Mistaken altimeter settings can kill you
Moderators: sky's the limit, sepia, Sulako, lilfssister, North Shore, I WAS Birddog
Re: Mistaken altimeter settings can kill you
Yes, I regularly check my altitude with a GPS, especially when flying in the uncontrolled airspace underneath Calgary's TCA. It's normally within 50ft agreement.
Re: Mistaken altimeter settings can kill you
Wouldn't one be inclined to look at their Radio/Radar Altimeter if they fear they're close/not close enough to terrain in cases like this?
They wouldn't have had a GPWS in 1988 but surely the King Air would have had a RadAlt...no?
They wouldn't have had a GPWS in 1988 but surely the King Air would have had a RadAlt...no?
Re: Mistaken altimeter settings can kill you
It did go down on the Lee side of the hill. I was based in YLD before this accident and knew just about everyone. I also know the guys that were hired by Max to clean up the wreckage after the investigation...on the lee side of the hill. In fact, Hank and I were business partners for awhile.
And since they were still out bound to the beacon, they were more than a thousand feet out...
There was lots of hearsay and innuendos at the time about a medic trying to down the aircraft. Having flown with them the night before, they were stressed but I doubt it.
And GPS???? That was pretty new and I am not sure if the Voyageur aircraft was equipped yet. Approach GPS were definitely not out yet.
And since they were still out bound to the beacon, they were more than a thousand feet out...
There was lots of hearsay and innuendos at the time about a medic trying to down the aircraft. Having flown with them the night before, they were stressed but I doubt it.
And GPS???? That was pretty new and I am not sure if the Voyageur aircraft was equipped yet. Approach GPS were definitely not out yet.
Re: Mistaken altimeter settings can kill you
Stephen, any chance you could provide a link to the report?
Also, you've mentioned several times that numerous mistakes were made.... could you list the mistakes so they're obvious when we read it?
Also, you've mentioned several times that numerous mistakes were made.... could you list the mistakes so they're obvious when we read it?
Re: Mistaken altimeter settings can kill you
Back in March, Skywest did the same thing in Calgary, except in this case their TCAS warned them before they descended on top of me. The reason was the same.Sidebar wrote:... a Canadair CL-600-2C10 (CRJ 700), N773SK operated by Skywest Airlines as flight SKW 619R, was on final approach for an RNAV approach to Runway 31 at Regina when the crew received a GPWS "too low gear" warning. The crew climbed and then continued the approach. The flight landed without further incident. The flight crew determined the altimeters had been set to 30.12 inches, while the altimeter setting provided by air traffic services was 29.12.
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Stephen Szikora
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- Joined: Sat Oct 13, 2007 6:39 pm
Re: Mistaken altimeter settings can kill you
Sorry for the delay responding. I thought I had replied but I guess it didn't get sent.
A link to the final report is included on Mark's website. As a side note, I'll tell you that it is interesting to read some of the preliminary drafts and see where they made changes. As for a list of mistakes, the weather one was a major one but smaller mistakes are included within the investigation file and are not apparent when reading the report. In fact, the weather analysis mistake was only apparent only after looking at the weather observers logs for Chapleau.
With regard to the exact location of the accident site, the info provided by Bob is helpful and I would encourage him to contact Mark so that he can contact some of the people involved. Mark has visited the general area while interviewing locals and plans to go back with a GPS to add to the data on the site. I will say this, the investigation found that the aircraft made contact with the trees at a descent angle of less than 5 degrees (estimated by initial tree cut but as little as 2 degrees as indicated in the instruments in the wreckage.) The initial descent profile that Mark has been able to piece together seems to indicate levelling off as the aircraft overflew the airport. In other words, the terrain rose up in front of them (airport alt is 1470' but 1465' shown at the time, and terrain at accident site was 1590' plus 50' trees.)
As for theories about the cause, there are a number of pieces of evidence in the file and elsewhere, that are consistent with the possibility that the aircraft was 1000' too low and the crew realized it too late. The problem with the investigation is that the weather mistake led the team to dismiss this theory too soon, resulting in missed opportunities to further investigate some aspects and perhaps to an incorrect conclusion.
The info posted by Bob above regarding the medics was something that was considered in the file but dismissed (I would conclude quite properly.) For those that don't know, one of the medics was vocal about safety concerns with the new Voyageur contract. He had even gone to the Ontario legislature the week before to appear in the legislature and had met with several people including then opposition leader Bob Rae. He warned that someone would get killed. The day of the accident (the first flight under the Voyageur contract) he had increased his life insurance. This led to an OPP investigation. At the accident scene, the co-pilot was found to not have his seat belt on. As well, relatives of the deceased captain made representations pointing to the medic saying that this could only have happened if they were distracted. All this was part of the investigation but did not form part of the conclusions in the report. Personally, having reviewed much of the file I don't put much into this theory. The most damning evidence against this angle (aside from the fact that it is just strange) is that both medics had their seat belts on. However, this is the kind of thing the investigators had to deal with.
Consider the following, however. The ATC tapes clearly show that the aircraft was cleared to begin its descent and approach to Chapleau by Toronto Centre and the pilots were instructed to contact Chapleau on the MF. At the time (it's different now) arriving aircraft were required to obtain the altimeter setting from Chapleau before commencing IFR procedures. The flight was scheduled to be into Chapleau at 2200 but didn't arrive until 2300 due to delays getting out of Timmins. The airport manager at Chapleau indicated that he was at the airport at the scheduled time and turned the lights on but was not contacted by the aircraft (as instructed by ATC and required by the rules in place for that airport at the time.) When asked what the altimeter setting was by the investigators, the airport manager (referred to as the attendant - in other words, this is the guy who drove the snowplow) made the exact same mistake as the investigators did and cited the setting from 24 hours after the accident. This is the same guy who didn't seem to understand the 24 hour clock because he kept referring to 11 o'clock as 2200 when speaking to ATC. That said, the altimeter settings in the aircraft wreckage were almost exactly what the proper settings were for Chapleau that night as recorded by the qualified weather observer in the airport logs before leaving her shift that night at 2100, and not the same setting as Timmins. Where did they get the setting if they hadn't contacted Chapleau? Why was there a split between the settings on the pilot and co-pilot altimeters? Why was the co-pilot's seat belt undone? Why, in the file has the airport manager's interview statement in the file been noted as shaky by the investigators who did the interview? All this could point to a mistaken altimeter setting and put the aircraft off by 1000' with a quick reset as they overflew the airport upon realizing the mistake but too late to avoid the hill in front of them. The alternative is that they got lucky with the setting themselves, knew they were very low and simply flew the aircraft into the hill. According to the airport manager, he radioed the aircraft as it overflew the airport and they "asked for the numbers" but the transmission was cut off as they crashed. Isn't it odd that they had approximately the correct altimeter setting at the time of the crash? Consider also that the altitude alerter setting was 2800'. This would be consistent with an initial setting at 3000', which would be lowered to 2800' in the normal course of the approach, but no further adjustment because the next step at 2600' would have been into terrain with a mistaken altimeter setting off by 1000'. Interesting to note also that the airport manager left his position shortly after the crash ("cracked up" and went on "long term disability" according to one person.) His replacement has been at Chapleau ever since.
It is amazing how something as simple as a weather report mistake may have caused the investigators to look look in the wrong direction and fail to ask the right questions. Why was the medivac flight delayed by an hour? That is an interesting question that wasn't explored. How was the site clean up and wreckage handled? Here's an example. The report indicates that the fuel pump was obtained and tested. No mention of the fact that the pilot's sister later walked the site and found it, took it home to the Muskoka airport and it was later retrieved from there. Or that wreckage was prematurely taken to the local dump which later had to be contacted and asked not to put anything on top of it. There's more in the file and beyond. In all, an apparently sloppy investigation that may well have reached the wrong conclusion.
A link to the final report is included on Mark's website. As a side note, I'll tell you that it is interesting to read some of the preliminary drafts and see where they made changes. As for a list of mistakes, the weather one was a major one but smaller mistakes are included within the investigation file and are not apparent when reading the report. In fact, the weather analysis mistake was only apparent only after looking at the weather observers logs for Chapleau.
With regard to the exact location of the accident site, the info provided by Bob is helpful and I would encourage him to contact Mark so that he can contact some of the people involved. Mark has visited the general area while interviewing locals and plans to go back with a GPS to add to the data on the site. I will say this, the investigation found that the aircraft made contact with the trees at a descent angle of less than 5 degrees (estimated by initial tree cut but as little as 2 degrees as indicated in the instruments in the wreckage.) The initial descent profile that Mark has been able to piece together seems to indicate levelling off as the aircraft overflew the airport. In other words, the terrain rose up in front of them (airport alt is 1470' but 1465' shown at the time, and terrain at accident site was 1590' plus 50' trees.)
As for theories about the cause, there are a number of pieces of evidence in the file and elsewhere, that are consistent with the possibility that the aircraft was 1000' too low and the crew realized it too late. The problem with the investigation is that the weather mistake led the team to dismiss this theory too soon, resulting in missed opportunities to further investigate some aspects and perhaps to an incorrect conclusion.
The info posted by Bob above regarding the medics was something that was considered in the file but dismissed (I would conclude quite properly.) For those that don't know, one of the medics was vocal about safety concerns with the new Voyageur contract. He had even gone to the Ontario legislature the week before to appear in the legislature and had met with several people including then opposition leader Bob Rae. He warned that someone would get killed. The day of the accident (the first flight under the Voyageur contract) he had increased his life insurance. This led to an OPP investigation. At the accident scene, the co-pilot was found to not have his seat belt on. As well, relatives of the deceased captain made representations pointing to the medic saying that this could only have happened if they were distracted. All this was part of the investigation but did not form part of the conclusions in the report. Personally, having reviewed much of the file I don't put much into this theory. The most damning evidence against this angle (aside from the fact that it is just strange) is that both medics had their seat belts on. However, this is the kind of thing the investigators had to deal with.
Consider the following, however. The ATC tapes clearly show that the aircraft was cleared to begin its descent and approach to Chapleau by Toronto Centre and the pilots were instructed to contact Chapleau on the MF. At the time (it's different now) arriving aircraft were required to obtain the altimeter setting from Chapleau before commencing IFR procedures. The flight was scheduled to be into Chapleau at 2200 but didn't arrive until 2300 due to delays getting out of Timmins. The airport manager at Chapleau indicated that he was at the airport at the scheduled time and turned the lights on but was not contacted by the aircraft (as instructed by ATC and required by the rules in place for that airport at the time.) When asked what the altimeter setting was by the investigators, the airport manager (referred to as the attendant - in other words, this is the guy who drove the snowplow) made the exact same mistake as the investigators did and cited the setting from 24 hours after the accident. This is the same guy who didn't seem to understand the 24 hour clock because he kept referring to 11 o'clock as 2200 when speaking to ATC. That said, the altimeter settings in the aircraft wreckage were almost exactly what the proper settings were for Chapleau that night as recorded by the qualified weather observer in the airport logs before leaving her shift that night at 2100, and not the same setting as Timmins. Where did they get the setting if they hadn't contacted Chapleau? Why was there a split between the settings on the pilot and co-pilot altimeters? Why was the co-pilot's seat belt undone? Why, in the file has the airport manager's interview statement in the file been noted as shaky by the investigators who did the interview? All this could point to a mistaken altimeter setting and put the aircraft off by 1000' with a quick reset as they overflew the airport upon realizing the mistake but too late to avoid the hill in front of them. The alternative is that they got lucky with the setting themselves, knew they were very low and simply flew the aircraft into the hill. According to the airport manager, he radioed the aircraft as it overflew the airport and they "asked for the numbers" but the transmission was cut off as they crashed. Isn't it odd that they had approximately the correct altimeter setting at the time of the crash? Consider also that the altitude alerter setting was 2800'. This would be consistent with an initial setting at 3000', which would be lowered to 2800' in the normal course of the approach, but no further adjustment because the next step at 2600' would have been into terrain with a mistaken altimeter setting off by 1000'. Interesting to note also that the airport manager left his position shortly after the crash ("cracked up" and went on "long term disability" according to one person.) His replacement has been at Chapleau ever since.
It is amazing how something as simple as a weather report mistake may have caused the investigators to look look in the wrong direction and fail to ask the right questions. Why was the medivac flight delayed by an hour? That is an interesting question that wasn't explored. How was the site clean up and wreckage handled? Here's an example. The report indicates that the fuel pump was obtained and tested. No mention of the fact that the pilot's sister later walked the site and found it, took it home to the Muskoka airport and it was later retrieved from there. Or that wreckage was prematurely taken to the local dump which later had to be contacted and asked not to put anything on top of it. There's more in the file and beyond. In all, an apparently sloppy investigation that may well have reached the wrong conclusion.
Re: Mistaken altimeter settings can kill you
Just read the latest mention in the news, looked at the 796 site and then here.
While there are a lot of problems with the report, what strikes me is that the report detailed
the altimeter settings as correct at the time. A one inch error would one
highly probably cause of the accident.
There are a large number of accident reports that omit essential factual information
that did not support the expected conclusions that often appear to be straight
out of TC's exam questions.
There is no prejudice or harm to a fresh investigation and or examination of the possible causes.
From my read of the report and the 796 site, Voyager's interests were a primary goal of the
investigation which resulted in a politically correct , libel free report that
conveniently omits anything that contradicts the preformed conclusions.
I'm sure that there are pilots out there who have relevant information that would shed
a light the cause of that accident.
What I've seen, is that across Canada and over the decades, there is a
deliberate blindness to accident causes that are not what a company wants to read.
Corporate influence into reports is going to continue to be a reason as to why
accident reports are tainted and unreliable.
While there are a lot of problems with the report, what strikes me is that the report detailed
the altimeter settings as correct at the time. A one inch error would one
highly probably cause of the accident.
There are a large number of accident reports that omit essential factual information
that did not support the expected conclusions that often appear to be straight
out of TC's exam questions.
There is no prejudice or harm to a fresh investigation and or examination of the possible causes.
From my read of the report and the 796 site, Voyager's interests were a primary goal of the
investigation which resulted in a politically correct , libel free report that
conveniently omits anything that contradicts the preformed conclusions.
I'm sure that there are pilots out there who have relevant information that would shed
a light the cause of that accident.
What I've seen, is that across Canada and over the decades, there is a
deliberate blindness to accident causes that are not what a company wants to read.
Corporate influence into reports is going to continue to be a reason as to why
accident reports are tainted and unreliable.
Re: Mistaken altimeter settings can kill you
I'd agree that some TSB reports are unreliable.Ramjet555 wrote:Corporate influence into reports is going to continue to be a reason as to why accident reports are tainted and unreliable.
TSB is required by law (http://laws-lois.justice.gc.ca/eng/acts ... index.html) to allow involved parties to review their draft report and propose changes. This includes flight crew or their next of kin.
Tainted? I disagree. Can you provide some specific evidence to support your assertion?Before making public a report under subsection (1), the Board shall, on a confidential basis, send a copy of the draft report on its findings and any safety deficiencies that it has identified to each Minister and any other person who, in the opinion of the Board, has a direct interest in the findings of the Board, and shall give that Minister or other person a reasonable opportunity to make representations to the Board with respect to the draft report before the final report is prepared.
Re: Mistaken altimeter settings can kill you
It can kill many,
A few years back, I had this happen in the YYZ TCA.
WX was at mins, and terminal had us on the RONLY ops due to congestion. Jazz pipes up to call a TCAS event. "we had to climb back up to XX" "GOOD, he says (Denis)...cu'z you almost took THU out." ???
They even called the error. 30 seconds later, they call, "that was our fault" "30.xx VS 29.xx".
They had been cleared to 1000' above us, but they had ACTUALLY tried to descend to "on-top" of us.
M. Nowicki shout out. Good times man. Always listen to that "Spidey Sense", It'll keep you alive.
This triggered a CBC investigation, and our crew were contacted for an interview into the "state" of Canadian Aviation Safety.
I put the Kybosh on that. This sh!t happens, not cuz of the pilots, but because of the tech.
When have you ever seen an avionics suite set-up by a pilot with 10thou+?
That's how it should be done, but it is not. We just do what we can with what we have to work with.
A simple solution, is to have the WAAS altitude set as a default display as a prominent indication; AND, a cross connected error default message triggered to the master caution.
Hey, I'm not an electronics tech, but the idea seems simple to me. It either works, or it don't, under an LSTC for modern GPS/WAN OPS SPEC.
The waas/gps default display ALWAYS shows sea-level-altitude, or, an error message. No matter what "page" you're on, the display is there, and the trigger is there. Simple.
Master Caution...Pay Attention Dumb Ass...
Under a "Master Caution", Ask for the current setting; cross confirm. Or climb, to the MOCA+1000'...
Very few local radars run, or even understand primary. SSR is the norm. So, what I tell you I'm doing, is what I'm doing. Even though the alt setting on board is out, controllers would have to be on their toes to even detect such a situation.
Actual, versus correction, versus station, versus pilot control error...versus waas.
So, why don't we have a standard?
I've been called many times on HDG. MAG vs TRU VS TRC..."HEY, are you going to YAT?"
So why can't the same precision be applied to altitude?
It can...we just need a few more to die...
A few years back, I had this happen in the YYZ TCA.
WX was at mins, and terminal had us on the RONLY ops due to congestion. Jazz pipes up to call a TCAS event. "we had to climb back up to XX" "GOOD, he says (Denis)...cu'z you almost took THU out." ???
They even called the error. 30 seconds later, they call, "that was our fault" "30.xx VS 29.xx".
They had been cleared to 1000' above us, but they had ACTUALLY tried to descend to "on-top" of us.
M. Nowicki shout out. Good times man. Always listen to that "Spidey Sense", It'll keep you alive.
This triggered a CBC investigation, and our crew were contacted for an interview into the "state" of Canadian Aviation Safety.
I put the Kybosh on that. This sh!t happens, not cuz of the pilots, but because of the tech.
When have you ever seen an avionics suite set-up by a pilot with 10thou+?
That's how it should be done, but it is not. We just do what we can with what we have to work with.
A simple solution, is to have the WAAS altitude set as a default display as a prominent indication; AND, a cross connected error default message triggered to the master caution.
Hey, I'm not an electronics tech, but the idea seems simple to me. It either works, or it don't, under an LSTC for modern GPS/WAN OPS SPEC.
The waas/gps default display ALWAYS shows sea-level-altitude, or, an error message. No matter what "page" you're on, the display is there, and the trigger is there. Simple.
Master Caution...Pay Attention Dumb Ass...
Under a "Master Caution", Ask for the current setting; cross confirm. Or climb, to the MOCA+1000'...
Very few local radars run, or even understand primary. SSR is the norm. So, what I tell you I'm doing, is what I'm doing. Even though the alt setting on board is out, controllers would have to be on their toes to even detect such a situation.
Actual, versus correction, versus station, versus pilot control error...versus waas.
So, why don't we have a standard?
I've been called many times on HDG. MAG vs TRU VS TRC..."HEY, are you going to YAT?"
So why can't the same precision be applied to altitude?
It can...we just need a few more to die...
Re: Mistaken altimeter settings can kill you
Mode C/SSR all work on pressure altitude (29.92) regardless of what altimeter setting you have plugged in.spaner wrote:
Very few local radars run, or even understand primary. SSR is the norm. So, what I tell you I'm doing, is what I'm doing. Even though the alt setting on board is out, controllers would have to be on their toes to even detect such a situation.
Re: Mistaken altimeter settings can kill you
I think this is correct, and that the ATC processing and display system corrects the readout for current QNH so that the controller sees baro-corrected altitude. Any ATC types out there to confirm?old_man wrote:Mode C/SSR all work on pressure altitude (29.92) regardless of what altimeter setting you have plugged in.
Re: Mistaken altimeter settings can kill you
Yes, that's correct; through the encoder.
He has one correction, you have another. (hopefully not)
I mentioned primary because it is independent of an encoder error. Also, primary radar is used as a control. Like a precision approach environment. So, yes they have to be on their toes with SSR to tell you to stop the decent, but that will take the 1000' anyway.
That's why you need the visual passage in place of the lateral separation, to cross altitude in a SSR environment.
Cu'z it's shite.
He has one correction, you have another. (hopefully not)
I mentioned primary because it is independent of an encoder error. Also, primary radar is used as a control. Like a precision approach environment. So, yes they have to be on their toes with SSR to tell you to stop the decent, but that will take the 1000' anyway.
That's why you need the visual passage in place of the lateral separation, to cross altitude in a SSR environment.
Cu'z it's shite.
Re: Mistaken altimeter settings can kill you
That could explain some accidents in Rodina Russia.
