Airblue down near Islamabad
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I always turned the egpws off once visual in the valley at TGU Honduras. It always started going off on base leg next to the hills so was a distraction. It is much easier to turn it off at 3,000 ft rather than 400 ft on base leg. TGU made the second most dangerous airport airport in the world last week on that 2 hr history channel program last week. Once you see the terrain you don't need it any more. I wonder why they flew into terrain. It couldn't happen at TGU because everybody was looking out the window, not fiddling with automation.
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The Question is: can you disable IRU updates on your Glass Boeing or y. Glass Airbus?
Iceman50 raised a bullshat flag. Good. Since I have never flown a Glass Boeing I wasn't aware that 757/767 had 18 mile map shifts on the procedure turn.
But I stlll need the questioned answered: on Glass Boeings can you disable automatic nav updates after you I.D. the primary navaid and commence approach? Of course in the developed world, maybe the navaid maintenance is good enough that you don't need to do this.
I have already explained that the first airbuses were not really designed for disabling auto updates; and initially, with many carriers, this precaution was not taken.
Although map shifts are increasingly rare in the Western world, they are not unknown in the developing world. I keep citing the first Airbus because that is where Toulouse cut it's teeth on Glass. IIRC, the honeywell FMC box would take a polling of all three IRU's and then average their position for the new center IRU position. Then it would skew the map with updates based on a complex algorithm. If one IRU update position was skewed 50 miles the wrong way because it decided to update itself off a VOR in a war torn country which was overheating, the whole moving map central position might get moved 5 to 10 miles the wrong way (depending on geometry and other logic).
Right?
Yes, you're supposed to keep the runway in sight. but if your moving map says you are close, it is a prelude for overconfidence. It was well documented in July, and August 1995, I believe, AW&ST that Airbuses where designed to reduce crew workload but instead, vastly increased it.
Last minute runway changes are the devil for a green First Officer to deal with. A new F/O will be damn lucky to get all his crap done before base turn. His head is now down pushing buttons and nobody is watching if his Airworthiness is even still alive over there. With that cursed sidestick he's already slumped down on the armrest like a patient donating blood at the Red Cross. How would the pre-occupied F/O even know if he was having a stroke? Who's watching him?
Only ATC is watching him, and one poster said they tried to save him.
Who's listening to the morse code?
Nobody.
Who's looking at the raw DME to see if it jives with the Moving Map?
Nobody.
Who's looking out the front windscreen while the old boy is looking over his shoulder behind him trying to reacquire the threshold?
Nobody
Crunch
Note: All my posts are just my opinion only.
But I stlll need the questioned answered: on Glass Boeings can you disable automatic nav updates after you I.D. the primary navaid and commence approach? Of course in the developed world, maybe the navaid maintenance is good enough that you don't need to do this.
I have already explained that the first airbuses were not really designed for disabling auto updates; and initially, with many carriers, this precaution was not taken.
Although map shifts are increasingly rare in the Western world, they are not unknown in the developing world. I keep citing the first Airbus because that is where Toulouse cut it's teeth on Glass. IIRC, the honeywell FMC box would take a polling of all three IRU's and then average their position for the new center IRU position. Then it would skew the map with updates based on a complex algorithm. If one IRU update position was skewed 50 miles the wrong way because it decided to update itself off a VOR in a war torn country which was overheating, the whole moving map central position might get moved 5 to 10 miles the wrong way (depending on geometry and other logic).
Right?
Yes, you're supposed to keep the runway in sight. but if your moving map says you are close, it is a prelude for overconfidence. It was well documented in July, and August 1995, I believe, AW&ST that Airbuses where designed to reduce crew workload but instead, vastly increased it.
Last minute runway changes are the devil for a green First Officer to deal with. A new F/O will be damn lucky to get all his crap done before base turn. His head is now down pushing buttons and nobody is watching if his Airworthiness is even still alive over there. With that cursed sidestick he's already slumped down on the armrest like a patient donating blood at the Red Cross. How would the pre-occupied F/O even know if he was having a stroke? Who's watching him?
Only ATC is watching him, and one poster said they tried to save him.
Who's listening to the morse code?
Nobody.
Who's looking at the raw DME to see if it jives with the Moving Map?
Nobody.
Who's looking out the front windscreen while the old boy is looking over his shoulder behind him trying to reacquire the threshold?
Nobody
Crunch
Note: All my posts are just my opinion only.
Last edited by Captain-Crunch; 29th Jul 2010 at 03:56. Reason: disclaimers
Crash site location thanks to Machaca, aterpster, BrooksPA-28. Brooks, your lat and long are probably the more accurate - this is a small amount further West, now that I look at it. The lat/long in the image below is in decimal degrees. Machaca's posted photo below, to compare.
The chart from aterpster showing the protected circling area indicated is helpful if only to see how far outside the circling area the crash site is. Wally Roberts' discussion of FAR and ICAO PAN-OPS Circling Procedures is well worth reading and may be found here, (1996) and here, (1997).
Cap'n Crunch, well said.
PJ2
The chart from aterpster showing the protected circling area indicated is helpful if only to see how far outside the circling area the crash site is. Wally Roberts' discussion of FAR and ICAO PAN-OPS Circling Procedures is well worth reading and may be found here, (1996) and here, (1997).
Cap'n Crunch, well said.
PJ2
PJ2
Thanks for bringing some good factual information to this thread. There has been far too much (yet again) idle speculation from too many of the contributers.
Captain Crunch
Please leave out the Airbus/Boeing red herrings! Map shifts can occur on any aircraft and are irrelevant to this debate. The whole point of a circling approach is to remain visual with the airfield and NOT to follow any magenta lines. Once the approach path has broken off from the ILS (or other electronic guidance) The pilots MUST remain visual.
Thanks for bringing some good factual information to this thread. There has been far too much (yet again) idle speculation from too many of the contributers.
Captain Crunch
Please leave out the Airbus/Boeing red herrings! Map shifts can occur on any aircraft and are irrelevant to this debate. The whole point of a circling approach is to remain visual with the airfield and NOT to follow any magenta lines. Once the approach path has broken off from the ILS (or other electronic guidance) The pilots MUST remain visual.
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PEI 3721:
When the Honeywell EGPWS was being certified, the senior Honeywell engineer on that project tried in vein to make a GPS sensor for the unit mandatory for otherwise non-GPS aircraft. The FAA was more strongly lobbied by a major, cheap airline to not require the optional $1,500 GPS add-on for non-GPS aircraft.
Rather than the regulators adjusting training and ratings, there would be much more value in mandating a relatively cheap GPS 'card' in EGPWS.
The whole point of a circling approach is to remain visual with the airfield and NOT to follow any magenta lines. Once the approach path has broken off from the ILS (or other electronic guidance) The pilots MUST remain visual.
Problem is, IMHO, that many airlines (mine included) train for such procedures in simulators where you lose sight of the runway going downwind and only pick it up again when you're halfway round the turn onto finals. The display of ground/terrain is rather half-hearted as well. The end result is that you fly it partly on the map/DME, etc. because there's little else to refer to, so it becomes a hybrid instrument/visual manoeuvre rather than a purely visual one. Not good procedure.
If you do plenty of this kind of approach in real life, no problem, but if you were not current and forced into circling at short notice in bad weather, you might try and make it easier by using the FMC/map "as a backup for SA", maybe even drawing a little circuit on the screen. Easy to press '7' when you meant '4' as they're next to each other...
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@CPT-Crunch
Very well said!
That's why in our airline during NP App one pilot has to use the raw data (rose) display.
Anyhow, I'm not sure that MAP shift was the problem with this accident. Didn't they say "rwy in sight", not to mention what to do during a circling app if you lose contact.....
Very well said!
That's why in our airline during NP App one pilot has to use the raw data (rose) display.
Anyhow, I'm not sure that MAP shift was the problem with this accident. Didn't they say "rwy in sight", not to mention what to do during a circling app if you lose contact.....
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Dessert Aviator & Circling Approaches
AT GF we just don't do circling approaches.... and with good reason !!!
More suitable name would be "Dessert Autopilot" !
PS.
If for whatever reason, one day,
you stay without instruments while "aviating",
what shall you do.....?
Land with any tailwind (can be 60 kts or more) or stay in the air forever ?
Last edited by Green Guard; 29th Jul 2010 at 07:31.
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Thanks PJ2,
Good to see you again. Nice Graphics w/Machaca.
Thanks guys for entertaining my unpopular anti-automation position. Bergerie1 makes a valid point that I shouldn't contrast too strenuously Airbus verses Boeing; but I maintain that they are in fact different. My indictment is really against over-reliance on glass and automation when manual flying skills are called for. But distractions can always happen when ATC issues a wind/runway change close in. At some outfits, the tyranny of company standardization will require the non-handling pilot to break out the laptop and recompute the landing distance, redo the ref, rebuild a centerline on the FMS, set up the missed approach while simultaneously talking to ATC, and participating in config changes, etc, etc, etc....
Of course, on a tight circle-to-land a new guy won't get half that stuff done right. If the crew didn't pre-brief the circle 100 miles earlier, it may be impossible to do. Even if he's good, with a patten that tight, he might not "rejoin" you until short final. I guarantee "Bergerie1" he won't know which way the aircraft is pointed when his head comes up. He also won't know if the handling pilot has lost the runway unless the handling pilot orally states that. Only the guy on the left side of the airplane is going to be able to stay visual with the Threshold if it's a left hand circuit.
This accident so far reminds me of the Wamea, Indonesian BAe-146 accident not long ago. That crash was not an FBW Airbus, so that should make the stickjockeys forgive me a little bit for my scorn of the joystick.
CC
Good to see you again. Nice Graphics w/Machaca.
Thanks guys for entertaining my unpopular anti-automation position. Bergerie1 makes a valid point that I shouldn't contrast too strenuously Airbus verses Boeing; but I maintain that they are in fact different. My indictment is really against over-reliance on glass and automation when manual flying skills are called for. But distractions can always happen when ATC issues a wind/runway change close in. At some outfits, the tyranny of company standardization will require the non-handling pilot to break out the laptop and recompute the landing distance, redo the ref, rebuild a centerline on the FMS, set up the missed approach while simultaneously talking to ATC, and participating in config changes, etc, etc, etc....
Of course, on a tight circle-to-land a new guy won't get half that stuff done right. If the crew didn't pre-brief the circle 100 miles earlier, it may be impossible to do. Even if he's good, with a patten that tight, he might not "rejoin" you until short final. I guarantee "Bergerie1" he won't know which way the aircraft is pointed when his head comes up. He also won't know if the handling pilot has lost the runway unless the handling pilot orally states that. Only the guy on the left side of the airplane is going to be able to stay visual with the Threshold if it's a left hand circuit.
This accident so far reminds me of the Wamea, Indonesian BAe-146 accident not long ago. That crash was not an FBW Airbus, so that should make the stickjockeys forgive me a little bit for my scorn of the joystick.
CC
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Originally Posted by PBY
But nevertheless, the circling should be done within 1.7 or 2 miles of the runway.
While c-c has made very valid points regarding 'uncontrollable' and 'unmonitored' automation, as I have said before there is something quite odd about this crash in its inexplicable distance from the field, just like the Yemeni at Moroni a while back. There we appear to have had another strange 'excursion' outside the normal area.
Have we seen that report yet?
The terrain visualisation for this crash (allowing for its limitations) does give me some puzzles in respect of the hills and valleys en-route to the site and I find myself wondering how they impacted where they did - it is almost like some 'hill and valley flying' that went wrong - aka 'letterboxing' - but why? Do we know if the ILS DME was working?
Ut Sementem Feeceris
will require the non-handling pilot to break out the laptop and recompute the landing distance, redo the ref, rebuild a centerline on the FMS, set up the missed approach while simultaneously talking to ATC, and participating in config changes, etc, etc, etc....
It's called non-technical skills. Workload management, cooperation, situational awareness. These are essential elements. A lot of discussion so far has talked of technical aspects (did this aircraft have GPS?) and possible mapshift. The only reason I can see that they ended up 7 miles north was a breakdown in the non- technical side of things which would of course be exacerbated by having a brand new FO in the other seat.
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Hi,
you can get some pretty interesting tailwinds when on the ILS to runway 30.
Here is some data from ISB airfield.
Elevation approx 1700ft.
Approx bearing of 320 degrees and 12nm from the airfield is a peak of approx 3900ft.
Landing dist on Rwy 12 is 3017m. Landing dist on Rwy 30 is 2743m. PAPI on both runways. Very basic approach lights avail on Rwy 12 (H-S).
Second half of runway 30 is downhill.
For a Cat c aircraft the circle to land is 850ft agl and with a vis requirement of 2.4km (not sure if aircraft is cat C or D).
Dont fly over the city to the south or through prohibited area 254 which is south also.
We have a note in our manual regarding possible GPS outage due jamming in ISB.
Heavy rain can cause mud on the runways and the obvious dangers of rubber deposits.
Its seems the wind favoured the circle to land in marginal conditions.
Rgds.
you can get some pretty interesting tailwinds when on the ILS to runway 30.
Here is some data from ISB airfield.
Elevation approx 1700ft.
Approx bearing of 320 degrees and 12nm from the airfield is a peak of approx 3900ft.
Landing dist on Rwy 12 is 3017m. Landing dist on Rwy 30 is 2743m. PAPI on both runways. Very basic approach lights avail on Rwy 12 (H-S).
Second half of runway 30 is downhill.
For a Cat c aircraft the circle to land is 850ft agl and with a vis requirement of 2.4km (not sure if aircraft is cat C or D).
Dont fly over the city to the south or through prohibited area 254 which is south also.
We have a note in our manual regarding possible GPS outage due jamming in ISB.
Heavy rain can cause mud on the runways and the obvious dangers of rubber deposits.
Its seems the wind favoured the circle to land in marginal conditions.
Rgds.
I just had a look at the plates, not having operated to ISB for a few years, and the place cries out for some sort of instrument approach for RW12. You probably could engineer a VOR/DME but it looks ideal for an RNAV: just come in from the W or SW and intercept the centreline about 6nm out, normal 3deg should suffice...
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C-C and A4 - you are risking 'frightening the horses' here with your tales of what dreadful tasks PNF would have to do to circle onto 12.
1) If you can land on a wet 30 with a tailwind you will be ok on a wet 12 with a headwind - therefore no re-computations
2) You do NOT need anything re-programming - a simple fix on the field and 2 mile circle if you must will more than do for a VISUAL manoeuvre - plus the 737 at least has a 'built-in' dotted white runway c/line in BOTH directions
3) G/A + missed does NOT change!!!! Do not confuse the great unwashed please
.
If the P2 was ex mil and knew Islamabad, is it possible the mil had some sort of 'in house' proc for 12?
1) If you can land on a wet 30 with a tailwind you will be ok on a wet 12 with a headwind - therefore no re-computations
2) You do NOT need anything re-programming - a simple fix on the field and 2 mile circle if you must will more than do for a VISUAL manoeuvre - plus the 737 at least has a 'built-in' dotted white runway c/line in BOTH directions
3) G/A + missed does NOT change!!!! Do not confuse the great unwashed please
.If the P2 was ex mil and knew Islamabad, is it possible the mil had some sort of 'in house' proc for 12?
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i was looking onto the circle to land procedure for the A320 series,which stated that when you come abeam the threshold u start timing 20 sec for 500 feet and then make a turn for the base and then finals.what does 20seconds for 500 feet mean relative to this incident that has occured.Please shed some light on this matter since the previous post tell me that he flew 7nm out.
Last edited by pilotsaab; 29th Jul 2010 at 11:51.
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Nothing significant or new in the Pakistani papers.
ATC apparently warned pilot of getting too close to high ground to which the captain said "we see that". If he had the hills in sight why would he fly into them?
I don't think these are the actual words spoken. Probably a paraphrase.
ATC apparently warned pilot of getting too close to high ground to which the captain said "we see that". If he had the hills in sight why would he fly into them?
I don't think these are the actual words spoken. Probably a paraphrase.
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An ILS on 12 would be good of course but they won't do that even now since they are building a new airport out west near a city called Fatehjang. No high ground around in that area.