but may have for this crew)). So with what I think are rare exceptions, (the ATR-72 aileron reversal...the CRJ hard-wing icing issue), I don't think the design of today's airliners are significant contributors to accidents.

On theories regarding why the early descent?

Late descent from cruise altitude (leading to rushing on the approach), poor approach briefing, casual attitude, complacency, non-stabilized rushed approach, poor-to-non-existent CRM, poor monitoring by the PM, poor command leadership in managing threats and errors, etc, etc., some or all of which may have contributed to the obviously non-existent altitude awareness, ignoring the information available on the PFD and esp. the ND, and an early descent.

In the one I'm familiar with, even the fact that when the airplane was leveled off and the glideslope remained centered didn't clue them in that it had failed. Why?

I am not a scientist, psychologist, MD so although I have some ideas, I don't know the actual cognitive sources or processes which make such absence of awareness possible.

All I know is that the overt signs of such losses of awareness are in the list above and, like dozens of other early descents without awareness, almost resulted in another CFIT.

Further, both of us know that everyone who flies is a candidate for the same mistake so believing one is too good to fail or that these kinds of serious incidents happen to others "but I'll never do something that stupid", are big danger signals.

Oddly, we read this and "know" it, but don't truly know this until something serious happens to us which has no serious outcome; all of a sudden, "we", "us"...we are fallible and that is the magic turning point in every aviator's life when but for (fill in the blank), "I" would be dead now. Some can imagine it and learn early before the airplane teaches one, but some pilots just have to pee on the electric fence.

Any pilot-training program that doesn't contemplate these things in terms of addressing them is not doing the job.

Edit: Yes, a huge and needless liturgy!

contractor25 29th Jul 2012 08:46

what happened to the very basic 5 x groundspeed is rate of decent in feet?

It gives a crude figure, it would have certainly made this crew realise quicker that something was not right.

BOAC 29th Jul 2012 09:28

c25 - remember we do not know where they started their descent on the 3.3 GP?


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