Turkish A330 incident, Kathmandu
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Location: Escaped the sandpit 53° 32′ 9.19″ N, 9° 50′ 13.29″ E
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first time in KTM and going below MDA in zero visibility on a non precision APP , you need guts...
Yeah, that's just what you need in a passenger airliner - a pilot who takes risks.....
I don't understand the mentality: "I will literally risk my life and all my passenger's lives by flying below the minima for this procedure/approach. That will 'prove' that I am a very good pilot"
Erm, no, think again. If these people want thrills why don't they go and fly Pitts Specials on their days off?
I've always had a nagging feeling about RNAV approaches. We are taught to very carefully check the approaches and the tracks and distances of the waypoints in the database, and are led to believe that the coordinates are very carefully checked and verified by the database suppliers. I will certainly be checking even more carefully in future, but how can we guard against incorrect data? There is no ground based reference to double check our approach.
I don't understand the mentality: "I will literally risk my life and all my passenger's lives by flying below the minima for this procedure/approach. That will 'prove' that I am a very good pilot"
Erm, no, think again. If these people want thrills why don't they go and fly Pitts Specials on their days off?
I've always had a nagging feeling about RNAV approaches. We are taught to very carefully check the approaches and the tracks and distances of the waypoints in the database, and are led to believe that the coordinates are very carefully checked and verified by the database suppliers. I will certainly be checking even more carefully in future, but how can we guard against incorrect data? There is no ground based reference to double check our approach.
Last edited by Uplinker; 20th Nov 2015 at 09:09.
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If they had seen the runway at da/mda , even with the incorrect threshold, a normal landing would have followed. The cause is not the database fault, but the decission to continue well below minimum.
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Uplinker:
The fault was with the state, not the database supplier. With any RNAV procedure, particularly RNP AR, if the source state procedure designers don't do their job, then the origin of the chain is contaminated. Nonetheless, had the crew had the required visual references at DA, this would have been a non-event.
Further, if the state had robust flight inspection, as many countries do, they would have flight inspected the modified procedure and have easily caught the erroneous data provided for the "temporary" displaced threshold.
All of this was probably done by the third-party designer of the original procedure. But, they weren't there for the jury-rigging done to account for the displaced threshold.
Even today, the procedure is not in compliance with ICAO DOC 9905, because the MAP is at the threshold instead of DA.
I've always had a nagging feeling about RNAV approaches. We are taught to very carefully check the approaches and the tracks and distances of the waypoints in the database, and are led to believe that the coordinates are very carefully checked and verified by the database suppliers. I will certainly be checking even more carefully in future, but how can we guard against incorrect data? There is no ground based reference to double check our approach.
Further, if the state had robust flight inspection, as many countries do, they would have flight inspected the modified procedure and have easily caught the erroneous data provided for the "temporary" displaced threshold.
All of this was probably done by the third-party designer of the original procedure. But, they weren't there for the jury-rigging done to account for the displaced threshold.
Even today, the procedure is not in compliance with ICAO DOC 9905, because the MAP is at the threshold instead of DA.
Below the Glidepath - not correcting
Interesting comment in the report about the cabin crew telling the flight deck that a diversion to Delhi would be a "burden". Not that this crew needed any more encouragement to "press-on" apparently, but from a CRM perspective that's a very negative CC input at a critical time.
If they had seen the runway at da/mda , even with the incorrect threshold, a normal landing would have followed.
Before descending below the DA, the pilot making the landing should already have seen external cues sufficient to confirm that the aircraft was properly placed and going in the right direction for a safe landing. There is limited info in the report (absence of CVR transcript) but it seems possible that there was no decision making at all, they simply ploughed on with the A/P engaged expecting something to show up. One has to wonder if the PM was also head up and not monitoring instruments as he appears not to have noticed the Autopilot Disconnect message on his FMA for some 15 seconds or more.
ICAO DA definition: "A specified altitude or height in the precision approach or approach with vertical guidance at which a missed approach must be initiated if the required visual reference to continue the approach has not been established..... The required visual reference means that section of the visual aids or of the approach area which should have been in view for sufficient time for the pilot to have made an assessment of the aircraft position and rate of change of position, in relation to the desired flight path."
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The later busses are capable of a GLS autoland
Interesting comment in the report about the cabin crew telling the flight deck that a diversion to Delhi would be a "burden". Not that this crew needed any more encouragement to "press-on" apparently, but from a CRM perspective that's a very negative CC input at a critical time.
Of course, it's up to the decision-maker, the person in Seat 0A, to consider all the inputs and act appropriately.
Last edited by Capn Bloggs; 21st Nov 2015 at 07:05. Reason: Grammar fix.
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Bloggs:
In the interests of proper management of the entire crew if Seat 0A decides "no" he or she is obligated to be diplomatic with the CC member. Otherwise, future communications are compromised.
I know you know that, but for the lurkers.
Of course, it's up to the decision-maker, the person in Seat 0A, to consider the all the inputs and act appropriately.
I know you know that, but for the lurkers.
Originally Posted by Aterpster
In the interests of proper management of the entire crew if Seat 0A decides "no" he or she is obligated to be diplomatic with the CC member. Otherwise, future communications are compromised.
At the risk of some thread driiifffttt...
Originally Posted by Aterpster
GLS needs SBAS and local augmentation. I believe the local augmentation equipment has to be within 25 miles.
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Capn Bloggs:
You are correct. But, the original concept included WAAS, more or less. 
From the FAA site:
Satellite Navigation - NAS Implementation
NAS Implementation - Procedures - Ground Based Augmentation System (GBAS) Landing System (GLS)
"GLS" is the acronym for Ground Based Augmentation System (GBAS) Landing System.
GLS was originally published as a placeholder for both Wide Area Augmentation System (WAAS) and GBAS minima and marked as N/A since no minima was published.
As the concepts for GBAS and WAAS procedure publication have evolved, it was decided that GLS will now only be associated with GBAS and will be on a separate approach chart. For more information on GLS approach procedures, please refer to the AIM section 1-1-21 and section 5-4-5.
My understanding is that GLS (the "GBAS Landing System") uses normal GPS from the satellites and is augmented only by ground-based gear eg a/the LAAS, as you say, close to the airport.
From the FAA site:Satellite Navigation - NAS Implementation
NAS Implementation - Procedures - Ground Based Augmentation System (GBAS) Landing System (GLS)
"GLS" is the acronym for Ground Based Augmentation System (GBAS) Landing System.
GLS was originally published as a placeholder for both Wide Area Augmentation System (WAAS) and GBAS minima and marked as N/A since no minima was published.
As the concepts for GBAS and WAAS procedure publication have evolved, it was decided that GLS will now only be associated with GBAS and will be on a separate approach chart. For more information on GLS approach procedures, please refer to the AIM section 1-1-21 and section 5-4-5.
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Final report
]Final report on the INVESTIGATION OF RUNWAY EXCURSION ACCIDENT OF TURKISH AIRLINES TC-JOC, A330-303, AT TIA, KATHMANDU, NEPAL ON 4th MARCH 2015
http://www.tourism.gov.np/uploaded//...-finalcopy.pdf
http://www.tourism.gov.np/uploaded//...-finalcopy.pdf
Quote:
On March 4th 2015, Turkish Airlines Flight TK-726 experienced a runway excursion whilst landing at Tribhuvan International Airport (TIA) at 01:59 hrs. TK-726 was operating a scheduled passenger flight from Istanbul to Kathmandu with a total of 224 passengers with 11 crew members (2 Cockpit and 9 cabin crew). During landing the aircraft touched down towards the left edge of Runway 02 with the left hand main landing gear off the paved runway surface. The aircraft veered further to the left and came to a stop on the grass area between taxiway D and C. All passengers were evacuated safely after a brief period of time. There was no injury to passengers and crew. Fire did not occur at the time of accident.
Quote:
The probable cause of this accident is the decision of the flight crew to continue approach and landing below the minima with inadequate visual reference and not to perform a missed approach in accordance to the published approach procedure.
Quote:
The auto-pilots remained coupled to the aircraft until 14 ft AGL, when it was disconnected, a flare was attempted. The maximum vertical acceleration recorded on the flight data recorder was approximately 2.7 G. The aircraft pitch at touchdown was 1.8 degree nose up up which is lower than a normal flare attitude for other landings.
On March 4th 2015, Turkish Airlines Flight TK-726 experienced a runway excursion whilst landing at Tribhuvan International Airport (TIA) at 01:59 hrs. TK-726 was operating a scheduled passenger flight from Istanbul to Kathmandu with a total of 224 passengers with 11 crew members (2 Cockpit and 9 cabin crew). During landing the aircraft touched down towards the left edge of Runway 02 with the left hand main landing gear off the paved runway surface. The aircraft veered further to the left and came to a stop on the grass area between taxiway D and C. All passengers were evacuated safely after a brief period of time. There was no injury to passengers and crew. Fire did not occur at the time of accident.
Quote:
The probable cause of this accident is the decision of the flight crew to continue approach and landing below the minima with inadequate visual reference and not to perform a missed approach in accordance to the published approach procedure.
Quote:
The auto-pilots remained coupled to the aircraft until 14 ft AGL, when it was disconnected, a flare was attempted. The maximum vertical acceleration recorded on the flight data recorder was approximately 2.7 G. The aircraft pitch at touchdown was 1.8 degree nose up up which is lower than a normal flare attitude for other landings.
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If interpreted the CVR excerpt correctly then they continued for appr. 24 seconds beyond the MDA until they started seeing the runway.
He said "Appearing" five seconds prior to disengaging the A/P, at which point the aircraft was already at 14'.
He said "Appearing" five seconds prior to disengaging the A/P, at which point the aircraft was already at 14'.
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What were they thinking?
Literally. Did they really think they could rely on the aircraft to get them on the runway in FINAL APP mode? Even if the runway threshold coordinates were correct, then still there are many ways in which you could end up in the wrong place:
-colder/warmer than standard temperature leading to under/overshoot of the threshold
-error in the reported/set QNH. 1011 in stead of 1012 is already a 30 feet difference over the threshold..
-any other database error, not uncommon in our present day databases, each year we get one or two interesting corrections per NOTAM
To bust minimums is bad enough, but to do it all the way to the deck, on a non-precision approach? What were they thinking?
Literally. Did they really think they could rely on the aircraft to get them on the runway in FINAL APP mode? Even if the runway threshold coordinates were correct, then still there are many ways in which you could end up in the wrong place:
-colder/warmer than standard temperature leading to under/overshoot of the threshold
-error in the reported/set QNH. 1011 in stead of 1012 is already a 30 feet difference over the threshold..
-any other database error, not uncommon in our present day databases, each year we get one or two interesting corrections per NOTAM
To bust minimums is bad enough, but to do it all the way to the deck, on a non-precision approach? What were they thinking?
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PENCO:
Agree with all you said except I'll quibble on the NPA aspect. If it were an NPA, it would have an MDA rather than a DA.
As to the database, this entire effort was a fiasco, starting with Nepal's aviation authority. RNP AR approaches are in a separate category from all other database approach procedures. There are many additional hoops for both the state aviation authority and the operator to jump through as part of their RNP AR authorization. Neither Nepal nor THY management did much of that.
To bust minimums is bad enough, but to do it all the way to the deck, on a non-precision approach? What were they thinking?
As to the database, this entire effort was a fiasco, starting with Nepal's aviation authority. RNP AR approaches are in a separate category from all other database approach procedures. There are many additional hoops for both the state aviation authority and the operator to jump through as part of their RNP AR authorization. Neither Nepal nor THY management did much of that.
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aterpster, in my company (large European airline) we fly all non precision approaches in our network as continuous final descent approaches and as such we are provided with a 'DA' for these approaches. Technically we can't fly non precision to an MDA anymore. You might be right in what you say, but this is how it is in my company..(and probably in TA).
http://www.code7700.com/cdfa.html
http://www.code7700.com/cdfa.html
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PENKO:
I understand that. It is a related but different issue than DA appearing on an RNP AR procedure.
aterpster, in my company (large European airline) we fly all non precision approaches in our network as continuous final descent approaches and as such we are provided with a 'DA' for these approaches. Technically we can't fly non precision to an MDA anymore. You might be right in what you say, but this is how it is in my company..(and probably in TA).