Turkish A330 incident, Kathmandu [Archive]

Luke SkyToddler

4th Mar 2015, 12:50

Kathmandu vs the A330 is an accident that's been long overdue to happen.

Poor vis and 10 kt tailwind component is the norm rather than the exception - and the reported tower wind is normally nothing like what's actually encountered.

Combined with that god awful VOR approach which as I recall requires -6 degrees FPA from 15 miles right down to 5 miles, even fully configured the speed is right up at the barber's pole at that 5 mile mark, you always get a late stabilization around 500 feet if you're lucky.

In addition, aircraft are normally tankering fuel therefore they are close to max landing weight, the runway is very short and has a dirty great hump in the middle.

It's really not a place the A330 or any other heavy jet should be going to, in my opinion.

There's a heavily built up slum right off the far threshold so they are very very lucky not to have a large fatality count.

skysod

4th Mar 2015, 12:51

Oh dear........hope for the flight crew's sake that they did not bust their minima!

tcas69

4th Mar 2015, 12:58

Thanks a lot for the RNP chart.
We used to fly into KTM with A310/330/340 on the VOR APP 02 which was much steeper but more aligned with the runway. The transition from 6degree to 3degree(or so) 'glideslope' at the minimum was hairy in marginal weather.
But basically straightforward with being (almost) aligned with the runway far out. I do not know if the curved RNP app which gives a lower minimum does not make the approach trickier. Does anybody know which approach they did?

deefer dog

4th Mar 2015, 13:20

This is gonna undue the value of the millions of dollars and euros spend on glossy advertising done post their Amsterdam crash. I would love to find out how much fuel was remaining when they stopped off piste here. And what minimus they were using. I've operated there and unless you are familiar its not easy to get the runway in sight with 5 times the viz reported in the metars posted above.

aterpster

4th Mar 2015, 13:36

tcas69:

But basically straightforward with being (almost) aligned with the runway far out. I do not know if the curved RNP app which gives a lower minimum does not make the approach trickier. Does anybody know which approach they did?

You can hook up the automatics on this approach and it should fly with ease. The last RF leg ends at waypoint KT520 at which point you exactly aligned with the runway centerline for 3.1 miles and still on the VNAV 2.8 degree path.

One of the requirements for an RNP AR approach is that it be exactly aligned with the runway passing the final roll out point (FROP.)

I've "flown" this particular approach several times in an RNP AR desktop trainer. It is a good approach.

ironbutt57

4th Mar 2015, 13:56

10,000...isn't exactly short, the traditional almost always thee tailwind from 210deg isn't exactly helpful, but this fellow seems to have not made it much past taxiway 5...as it used to be called anyway...

aterpster

4th Mar 2015, 15:04

V0030/15 - [DOD PROCEDURAL NOTAM] RUNWAY DISPLACED. RUNWAY 02 DISPLACED 120
METERS UNTIL FURTHER NOTICE. 19 FEB 17:45 2015 UNTIL 31 MAR 00:01 2015. CREATED:
19 FEB 17:49 2015

A0050/13 - THE NEW SIGNAGE FOR RUNWAY AND TAXIWAY AS PER ANNEX 14 ARE INSTALLED UNDER TEST AT TRIBHUVAN INTL AIRPORT.THE DETAILS ARE AS FOLLWS: 1)TAXIWAY SIGNS HAVE BEEN CHANGED FROM NUMERIC 1, 2, 3, 4 AND 5 ALPHABETIC DESIGNATION AS A, B, C, D AND E RESPECTIVELY 2)NEW SIGNAGE FOR DOMESTIC APRON, HELICOPTER APRON, LINK TAXIWAY AND PARALLEL TAXIWAY HAVE BEEN INTRODUCED AS H,J,G AND F RESPECTIVELY 3)AVBL RWY LENGTH FROM EACH TWY INTERSECTION IS ALSO DISPLAYED 4)VOR AERODROME CHECK POINT SIGN WITH VOR FREQ, BEARING AND DISTANCE FROM DME IS AVAILABLE AT TAXIWAY HOLDING POINT A AND E. 02 APR 10:30 2013 UNTIL PERM. CREATED: 08 APR 11:46

http://i201.photobucket.com/albums/aa214/aterpster/10-9_zpscfnz8fdl.jpg

ironbutt57

4th Mar 2015, 15:06

aha!!...so somewhere between "E" and "D" perhaps?

Capt Fathom

4th Mar 2015, 15:55

Anyhow, according to videos made by passengers just after getting out of the airplane one can see that the visibility must have been well below any minima

How can you possibly know what the actual visibility was at the time of landing. You can't base it on a video taken 5 minutes after the event!

ATC Watcher

4th Mar 2015, 17:14

How can you possibly know what the actual visibility was at the time of landing. You can't base it on a video taken 5 minutes after the event!

If you know KTM you will know that this mist/fog is due to temp/dew point combined with heavy city pollution and zero wind . it clears gradually when temp rise , not on and off like other places. TFN for instance where the "fog" is in fact passing Cu clouds hanging on the slopes. and where changes in VIS are immediate and on and off.

Ottoforce

4th Mar 2015, 18:46

Very sad to hear about this.
Although unfortunate it's only one of many serious! incidents, not surprising accoding to past Saferty Bulletins it was always likely to happen and lucky it's not a total disaster, that's in the near future possibly, maybe, likely, very likely.

levelchange

4th Mar 2015, 18:55

https://www.facebook.com/video.php?v=625852884214283

looks more like LVO wx!!!

Going Nowhere

4th Mar 2015, 20:05

On the video it looks like the L1 slide didn't deploy.

FiveGirlKit

4th Mar 2015, 20:11

Why were the pax buses waiting before the pax were evacuated? It seems the aircraft crashed, emergency services and buses arrived, and then there was an evacuation - strange sequence of events?

llagonne66

4th Mar 2015, 20:25

Just guess the firemen spread some foam to be sure that there will be no fire before evacuating the A/C.
Buses would have arrived while the firemen were in action.

nivsy

4th Mar 2015, 21:09

What gets me is that just about all pax and staff seen in vid all had cameras or phones aimed at the aircraft...sign of the times we live in.

agread

4th Mar 2015, 22:17

Still wondering how much extra fuel would be carried by flights out of KL? At least two flights that I know of returned there yesterday after nearly reaching KTM. How many hours/miles does this cater for, does anyone know?

Metro man

4th Mar 2015, 22:30

Completed about ten holding patterns at FL210, then proceeded to KTM, made a go-around, tried for a second time and then ended up beside the runway apparently. "Landing" time at around 0200z, after two hours in the hold.

Did he still have enough fuel left to divert after this, or was he committed to land ?

Bigpants

4th Mar 2015, 22:30

Who insures this airline and why?

Toruk Macto

4th Mar 2015, 23:24

Be interesting to know how much fuel he had before that final approach commenced ?

Anilv

5th Mar 2015, 00:01

I believe the cost of fuel is high in KTM, as a result airlines might choose to tanker fuel for the return leg. If this was the case the planes which returned to KUL would have more than enough to get back.

India is similarly very expensive.. to the extent that when flying KUL-DEL-SHJ we would fill up as much as possible (considering landing weight)... we are talking about almost 30tons here on occasion.

Speed of Sound

5th Mar 2015, 00:16

https://www.facebook.com/video.php?v=625852884214283

Jeez, did you see the size of some of those rucksacks that people managed to get into the cabin as carry on?

JammedStab

5th Mar 2015, 01:35

If they did a VOR/DME approach yet the vis was so poor at the accident site soon after, one has to wonder if there was a bit of a break in the fog allowing then to see just enough to continue for landing but then the vis dropped immediately after touchdown/selection of reverse thrust.

KATLPAX

5th Mar 2015, 03:16

Watch the entire video in the prevous Facebook link, towards the end (2:24); it shows just post stop inside and just before pax evac (I assume). It is out of sequence. https://www.facebook.com/video.php?v=625852884214283

I would have thought that if pax had time to sit around, fill the aisles with luggage (lots of luggage and all overhead bins are open), that an emergency evac would not have been started? Something seems off. Thoughts?

Captain Partzee

5th Mar 2015, 04:56

"I believe the cost of fuel is high in KTM, as a result airlines might choose to tanker fuel for the return leg. If this was the case the planes which returned to KUL would have more than enough to get back."

Don't forget the Maximum Landing Weight (KTM Apt Elev 4395').
The tankering fuel is limited.
"Speculation". No more than two hours.

fanfree

5th Mar 2015, 06:40

The best airline in Europe 2014!?

readywhenreaching

5th Mar 2015, 06:41

this morning 0545UTC, TK sends a pair of A330s to Tribhuvan
TK 5826 (TCJNM) and the regular TK 726 (TCJOA), so things must have cleared by then..

Volume

5th Mar 2015, 07:29

On the video it looks like the L1 slide didn't deploy. This one reason why the regulation requires to do the evacuation test with only 50% of the available exits. This is why we have cross-aisles at every large emergency exit. It is expected, that not all doors are available, for whatever reason. Not ideal, but normal and expected. You can not check the slides prior to every flight, and if you would test them regularly, it would tell you nothing because you have to re-pack after.

Bearcat

5th Mar 2015, 07:42

Doesn't look 900m RVR which appears to be req mins for the Rnav appr from that face book video. Looks like pea soup.

jack11111

5th Mar 2015, 07:42

As the nose is resting in the dirt CC may have elected to disable the slide.

clipstone1

5th Mar 2015, 08:05

Lots of insurers will cover Turkish, like they do all airlines. Like all insurance, it is just a matter of balancing the books across the many.....

MH have no problems getting insurance....Turkish won't either.

despegue

5th Mar 2015, 10:31

The Popular Turkish bashing has started again I see, even before any accident report has appeared:ugh:
Very Professional guys:rolleyes:

Every airline, including so called legacy carriers have incidents regulary.

KLM likes to take off from wrong runways/taxiways or without clearances ( even at home base:hmm:)

BA helps in demolishing buildings next to taxiways through the aid of B747 wings

Lufthansa has a nick for landing on a construction site

Emirates has the regular tail strike

AF...no further comment required...

Etc etc.

Consequence: zero. No fatalities, keep moving people. Nothing to see.

But when TK has an incident, the blaming, insulting etc. Is all over the place.

In my opinion, the incident has nothing to do with busting minima. They went off the runway, so whatever went wrong, went wrong AFTER touchdown. Busting minima results in potential CFIT. Not the case here it seems.

fireflybob

5th Mar 2015, 10:41

Rather than the type or number of incidents/accidents being significant it's the reasons/causes behind them that really counts.

At this stage we don't know all the facts but we will eventually.

TBSC

5th Mar 2015, 11:47

But when TK has an incident, the blaming, insulting etc. Is all over the place.

Let's stick to the facts then. Since 1994 they had 7 incidents (excluding Kathmandu) where the aircraft was written off (4 with casualties), 6 of those happened during landing. Other operators (mentioned by you) does not seem to have such number of re-occurence.

Sam Ting Wong

5th Mar 2015, 11:47

Thanks for the charts, Aterpster.

_Phoenix_

5th Mar 2015, 12:07

Of course it's pay to fly. I always have to pay as a passenger.
Passenger on seat 0A... after two hours on hold pattern, a go around and a fully automated approach in dense fog, up to the runway threshold, I guess the moment of touch down was a combination of high stress and startle effect that overwhelmed PF.

Wrist Watch

5th Mar 2015, 12:43

Anyone knows what avionics THY's A330s are equipped with (FLS capability)?

sarge75

5th Mar 2015, 13:33

despegue (http://www.pprune.org/members/59407-despegue)

Love the way you attack people for speculation and tell them to wait for the investigation.

Then you tell us that it happened after touchdown, how they left the runway.

Yet you are speculating. Hypocritical and wrong :D

The aircraft can't veer off a runway if it was never properly on the runway.

Would poor visibility lead to an aircraft landing with landing with at least one set of wheels off the tarmac?

Alloy

5th Mar 2015, 13:37

Turkish Airlines plane crashes since 1970 (http://www.airsafe.com/events/airlines/turkish.htm)

Microburst2002

5th Mar 2015, 13:48

It is a runway veer off. That's all we know for certain as of now.

the fact that it is Katmandu and that there was low visibility might not be related with it, although of course it can be.

They can have touched down on the runway normally (after Katmandu and lo vis) and only then they veered off. It can be related to the approach or not.

Everyone has a guess and thinks any other theory makes no sense, but I have been wrong about other cases so often, even when they seemed so clear that I can't trust any theories until we know more.

My theory now would be: unstable approach, hard landing, tyre burst, veer off.

FLYDHC8

5th Mar 2015, 13:59

The aircraft can't veer off a runway if it was never properly on the runway.

Interesting statement by sarge75. So what happened to KLM flight 566, B747 from Nairobi to Amsterdam? Not saying it's what happened here, just replying based on that statement made.

slowjet

5th Mar 2015, 14:01

I know it's a hard commercial world but I have to ask ; Any Commanders out there ? Haven't waded through all posts but what was the FORECAST weather at time of departure? Don't care about the actual. I used to work for a fabbo outfit that forbade a departure if the forecast, for the time of arrival was below limits.

Yes we tank as much fuel because of the high cost out of KTM. Gives credibility to departing and taking up the hold but a very weak commercial decision eh ? I pointed out to Commercial that it costs fuel to carry fuel and if we knowingly depart in order to take up a two hour hold, we might, surely be facing tea & bickies with the Fleet Manager (?).............I was politely shown the door !

I checked in, another time, for KTM, faced the same old problem and delayed departure for two hours. We got in at the first attempt as the "fog" cleared rapidly within twenty minutes of arrival. Again, back at Base, ventured up to Commercial to ask why we scheduled arrivals, not only to KTM but all over Northern India into known fog ! Big delays, huge disruption etc. Quick tweak of around two hours and problem solved. Again, I was shown the door.

Commanders out there....................make that Command decision and delay departure. Might save a prang and might save lives.

cucuotto

5th Mar 2015, 15:02

TAF VNKT .........TEMPO 0400/0403 500 FG

flite idol

5th Mar 2015, 15:10

In the FAA/FAR world I operate in, 121.613 is your friend in that instance. Many years since I did Air Law exam in CAA world but I imagine there are similar provisions there and under most authorities. No?

Avenger

5th Mar 2015, 15:12

SIA 777 attempted go-around before Munich veer-off - 1/31/2012 - Flight Global (http://www.flightglobal.com/news/articles/sia-777-attempted-go-around-before-munich-veer-off-367589/)

Of course it can veer off, the question remains if it was ever "on"

ironbutt57

5th Mar 2015, 16:08

Slowjet....more realistic advice is commanders, exercise that command authority and divert to your alternate if the conditions are unsafe...the only way any carrier will learn to adjust their schedules accordingly, is when it becomes expensive to carry on as usual...our commercial department at a previous employer used to schedule our arrivals there early morning during winter..fog...and afternoon hours during summer...thunderstorms...seems most other airlines did the same, as we always saw all the "usual suspects" either holding at GURAS, or diverting elsewhere when the weather didn't co-operate....

sarge75

5th Mar 2015, 16:09

Flydhc8

Was what I was told by engineers when in KTM this morning.

That is not therefore 100% reliable information nut they had no reason to lie to me so I do believe them

Algol

5th Mar 2015, 16:14

Were the crew local or expat?

Soft Altitude

5th Mar 2015, 16:48

Slowjet and Ironbutt, totally agree, you nailed and summarized what should be and/or should have been done:
the commercial doesn't care, my current employer shows it on a daily basis, they don't fly those planes to dodgy destinations, hence diversion is your friend. If company doesn't listen to your concerns and does not back you up , why should you go out of your way to satisfy it's ambitions. Pilot professionalism comprises "safety first" as well ! Tankering, not tankering, expensive diversion, who cares, how expensive is this landing at destination going to be now ? Way more expensive than a diversion ? You bet !!!
Save yourself first !

PT6Driver

5th Mar 2015, 17:45

Bearcat

Doesn't look 900m RVR which appears to be req mins for the Rnav appr from that face book video. Looks like pea soup.

It doesn't matter what the video shows or apears to show apart from the fact that it is foggy!

What matters for legality is what were the RVRs passed to the crew and when.
One can have above minimum RVR and still not have sufficient visual reference. Equally you can have a deterioration once inside the outer marker and still have enough visual reference.

In this case we do not at the moment have enough information to say whether or not the RVR was too low to make an approach.

ATC Watcher

5th Mar 2015, 17:55

Sarge 75 , I have heard similar comments from ATC there. But let's wait a few more days.
I was in KTM for work a couple of years ago, and the bad vis/fog/smog in the morning was a fact of life in this time of year. Delays , diversions and/or cancellations the norm, but this was before RNAV and during the VOR / 9 deg glide slope era.

In view of other incidents in other airports with visual RNAV APP, My question to crews operating there today would be , does the RNP creates a feeling that more is possible with it, and bringing more trust into the system . In other words, would you attempt an APP today in certains conditions with RNP that you would not have done a few years ago ?

bob777

5th Mar 2015, 18:04

ATC watcher kind of a stupid question. The criteria to continue or discontinue the approach ( approach ban ) and minima for the approach are both clearly stated in any operator manual A & C. There is no guessing or feeling...Anything outside of that would be a violation of company regulation. Let's wait to see what comes out of the investigation.

Oasis

5th Mar 2015, 18:16

Take it easy there, bob777. No reason calling anyone stupid.

ironbutt57

5th Mar 2015, 18:24

with the reported vis at published minima 1600m, the VOR approach was a waste of time, never bothered until it rose to 3000m at least...the RNP approach seems to position one better to successfully complete the approach at it's lower published minima, so my answer to ATC watcher would be yes.I would be more inclined to operate the RNP with the reported vis at published minima for that approach, but it was the good old VOR-A in my day.....and yes I have operated both 767 and 320 into KTM on more occasions than I can count...think you missed the point of his question Bob...

Boeingrestricted

5th Mar 2015, 18:25

" Were the crew local or expat? ".

Will your professional opinion depend on the answer to your question.

ULMFlyer

5th Mar 2015, 18:48

Avherald states that ATC reported 1000 RVR during 2nd approach. While on final, "airport was suddenly covered with dense fog."

At ~1200 AGL, ATC asked if RWY was in sight but got no response. Next transmission was to inform ATC they were off RWY.

ATC Watcher

5th Mar 2015, 20:04

Bob 777 : :rolleyes:

Ironbutt57 : Thank you this does answer my question .

OK465 : Could you cite some of what you're referring to here

One that comes to mind : also the report of that one ( February 2012, BEA) refers to multiple incidents by same airline at this perticular airport.
The RNAV Visual Approach to runway 26 was proposed to all arriving aircraft indiscriminately. The lack of RNAV Visual Approach training at Air XXX at the time of the occurrence caused the captain fail to anticipate possible problems during the approach briefing, that the first officer might encounter during the unusual approach. In addition, the lack of understanding of how open descent, open climb and autothrottle work with the crew believing the autoflight systems would still ensure maintaining correct airspeed led to lack of monitoring of airspeed. The lack of identification of such risk factors led to the aircraft entering the turn to final in low energy state, given its configuration and the nose up inputs the speed warning and Alpha Floor activated.

IFALPA has also issued a bulletin last month on Visual RNAV APP : http://www.ifalpa.org/downloads/Level1/Briefing%20Leaflets/Air%20Traffic%20Services/15ATSBL03%20-%20The%20RNAV%20Visual.pdf

but thanks for your answer, point taken.

andrasz

6th Mar 2015, 05:18

@slowjet & ironbutt57

I know it's a hard commercial world but...

In a hub & spoke operation of the kind that TK (or the ME3 and many other majors) do, there is no such thing as 'simply shift departure by 2 hours'. Either the flight can be fitted into the connecting banks, in which case it can be operated successfully, otherwise it is commercially not viable. Low-costs are free to shift departure times as they please because they only cater to point-to-point traffic (and to a significant extent this is why they can have a lower cost structure, but in return they also limit their market access).

This being said, in a well-ran outfit scheduling listens to flight-ops and monitors statistics to make sure that the flight can actually be operated in the scheduled timeframe. Many moons ago when I had responsibility for scheduling I had a half-day blocked off each week to take a cockpit ride on one of the problem flights and discuss with crew and experience first hand the issues and possible fixes. In some cases the conclusion was to axe the route after flight ops could not reliably meet commercial requirements.

I visit this forum for the same reason, to listen and to learn. Unfortunately at some outfits (likely including the subject of this thread) this is not in the culture.

Right Way Up

6th Mar 2015, 07:32

Would be interested to see if Turkish were certificated for this sort of approach. We had issues at my company where our aircraft were capable and we were trained but to operate to lowest minima we required Airbus certification for each aircraft to carry out this approach at a cost of circa £100,000 per aircraft. :eek:

andrasz

6th Mar 2015, 11:10

???? ?????? ????? :: Nepal, Political News, Science, Social, Sport, Ecomony, Business, Entertainment, Movie, Audio, Video, Nepali Model, Actor, Actores, Interview (http://www.onlinekhabar.com/2015/03/249076/)

ironbutt57

6th Mar 2015, 12:49

Andrasz...you may note that indeed I did NOT advocate PILOTS shifting departure times, an authority not afforded the pilot at most airlines..operational control (delaying/cancelling flights) rests on the folks in ops...diverting once in flight however, is the prerogative of the Commander..

aterpster

6th Mar 2015, 13:04

Right Way Up:

Would be interested to see if Turkish were certificated for this sort of approach. We had issues at my company where our aircraft were capable and we were trained but to operate to lowest minima we required Airbus certification for each aircraft to carry out this approach at a cost of circa £100,000 per aircraft.

Don't know what model you operated but the 330 should "come out of the box" certified for RNAP AR approaches to 0.10. The other part of the equation is for the operator to get approval from its certificate holder to fly such approaches. That would including the requisite training of the flight crews, ground school and simulator and a specified number of 0.30 approaches on the line before lower RNP values can be used.

I can't speak for Turkey, but in the U.S. RNP AR approaches are not in the database until the approval process is completed.

andrasz

6th Mar 2015, 13:59

Ironbut57, emphasis noted. My post was primarily to underscore the need for scheduling to understand operational constraints and flight operations to understand commercial needs. Without this understanding, sooner or later there will be a bunch of unemployed aviation professionals hitting the job market.

The Ancient Geek

6th Mar 2015, 14:29

Am I the only one concerned about the 2 hour hold ?
Rather divert before you end up with insufficient fuel and having to land in bad conditions.

PT6Driver

6th Mar 2015, 14:40

Geek

How do you know how much fuel they had left?

Agreed a timely decision to divert rather than being forced to make an approach under less than ideal conditions, is the way forward. However we simply do not know how much they had remaining, for all we know they could have had enough to return to IST :rolleyes:

silvertate

6th Mar 2015, 16:26

Blackpud

Is the 330 approved to do RNP AR approaches ?

The aircraft is probably certified. However, as far as I am aware Turkey has not given approval to any carriers as yet, and no crew training has been done.

Anyone know if that has changed? Load of crews still do GNS approaches, even though no training has been given, and no requirements specified. They seem to regard the presence of an approach plate to be authorisation.

Boeingrestricted

6th Mar 2015, 20:35

In these times, the aviation industry is in need of professionals who can see accurately by merely looking at pictures pinpointing the culprit. Shooting down a colleague , alleging by assumption that "the presence of a chart" is that the AUTHORIZATION REQUIRED has been fulfilled by an unknown colleague, surely he is more valuable/professional than this unknown Captain. ................ I am sorry but I just have zero tolerance for crap like this, no matter what nationality the pilot is. I just hate pilot bashing full stop. It just happens too often in my opinion.

aterpster

6th Mar 2015, 23:01

silvertate:

The aircraft is probably certified. However, as far as I am aware Turkey has not given approval to any carriers as yet, and no crew training has been done.

Anyone know if that has changed? Load of crews still do GNS approaches, even though no training has been given, and no requirements specified. They seem to regard the presence of an approach plate to be authorisation.

If management and the Turkish aviation authority were doing their job, and I have no basis to conclude otherwise, the RNP AR approach would not have been in the database unless the crew were qualified.

Unless someone has some hard information to the contrary, the presumption should be the crew was qualified and legal to fly the RNP AR approach.

Metro man

6th Mar 2015, 23:10

That's a big presumption, we have approaches in our data base which we aren't certified to use therefore we don't fly them.

Just because the approach is there it does't necessarily mean that that the crew are qualified to use it.

aterpster

7th Mar 2015, 00:54

Metro and Ecam:

I presume you are not operating under FAA rules.

Probably not ICAO rules, either, in this respect. But, ICAO is weak.

JammedStab

7th Mar 2015, 01:08

Am I the only one concerned about the 2 hour hold ?
Rather divert before you end up with insufficient fuel and having to land in bad conditions.

Maybe they had lots of fuel. You are just making an assumption.

Toruk Macto

7th Mar 2015, 01:44

If I was a senior manager at Turkish Airlines I would be letting it be known that the 330 had enough fuel to fly another 10 hours when it landed . If it did !

TypeIV

7th Mar 2015, 05:03

Turkish Airlines and another carrier in Turkey both have the approval for RNAV AR.

TurnOne

7th Mar 2015, 05:36

Our crews are qualified, we have the Airbus certified equipment to fly RNP APP's but the the paperwork has been stalled at our CAA in tray for the last few months.
Very frustrating

TypeIV

7th Mar 2015, 08:14

Alright but what does that have to do with Turkish Airlines if the company you mention is another airline?

Stone_cold

7th Mar 2015, 08:27

Type IV . He is defending himself against someone who implies that the AR approach cannot be in the database unless it was approved .

TypeIV

7th Mar 2015, 09:05

My apologies, I understood it as if another company didn't have the full approval that also meant that Turkish Airlines probably wouldn't either due to the presumptive and slanderous nature of most Turkish Airlines related threads.

B777_TRE

7th Mar 2015, 14:33

Turkish Airlines has the approval for this approach , the aircraft and the crew were certified and they had the necessary sim training for this app to ktm

sarge75

7th Mar 2015, 14:33

East West | Travel Blog by Kunda Dixit | Nepali Times | nepalitimes.com » Blog Archive » Disaster averted, unfolding disaster (http://nepalitimes.com/blogs/kundadixit/2015/03/07/disaster-averted-unfolding-disaster/)

Interesting read.

NB. I was not one of those making comments!

Chronus

7th Mar 2015, 17:12

According to a Turkish daily great difficulties are being experienced in moving the aircraft. For recovery photos see:

Nepal'de pistten ç?kan Göbeklitepe uça?? imkans?zl?klar içinde kurtar?lmaya çal???l?yor - Milliyet Haber (http://www.milliyet.com.tr/nepal-de-dusen-gobeklitepe-ucagi/dunya/detay/2024612/default.htm)

The aircraft`s name painted below the cockpit, translated from Turkish reads:

Belly Hill

Rather an ironic coincidence.

silvertate

7th Mar 2015, 17:43

B777

Turkish Airlines has the approval for this approach , the aircraft and the crew were certified and they had the necessary sim training for this app to ktm

As a matter of interest, does the A330 give adequate error warnings for this type of approach? Our more steam-driven type does not adequately inform you if it has not gone to RNP 0.3 mode; it gives little warning of deviating from lateral track; and gives no gives warnings for deviating from vertical track (just the path indicators). At least the ILS will shout 'glideslope' at you.

In a similar fashion, our steam-driven FMC gives very little indication that it has lost GPS signal, or is getting GPS ghosting from mountains etc: Our current FMC manual gives no error messages for RAIM monitoring of the GPS. Some warnings may be in the box, for all I know, but they are not in the current manual. And I have seen no method of verifying "RAIM OK" before making an approach. And since there is no WAAS in Turkey (and most of Europe), you are entirely reliant on RAIM checking the satellites correctly - especially in somewhere like KTM or Turkey where signal ghosting from high ground may be problematic.

This is why our outfit is not certified for GNS approaches, and why crews should not be doing ad-hoc GNS approaches just because they are in the database. Someone said earlier that we should stop blaming crews? Who is blaming the crew? The problem is that various CAAs have started leaking out GNS approaches without informing anyone as to the requirements. And many companies have been slow to act with clear policies and instructions.

cucuotto

7th Mar 2015, 19:18

Both captain and FO Turkish nationals. Female captain I' m been told. Touched down out of runway at least with one mlg...possibly confused edge with centerline.All actors RNP approach certified but approach type seems to have no influence on event. I stand to be corrected.Info coming from friend working in THY.

turker339

7th Mar 2015, 20:22

As mentioned above, Turkish was authorized for the RNAV AR approach and the pilots that fly it were trained and signed off for it.

Apparently pilot announced a hold of 90 mins but told pax not to worry as they had more than enough fuel for it.

aterpster

7th Mar 2015, 23:09

Silvertate:

As a matter of interest, does the A330 give adequate error warnings for this type of approach?

Dual GNSS
Dual FMS
FMS most provide continuity, integrity, accuracy, and alerting.

Auto-flight
Auto-throttles

This is the case with all airframes certified by the O.E.M. for RNP AR. Additionally, for RNP of less than 0.3, and/or missed approach of less than 1.0, there must be at least one IRU or its equivalent.

ATC Watcher

8th Mar 2015, 08:40

Touched down out of runway at least with one mlg...possibly confused edge with centerline.All actors RNP approach certified but approach type seems to have no influence on event.

Well if your info is correct that confirm us that there was not 900m vis.

As to whethter the APP type had nothing to do , well. we'll see but one has to remember the definition of RNP 0.3. . the GPS is not designed to align you with centre line and to maintain you there , but just to align you with the runway with a precision of 0.3 of a NM orv 500 meters.

Capn Bloggs

8th Mar 2015, 09:16

one has to remember the definition of RNP 0.3. . the GPS is not designed to align you with centre line and to maintain you there , but just to align you with the runway with a precision of 0.3 of a NM orv 500 meters.
In theory... but do you really think a system would be approved for RNP 0.3 (eg RNP Approach LNAV) if all it could do was put you within 0.3nm of the Centreline? That is "miles" off and you'd never get in on any min-vis approach. What about RNP-AR at RNP 0.1? "What are you complaining about? You're only 200m off the centreline!".

ATC Watcher

8th Mar 2015, 09:34

I'm with you but that is what the system is certified to , due various factors among which is the integrity of the signals . That is why some build expensive ground augmentation system to get precision approaches . We agree 95 % of the time GPS will get you single meters precision , but in the other 5% you can be off mark and it can be sometimes quite a bit. Fact of GPS life.
I am not saying this is what happened here , no idea , like most of us , but something to keep in the back of one's mind when trying to disregard the approach type as a contributing factor.

de facto

8th Mar 2015, 10:38

JFI there are hundreds of below standard Expats CP's (I've been exposed to at least 50+ in the sims and Check flights) out there operating day in ant out! Ask yourself every day "Do you feel lucky" or are you really doing your job?

Were you working at THY as TRI/TRE?

aterpster

8th Mar 2015, 14:11

ATC Watcher:

Well if your info is correct that confirm us that there was not 900m vis.

Isn't the AB330 an Approach Category D airplane? I so, then minimums were DA of 4670 (352) and 1600 meters. Or, if the ALS were considered inoperative because of the temporary displaced threshold, then visibility minimum of 2000 meters.

As to whethter the APP type had nothing to do , well. we'll see but one has to remember the definition of RNP 0.3. . the GPS is not designed to align you with centre line and to maintain you there , but just to align you with the runway with a precision of 0.3 of a NM orv 500 meters.

Agreed. But, the airplane would only be off by .3 of a NM 5% of the time on a statistical basis. Usually, with autoflight connected the lateral displacement would be significantly less. Something that could easily be handled with visibility of 1600 meters.

Stone_cold

8th Mar 2015, 16:00

Actually ATP , the A330 is cat C/D depending ...not sure what weight variants TK was using .

Re your comments regarding "out of the box " RNP AR certified and ICAO . The aircraft are not necessarily certified out of the box , it depends on operator requirements and many operators have databases and charts for approaches that they are not approved for( in other parts of the world ), read ICAO . E.g. RNAV / CAT II/III ,Circling .

Seems you are not so critical of the Delta runway excursion which seems to be closer to your area of regulatory oversight and happened on the same day .

Bus Driver Man

8th Mar 2015, 16:16

Isn't the AB330 an Approach Category D airplane? I so, then minimums were DA of 4670 (352) and 1600 meters. Or, if the ALS were considered inoperative because of the temporary displaced threshold, then visibility minimum of 2000 meters.
The A330-200 is a Cat. C airplane. I assume that the A330-300 is Cat. C as well.

According to AVHerald, the visibility was 1000m at the time of the approach.
The minimum required visibility is 900m, according the AIP approach chart.
However, according the THY approach chart from their LIDO database, the minimum visibility is 1.5km, which means that THY is only allowed to fly the RNP AR approach with a higher required visibility.

Algol

8th Mar 2015, 16:43

Algol:" Were the crew local or expat? ".

Boeingrestricted: "Will your professional opinion depend on the answer to your question".

Many early contributors to this thread made derogatory references to pilot standards at THY. The drift was the Turks are all dangerous.
My question was meant to remind them that there are many expat pilots on the A330 at THY.

I was wondering how they'd react if the crew turned out to be wholly or partly Expat.

Hope that answers your question.:cool:

silvertate

8th Mar 2015, 16:52

Cpt Blogs

In theory... but do you really think a system would be approved for RNP 0.3 (eg RNP Approach LNAV) if all it could do was put you within 0.3nm of the Centreline? That is "miles" off and you'd never get in on any min-vis approach. What about RNP-AR at RNP 0.1? "What are you complaining about? You're only 200m off the centreline!".

On all the GNS approaches I have done (practice VFR approaches for training), the approach is a pseudo non-precision, and not an ILS replacement. The idea is to facilitate difficult approches in high terrain. So many of them bring you in with a large approach offset, terminating in a decision of about 1,000 ft or so.

If you have a 3 nm missed approach point, there is not much point in having lateral accuracy much greater than 0.3nm. The approaches are nice, down the valleys etc. But there are gotchas, like where do you go if the FMC loses the curving path half way down.

silvertate

8th Mar 2015, 17:22

It wasn't my point. As far as I read it, Capt Blogs was saying the system should be better than 0.3 nm rnp. I am just saying that for all the GNS approaches I have done, 0.3 nm was quite sufficient because of the offset and high missed approach point.

I note on page 2 of this thread, that the GNS approach at VNKT is actually straight in for the last 3 nm, with a decision of just over 300 ft. That is a max 15º lateral turn to achieve the threshold, if you are at the margins of the 0.3 nm error for some reason. Not too bad. I'm sure someone has worked out that that is a sufficient margin. But do bear in mind that the rnp is only a 95% probablity, so five times in every hundred approaches you could be off by more than that.

silvertate

8th Mar 2015, 17:53

Aterpster

Dual GNSS
Dual FMS
FMS must provide continuity, integrity, accuracy, and alerting.

Indeed, that's what ours says too. But as far as I am concerned a little message on the scratch-pad of the FMC or on the PFD, is not the same as a big red flag on the PFD or the GPWS shouting 'glideslope'.

And dual GPS receivers are of no benefit if there is ghosting or other signal interference, as both receivers will pick up the same error. GPS signals are not as strong as an ILS, and low-level GNS navigation is a whole new ball-game.

aterpster

8th Mar 2015, 17:59

The alert is supposed to be in your primary field of view. And, of course both receivers will pick up the same error, but the receivers will detect such and send it to the FMSes.

aterpster

8th Mar 2015, 18:06

Silver:

On all the GNS approaches I have done (practice VFR approaches for training), the approach is a pseudo non-precision, and not an ILS replacement. The idea is to facilitate difficult approches in high terrain. So many of them bring you in with a large approach offset, terminating in a decision of about 1,000 ft or so.

There cannot be any offset in an RNP AR approach that has RF legs. The final roll out point (FROP) must be aligned with the runway centerline.

If you have a 3 nm missed approach point, there is not much point in having lateral accuracy much greater than 0.3nm. The approaches are nice, down the valleys etc. But there are gotchas, like where do you go if the FMC loses the curving path half way down.

If the approach value is less than 0.3 and/or the missed approach is less than 1.0, then you must have independent position information that provides sufficiently accurate position information for extraction (typically one or more IRU). It's called extraction because you may get "unable RNP" well prior to the MAP.

"Dual string" is the term the avionics engineers use. The VNKT approach is dual string because of the missed approach requirements.

Capn Bloggs

9th Mar 2015, 00:48

Silvertate, I don't want to be harsh but it seems that you and I have been on different GPS-Approach planets for over a decade. I have done dozens and dozens of these over a decade or more using three different systems and the navigation accuracy is "on the centreline", and they were not RNP-AR systems.

I am just saying that for all the GNS approaches I have done, 0.3 nm was quite sufficient because of the offset and high missed approach point.
Most of ours (RNP APCH LNAV) have MDAs of around 450-500ft. Very few are offset. 0.3nm is not "quite sufficient" to be able to get in if you pop out at the MDA.

I note on page 2 of this thread, that the GNS approach at VNKT is actually straight in for the last 3 nm, with a decision of just over 300 ft. That is a max 15º lateral turn to achieve the threshold, if you are at the margins of the 0.3 nm error for some reason. Not too bad.
Are you serious?? 0.3nm offset from the centreline "at just over 300ft". I defy anybody to safely get a medium/big jet onto the runway from that far off the centreline. Have you actually tried it? I am sometimes 0.1nm off and it is very hard work to get onto the runway. BTW, there is no offset on the approach posted on page 2. The runway QFU is 022° and the approach track is also 022°.

But do bear in mind that the rnp is only a 95% probablity, so five times in every hundred approaches you could be off by more than that.
That's nice to know; we and I assume hundreds of other operators around the world are using dual-GPS sensors for sole-means approaches. No other navaids, and no alternates. If a VOR, NDB or ILS approach had such bad "reliability" it would never be certified.

ATC Watcher

9th Mar 2015, 08:36

That's nice to know; we and I assume hundreds of other operators around the world are using dual-GPS sensors for sole-means approaches. No other navaids, and no alternates. If a VOR, NDB or ILS approach had such bad "reliability" it would never be certified.

What Silvertate said is quite correct . It is 95% of the time for RNAV and no, VOR DME or ILS Approaches performances are not the same because they are fixed based and their exact position is known 100% of the time..GPS stand alone APP is no ILS substitute . The 5% uncertainty are still there and will remain there as long as GPS ( as opposed to EGNOS , etc..) is used.
I am very surprised this fact is not known to Pilots operating the sytem.

Just a reminder for the younger generation :
When RNAV/RNP was designed RNP1 was the lowest. RNP 5 the norm aimed at. . "Nav capabilities based on sensors able to calculate your position within 5 ( or 1) NM radius 95% of the time" .
This was designed initially to reduce lateral separation on non-radar enviroment, and allow the design of closely parallel routes in radar airspace.

RNP 0.3 was intially never designed for precision APP but for helicopters in Terminal aereas. How it progressed to what it is now is due to the pressure ( lobby) of operators ( Alaska Air was the first if I remember correctly to test it in remote places in Alaska where no ground aids were available)
Nobody at the time expected the thing to be used in KTM by a non-based airline in bad weather /visibility. ( no pun meant against TK, just to illustrate a foreign crew using a system in a difficult airport a few times a year and again , not suggesting this is the cause of this accident.)
RNP 0.3 may be used in KTM in 2015 with 900m RVR successfully by many, but it is still a GPS and 95%, plus a having a USAF general somewere having access to a button that can further degrade accuracy (SA). But this is probably included in the 5%.:E

8che

9th Mar 2015, 10:11

ATC Watcher,

Accuracy 95% of the time has nothing to do with GPS. That lost 5% can not be affected by a USAF general !

ANP is a measure of the FMC POSITION accuracy not GPS. The FMC generates its position using a combination of inertial/DME-DME/LOC-DME/VOR-DME/GPS etc. The GPS is just one sensor that it can use but the ANP is a measure of FMC ability 95% of the time not GPS. Latest Boeing FMC's are authorised to 0.3 without GPS even being fitted !

and without GPS a bad radio update can certainly affect position even if they are cemented into the ground. That's why radio inhibit/purge functions are fitted to FMC's.

Anything less than 0.3 RNP (RNP-AR) and yes we currently have to use GPS but that's because ILS's don't bend around corners. Yes most of us have GPS fitted these days but lets not forget its the FMC that ultimately produces the position not the GPS.

I understand the argument between ground based and shall I say "aircraft based approaches" but ground based systems are far more expensive and limited in there geographical options and dependent on variable servicing standards throughout the world. There are almost daily reports of scalloping/interference etc. The FMC/GPS approaches are statistically more reliable and we never have and never will operate to risk free standards. All we do is manage the risk. Every approach in Pans-OPS or TERPS has a calculated probability of crashing. It may be small but its there.

aterpster

9th Mar 2015, 13:49

The 95% probability of being within 1 X RNP is a statistical probability. The 5% excursion may occur on the first RNP AR approach or it may not occur until the 100,000 approach. And this probability is for the entire fleet (world-wide) of RNP AR aircraft, not any given aircraft. So, it will occur to some aircraft in the fleet and not to others.

Further, this probability is not for GPS, or for that matter GNSS, because performance based navigation is considered to be sensor independent. As some others have said, the position used for the navigation solution goes through quite a process in an RNP AR certified aircraft.

This is not like lousy VOR radials are even more lousy NDB bearings. Odds are that you could fly the VNKT RNAV (RNP) Rwy 2 approach every day of your 35 year career and be on, or within a few feet of centerline every time.

And, to not be on, or within a few feet of center without having received an "Unable RNP" message is quite remote.

But, the engineers must deal with statistical theory when providing RNP containment areas without any secondary obstacle clearance areas that conventional PANS-OPS and TERPS have. Thus, the RNP AR containment area is 2 X RNP. And, with lower RNP values other mitigations must be included in the navigation solution, including EGPWS with enhanced database capabilities in an obstacle rich environment.

Finally, RNAP AR approaches are not "all weather" procedures, unlike fail-active CAT III autoland. RNP AR approaches have as their primary purpose the avoidance of terrain at terrain-rich locations. And, there are airports where it simply is not possible to design an effective RNP AR approach because the terrain is simply too onerous.

kinteafrokunta

9th Mar 2015, 16:23

8che...right on the money! ATC Watcher, please state your points but kindly refrain from mocking pilots operating the system " for not knowing ". The eggs can come in flying fast! Incoming.......

silvertate

9th Mar 2015, 17:00

8che

ANP is a measure of the FMC POSITION accuracy not GPS. The FMC generates its position using a combination of inertial/DME-DME/LOC-DME/VOR-DME/GPS etc.

Sorry, but I can only assume you have never seen the system in operation.

The fact of the matter is that the FMC position will closely shadow the GPS fixes, to the detriments of all other aids. The IRS and VOR-DME fixes can be miles away, and the FMC will still follow the GPS. I think the system bias must be 95% to the GPS fixes.

And therein lies another problem, because if the GNS detects a RAIM error it will stop using the GPS and 'revert to the IRS/VOR fixes', as the manual says. Yet the IRS/VOR positions could be miles away. The manual rather unhelpfully does not say how fast this transition will take, but if it is within a minute or so, you could end up with a dramatic map-shift just when you do not want it.

Regards the 95% probability, this is a sum of ALL the errors that can effect the system, especially when on the approach. It is not a measure of GPS accuracy per-se. It includes errors from the VOR-DME fix, GPS signal ghosting or reception errors, satellites not in optimal positions, insufficient satellites, atmospheric refraction, hardware noise, IRS heading errors and much else besides. Grind all that together, and you have only a 95% probability of your position being within 0.3nm. And don't complain to me about this - that is what the system says in the manual. If you don't like it, complain to the OEM manufacturer.

And finally, regards Capt Blogs. Sorry, but if you are doing a 0.3nm rnp GNS approach, that is all you are going to get. You cannot assume that the runway will always be in front of you. Why? Because that is what the system says on the tin. The 0.3 nm rnp is a pseudo non-precision approach, and not a pseudo ILS. Especially if you have no WAAS system (which Europe does not have) and don't know if someone has a $50 jammer on the airfield boundary. And if you don't like the 15 degree turn to achieve the runway, speak to the CAA who designed that approach, or speak to your flight manager and get an extra 'company 200ft' added to the minima. But whatever you do, don't always expect the GNS approach to be perfect, if you do not have WAAS augmentation and checking.

silvertate

9th Mar 2015, 17:08

aterpster

The 5% excursion may occur on the first RNP AR approach or it may not occur until the 100,000 approach. And this probability is for the entire fleet (world-wide) of RNP AR aircraft, not any given aircraft.

You obviously don't know what a probability is.

Tell you what - get one of those 20-sided dice that they have in modern board games. Now throw it 100,000 times, and see how often your chosen number comes up. See the problem now?

aterpster

9th Mar 2015, 17:58

Silver:

You obviously don't know what a probability is.

Tell you what - get one of those 20-sided dice that they have in modern board games. Now throw it 100,000 times, and see how often your chosen number comes up. See the problem now?

Two different issues. You flip a coin and over many flips it will be heads 50% of the time. Same idea with your 20-sided dice.

If it is like the roll of a dice, we better get rid of RNP AR before someone hits a mountain.

aterpster

9th Mar 2015, 18:28

From the FAA AIM:

Section 2. Area Navigation (RNAV) and Required Navigation Performance (RNP)

1-2-1. Performance-Based Navigation (PBN) and Area Navigation (RNAV)

a. Introduction to PBN. As air travel has evolved, methods of navigation have improved to give operators more flexibility. Under the umbrella of area navigation, there are legacy and performance-based navigation (PBN) methods, see FIG 1-2-1. The legacy methods include operations incorporating systems approved under AC 90*45, Approval of Area Navigation Systems for Use in the U.S. National Airspace System, which allows two *dimensional area navigation (2D RNAV) within the U.S. National Airspace System (NAS). AC 90*45 describes 2D RNAV in terms of both VOR/DME dependent systems and self* contained systems such as Inertial Navigation Systems (INS). Many operators have upgraded their systems to obtain the benefits of PBN. Within PBN there are two main categories of navigation methods: area navigation (RNAV) and required navigation performance (RNP). For an aircraft to meet the requirements of RNAV, a specified RNAV accuracy must be met 95 percent of the flight time. RNP is an RNAV system that includes onboard performance monitoring and alerting capability (for example, Receiver Autonomous Integrity Monitoring (RAIM)). PBN also introduces the concept of navigation specifications (Nav Specs) which are a set of aircraft and aircrew requirements needed to support a navigation application within a defined airspace concept. For both RNP and RNAV designations, the numerical designation refers to the lateral navigation accuracy in nautical miles which is expected to be achieved at least 95 percent of the flight time by the population of aircraft operating within the airspace, route, or procedure. This information is introduced in International Civil Aviation Organization's (ICAO) Doc 9613, Performance*based Navigation (PBN) Manual (Fourth Edition, 2013) and the FAA Advisory Circular (AC) 90*105A, Approval Guidance for RNP Operations and Barometric Vertical Navigation in the U.S. National Airspace System and in Remote and Oceanic Airspace (expected publication date in late 2014) further develops this story.

whitelabel

10th Mar 2015, 05:43

So if we check RNP agains EPE how reliable is that info then? Is that position error really the figure its indicating or can that still be very different 5% of the time? Seems highly unlikely with vor/dme/ils/irs/gps updating. The system has to warn us if data input from the gps sensors is not correct but how can it do that if it does not know that the data is false or unreliable..

LeadSled

10th Mar 2015, 06:44

The 5% uncertainty are still there and will remain there as long as GPS ( as opposed to EGNOS , etc..) is used.

I am intrigued.
Why will EGNOS change this situation, particularly if you consider the new generation GPS going up now. What is "etc.", Galileo, sundry Russian or Chinese systems? Beware the world's most accurate PR claim.

ATC Watcher

10th Mar 2015, 07:24

Ah EGNOS ! like a beautiful lady promising you things but always failing to show up at the rendez-vous!
It is an augmentation system ( similar to WAAS in the U.S. ) supposed to give you meter precision . Initially planned for 2009 , now 2020 for aviation if I am correct. But by coincidence I am going to a meeting with normally them in it tomorrow . I will ask their current status .
The "etc." . In my earlier post was referring to the various augmentation systems avail or planned , including fixed ones , to allow precision APP .

sarge75

10th Mar 2015, 07:35

Would love to hear the recording from tower, along the lines of:

ATC: "are you visual?"

Capt/FO "No"

About 20 seconds later, everyone at the airport hear a loud bang...

silvertate

10th Mar 2015, 12:23

aterpster

Two different issues. You flip a coin and over many flips it will be heads 50% of the time. Same idea with your 20-sided dice.

If it is like the roll of a dice, we better get rid of RNP AR before someone hits a mountain.

Unfortunately the rnp error probability is very nearly the same as a simple dice roll. The only difference is that a 20-sided dice has a definite 5% probability of giving any one particular number. Conversely, the rnp has an indeterminate 5% probability of being wrong at any one time. The rnp probability cannot be definite, because there are too many variables involved, and each variable has its own probability of being in error. And you will probably need a series of incorrect variables to coincide before you find yourself off track. But the total probability of error is still up to a maximum 5% chance of being off track at any one time.

And your highlight of 'population of aircraft' does not help with the probabilities, because each individual aircraft is a part of the population and therefore a part of the probability matrix. Having 5% of aircraft being probably off track, is exactly the same as saying your individual chance of being probably off track is 5%. You cannot say that any one 20-sided dice, out of 1,000 such dice, is excluded from the probability matrix.

Put it this way. If the probability of an excursion away from 0.3 nm rnp were one in 100,000 flights, as you intimated, the manufacturer of GNS systems would say:

... rnp 0.3 is expected to be achieved at least 99.999% of the flight time.
but they do not, they say:
... rnp 0.3 is expected to be achieved at least 95% of the flight time.

There is a good reason for that very large 95% caveat. The total GNS system, including all the many variables and disturbances that go together to determine the probability of your position, is not as reliable as many pilots seem to think. Especially if you are weaving through high terrain.

1,000 ft decision, anyone....?

silvertate

10th Mar 2015, 12:40

OK465

So if your only options are between a VOR NPA approach with at 6 degree descent angle or an RNP-AR APV with a 3 degree descent angle, which will you prefer to fly?

That depends, doesn't it.

If we had 20 years of experience of successful GNS approaches, we could narrow the probabilities down a bit. But launching into a new system and pretending that it is the same or better than an ILS is somewhat premature. Especially when it is only has a guaranteed 95% probability of being correct.

I was reasonably happy with the 1,000 ft decision we used in training, but less so with the 300 ft decision at this airport. And I am still not happy with a pseudo-glideslope that does not call out vertical profile errors. Do you know what the max vertical error is for the approach? And was the PNF monitoring it, all the way down the approach? Do you always know the escape procedure, if the GPS loses the plot and deletes the trackline while on the approach?

I give you the example of TCAS, which was launched as the latest thing in improved flight safety. And then the first thing TCAS does, is cause an inflight collision. The same difference exists here. Let's think through the possibilities and pitfalls a bit more, and walk before we run.

Capn Bloggs

10th Mar 2015, 13:14

Silvertate, I think you doing a bit of raving.

Please explain the GNSS error "satellites not in optimum positions" you mentioned a few posts back.

And I am still not happy with a pseudo-glideslope that does not call out vertical profile errors. Do you know what the max vertical error is for the approach? And was the PNF monitoring it, all the way down the approach?
Ever heard of, or seen, Nav Performance Scales?

Do you always know the escape procedure, if the GPS loses the plot and deletes the trackline while on the approach?

Ever heard of an IRS (as explained by aterpster earlier but which you obviously missed).

And then the first thing TCAS does, is cause an inflight collision.
What nonsense.

320goat

10th Mar 2015, 14:17

RNP-AR

There are issues with terrain masking and RAIM outages, but you look at these prior to dispatch.

As has been pointed out, if the GPS goes you revert to standard drift rate of the IRS so not a major problem immediately.

We have a procedure of checking the altimeters at the FAF and they have to be within a certain tolerance (can't remember just now as we don't have approval just yet).

If you want a gross error check on vertical profile, I tend to use 320' per nautical mile for a 3 degree glide.........not too difficult.

aterpster

10th Mar 2015, 16:19

ok465:

A Powerpoint Honeywell presented a few years ago:

https://aerospace.honeywell.com/~/media/Brochures/Gulfstream%20PlaneView%20RNP%20Economic%20Benefit.ashx

Not exactly a roll of the dice.

silvertate

10th Mar 2015, 19:34

Capt Blogs etc:

>>Satellites not in optimal positions.

The satellite constellation is fixed, while the Earth rotates inside it. Thus the number of satellites you can see, and the declination and azimuth of those satellites, will change during the day (and with your location). Some locations and times are better than others - especially if there is a satellite outage in your area.

>>Nav Performans Scales
>>and vertical profiles

Not fitted in our steam driven Boeing. But we do have the approaches in the FMC. Beginning to see the problem of the lack of regulatory oversight?

>>IRS backup.

Worse than useless. As I said before, our IRS fix can easily be a couple of miles away from the GPS fix, and the VOR/DME is not much better in mountainous terrain. So if you lose the GPS on the approach, and the FMC position reverts to IRS fix position, you get a rapid 2nm map-shift. Ok, so the nearest mountain peak is only a couple of nm away, and the autopilot is trying to recapture the new IRS trackline which is 2nm away - your move, as they say...

>>TCAS assisted incidents.

The Swiss collision would not have happened without TCAS. It was a total system usage error that had not been fully thought through and promulgated to all airlines and crews before the incident.

>>RAIM outages.

RAIM is real-time monitoring of the satellite constellation. You cannot determine RAIM outages by NOTAMS. Or are you telling me that the NOTAMS know exactly when the next satellite will be hit by some space debris, or lose its IRS stability system?

>>300ft per nm

Brilliant. The max altitude deviation on a 0.3 nm rnp approach is just 75ft, and the hills are all around you. Is that a satisfactory check? Do you really monitor ILS glideslope excursions by doing a 3x crosscheck?

de facto

10th Mar 2015, 20:18

Troll alert.

Aterpester..good link:ok:

aterpster

10th Mar 2015, 20:48

de facto:

Troll alert.

At the least, hasn't been through the training.

silvertate

10th Mar 2015, 21:51

aterpster

A Powerpoint Honeywell presented a few years ago:
https://aerospace.honeywell.com/~/media/Brochures/Gulfstream%20PlaneView%20RNP%20Economic%20Benefit.ashx (https://aerospace.honeywell.com/%7E/media/Brochures/Gulfstream%20PlaneView%20RNP%20Economic%20Benefit.ashx)

Not exactly a roll of the dice.

Sorry, but did you read that Powerpoint link? It says (p10), quote:

RNP ... indicated by RNP-X is a value in nautical miles from the intended horizontal position, within which an aircraft would be at least 95% of the total flying time.

That means with rnp 0.3 you will be within 0.3 nm of your intended position 95% of the time, which is what we have been saying. So what point were you trying to make with this link?

ok465

Would you personally fly one without authorization just because nobody was watching?
I think you can gather from my posts, that I would not (except in VFR as a pseudo visual). But that did not stop half the fleet doing these approaches, because no guidance had been given. And it did not stop other operators either, because one inbound would do the GNS approach and the next from the same operator would say 'we don't have authorisation'. Confusion seems to be the order of the day.

And the multiplicity of notation does not help. The USA might have RNP-AR, but in Europe we generally have RNAV GNSS. EPKT Katowice in Poland or EGBB Brum in the UK are GNSS approaches. There are a few around. LTBS Dalaman GNSS in Turkey is more pertinent to this thread, as it goes through the hills and is offset.

And then when you get to Spain we have the LEMG Malaga GLS approach. Now a GLS is actually a GBAS Landing System (GLS) - an approach that uses a WAAS or an EGNOS. I hope you got all that. In other words, Malaga uses the new EGNOS system, which is the European WAAS lookalike, and therefore eradicates most of the problems discussed here.

EGNOS augmentation:
EGNOS in Aviation: Vertical Precision for Improved Approaches | European GNSS Agency (http://www.gsa.europa.eu/node/226)

de facto

Troll alert. Aterpester..good link :ok:

I see it is play time at school again.

If the THY A330 had not been perfectly aligned with the centerline, due what has been discussed here, then the resulting landing may have been more tricky. Just sayin'.

HardCorePawn

10th Mar 2015, 22:08

>>RAIM outages.

RAIM is real-time monitoring of the satellite constellation. You cannot determine RAIM outages by NOTAMS. Or are you telling me that the NOTAMS know exactly when the next satellite will be hit by some space debris, or lose its IRS stability system?

Wait what? So what exactly is this RAIM prediction feature that the local airways services outfit provides on it's web based flight planning/NOTAM service all about then? Or for that matter, the RAIM calculation built into many GPS units (Garmin 430/530, G1000 etc)???

I'll think you'll find that RAIM prediction is very much possible due to the "fixed" nature of the constellation, and being able to calculate if there will the appropriate number of satellites available to facilitate the use RAIM at a given place at a given time.

Obviously, the RAIM in the onboard system will then make sure everything is working nicely, "in realtime", when you actually get there... And provide the appropriate "RAIM unavailable" type warnings should anything be amiss (like a satellite getting hit by debris in the interim etc)

aterpster

10th Mar 2015, 23:15

Silver:

Sorry, but did you read that Powerpoint link? It says (p10), quote...

Indeed, many times. Did you note ANP? RNP is a performance minimum. ANP is much better on RNP AR approaches or alerting will require the pilot execute an extraction.

As to IRU drift, on any airframe approved for RNP AR of less than 0.30, there are generally three IRUs, with blended position updated continuously by GPS/GNSS. So, if an alert is received that requires extraction, the IRU position is the same as the GPS position was when the alert is received. From that point on (which is very rare) the IRUs begin drifting. This drift is accounted for very conservatively in RNP AR missed approach criteria.

RNP AR is presently the term used for this type of approach throughout the world. The U.S. stopped using RNP AAAR several years ago.

Capn Bloggs

10th Mar 2015, 23:25

>>TCAS assisted incidents.

The Swiss collision would not have happened without TCAS. It was a total system usage error that had not been fully thought through and promulgated to all airlines and crews before the incident.
Rubbish; the TCAS was going to save them; the Russians didn't follow the TCAS instructions like they were supposed to. Don't blame the (pretty simple) technology for human incapacity.

And the multiplicity of notation does not help. The USA might have RNP-AR, but in Europe we generally have RNAV GNSS. EPKT Katowice in Poland or EGBB Brum in the UK are GNSS approaches. There are a few around. LTBS Dalaman GNSS in Turkey is more pertinent to this thread, as it goes through the hills and is offset.
Come on. Working out the difference between RNAV GNSS and RNP-AR is pretty basic stuff. Surely you don't just call up an approach in the database and say "gee this looks good, let's give it a go!"?. That Turkey approach (https://fly.rocketroute.com/plates/adminview/LTBS_IAC_04_-_RNAV_(GNSS)_RWY_19.pdf?cmd=pdf&docid=400000000091023&icao=LTBS) is a bog-standard RNAV (GNSS) that the world has been doing for years and is "tiger moth" stuff compared to an RNP-AR. It has got a minor kink early on but is dead straight from 3000ft down. Offset? Yes, and that is much less desirable than that RNP-AR at Kathmandu. As pointed out earlier, RNP-AR has an aligned final. You seriously need to get into Google and understand what you're talking about before carrying on here.

The satellite constellation is fixed, while the Earth rotates inside it. Thus the number of satellites you can see, and the declination and azimuth of those satellites, will change during the day (and with your location). Some locations and times are better than others - especially if there is a satellite outage in your area.
You can't be serious...

>>IRS backup.

Worse than useless. As I said before, our IRS fix can easily be a couple of miles away from the GPS fix, and the VOR/DME is not much better in mountainous terrain. So if you lose the GPS on the approach, and the FMC position reverts to IRS fix position, you get a rapid 2nm map-shift. Ok, so the nearest mountain peak is only a couple of nm away, and the autopilot is trying to recapture the new IRS trackline which is 2nm away - your move, as they say...
I now see why you're so worried about the "mystical" GPS. If you "lose the GPS" and have a sudden 2nm map-shift your outfit shouldn't be doing GPS approaches, period. Sounds like a bunch of cowboys trying to do the good stuff with totally unsatisfactory gear.

NSEU

11th Mar 2015, 01:07

The satellite constellation is fixed, while the Earth rotates inside it. Thus the number of satellites you can see, and the declination and azimuth of those satellites, will change during the day (and with your location). Some locations and times are better than others - especially if there is a satellite outage in your area.

To expand on Capt Bloggs useful remark...

Global Positioning System - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Global_Positioning_System)

The satellite constellation can be varied, and the satellites do rotate around a rotating earth if you believe Wikipedia (at twice the earth's speed). The satellites are not fixed in space relative to the earth, if that's what you mean. Their altitudes are about 3 times the diameter of the earth, so this helps coverage greatly. The official websites do say that 6 should be available almost anywhere on earth, but if you read some websites, it says that these satellites should be "above the horizon". If you're in a deep valley or flying below the top of a mountain range, your horizon may well be limited. With a satellite out, perhaps GPS coverage could get pretty sparse. However, depending on your navigation system, your map position shouldn't suddenly start moving sideways to the pure IRS position when you lose your GPS. The nav system should maintain a constant bias towards the previous radio-based position until you reacquire a new radio position or the system is reset. The difference is not (normally) suddenly washed out.

Luke SkyToddler

11th Mar 2015, 02:49

So do any of you guys have any info relevant to this KTM accident, was there in fact some issue with how the Turkish pilots flew the RNP approach on that day, or are you just having a willy waving contest over who knows the most intricate knowledge of RNP / RNAV?

It's all very interesting but I'll bet my bottom dollar it's completely irrelevant to this accident. The approach was fine until the point where they actually had to look out the window and determine if they could see the bloody runway or not.

It doesn't matter what kind of high tech you have on board, what approvals you have, or what kind of approach you do, if you elect to continue below minima without sufficient visual reference.

Capn Bloggs

11th Mar 2015, 05:04

Not willy-waving, Luke, education. :ok:

sarge75

11th Mar 2015, 05:13

Luke, for what happened, see my last post.

May not be word for word but is how it was described by someone on the radio at KTM at the time

ironbutt57

11th Mar 2015, 05:15

I found our OM-C comments re the KTM VOR approach.."in the event of loss of VOR or DME a missed approach is required..."...hmmmm that would have been interesting in our non-GPS 767.

PT6Driver

11th Mar 2015, 05:20

Educated willy waving then?:O

Boeingrestricted

11th Mar 2015, 10:14

couldn't agree more , willy waving - since this is getting your education on a rumor network instead of your officially backed books.

Capn Bloggs

11th Mar 2015, 11:22

So Boeingrestricted, where in his "books" is silvertate going find out about RNP-ARs? Perhaps you don't realise it, but there is a great deal of knowledge put forward by members of Prune. If one is a professional pilot who has a basic handle on things, it is easy to sort the wheat from the chaff and learn a lot.

Pininstauld

11th Mar 2015, 11:53

The post-crash selfies look as if they were taken in pretty thick fog. Did I miss something...

Black Pudding

11th Mar 2015, 13:13

I have to agree totally with Luke SkyToddler (http://www.pprune.org/members/5812-luke-skytoddler) post

He posted

So do any of you guys have any info relevant to this KTM accident, was there in fact some issue with how the Turkish pilots flew the RNP approach on that day, or are you just having a willy waving contest over who knows the most intricate knowledge of RNP / RNAV?

It's all very interesting but I'll bet my bottom dollar it's completely irrelevant to this accident. The approach was fine until the point where they actually had to look out the window and determine if they could see the bloody runway or not.

It doesn't matter what kind of high tech you have on board, what approvals you have, or what kind of approach you do, if you elect to continue below minima without sufficient visual reference.

The questions I would like to ask are these

What was the reported viz before they commenced each approach, how much fuel did they have left after their second approach and what was their planned diversion strategy ie to where and did they have enough fuel to get there ?

de facto

11th Mar 2015, 13:23

Actually reported vis is the main point at their approach ban and minima.
Seeing the runway with reported fog may not warrant a safe landing.
Entering the flare and the fog at the same time could lead to obvious difficulties eventhough you saw the runway from a different height/angle.
Respecting given visibility is paramount to a safe and legal approach and landing.

silvertate

11th Mar 2015, 21:21

Luke

So do any of you guys have any info relevant to this KTM accident? Or is this willie-waving?

If the KTM A330 was not aligned with the runway centerline, due to an rnp offset as discussed here, it could have contributed to this incident. It is a possibility to consider.

However, having mentioned these innacuracies of the GNS approach system, various critics came out of the woodwork claiming that GNS is a navigational panacea that is never wrong. And they are still claiming that GNS works to the accuracy of the ANP, when ANP is only the performance at this moment in time. Clearly, some operators need to set up training programs to discuss the design, operation and pitfalls of the standard GNSS approach system.

The known inaccuracies of GNSS is why the WAARS and EGNOS augmentation systems are being developed. Why spend all that money on a new augmentation system, if the original GNS is always 100% accurate? Answer - it is not that accurate, which is why it says 95% accurate on the tin.

P.S. Yes, the orbits of the satellites stay fixed, while the Earth rotates underneath them, just as I said. So the azimuth and declination of the satellites is constantly changing - with satellites setting behind the hills as you make the approach.

Below is a nice GPS satellite animation.
Note that the orbits remain fixed, resulting in an ever-changing azimuth and declination of the satellites your receiver is tracking.
The blue satellites are the ones that are visible. Note the changing number of satellites visible, and remember that this number will be less in high terrain.
The green lines indicate the azimuth and declination of each satellite. Note how satellites drop behind the horizon and are then deleted.
Remember that satellites in the zenith (overhead) provide little or no lateral navigation input, while those on the horizon are subject to refraction errors.

http://upload.wikimedia.org/wikipedia/commons/9/9c/ConstellationGPS.gif

ok 465

Actually GLS and WAAS are two different animals.
No they are not. WAAS and EGNOS are both GBAS (ground based augmentations systems) for GNSS approaches.

A GNSS approach plus a GBAS equals a GLS. So they are all part of the same system - a system that will eventually eradicate the errors being discussed here.

aterpster

11th Mar 2015, 22:33

ok465:

Lots of folks don't realize that Hawaii doesn't have WAAS either.

Capn Bloggs

11th Mar 2015, 23:38

The known inaccuracies of GNSS is why the WAARS and EGNOS augmentation systems are being developed. Why spend all that money on a new augmentation system, if the original GNS is always 100% accurate? Answer - it is not that accurate, which is why it says 95% accurate on the tin.

For goodness sake! WAAS gives better accuracy: lower minima eg for LP and LPV approaches! That is all!

GLS same: lower minima, no need for expensive ILS gear.

Do you really think someone didn't think of "hey hang on, that satellite is going to drop out of view! What is a crew going to do then?!" That's what RAIM, FD and FDE is all about.

reynoldsno1

12th Mar 2015, 00:43

WAAS and EGNOS are both GBAS (ground based augmentations systems) for GNSS approaches
I think you'll find that's SBAS (space based augmentation system).

aterpster

12th Mar 2015, 01:09

Gastineau Channel: Alaska Airlines has continued to defy the 95% probability.

Otherwise, they would be out of business because of all the fatal CFITs.

Say Mach Number

12th Mar 2015, 07:29

I understand from the info I have there are no runway centre line lights at this airport.

When i saw this it reminded me of something that happened to me and who knows might have been a factor with the THY.

Thanks to a good co pilot I got away with it.

Landing from minimums with low vis and blowing crosswind, when I broke out of cloud with the aircraft in a crab I got sight of the lights and continued towards what I thought was the centreline however it was the left edge of the runway.

My co pilot called go-around, which at the time I didn't understand but knew he must have had a good reason.

Going downwind he explained and then it dawned on me what I had done. During the approach briefing I had made no mention of no centre line lights and assumed the airport had them.

Landed from the second approach but was shocked how my mind had convinced me of an image that looked absolutely right at the time.

In other words did they line up with the edge lights thinking they were on the centre line?

andrasz

12th Mar 2015, 07:34

aterpster, don't confuse probability with overall accuracy. GPS navigation is perfectly fine for terrain avoidance as long as one gives a wide-enough margin to allow for the inherent inaccuracy. One does not buzz a peak in IMC with a 50ft clearance if one can avoid it. On the other hand, that 50 feet will make the difference between green and grey on a landing.

I use GPS waypoints in the Sahara regularly, and it is common occurrence to find marked points be off the actual position by 5-10 metres on a return years later, and that is without the altitude component.

That being said, me too would welcome a return to the thread topic.

sleeper

12th Mar 2015, 10:53

Whatever the accuracy of the RNP-AR, it is still a requirement to fly the part below minimum manual AND be visual with the runway(environment). If not, Go Around.
The approach is designed to be safe and get you to a position near the runway if you stay within the designed limits.
If the .3 or .15 allowable deveation does not bring you to an acceptable, but safe, position to land, then don't land.
If it looks good at MDA continue, but keep in mind that any weatherdeterioration after that also mandates a Go-Around.

Gordomac

12th Mar 2015, 15:19

andasz ; I too welcomed a return to topic but my post was removed. Mods like this stuff here rather than in the Tech Log pages. All of us know what happened at KTM, it was always waiting to happen. It will happen again. No amount of willy waving will make a cloudbreak procedure a safe Cat111.

aterpster

13th Mar 2015, 00:46

sleeper:

If it looks good at MDA continue, but keep in mind that any weather deterioration after that also mandates a Go-Around.

Good point and perhaps "on point" for this accident. But, keep in mind this VNKT RNP AR approach, and all RNP AR approaches have a DA, not an MDA.

aterpster

13th Mar 2015, 00:53

Gordomac:

All of us know what happened at KTM, it was always waiting to happen. It will happen again. No amount of willy waving will make a cloudbreak procedure a safe Cat111.

I don't think all of us know what happened at KTM. No doubt RNP AR is not a precision approach for purposes of landing. Such procedures are better than, "cloud break" (I like that colorful phrase) but they are not non-precision IAPs, rather more like LNAV/VNAV at DA.

andrasz

13th Mar 2015, 06:27

All of us know what happened at KTM

Perhaps this is a too strong statement to agree with, let's just say neither the airline nor the airfield come as a complete surprise in the context of this accident. I think the only ones who really know what happened are the ones who were sitting in the front row, and they are still busy figuring out exactly what to remember.

ECAM_Actions

13th Mar 2015, 07:42

The whole discussion of RNAV RNP is pointless as the end of the approach is VISUAL, because it is a NON-PRECISION APPROACH.

If indeed they were flying an NPA, they reached MDA, they made the call to land, and the rest is history.

As for the rest of it...I'm waiting for the official report as always.

sleeper

13th Mar 2015, 08:07

Aterpster,
DA/MDA same principle. Below it is visual and manual.

golfyankeesierra

13th Mar 2015, 08:22

In other words did they line up with the edge lights thinking they were on the centre line?
Good point Mach!
Exactly what I thought when I read they touched with one gear outside the runway.
This one is shouting visual illusions...

Capn Bloggs

13th Mar 2015, 08:27

The whole discussion of RNAV RNP is pointless as the end of the approach is VISUAL, because it is a NON-PRECISION APPROACH.

Well there ya go! Here's me thinking that all the (Cat 1) ILS's I've flown also had a visual bit at the end, just like all the NPAs I've flown, and just like this RNP-AR! How wrong I was. No need to look out the window to land visually at all, apparently, given an ILS is a PRECISION approach.

The fact of the matter is that, within a bulls-roar, this RNP-AR would have placed the aircraft in exactly the same spot (horizontally and vertically) as if it had been an ILS. The actions required by the crew at the Decision Altitude (yes, on this non-ILS approach) would have been exactly the same.

ECAM_Actions

13th Mar 2015, 08:56

@Capn Bloggs: You're right. NPA isn't the only type of approach where you land visual at the end. Whilst your sarcasm is duly noted, I hope the essence of my post wasn't lost upon you.

Allow me to re-phrase: regardless of how the aircraft got to MDA, the pilots decided to land. Let's wait for the hopefully accurate analysis of the FDR/CVR for the rest.

sarge75

13th Mar 2015, 15:58

Heard from someone on the plane that it took almost 10 minutes before they opened the doors to let them out

aterpster

13th Mar 2015, 19:06

sleeper:

Aterpster,
DA/MDA same principle. Below it is visual and manual.

Yes indeed. Except at DA you are in the slot, so to speak, and presumably the aircraft is in final configuration for landing. No so on approaches with MDA.

sleeper

13th Mar 2015, 19:46

Semantics again. For both you need enough visibility to make a safe landing.
And yes for a nonprecision it is more.
If some-one lands on the runway-edge lights he/she clearly did not see enough.

ATC Watcher

14th Mar 2015, 07:02

For those that want to learn something here : just back from a meeting with some experts on RNP present . (i.e. EGNOS and Airbus ) I asked a few questions and now know a little bit more about RNP APPs and this is how it works ( on Airbus aircraft at least ) in simple terms.

The 0.3nm accuracy is only for the last part of the App segment not for the whole APP . 2 minutes before FAF , the RAIM box inside the aircraft will verify if all the satellites are aligned and if the position they received is correct and will be guaranteed for the next 5 minutes . The guaranteed precision you will get is still 0.3,NM either side of track , but in practice it is better . The correct definition is “ The system will guarantee that in the next 5 minutes your deviation will not be superior to your RNP value “

If the RAIM cannot guarantee the integrity it will issue a warning that should result in a go around (if IMC ),but this accuracy is only guaranteed for 95 % of the time.( although in practice it is better ) Only with an augmentation system ( such as WAAS or EGNOS ) you will get more than 99% . But Never 100%, mainly because of solar activity . 2014 had a very strong solar peak activity and the lowest was 99,4 . Better availability is expected in 2015.
EGNOS is already available today for regional’s and business jets , for large airliners the first aircraft fully factory equipped is the A350 . Retrofit for older types is expensive. But remember EGNOS is only for Europe .

What is more interesting is he obligation to follow certain rules to actually perform an RNAV-AR APP :you need certified aircraft, certified and trained crews , a certified airport and trained air traffic controllers . It is not because it is in the aircraft data base that you can use it . And there lies our first problem.
.
The other is when an airport changes things in the ground or in the runway and do not tell the people that make the data bases . Remember that one .

Next : some airports have issued visual RNAV APP plates on their own and there are currently no official procedures for them , hence the (correct) IFALPA warning.

Finally all strongly ay that RNP is not and never will be a substitute for ILS,. It is still a non precision APP and should be treated as such.
Now I put my willy back where it belongs and leave the discussion over to the "real" experts here.

320goat

14th Mar 2015, 07:32

Thank you for taking the time to post that. Interesting.

Capn Bloggs

14th Mar 2015, 08:54

Thanks ATC Watcher. Interesting. I think the first thing that needs to happen is understanding the changing, blurring concepts of approaches. In the old days, we had ILS (THE precision approach) and all the others (NPAs). That's changed because now some GNSS approaches are also classed as precision approaches eg GLS.

The new descriptions are 2D and 3D approaches (http://www.icao.int/Meetings/PBN-Symposium/Presentations/Workshop%20B/1.%20Flight%20Operations%20Requirements%20Forum/F04%20-%20Miguel%20Marin/PBN%20Symposium%20-%20Flight%20Ops%20Workshop%20Approach%20Classification.pdf); 2D being lateral guidance only (VORs, NDBs, RNP APCH eg RNAV (GNSS) ) and 3D, being lateral and vertical guidance eg ILS, MLS, GLS, RNP APCH LNAV/VNAV, LPV and RNP-AR.

As I mentioned before, for all intents and purposes, an RNP-AR is virtually a precision approach because you are required to follow the vertical guidance/path, just as you have to on an ILS. It puts you at 300ft on final 1nm out. A GLS puts you on final at 200ft and 2/3nm out. We should therefore be talking about 2D and 3D approaches now, not Non-Precision and Precision.

As for the idea that a crew would try to use an RNP-AR when they hadn't been trained or approved for it, that equates to gross negligence on the part of the company for not ensuring that it's pilots knew that, as well as the regulator for letting it happen (and of course the crew for being so ignorant).

airport30

14th Mar 2015, 13:33

You can find new picture from the Airbus 330
“GÖBEKLÝTEPE” BU HALE GELDÝ (http://www.airkule.com/haber/GOBEKLITEPE-BU-HALE-GELDI/19835)

Toruk Macto

14th Mar 2015, 15:21

Expensive fix ? Will she even fly out ?

Una Due Tfc

14th Mar 2015, 15:24

Less than a year old so more than likely she's worth saving

Super VC-10

14th Mar 2015, 15:40

Looking at the photos in the link posted by Airport 30, it's going to have to be fixed at Kathmandu, isn't if? I'd say that would mean it would take a lot longer than would otherwise be the case.

fox niner

14th Mar 2015, 19:33

Well, they have already removed "Turkish" from the paint scheme. Is that significant?

jack11111

14th Mar 2015, 20:07

Normal face-saving SOP.

ATC Watcher

15th Mar 2015, 06:55

2D-3D , yes agreed ! What I find very confusing is the multitude of abbreviations basically reffering to the same thing (i.e. 3D, APV, LPV, GBAS, GLS, RNP Precison APP, pseudo ILS, etc..) If everyone would use the term " with vertical guidance " and clearly separating basic GPS navigation from the Nav with augmented systems ( WAAS and EGNOS) instead of using " RNP " for both , things would be a little clearer for everyone I guess.

Back to KTM : the RNAV APP there is a basic GPS one , not with vertical guidance and it is a 2D and non-Precision APP .

Re Training : I was not targeting the crews here, but also the controllers.
Certification is easy, training all staff is more compicated. Throwing a couples of photocopies from a training manual into the lockers can hardly be called training, yet it is sometimes what is done in some places, and not only in the thirld world.
Reading the BEA report I was refering to in post #80, http://www.bea.aero/docspa/2012/f-pe120403.en/pdf/f-pe120403.en.pdf lack of undertanding the procedure due lack of proper training is highlighted here with multiples incidents by same airline at same airport.

Often both controllers and crews do not see the difference between "offering" an RNAV APP and "instructing" to do one. There lies the source of many problems if you ask me.

Capn Bloggs

15th Mar 2015, 08:19

Back to KTM : the RNAV APP there is a basic GPS one , not with vertical guidance and it is a 2D
I doubt it, if you're referring to the approach in Aterpster's post 22.

Our CAA rules for conduct of an RNP-AR approach: "After the aircraft has passed the FAP or VIP on an approach, deviation from the defined vertical path must not exceed the limiting value for vertical deviation stated in the operator’s RNP AR operating procedures." = 3D approach.

Note that the minima is a DA; no point in trying to fly to a DA, especially with a vis limit of 900m, if you're flying some sort of pilot-created profile.

sleeper

15th Mar 2015, 09:50

ATC Watcher,
Back to KTM : the RNAV APP there is a basic GPS one , not with vertical guidance and it is a 2D and non-Precision APP .

It is a fullblown 3d , as you call it, rnp ar approach with a 2.8 degree glidepath.
See: http://www.caanepal.org.np/publication/AIP%202011%20Amendment/AIP_AMDT_AIP_SUP_2012/RNP%20AR_AIRAC%20AIP%20SUP%2003%20May%202012_22-05-2012%20Final.pdf

ATC Watcher

15th Mar 2015, 10:20

You are both right, I stand corrected.

from the AIP sup point 2.6 :
The vertical guidance is based on Baro VNAV with GNSS and requires RNAV equipment which uses barometric altimeter input.

What confused me was the fact that the guys at the meeting kept reffering to the 3D in conjunction with the "ground augmented" LVPs APPs.
While it would seem Baro VNAV is indeed part of a 3D APP.

The rest of the AIP sup is interesting too, thanks Sleeper.

Wookey

15th Mar 2015, 12:50

Well, they have already removed "Turkish" from the paint scheme. Is that significant?

Looks like the guy with the white paint has tried to be a bit creative with the starboard side!

aterpster

16th Mar 2015, 01:08

ATC Watcher:

What is more interesting is he obligation to follow certain rules to actually perform an RNAV-AR APP :you need certified aircraft, certified and trained crews , a certified airport and trained air traffic controllers . It is not because it is in the aircraft data base that you can use it . And there lies our first problem.

In the U.S. it won't be in your database unless all certification and qualifications have been met.

I would add to the experts take on RNP AR. AB's airplanes that can do RNP AR 0.30 approaches are ready and able to do RNP 0.10. If a pilot flying into VNTK is worried about being offset up to 0.30, he/she can force the FMS to use 0.10. Thus, the 5% probability maximum offset would be 608 feet. An FMS calculated exceedence in excess of RNP 0.10 would alert 'Unable RNP."

And, of course, the RNP AR pilot is always seeing a value for ANP.

deefer dog

16th Mar 2015, 10:05

Judging by this thread those who dreamt up, designed, drew the charts, named the procedures, certified them, trained for their use and worked in ATC to control aircraft equipped to use this new technology have actually increased the margin for error because so few of those who use it haven't for a clue of what it is all about!

If ever there was a topic that needed a clear and unambiguous explanation and training material, this for sure must be one. Jesus, I don't even understand the naming conventions associated with RNP, but I'm still permitted to fly the approaches!

Cognoscenti

16th Mar 2015, 22:42

For those whom may want a basic understanding of RNAV approaches.

oxWm81YHPlg

Eurocontrol RNAV Factsheet (http://www.eurocontrol.int/sites/default/files/publication/files/2013-rnav-approaches-factsheet.pdf)

aterpster

17th Mar 2015, 14:28

Notice that the fact sheet mentions RNP AR only at the bottom left.

aterpster

17th Mar 2015, 14:34

deefer dog:

If ever there was a topic that needed a clear and unambiguous explanation and training material, this for sure must be one. Jesus, I don't even understand the naming conventions associated with RNP, but I'm still permitted to fly the approaches!

I can only speak for the U.S. The training, avionics familiarity, simulator time, and line qualifications makes any pilot quite conversant in all aspects of RNP AR. And, the RNP AR IAPs are a separate database the Jeppesen, etc, will not provide for the aircraft until the requirements are met. The FAA is very insistent that all the squares be filled it correctly.

silvertate

19th Mar 2015, 00:50

Capt blogs

The new descriptions are 2D and 3D approaches (http://www.icao.int/Meetings/PBN-Symposium/Presentations/Workshop%20B/1.%20Flight%20Operations%20Requirements%20Forum/F04%20-%20Miguel%20Marin/PBN%20Symposium%20-%20Flight%20Ops%20Workshop%20Approach%20Classification.pdf);
2D being lateral guidance only (VORs, NDBs, RNP APCH eg RNAV (GNSS) )
3D, being lateral and vertical guidance eg ILS, MLS, GLS, RNP APCH LNAV/VNAV, LPV and RNP-AR.
You are getting confused again, Capt Blogs. The vast majority of GNSS approaches are 3-D approaches, with both lateral and vertical guidance (baro vertical tracking). I presume your RNAV-AR approach has some kind of LAAS/WAAS ground augmentation, and is therefore more accurate, but I presume it is still only a baro vertical tracking system.

The KTM approach is a GNSS with baro vertical guidance (but called here RNAV RNP). As ATC Watcher said, the confusing terminology does not help here - with many different acronyms for the same type of approach, that do not exactly explain the differences between them (RNP-AR, RNAV RNP, GPS RNAV, GNS, GNSS, GLS).

And sorry, but this GNS debate is relevant to this thread. I know several companies whose pilots were all doing GNSS approaches last year, even though the company had no certification, the Part A had no information, and the pilots had no training. Not saying that is what happened here, but there is definitely a regulatory lacuna here.

It could also be a factor if the training that was given did not point out that GNSS is only a non-precision approach. It would appear that many posters even on this thread, thought that GNSS was a precision approach. So the first time the GNSS approach displaces you 0.25 nm left or right of the centerline might come as a bit of a shock. This is why I questioned the 350' decision at KTM, because this seems a bit low for a possible 0.25 nm displacement.

Oh and as an aside WAAS is a GBAS, it is just that the signals are relayed via standard comms satellites, because it is a wide angle system (a large area system) and not a local system. So what I said is correct - the WAAS system itself is a ground based system and NOT a satellite based augmentation system. (How can a geostationary satellite augment a low-earth orbit satellite? :ugh:) See the quote below.

Quote:
The Wide Area Augmentation System (WAAS) uses a system of ground stations to provide corrections to the Global Positioning System navigation signal. A network of precisely surveyed ground-based WAAS wide-area reference stations is strategically positioned across the country including Alaska, Hawaii, Puerto Rico, Canada, and Mexico to collect GPS satellite data...

GNSS Frequently Asked Questions - WAAS (http://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/techops/navservices/gnss/faq/waas)
GNSS Frequently Asked Questions - GBAS (http://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/techops/navservices/gnss/faq/laas/)

The links posted previously in this thread are confusing in their terminology - as is most of the terminology used in these systems. The distinction should be between WAAS and LAAS, and not between WAAS and GBLS. Both WAAS and LAAS are GBLS systems (ie: ground based augmentation systems) - it is just the former is a wide area system via satellite and the latter is a local area system via VHF. But it is true that WAAS and LAAS are not compatible, because they receive the ground-based corrections via different antennae.

Oh, and Capt Blogs. Do you now understand that the orbits of the GPS satellites are fixed? The last time you responded by saying: "You can't be serious...". Do you understand how the system works now? You have gone quiet all of a sudden.

And when I said that GNSS is non-precision (because of its low 0.3nm lateral precision, even though it has vertical guidance), you ridiculed that assertion. But now you respond with: "For goodness sake! WAAS gives better accuracy ... That is all!" Hmm, I think you will find that is what I have been saying from day one, but you did not understand the limitations of the system you are using.

GNSS is a non-precision 3-D landing system.
GNSS plus WAAS-LAAS is a precision 3-D landing system.

And GNSS plus a WAAS-LAAS is a GLS (err, usually). But the terminology is very imprecise here. Since the WAAS and the LAAS have different receivers, they should clearly notate the different approaches to reflect this - something like GLS-W and GLS-L. Or even better, just have GNSS, GNSS-W and GNSS-L.

I hope that is clear - sort of.

silvertate

19th Mar 2015, 01:34

Sleeper

It is a fullblown 3d , as you call it, rnp ar approach with a 2.8 degree glidepath.
See: http://www.caanepal.org.np/publicati...12%20Final.pdf (http://www.caanepal.org.np/publication/AIP%202011%20Amendment/AIP_AMDT_AIP_SUP_2012/RNP%20AR_AIRAC%20AIP%20SUP%2003%20May%202012_22-05-2012%20Final.pdf)

Interesting, because the approach plate displayed earlier in this thread does not say that (no mention of -AR on the plate). It is May '14, so not sure if it has been updated or not. More problems with naming conventions?

Capn Bloggs

19th Mar 2015, 03:51

And GNSS plus a WAAS-LAAS is a GLS (err, usually).
Rubbish. A GLS (http://www.skybrary.aero/index.php/GBAS_Landing_System_(GLS)) does not include or use WAAS. It has it's own single ground station on (or close to) airport. Similar in principle to a LAAS, but not the same.

It is a fullblown 3d , as you call it, rnp ar approach with a 2.8 degree glidepath.
Interesting, because the approach plate displayed earlier in this thread does not say that (no mention of -AR on the plate). It is May '14, so not sure if it has been updated or not. More problems with naming conventions?
Rubbish again. Do you know how to read Jeppesen plate notes? Do some RNP-AR training and then you will realise what the note "Authorisation Required" means and what it allows you to do and how the approach works.

GNSS is a non-precision 3-D landing system.
GNSS plus WAAS-LAAS is a precision 3-D landing system.
When you understand how the various systems are now being used, you'll realise that the terms "Non-Precision" and "precision" are becoming meaningless. 2d and 3d are all that is necessary to describe an approach type and procedures. After that, it is the minima that counts, nothing else whether it is an ILS to 200ft or a GLS to 200ft or an LPV to similar, the (3D) approach is flown in exactly the same manner.

Satellite positions/orbits/rotations are irrelevant; RAIM predictions take that into account, including planned outages. I assume you have been doing RAIM predictions before launching for Turkey and the RNAV (GNSS) you do at Dalaman?

I will agree with ATC Watcher and Deefer Dog that to the untrained eye, the naming convention for RNP approaches is confusing. An RNAV (GNSS) is actually now an RNP APCH LNAV and an RNAV (RNP) is actually an RNP AR APCH. I don't know what the solution is, though. Here, most GNSS' are RNAV-Z and RNP-ARs are RNAV- (insert other letters eg M, U, P).

The only reason I've been quiet is because you haven't been posting furphies recently...

deefer dog

19th Mar 2015, 09:55

Only another 7 years of confusion remaining!

The meeting may wish to note that the amendment regarding the conversion of area navigation (RNAV) approach procedure depiction to required navigation performance (RNP) in the PANS-OPS, Volume II is required to align charts with the PBN navigation specifications thereby reducing confusion on operation approvals and flight planning requirements. A one-step eight-year transition period, starting 13 November 2014, is being proposed......

International Civil Aviation Organization
Performance Based Navigation Sub-Group (PBN SG)
First Meeting
(Cairo, Egypt, 1 - 3 April 2014)

aterpster

19th Mar 2015, 15:45

Silvertate:

Interesting, because the approach plate displayed earlier in this thread does not say that (no mention of -AR on the plate). It is May '14, so not sure if it has been updated or not. More problems with naming conventions?

http://i201.photobucket.com/albums/aa214/aterpster/VNKT%20AR%20Snippet_zpswhjle8as.jpg

reynoldsno1

19th Mar 2015, 22:08

WAAS consists of multiple ground reference stations positioned across the U.S. that monitor GPS satellite data. Two master stations, located on either coast, collect data from the reference stations and create a GPS correction message. This correction accounts for GPS satellite orbit and clock drift plus signal delays caused by the atmosphere and ionosphere. The corrected differential message is then broadcast through 1 of 2 geostationary satellites, or satellites with a fixed position over the equator. The information is compatible with the basic GPS signal structure, which means any WAAS-enabled GPS receiver can read the signal.

WAAS is a satellite based augmentation system
EGNOS is a satellite based augmentation system (ICAO definition)
SBAS is a wide coverage augmentation system in which the user receives augmentation information from a satellite based transmitter (ICAO definition)

de facto

29th Mar 2015, 12:35

Any news of what happened?Is the aircraft still there?

Don Quixote

30th Mar 2015, 09:14

Was still there a week ago ...

Nemrytter

30th Mar 2015, 09:31

Oh, and Capt Blogs. Do you now understand that the orbits of the GPS satellites are fixed? That's a bit of a simplification - they are only fixed when considering short periods of time. Over the course of hours their orbits will change due to outside influences (sun, moon, etc) and the shape of the Earth.

sarge75

31st Mar 2015, 15:27

Still there this morning.

Think it will still be there in 3 months

7478ti

31st Mar 2015, 19:11

The real issue here is the unnecessarily and inappropriately high DA(H). Properly designed RNP procedures with correctly applied Baro VNAV VEBs are typically good enough technically to support DA(H)s down to about 250' HAT or even somewhat below. So any unnecessarily high DA(H) situation leads to potential risk of visually mishandling the trajectory below DA(H), ...just as with the KSFO B777, KBHM A300, or recent Libreville B747-8 hard landing for that matter. So while these RNP approaches provide vastly better vertical guidance to about 200' HAT than any other VOR, VOR/DME, NDB, LOC, or BCRS approach, ....we still eventually also need the benefit of GBAS/GLS, to provide the accuracy, integrity, and availability to support use of LAND3/AIII modes all the way through flare and rollout for these kinds of marginal visibility situations. GLS/GBAS is both entirely possible and economically practical at places like VNKT, to augment and complete these already better RNP approaches than any other alternative.

Both the terms "Precision and Non-Precision" are long obsolete as a practical matter, and were even dropped from use in references like FAA AC120-28D and AC120-29A. The FAA/JAA/Industry AWO HWG even tried to once move ICAO and ANSPs toward simply designating approaches as 2D or 3D, recognizing that any and all approaches need to be flown "precisely". Further, RNP is vastly more precise than even ILS for much of the total track mile distance of the arrival procedure, until typically very close to the runway, and for ALL of the MAP. hence it is instead ILS that, for locations like VNKT, would more appropriately be considered as "Non-Precision".

WAAS and EGNOS are SBAS. WAAS IS NOT CONSIDERED to be GBAS, period, even though it uses a few ground reference stations to derive the space broadcast corrections.

Only GLS (and JPALS and Portabas and equivalent) are considered as GBAS.

None of these RNP procedures should need to be considered as AR any more by authorities globally, beyond simple applying criteria like FAR121.445 compliance. RNP and GLS, as well as use of LAND2/LAND3 are now basic elements of safe routine operation of any modern transport jet. Instead, it is ADF/NDB, VOR, LOC, BCRS, PAR, and "Circles" that perhaps now ought to be considered and treated as "AR".

FO Cokebottle

1st Apr 2015, 13:52

So any unnecessarily high DA(H) situation leads to potential risk of visually mishandling the trajectory below DA(H), ...just as with the KSFO B777, KBHM A300, or recent Libreville B747-8 hard landing for that matter. :ugh:

With the current debate regarding experience and inexperience of Air Transport category pilots what are you advocating here...........that's a rhetorical questions - don't answer.

Being a pilot requires you to PILOT the aeroplane. If you do not possess or maintain the skills, at least for the last 600' to point it at your aim point, to do so, you should seriously consider your future.

What is precision and non-precision whether 2d or 3D are all mute points. The real issues in this incident are these:

1. Company dispatching policy when weather is forecast and known to be below minimums at the destination at the scheduled time of arrival (if a nil divert policy was in place).
2. Adherence to company fuel policy and minimum divert fuel policy.
3. Airmanship by not allowing yourself nil safe alternative options.
4. Lack of Technical and Procedural knowledge regarding the requirements for the approach to be flown - centre line guidance is required to conduct an Autoland legally
5. Adherence to Company SOP's - Company visibility minimums for this approach at this destination.

These are the issues that require redressing.

The technical aspects of designing approaches, whether PANS-OPS or TURPS, at the pilot level, are adequately dealt with in Jeppesen VOL 1.

The AOM/FCOM of the aircraft details in the limitations section the requirements and equipment serviceability/redundancy needed to conduct the approach - whether ILS (glideslope max/min angle for an Autoland as an example) if CAT I/II/IIIa/IIIb, VOR, NDB, RNAV/GNSS or APV - IAW Company OPS SPEC.

The Company Training/Standards Manuel will have the necessary training and recurrency requirements for conducting its day to day operations which also include LVO OPS using the different approaches/NAV AIDS, again IAW with Company OPS SPEC.

This information is all in the books and is expected that the pilot to be at least aware of and know where to reference the information in the books - The books concerned are required to be on the aircraft.

JanetFlight

2nd Apr 2015, 20:10

Seen from inside:

GkLUriZPqIM

& part 2

https://www.youtube.com/watch?v=sr7Y65quulU

Capn Bloggs

3rd Apr 2015, 00:11

If that is the accident flight, that video puts to bed any question of the visibility at touchdown! :eek:

2:28 shows the left side 300m fixed distance marking clearly visible from the window. The centreline of the aircraft must have been very close to the left edge of the runway.

7478ti

3rd Apr 2015, 01:30

@ Cokebottle. Yes, better following SOP, the FCOM, and FCTM (and common sense) certainly helps. But we've been having jet transport hull losses in similar circumstances, by very experienced pilots trying to do the right thing for the circumstances encountered, since the dawn of the jet age, and before, ...in fact back to the 1930s, with the advent of the first radio nav aids. Accidents like this are now completely unnecessary, as much as an accident due to an R2800 blown jug or shedding an R3350 or Allison 501 prop blade are no longer necessary. That landing would have been entirely routine, with fully using RNP combined with GLS, and use of the autoflight modes already installed and long available to that flight crew. So this failure is a failure of the entire system, ...from authorities, to ANSPs, to airports, to the operator not insisting on cost effective options and solutions when making aircraft purchases, and it is not just for the flight crew to take 100% of the blame. Let's not go another decade now, unnecessarily costing jets and risking crew and passenger lives, with accidents like this one, and CYHZ. There is now a much better way, for equivalent or less cost.

FO Cokebottle

3rd Apr 2015, 03:20

JanetFlight:

You beat me to it.

Just viewed the link to the video and was going to post it here.

Yes indeed - pretty well puts it into the slumber party category.

Tom Imrich:

That landing would have been entirely routine, with fully using RNP combined with GLS, and use of the auto flight modes already installed and long available to that flight crew.

The GNSS Landing System does not provide for centre line guidance - only the "Back Course" of the ILS or MLS can provide such guidance for an autoland.

What you are praising is LPV. Please read the direct copy and paste from Wikapidia....

"Localizer performance with vertical guidance (LPV) are the highest precision GPS (WAAS enabled) aviation instrument approach procedures currently available without specialized aircrew training requirements, such as required navigation performance (RNP). Landing minima are usually similar to those in an instrument landing system (ILS), that is, a decision height of 200 feet (61 m) and visibility of 1/2 mile.[1] Although precise and accurate, it is still considered a Non-Precision approach. According to the Instrument PTS, you may use a GPS approach down to LPV minimums to substitute a precision approach."

There is NIL centre line guidence for an auto land with a GPS based navigation system. The Pilot's either did not know this fact or had no other option due to poor decision making.

There was nothing routine about this landing.

sabbasolo

3rd Apr 2015, 04:36

Interesting towards the end of the video part 3, that the cabin crew are seen standing around with their cabin baggage on the runway - not only did the passengers take it with them down the slides, so did the crew !

7478ti

6th Apr 2015, 23:44

@ Cokebottle. Your assertion reference RNP and GLS/GBAS, that "GLS does not provide rollout guidance", is completely false and incorrect. GLS provides outstanding rollout guidance, over the full runway, from and for ANY approach direction, including for any runway that would be applicable at VNKT. It (GBAS) also as well provides an extremely accurate positioning signal to assist in providing very low RNP values for missed approach (e.g., RNP.003) for the initial missed approach segment, until the path returns to using some higher but still adequate RNP level (e.g., RNP .1) as needed. Further, Wikipedia is not the appropriate place to be finding key modern aviation criteria. Instead, try sources like AC120-28D Table 4.5.1-1, and similar provisions. LPV and SBAS remain an obsolete, virtually useless waste of money, in this kind of global air-transport environment, needing RNP paths to a short FAS, able to benefit from LAND3/AIII (or Airbus equivalent) AFDS modes.

MrSnuggles

7th Apr 2015, 09:58

I enjoyed the lax attitude from passengers and crew alike.

"Oh, we actually landed in one piece! Great, now get your things and go out. What, the stairs don't work? That's OK, we're used to the slides, just let me get my Big Bag of Precious Things here... Cabin Crew, you don't forget your suitcases this time! It was a helluva lot of work to retrieve them last time something happened!"

Found it hilarious. Sure, I know the dangers about runway excursions, overruns, landing short etc. But this seemed like a planeload of people that went there, done that, bought the tshirt already.

fox niner

7th Apr 2015, 11:28

More than a month ago now. Has any preliminary report emerged out of these foggy circumstances?

Kirks gusset

7th Apr 2015, 12:15

Just the " internal report" :ok:

slast

7th Apr 2015, 12:32

FO Cokebottle, if I were you I'd be a bit cautious about backing Wikipedia against Tom Imrich - just research his bio!

aterpster

7th Apr 2015, 13:38

I would agree with that.

But, I strongly disagree with Tom about the merits of LPV. LPV has made possible CAT I precision minimums for well over 1,000 U.S. light airplane airports that previously had lousy instrument approaches (IFPs) or no IFPs at all.

OTOH, the bar for RNP AR is set so high by the FAA only the airlines and high end business jets can enter that "club." For business aviation even those who have qualified RNP AR airframes, the price of qualifying and maintaining the equipment, crews, and avionics is simply not worth the price or effort to many of those operators.

RNP AR feathering to GLS may be wonderful in 20 or 30 years.

7478ti

8th Apr 2015, 18:14

Aterpster, I agree that LPV was once a useful idea, back in the 50s and 60s, and maybe continuing into the 70s. But we had the chance to make the change in the 90s to go directly to (vastly superior) RNP, and bypass the entire generation of SBAS driven angular-straight-in criteria and systems. Sadly authorities didn't capitalize on the opportunity. Now we have a global mess, just as predicted. But I do agree that LPV is (temporarily) less bad than VOR, NDB, LOC, BCRS and even 2D RNAV, .... but that could easily and instantly change with simple revision of authority criteria. It is an authority issue, that primarily fouled this all up, and it is now up to the industry to help fix it. RNP can be simple, easy, and done by anybody down to LSAs. It isn't rocket science. It is only being made unnecessarily complex by authorities lacking vision, experience, and technical knowledge to implement the right criteria. Remember back to the days when basic TJ minima were 300 and 3/4, and only "expert pilots" could fly Cat I minima!!! That was all baloney, fixed by any modern AFDS, so that now any basic instrument pilot flying a C172 can do it, as well as any air-carrier airplane delivered out of the box. The exact same possibility could now be true for RNP. It is vastly safer, simpler, easier, better, more capable for efficient airspace use, and could even be less costly than any other alternative. The same goes for GBAS/GLS which is already vastly better (and safer) than the Wilcox ILSs we first approved for Cat III use back at KIAD, KDEN, KATL and KSFO, as well as the AN-GRN27s we used at the 31 other sites nationally with publication of AC120-28B on Dec 1st 1977.

FO Cokebottle

11th Apr 2015, 12:15

My reply to Tom Imrich...now known as 7478ti

1. Wikipedia was used as it provided the simplest and shortest definition, in layman's terms, to explain the aspects of what was being discussed. Remember KISS.

2. GLS/GBAS - Yes point conceded if the airport has the suitable equipment to provide the GBAS portion of the marriage. However, the procedure approach flown was a RNAV(RNP) not a GLS/GBAS

Your specific reference AC120-28D also states:
AC 120-28D
07/13/99
Page
48
1. Operations Specification.

Pilots and aircraft dispatchers should be familiar with, and properly
able to apply, operations specifications applicable to Category III landing or low visibility takeoff.

2. Normal and Non-normal Procedures.

Pilots should be familiar with appropriate normal and
non-normal procedures including crew duties, monitoring assignments, transfer of control during normal operations using a "monitored approach," appropriate automatic or crew initiated call-outs to be used, proper use of standard instrument approach procedures, special instrument approach procedures, applicable minima for normal configurations or for alternate or failure configurations and reversion to higher minima in the event of failures.

3. Weather and RVR.

Pilots and aircraft dispatchers should be familiar with weather associated
with Category III and proper application of runway visual range, including its use and limitations, the determination of controlling RVR and advisory RVR, required RVR equipment, appropriate light settings for correct RVR readouts and proper determination of RVR values reported at foreign facilities.

4. Use of DA(H) or Alert Height.

Pilots should be familiar with the proper application of Decision Height or Alert Height, as applicable, including proper use and setting of radar altimeter bugs, use of the inner marker where authorized or required due to irregular underlying terrain and appropriate altimeter setting procedures for the barometric altimeter consistent with the operators practice of using either
QNH or QFE.

5. Use of Visual Reference.

Pilots should be familiar with the availability and limitations of visual
reference encountered for taxi, takeoff, and approach. Approach visual reference limitation information should at least address aircraft geometry limitations on visual reference, actions to take with loss or partial loss of visual reference, risks of inappropriate use of visual reference, and necessary visual references for continuation after Decision Height, if a Decision Height is applicable. Issues listed in section 6.2.7 above for continuation or discontinuation of an approach in deteriorating weather conditions should be comprehensively addressed.

Pilots should be familiar with procedures for an unexpected deterioration of conditions to less than the minimum visibility specified for the procedure during an approach, flare or roll out including the proper
response to a loss of visual reference or a reduction of visual reference below the specified values when using a Decision Height and prior to the time that the aircraft touches down.

The operator should provide some means of demonstrating the expected minimum visual references that occur on approach when the weather is at acceptable minimum conditions, and the expected sequence of visual queues
during an approach in which the visibility is at or above the specified landing minimums. This may be done using simulation, video presentation of simulated landings or actual landings, slides or pictures showing expected visual references, computer based reproductions of expected visual references, or other means acceptable to the FAA

In this case the RNAV(RNP) VIS MINIMA is 900M for CAT C Aircraft. I have been led to believe that the Company MINIMA for this approach is 1500M.

Hence my point regarding the decision making processes in this "actual" accident.

I understand the debate for more automation vs pilot experience requirements - However, I stand on the latter side of the arguement. I have witnessed the actions of those who fly by the ADFS when it stops doing what they wanted it to do - KSFO RWY 28 QUIET BRIDGE as a specific and perfect example.

In the end, I am just a line driver that follows Company Procedures (including being familiar with Jeppesen VOL 1) to allow me to keep working and earn a pay cheque. Not doing so will get you terminated. Anything more out on the line is akin to going down a "Rabbit Hole".:ok:

7478ti

11th Apr 2015, 16:55

Yes Cokebottle, those were some of the very words that I originally wrote, now decades ago...

But my point is that in an era when we can reliably land UAVs on pitching, rolling, carrier decks blind, within a foot laterally and a few feet longitudinally, with sensors now on virtually all modern production transport jets, using the computing power of about an iPad, and modes like LAND3/LAND2/AIII, using techniques like RNP and GLS/GBAS (or JPALS), ... then the hull losses at places like VNKT, KSFO, KBHM or CYHZ are completely unnecessary.

I'm advocating that we all, just like or forefathers argued in 1939 for ILS versus NDB/ADF (the experienced airline pilots and airlines supported ILS [Air-Track, YB, and NBS], versus the Air Corps that instead supported the A-1 Hegenberger system [ADF]), ... we all should now argue globally for the substantive near term full implementation of the vastly better RNP and GLS/GBAS, allowing for full use of our FMSs and AFDS modes like LAND3/AIII.

Both we, and our passengers and cargo, will then be able to confidently put these kinds of unfortunate unnecessary accidents in the past.

aterpster

11th Apr 2015, 17:57

Cokebottle:

In this case the RNAV(RNP) VIS MINIMA is 900M for CAT C Aircraft. I have been led to believe that the Company MINIMA for this approach is 1500M.

Isn't the AB330 a CAT D airplane?

Another factor is this NOTAM, which was in effect on the date of the accident:

V0071/15 - [DOD PROCEDURAL NOTAM] RUNWAY DISPLACED. RUNWAY 02 THRESHOLD DISPLACED 120 METERS (400 FT) UNTIL FURTHER NOTICE. 09 APR 20:05 2015 UNTIL 01 JUN 00:01 2015. CREATED: 09 APR 20:05 2015

In the U.S., at least, the RNP AR would have been NOTAMed OTS until the threshold is no longer displaced.

FO Cokebottle

11th Apr 2015, 18:05

7478ti I have heard that "drone drivers", sitting in their air conditioned connexes, are putting them in an alarming rate - but that maybe another argument/thread for another day.

Automation dependency and complacency will always be a factor which can not be ignored. Then there are the "knowledge" and "experience" factors that are required so that you now what is doing and what it has to do next, thus actively "monitoring" the FMA changes, speeds, decent rates and distances to which where derived from the NAV Database and how they relate to the approach chart for your category of aircraft.

In short, you have to know what it all means and how it applies and remains within legality.

Anyone can select RWY xx RNAV APP with a XXXXX TRANSITION and sit back and watch letting it fly all the way to touch down and roll out - its knowing why and for what reason at the particular airport for this runway and what to do when degradation occurs both the aircraft required systems and from the signal.

After all, this particular accident occurred after RNAV(RNP) approach with a DA(H) of 4650' with a threshold height of 4318 which will give a required visual segment of 332'. However, due to "legalities" this approach is to be conducted as a non-precision approach, so, an additional 50' has to be added to the DA(H). The resultant vertical/height minima is well above the standard CAT I to which you are expected to perform a manual landing after "breaking out" and with runway "environment" visual. In fact, it is common to fly a CAT I ILS manually.

My point is that it is necessary to understand what is going on and the "flight" is in accordance with the Company's OPS SPEC.

The posted pax video indicates that the aircraft descended into fog well after the DA(H). I hark back to the decision making process from the beginning back in Istanbul.

Believe it of not 7478ti, but out on the line, doing a basic GNSS/LNAV approach, the number of times I have said., "you're in VNAV ALT - you know that, right" and the response was "yes, I know" and then we go over the FAF and bloggs just sits there staring at the PFD - looking at what?? who knows. My intervention then is required. OR they do it when they are in VNAV SPD.:ugh:

System understanding let alone understanding VNAV is in very short supply - most don't know they are required to look at the RNP value to check it is within the required value before conducting the approach - and you want them to get their heads around GLS/GBAS?

FO Cokebottle

11th Apr 2015, 18:21

aterpster,

You would think it was CAT D but it is not. It is classed as a CAT C aeroplane.

This accident occurred on the morning of MAR 4th, so a NOTAM effective from the 9th APR has nil bearing on the actual accident flight.

A possible cause for the issuance of the NOTAM may well be due to landing threshold pavement damage due to the "hard landing" of the accident aircraft.

aterpster

11th Apr 2015, 22:34

Cokebottle:

This accident occurred on the morning of MAR 4th, so a NOTAM effective from the 9th APR has nil bearing on the actual accident flight.

A previous version of the NOTAM was effective at the time of the accident. I mentioned it in Post #29 on March 4th. Here is the NOTAM on the date of the accident:

V0030/15 - [DOD PROCEDURAL NOTAM] RUNWAY DISPLACED. RUNWAY 02 DISPLACED 120 METERS UNTIL FURTHER NOTICE. 19 FEB 17:45 2015 UNTIL 31 MAR 00:01 2015. CREATED:
19 FEB 17:49 2015

Also, you mentioned above having to add 50 feet to the VNKT DA if I understood you correctly. It's a DA, so that must be an operator specific requirement. It would not be for a U.S. operator.

iceman50

12th Apr 2015, 01:59

A330 IS a CAT D aircraft, I operate it!

Stone_cold

12th Apr 2015, 04:59

Maybe in HKG ( Cathay ) . I previously replied to ATP on this .

http://www.airbus.com/fileadmin/media_gallery/files/tech_data/General_information/Airbus_ICAO-ARC_FAA-ADG_App-Cat-Feb2013.pdf

This suggests that the standard is in fact C , but I believe that there cat D variants . Don't assume that your Airlines Procedures or variants are the standard . Heaven forbid , a "Heavy" is CAT C .

Hope it is not a blow to the ego that that some 321's are CAT D .

RunSick

12th Apr 2015, 05:14

How can somebody that operates a heavy jet not know which category the airplane is? :ugh:

Isn´t this related to speed above the threshold, which, should be an important speed to know? At least as a rough guess?

RunSick

12th Apr 2015, 05:16

Or does your company make you do flapless landings as part of the SOPs for fuel savings??? :}

FO Cokebottle

12th Apr 2015, 05:33

aterpster:

1. NOTAM - Okay, understand now and agree (missed your #29 post). In this age of self dispatching armed only with your "flight pack" just printed off by yourself, how many pilots actually review NOTAMS and provide a NOTAM Brief to all the operating tech crew, especially when under time pressure?

2. +50' - Refer to ICAO Annex 6 Part 1, Chap 4 which deals with Aerodrome Operating Minima (AOM). Operators may determine their own AOM after considering the factors listed in Annex 6 or alternatively that can add 50' to the charted DA/MDA. This is dependent on the approach design criteria of PANS-OPS (new/old) and State Rules and Procedures which can be found in Jeppesen VOL 1.

The USA uses TERPS design criteria.

The definitions of DA and MDA (non-precision) is the main contributing factor for Company's requiring a +50' additive.

A DA is an altitude whereby a "decision" to continue or execute a missed approach must have been made - the aircraft is permitted to decent below that altitude either for the purpose of continuing the approach or in the process of executing a missed approach.

A MDA (Minimum Decent Altitude) is used for non-precision approaches and is an altitude that can only flown below if the approach is to be continued. The aircraft is not allowed to decent below this altitude when executing a missed approach.

Hence, for non-precision approaches, Company's mandate the +50' additive to ensure legal compliance in the event of a missed approach being executed.

Here are some direct copy and pastes from my Company's SOP:
Non-precision approaches are ILS Localiser only, VOR, NDB, RNAV(GPS), RNAV(GNSS) or GPS and may be conducted using VNAV to define the vertical approach path.
Approaching the FAF, set the MCP ALT to the MDA +50 feet

iceman50:

Well congratulations and I guess you have it up on me because I don't operate it.:cool:.

I assumed "it" to be CAT D also )through ignorance) but in a previous post in this thread it was stated that THY has their A330 as CAT C. (Stone_cold has clarified this now - thanks). Hence I based my short reply on that post as that post was answering a question related to why the crew elected to do the initial approach when VIS was reported to be 1000M. Keep in mind that the initial approach resulted in a missed approach because the runway environment was not visual at the DA(H).

Being CAT D only increases the MINIMA for height and VIZ.

This debating and splitting of hairs is all great but the "elephant in the room" is still in the room gentlemen. The PIC intentionally or unknowningly (or combination of both) disregarded SOP and State Rules and Procedures for this flight.

The key word in all this is "POTENTIAL" - what was the potential for an accident. The responsibility of every pilot is to mitigate the potential for an accident. Sh@te, that is why we are there!

In this case, the potential was instigated back in Istanbul dispatch and only increased as the flight progressed because of the "decision making processes" of the flight crew.

RunSick:

Cynicism young man - Cynicism........:D

Handling Speeds are used to establish aircraft category and are set out in State AIP and Jeppesen for those who actually care enough to look.

The aircraft weight standard is Certified MLW and the resultant speeds are defined for approach segments:
1. Vat
2. IAF
3. FAF
4. Visual manoeuvring (Circling)
5. Max SPD for Missed Approach

sleeper

12th Apr 2015, 11:48

RunSickHow can somebody that operates a heavy jet not know which category the airplane is?*

Isn´t this related to speed above the threshold, which, should be an important speed to know? At least as a rough guess?

Depends on the type of aircraft your company has. For instance, mine has the B777-200 and -300. The first is cat C , the second cat D.
So if you fly for an airline with only -300 type, you wouldn't know the -200 is a different cat.
I imagine the airbustypes have the same category differences.

RunSick

12th Apr 2015, 11:57

@sleeper

Yes, you´re right about the category changes accoding to variants. That is the case of the A340 for example.

However, ALL A330 variants are CAT C.

Cheers.

aterpster

12th Apr 2015, 13:25

Coke:

1. NOTAM - Okay, understand now and agree (missed your #29 post). In this age of self dispatching armed only with your "flight pack" just printed off by yourself, how many pilots actually review NOTAMS and provide a NOTAM Brief to all the operating tech crew, especially when under time pressure?

I have my views about the crew and NOTAMs but that isn't my point. My point is that the aviation authority with responsibility for the VNKT Rwy 2 RNP AR approach should have (still should) issue a NOTAM to not authorize the approach until the threshold work is completed. And, approach control/tower should not be using that approach until the runway is restored to the same threshold that is in the FMS database.

FO Cokebottle

13th Apr 2015, 00:45

aterpster:

I agree with you, however, never assume that ATC (including the hapless chappie in the TWR) read NOTAMS. I can list many personal experiences.:ok:

With technical crew......need I continue?

deefer dog

13th Apr 2015, 01:00

Most of us know what happened here. It will all come out in the report. Be patient and spare the mud slinging.

Maybe the report will highlight just how confusing and unclear the regs are to normal operating pilots, and point out that those operating the aircraft need to receive clarity so we know what the fcuk we are allowed to to, and what we are not!

I'm authorized to carry out these approaches (and have had sim training) at this airport as a private operator, but now I'm confused! It would appear to be the case that my authority is confused also.

Stone_cold

13th Apr 2015, 04:53

Don't think it's mudslinging .

Regardless of the type of NPA , from some point (MDA/DA) , to continue the approach ,visual contact with the runway must exist . As this was not CAT111 B NO DH ,the crew should have initiated a go-around if they lost visual contact at any time after this point .

The 3D/2D RNAV , GPS , LPV GBAS , AR etc. , the legality/requirements to commence approach , the notams , minimums are all nice discussion items , but would be probably deemed contributory . They didn't hit anything on the approach , they impacted the airport surface after supposedly being visual . Maybe they mis-identified the runway/taxi-way ? But this was in the landing / visual phase .

ATC Watcher

13th Apr 2015, 08:36

approach control/tower should not be using that approach until the runway is restored to the same threshold that is in the FMS database.

ATC is not in a position to do that. Only the Nelaese Aviation authority can close the APP. A controller never force you to do any kind of approach, it can propose one , but up to the crew to accept or not depending on their own equipment, its qualifications and its company minima. And it that include integrating NOTAMs changes such as this one .
Just to remind you that NOTAMS are asumed to be read by the crew when contating ATC. We do not have to check, and frankly do not have time.

Also, to understand this particular case, remember this is a A330 from a large International carrier coming to a third world country, the local ATC is very unlikely to challenge a pilot decision there.

aterpster

13th Apr 2015, 14:29

Coke:

I agree with you, however, never assume that ATC (including the hapless chappie in the TWR) read NOTAMS. I can list many personal experiences.

With technical crew......need I continue?

Nonetheless, the procedure should have been NOTAMed OTS because of the displayed threshold. Then, the tech crew may have seen the NOTAM.

I think the ICAO folks wouldn't be pleased with the lack of such a NOTAM then and now. But, they advise, not control such circumstances. It could have an affect on the accident report, though.

aterpster

13th Apr 2015, 14:35

ATC Watcher:

ATC is not in a position to do that. Only the Nelaese Aviation authority can close the APP. A controller never force you to do any kind of approach, it can propose one , but up to the crew to accept or not depending on their own equipment, its qualifications and its company minima. And it that include integrating NOTAMs changes such as this one .

I understand what you are saying, but when an approach is NOTAMed OTS because of a runway problem, then local ATC should be briefed to not use the approach for safety reasons, sort of like a closed runway.

At KLAX, for example, when they had a long term project to reconfigure the taxiways to accept the A380, the construction equipment didn't close 25R but it render the ILS unusable for months. Approach control knew this and cleared aircraft for the RNAV approach or if the crew couldn't do RNAV, they were assigned a different runway with a useable ILS.

Of course, this is academic at VNKT, the approach wasn't (and isn't) NOTAMed OTS.

JammedStab

13th Apr 2015, 16:01

Most of us know what happened here. It will all come out in the report. Be patient and spare the mud slinging.

Maybe the report will highlight just how confusing and unclear the regs are to normal operating pilots, and point out that those operating the aircraft need to receive clarity so we know what the fcuk we are allowed to to, and what we are not!

Most of us know what happened? Well not all of us know. How about telling us as a report may not be out for two years and in that time, some of us that don't know what happened could encounter the same situation.

Help prevent a repeat accident by telling us what happened. By not doing so, you could be one of the holes in the Swiss cheese if it happens again.

ATC Watcher

13th Apr 2015, 16:38

aterpster :

I agree fully , the hint was in my last sentence.
LAX is not KTM ,and the 300 USD/month local TWR controller is not going to challenge the authority that issued the NOTAM and who apparently thought a 400ft displaced threshold was no problem for the RNAV procedure , and is also not going to challenge the crew of a TK A330 who apparently agreed to perform that approach.

Somewhere down the line it would appear that very few people understand what " AR " really means, and I include myself in this.
But that said, I do not think one of the main cause of this accident was the displaced threshold.

aterpster

14th Apr 2015, 01:09

ATC watcher:

Somewhere down the line it would appear that very few people understand what " AR " really means, and I include myself in this.

No doubt about that. But, the crew was, or should have been, trained to understand it. Same for the aviation authority of Nepal. (although the approach was probably designed by experts outside of Nepal and, in fact, the aviation authority of Nepal may not have understood it, at least not as to the important nuances.)

But that said, I do not think one of the main cause of this accident was the displaced threshold.

Probably not. But, then again the illusions created by the airplane being in a vertical position in space at DA to land on a runway 400 feet closer could have been a contributing factor. hypothetical: "Reduce your descent, Captain, we are too low."

FO Cokebottle

14th Apr 2015, 04:36

aterpster:

then again the illusions created by the airplane being in a vertical position in space at DA to land on a runway 400 feet closer could have been a contributing factor.

"illusion" implies you can see the object concerned - in this case the runway. In this case the aircraft descended into fog (see previous posted video clip). I will not even discuss "slant visibility" and its effect on "forward visibility" as this is basic knowledge.

ATC watcher:

Exactly - welcome to the real world - not the 1st world.

JammedStab:

Help prevent a repeat accident by telling us what happened. By not doing so, you could be one of the holes in the Swiss cheese if it happens again

By ignoring just about every basic rule/regulation regarding the IFR, including but not limited to:

1. Flight Planning (Dispatch)
a. Alternate requirements
b. Fuel Requirements
i. holding fuel
ii. minimum fuel [including minimum divert fuel]

2. Holding and Instrument Approach to Land Procedures
a. Meteorological minima for the approach

3. Aerodrome Meteorological Minima
a. Landing Minima
b. Low visibility operations/procedures (application of such procedures)
c. Application of Aerodrome Meteorological Minima
i. Pilot responsibilities
ii. ATC assessment

In short, the PIC may have had all these cards in their hand but due to the decision making processes, for what ever reason, discarded them one-by-one until there was nil other alternative/option other than to land in such weather conditions by conducting a Low Visibility Operation (LVO) autoland onto a runway that, as aterpster has pointed out, was NOTAM'ed with a displaced threshold, which is a lesser issue than that of the runway, itself, was not to the equipment/facility standard required to conduct such a landing in LVO conditions.

The belief that an RNAV/RNP, RNAV/GNSS approach makes you bullet proof is a fantasy that has invaded the profession. As discussions with 7478ti have disclosed, there is so much more that has to be in place to conduct these approaches to a CATII, CATIIIa/b minima/standard both in the airborne equipment and training of aircrew to the ground based facilities and training of ATC.

As an example compare the VOR and RNAV/GNSS approach minima to RWY 35 at OEMA.

This "accident" will no doubt be used, in the future, as a valuable lesson in CRM and application of SOP, Rules and Procedures and how they are incorporated into the decision making process of pilots.

JammedStab

14th Apr 2015, 13:55

JammedStab:

By ignoring just about every basic rule/regulation regarding the IFR, including but not limited to:

1. Flight Planning (Dispatch)
a. Alternate requirements
b. Fuel Requirements
i. holding fuel
ii. minimum fuel [including minimum divert fuel]

2. Holding and Instrument Approach to Land Procedures
a. Meteorological minima for the approach

3. Aerodrome Meteorological Minima
a. Landing Minima
b. Low visibility operations/procedures (application of such procedures)
c. Application of Aerodrome Meteorological Minima
i. Pilot responsibilities
ii. ATC assessment

In short, the PIC may have had all these cards in their hand but due to the decision making processes, for what ever reason, discarded them one-by-one until there was nil other alternative/option other than to land in such weather conditions by conducting a Low Visibility Operation (LVO) autoland onto a runway that, as aterpster has pointed out, was NOTAM'ed with a displaced threshold, which is a lesser issue than that of the runway, itself, was not to the equipment/facility standard required to conduct such a landing in LVO conditions.

Not sure I understand. I heard they held for quite a while due to poor weather. Did they hold for such a long time that they could no longer get to their alternate? Was their alternate New Delhi which has CAT III?