BE1900 IMC CFIT in Alaska
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Annex 14:
Terrain is flat until you head for the course-reversal hold at ZEDAG. The 2550' mountain is smack in the center of the holding pattern. ATC should have climbed the flight to 5,400 before they entered the downwind TAA.
http://aeronav.faa.gov/d-tpp/1303/05166R19.PDF
Iīd like to say now there is even more than a mystery why they had to hit that mountain. The Speed / Altitude graph clearly shows they were at a safe altitude until few minutes before the crash.
http://aeronav.faa.gov/d-tpp/1303/05166R19.PDF
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Fully agree!!
At the very moment they turned off AWY V 453 MEA no longer was valid for them, instead the mentioned MOA 5400 ft.
With that now no longer applicable " to maintain or above 2000 ft" part of their clearance in mind the crew might have expected to be safe under RADAR control and probably too pre-occupated with the weather at Dillingham to catch the flaw.
Would be also interesting to get to know what their filed FL on the flightplan was.
Anyway, according the Metars no chance to break clouds from that 2000 ft altitude. Guess thatīs the reason why they went inbound ZEDAG for a normal RNAV approach.
At the very moment they turned off AWY V 453 MEA no longer was valid for them, instead the mentioned MOA 5400 ft.
With that now no longer applicable " to maintain or above 2000 ft" part of their clearance in mind the crew might have expected to be safe under RADAR control and probably too pre-occupated with the weather at Dillingham to catch the flaw.
Would be also interesting to get to know what their filed FL on the flightplan was.
Anyway, according the Metars no chance to break clouds from that 2000 ft altitude. Guess thatīs the reason why they went inbound ZEDAG for a normal RNAV approach.
Last edited by Annex14; 17th Mar 2013 at 08:45.
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Still no-one able or willing to answer my query about ATC in those parts and what sort of service the a/c might have been having.
1) Before we start lambasting the controller, based on what we know the a/c was NOT 'descended' to <2550' by ATC. The crew either deliberately did it (in the wromg place) or some event caused it. To say "ATC should have climbed the flight to 5,400 before they entered the downwind TAA" implies the controller had descended the a/c - which I am not seeing, and also that he/she was aware of its altitude which is not stated.
2) It is to me an unusual 'clearance', but not one that would have caused me any difficulty, merely given me great flexibility in what was, I assume, a quiet piece of sky. 'Downin3' says it was an 'incorrect' clearance ("However, ATC procedures were changed as a result of that accident...When not on a pulbished segment and subsequently being "cleared for approach", the correct phraseology is "Maintain xxx until ESTABLISHED on the approach, cleared for...") - incorrect at all times or only when under ATC control?
3) What is the significance of the min 2000' clearance - does some sort of airfield zone start there?
So - for the 'locals' - what sort of 'control' was this? Would radar be used, a/c identified and full control be expected? Would an altitude squawk be available to whoever was 'controlling'? Can a crew elect in IFR to 'pass;' on a full service?
1) Before we start lambasting the controller, based on what we know the a/c was NOT 'descended' to <2550' by ATC. The crew either deliberately did it (in the wromg place) or some event caused it. To say "ATC should have climbed the flight to 5,400 before they entered the downwind TAA" implies the controller had descended the a/c - which I am not seeing, and also that he/she was aware of its altitude which is not stated.
2) It is to me an unusual 'clearance', but not one that would have caused me any difficulty, merely given me great flexibility in what was, I assume, a quiet piece of sky. 'Downin3' says it was an 'incorrect' clearance ("However, ATC procedures were changed as a result of that accident...When not on a pulbished segment and subsequently being "cleared for approach", the correct phraseology is "Maintain xxx until ESTABLISHED on the approach, cleared for...") - incorrect at all times or only when under ATC control?
3) What is the significance of the min 2000' clearance - does some sort of airfield zone start there?
So - for the 'locals' - what sort of 'control' was this? Would radar be used, a/c identified and full control be expected? Would an altitude squawk be available to whoever was 'controlling'? Can a crew elect in IFR to 'pass;' on a full service?
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It is not that rare that a very dangerous ATC clearance is in place. In my case, 3 times in 40 years of flight.
Crews have no business accepting clearances without at least an appropriate degree of safety confidence.
Crews might think that during radar vectors on a familiar route in day VMC and all good english speaking crews might not need the same type of situation awareness as more demanding circumstances. There is more risk with the latter, but I could have been just as dead with one instance of the former.
Some of us have been distressed to learn of the loss of a friend due CFIT. Avoiding CFIT starts a long time before take-off. Maintain SOPs, crew management, sober and rested and study unfamiliar routes will all help. Then when that slightly suspect ATC clearance appears, crews will be less diverted by narrow perceptions and lack of preparation. Just "being carefull" is not enough.
Crews have no business accepting clearances without at least an appropriate degree of safety confidence.
Crews might think that during radar vectors on a familiar route in day VMC and all good english speaking crews might not need the same type of situation awareness as more demanding circumstances. There is more risk with the latter, but I could have been just as dead with one instance of the former.
Some of us have been distressed to learn of the loss of a friend due CFIT. Avoiding CFIT starts a long time before take-off. Maintain SOPs, crew management, sober and rested and study unfamiliar routes will all help. Then when that slightly suspect ATC clearance appears, crews will be less diverted by narrow perceptions and lack of preparation. Just "being carefull" is not enough.
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While I agree the pilots should have questioned the altitude clearance, if they were in a radar environment ATC could descend them below the published MEA/MSA down to the MVA (since the MVA is a more detailed charting of minimum safe altitudes). The pilots most likely would have had no available reference for MVA. Many pilots fall into the trap of trusting ATC too much and at worse it appears these pilots fell victim to controller error and complacency.
That was a very weird altitude clearance though, I believe standard practices require that ATC only descend an aircraft to the IAF or FAF crossing altitude and then clear them for the approach. I've never seen ATC arbitrarily select an altitude for descent.
That was a very weird altitude clearance though, I believe standard practices require that ATC only descend an aircraft to the IAF or FAF crossing altitude and then clear them for the approach. I've never seen ATC arbitrarily select an altitude for descent.
Last edited by Island-Flyer; 17th Mar 2013 at 10:23.
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Island-Flyer
User groups and safety organizations have been begging for cockpit MVA/MIA references, especially now that electronic moving maps could facilitate them.
This article from nearly ten years ago:
http://flightsafety.org/fsd/fsd_sept04.pdf
The pilots most likely would have had no available reference for MVA.
This article from nearly ten years ago:
http://flightsafety.org/fsd/fsd_sept04.pdf
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We are nibbling at the edges here:-
It is being implicitly assumed (unproven) that the pilots were being 'vectored'.
I believe these pilots did NOT need MVA or any other trigraph except MSA/SSA which I assume is on the charts?
What possible use is MVA (or MEA) if you are not under radar control?
I'm still slightly puzzled by the speeds shown on Annex14's link and the rates of descent.
It is being implicitly assumed (unproven) that the pilots were being 'vectored'.
I believe these pilots did NOT need MVA or any other trigraph except MSA/SSA which I assume is on the charts?
What possible use is MVA (or MEA) if you are not under radar control?
I'm still slightly puzzled by the speeds shown on Annex14's link and the rates of descent.
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BOAC
An MIA chart could have enabled the crew to detect the erroneous altitude assignment by ATC.
When the approach clearance was issued, the airplane was in a 2000' MIA sector, but traveling toward rising MIA's.
What possible use is MVA (or MEA) if you are not under radar control?
When the approach clearance was issued, the airplane was in a 2000' MIA sector, but traveling toward rising MIA's.
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OK, then -- "Clearance".
From the NTSB Preliminary:
From the NTSB Preliminary:
The ARTCC specialist on duty subsequently granted the request by issuing the clearance, with instructions to proceed direct to the Initial Approach Fix (IAF) to begin the approach, and to maintain an altitude of 2,000 feet or above.
Last edited by Zeffy; 17th Mar 2013 at 13:20.
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Zeffy
Plse check aterpster # 44 link to the approach map. You will see there is no procedure altitude of 2000 ft at the IAF ZEDAG.
The 2000 ft (plus) clearance was only good on that awy V 453. Leaving that safe track automatically required MOA 5400 ft - depicted in that app map - or with a clearance of ATC for a RADAR vector towards ZEDAG and the minimum for the RNAV procedure at that point - 4300 ft.
Anything else in the weather and terrain situation at hand would have been guesswork. And for the latter there is very impressive phrase - Never base control on assumptions!!!!. This sentence was sadly proven to be correct from both parties involved - ATC and the two pilots.
The 2000 ft (plus) clearance was only good on that awy V 453. Leaving that safe track automatically required MOA 5400 ft - depicted in that app map - or with a clearance of ATC for a RADAR vector towards ZEDAG and the minimum for the RNAV procedure at that point - 4300 ft.
Anything else in the weather and terrain situation at hand would have been guesswork. And for the latter there is very impressive phrase - Never base control on assumptions!!!!. This sentence was sadly proven to be correct from both parties involved - ATC and the two pilots.
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Annex14
No argument there and the charts are familiar to me.
Only proposing that pilot knowledge of MIA might have been helpful.
Your point is a good one, though.
Since it appears that the crew ignored or failed to properly consult the approach chart -- and appeared to place sole reliance on the ATC clearance -- it might be a stretch to assert that they would have displayed any other available source for minimum off-route altitude.
However, it remains to be seen whether ATC radar was ever terminated. It sounds as though the flight was still receiving radar services at the time the erroneous ATC clearance was issued.
Plse check aterpster # 44 link to the approach map. You will see there is no procedure altitude of 2000 ft at the IAF ZEDAG.
Only proposing that pilot knowledge of MIA might have been helpful.
Your point is a good one, though.
Since it appears that the crew ignored or failed to properly consult the approach chart -- and appeared to place sole reliance on the ATC clearance -- it might be a stretch to assert that they would have displayed any other available source for minimum off-route altitude.
However, it remains to be seen whether ATC radar was ever terminated. It sounds as though the flight was still receiving radar services at the time the erroneous ATC clearance was issued.
Last edited by Zeffy; 17th Mar 2013 at 16:37.
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The sad part of the story is - according that FlightAware record > see #40 link - untill few minutes before the crash they were at a safe altitude.
So, what made them descend so rapidly ??
- a yet unknown weather related problem ?
- an attempt to brake clear of clouds early and proceed VMC to Dillingham?
- a fatal trust on a clearance for an altitude that became invalid by the track they were sent to?
Many open questions and only the CVR - if installed and active - and ATC tapes of RADAR and Radio data may give an answer.
So, what made them descend so rapidly ??
- a yet unknown weather related problem ?
- an attempt to brake clear of clouds early and proceed VMC to Dillingham?
- a fatal trust on a clearance for an altitude that became invalid by the track they were sent to?
Many open questions and only the CVR - if installed and active - and ATC tapes of RADAR and Radio data may give an answer.
Last edited by Annex14; 17th Mar 2013 at 17:17.
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I was told the NTSB will start its work on Monday and that shortly after a new intermediate report will be issued.
Then we will know what kind of ATC service was provided by ATC and if the clearance issued was standard or not for that type of service. .
Now from a pilot point of view, I find this RNAV chart crazy, considering the RNAV/GPS nature of the procedure who on earth decided to put an IAF so close to the only peak in the whole area ?
Reminds me the old APP chart for Santa Maria in the Azores, it you were inbound on the wrong VOR ( SMR or SMA, I can't remember) coming from the East ,the APP track made you overfly the only bloody (high) peak in the whole island.
It was an accident waiting to happen, and sadly a US B707, did get caught with a wrong QNH one day, and all on board died as a result.
Very often guys designing these charts do that from an office, very far away from the actual location and with no real flying experience . Not saying this was the case here, but it smells like it.
Then we will know what kind of ATC service was provided by ATC and if the clearance issued was standard or not for that type of service. .
Now from a pilot point of view, I find this RNAV chart crazy, considering the RNAV/GPS nature of the procedure who on earth decided to put an IAF so close to the only peak in the whole area ?
Reminds me the old APP chart for Santa Maria in the Azores, it you were inbound on the wrong VOR ( SMR or SMA, I can't remember) coming from the East ,the APP track made you overfly the only bloody (high) peak in the whole island.
It was an accident waiting to happen, and sadly a US B707, did get caught with a wrong QNH one day, and all on board died as a result.
Very often guys designing these charts do that from an office, very far away from the actual location and with no real flying experience . Not saying this was the case here, but it smells like it.
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ATC Watcher - nothing 'crazy' there - why not ask why someone built a 2550' hill near the approach to R19? With the MSAs around there, a 13 mile IAF is about right - could not be closer. In any case, you need almost 60mb altimeter mis-setting to hit the hill!
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The RNAV procedure as published is safe, though it shows a weird holding pattern !!
However, that is only correct to say if the published altitudes are obeyed.
Moving the IAF closer to the rwy means lower altitude at IAF, most probably causing terrain clearance problems in procedure construction.
However, that is only correct to say if the published altitudes are obeyed.
Moving the IAF closer to the rwy means lower altitude at IAF, most probably causing terrain clearance problems in procedure construction.
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The RNAV procedure as published is safe, though it shows a weird holding pattern !!
However, that is only correct to say if the published altitudes are obeyed.
However, that is only correct to say if the published altitudes are obeyed.
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Because it is right hand and towards the only real obstacle in miles.
To have it mirrored and flown in standard turns canīt be that big of a problem.
Had the pattern been on that side it appears very likely they hadnīt hit the rocks.
To have it mirrored and flown in standard turns canīt be that big of a problem.
Had the pattern been on that side it appears very likely they hadnīt hit the rocks.
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BOAC
you were too fast for me to enter that of course it doesnīt make a difference to fly right or left hand holding patterns. But in my - past world - there was a preference and that was called left hand standard pattern.
you were too fast for me to enter that of course it doesnīt make a difference to fly right or left hand holding patterns. But in my - past world - there was a preference and that was called left hand standard pattern.