Clip4
Final Approach
To determine if there is an issue that may affect other models.
Video and Discussion - Burley, ID accident. Was "Gryder"
- Thread starter LesGawlik
- Start date
To determine if there is an issue that may affect other models.
Salty
Touchdown! Greaser!
Tearing down the engine for a stuck carb float will determine if there is an issue that may effect other models? How does that work?
Clip4
Final Approach
Bad parts. Maybe even bogus parts.
Salty
Touchdown! Greaser!
Bad parts in the engine caused the carb float to stick? Engine - carb. Two different things.
Clip4
Final Approach
You know they are not dissecting the carb?
Salty
Touchdown! Greaser!
All I know is that they are tearing down the engine, or at least that’s what I was told. My question is why would they do that if they suspected a stuck carb float.
Sometimes, they find other problems when they dig deeper. I have read accident reports where there were recommendations for items discovered during the investigation unrelated to the accident cause. And if they only suspect a stuck carb float, perhaps they are not 100% convinced and therefore are using a process of elimination.
Salty
Touchdown! Greaser!
I'm dubious because the FAA lady said they would do a tear down even before they even got my report. Makes no sense to me, but whatever. Maybe it's a random luck of the draw thing. They have to do x tear downs a year, I was probably the first one in this FSDO for the year, so I got tagged. I dunno. It just seems like a waste of time to spend 5 months screwing around on a non-injury accident that showed no obvious evidence of a mechanical failure.
FYI: there is a set procedure the NTSB must follow with every accident investigation. Everybody draws the same number. I believe you can still download those procedures if you would like to read them. Injury or non-injury makes no difference and the FSDO has zero say-so in the matter.
I have gotten the following impressions from the posts on the two threads on this accident.
(a) This approach is an example of the occasional threat that lies out there for pilots, who need to be aware of the obstacle hazards that can lie in the visual segment.
(b) In order to strike this obstacle, one has to deviate below the published descent path on this approach.
(c) There is significantly less margin on this approach than the majority of similar approaches when it comes to getting low in terms of an obstacle threat.
(d) If you are fortunate enough to have a modern avionics system such as the newer Garmin units, an electronic descent path is provided for guidance assistance to the runway.
(e) While an electronic guidance system does not guarantee safe obstacle clearance, in the case of this approach, the electronic guidance system does provide clearance.
(f) We are unaware what avionics were available to the pilot and in what manner they were used.
(g) Poor weather increases the likelihood of not seeing the obstacle in a timely manner.
(h) If one sees a steeper than normal descent path at an airport, it could be due to a close-in obstacle and therefore, should ensure that they don't get low as the likelihood of a threatening obstacle is higher than on average.
(a) This approach is an example of the occasional threat that lies out there for pilots, who need to be aware of the obstacle hazards that can lie in the visual segment.
(b) In order to strike this obstacle, one has to deviate below the published descent path on this approach.
(c) There is significantly less margin on this approach than the majority of similar approaches when it comes to getting low in terms of an obstacle threat.
(d) If you are fortunate enough to have a modern avionics system such as the newer Garmin units, an electronic descent path is provided for guidance assistance to the runway.
(e) While an electronic guidance system does not guarantee safe obstacle clearance, in the case of this approach, the electronic guidance system does provide clearance.
(f) We are unaware what avionics were available to the pilot and in what manner they were used.
(g) Poor weather increases the likelihood of not seeing the obstacle in a timely manner.
(h) If one sees a steeper than normal descent path at an airport, it could be due to a close-in obstacle and therefore, should ensure that they don't get low as the likelihood of a threatening obstacle is higher than on average.
Hang 4
Pattern Altitude
- Joined
- Aug 18, 2017
- Messages
- 2,328
- Display Name
Display name:
Hang 4
See comments in RED.
Turbo-Arrow-Driver
Pre-takeoff checklist
Your use of the word clearance is possibly ambiguous here. To be clear, Clarence, following the vertical guidance exactly will not collide with obstacles (i.e. it provides physical clearance), but it will not keep the aircraft a safe distance from obstacles (FAA required clearance).
Palmpilot
Touchdown! Greaser!
One has to descend below the MDA to land and many have quite successfully. But one should not get too low on final approach. It appears that happened in this case.
Hang 4
Pattern Altitude
- Joined
- Aug 18, 2017
- Messages
- 2,328
- Display Name
Display name:
Hang 4
OK - Descend below MDA based solely on an advisory glideslope without the runway in sight. The point I was trying to make a non-precision, advisory glideslope does not provide obstacle clearance below MDA. See the Google earth example above. That is regardless of how "advanced" your equipment is, which your original post implied.
I
My original post.......
"(b) In order to strike this obstacle, one has to deviate below the published descent path on this approach."
.....implies only what it says.
Another person on another discussion about this accident stated "Why was the pilot of the Caravan 75-80' agl, only 2500' from the threshold? This was not the fault of any tower on the processing plant."
It is a good question. There has been some discussion here about it. We know the visibility was poor. I go on the assumption that there was visual acquisition of some sort on this approach. Was it any of the required visual references? Unknown. But we now see the hazards of going low to get in. In most cases, the approach is reasonably clear. But not this case. I remember reading an article many years ago with a section in it titled...."Alligators Below The MDA". This is a perfect example of one of those alligators.
My original post.......
"(b) In order to strike this obstacle, one has to deviate below the published descent path on this approach."
.....implies only what it says.
Another person on another discussion about this accident stated "Why was the pilot of the Caravan 75-80' agl, only 2500' from the threshold? This was not the fault of any tower on the processing plant."
It is a good question. There has been some discussion here about it. We know the visibility was poor. I go on the assumption that there was visual acquisition of some sort on this approach. Was it any of the required visual references? Unknown. But we now see the hazards of going low to get in. In most cases, the approach is reasonably clear. But not this case. I remember reading an article many years ago with a section in it titled...."Alligators Below The MDA". This is a perfect example of one of those alligators.
Or maybe they get relentlessly pushed into careers ahead of other people by third parties more interested in political agenda than safety first.
John Collins
En-Route
I was originally in the "pilot screwed the pooch" camp, but Max Trescott had some interesting information in his podcast a couple weeks ago:
http://aviationnewstalk.libsyn.com/...cessna-208-caravan-crash-in-burley-id-ga-news
Apparently the many stacks randomly release hot steam. It's possible one of these steam clouds was released right in front of her, killing both lift and engine performance and obscuring already poor visibility. When the g1000 data is analyzed they should be able to get a good idea if it was pilot error or plain bad luck. It's a more complicated story than I thought.
http://aviationnewstalk.libsyn.com/...cessna-208-caravan-crash-in-burley-id-ga-news
Apparently the many stacks randomly release hot steam. It's possible one of these steam clouds was released right in front of her, killing both lift and engine performance and obscuring already poor visibility. When the g1000 data is analyzed they should be able to get a good idea if it was pilot error or plain bad luck. It's a more complicated story than I thought.
Hang 4
Pattern Altitude
- Joined
- Aug 18, 2017
- Messages
- 2,328
- Display Name
Display name:
Hang 4
@John Collins answered this far better than I did. I'll only add you are mixing two different things. The "published descent path" doesn't really exist below MDA. You're either able to descend visually or not. The ADVISORY glide slope in any GPS has no idea where MDA is. It will gladly take you into an obstacle if you follow it below MDA. You're correct there are alligators there, but the "published descent path" won't keep you away from them. Descending to MDA then shifting to a visual approach if you can before the MAP will. No visual, go missed.
Turbo-Arrow-Driver
Pre-takeoff checklist
Don't forget there is a witness who saw the a/c fly into the steam cloud. That person will likely be able to say whether the steam had just appeared prior, or was already there. This is something the NTSB will sort out, and it's frustrating for us that we must wait at least a year to find out.
Things can be worded as you like but If she had continued on the descent angle that coincided with the VDA, no accident would have happened. She went low and hit the obstacle. If you have a nice VDA path being displayed and get the required visual references at minimums, don't start increasing the descent angle for whatever reason unless you can be 100% sure that you can see everything clearly(such as a nice day). You may get away with it most of the time but this shows what can happen.
Someone has confirmed that there was a G1000 which I believe provides a 'path' to the runway. They say that it should not be used but I say....if you see if it giving a fly-up indication in marginal visibility, you might want to use it. You may have been fooled by a visual illusion out the window.
Last edited:
martym
Pre-takeoff checklist
That's a pretty wild hypothesis.
Is it though? What's the DA of 100% humidity and 212+ degree air? That's quite a charge from the near freezing ambient temperature. What's that do to an engine? The steam is apparently full of potato starch too. I don't know, but it certainly seems plausible that you could lose a hundred feet real fast.
Todd82
Line Up and Wait
The steam wouldn't be 212+. It has already vaporized. Put your hand a few inches above a pot of boiling water, it's not 212, now think a few hundred feet high. A tall stack means the steam is well removed from the boiling source, it would be WELL under 212. The steam hitting the cold airframe and icing it up would be far more likely than it affecting lift/power because of density altitude.
Tarheelpilot
Final Approach
- Joined
- Dec 5, 2010
- Messages
- 7,386
- Location
- North Carolina once again.
- Display Name
Display name:
Tarheelpilot
You have quite the imagination.
hindsight2020
Final Approach
- Joined
- Apr 3, 2010
- Messages
- 6,723
- Display Name
Display name:
hindsight2020
She ducked under and lost. Sucks, but that's the pressure/anxiety to get down while relatively inexperienced for ya (second/third approaches in inclement have a bad completion record). Single pilot freight doggin' is a herd-culling affair, always has been. Not all the baby turtles make it to the ocean type of thing, and that is a tragedy.
LesGawlik
Line Up and Wait
- Joined
- May 6, 2006
- Messages
- 956
- Display Name
Display name:
Good Guy
The effect of the steam was picked up by Max Trescott. He is as un-Gryder as you cane get. He had a contributor who said there in no available O2 in steam. I'm not saying I buy this explanation, but it is interesting and worthy of consideration.
I can take the MAYBE out of the cloud of steam. I have direct experience in what happens in a much more dramatic version.
I flew a Cessna 172 what I expected to be across, 20 or 30 feet above the two plumes from a power plant,, about half a mile down wind from the plant. Each was plume the product of a generator operating at 500,000,000 watts. What I did not allow for was the heat transfer from the visible plume of combustion exhaust, into the air above it. Passing over the first plume, in the 100 feet of flight in air hotter than 500 degrees, lift was reduced, and I descended about 30 feet.
The next plume itself was hit, and had no oxygen in it, the engine cut off, but continued to turn, just idle speed. We dropped another 30 feet, and the gasses entering through the vents was extremely hot, and devoid of oxygen. A moment later, back in clean air, engine back to the same power as before entering, and we opened the windows to clear the fumes.
Passing through those small plumes of steam from stacks a couple of feet in diameter might cause as much as 5 or 10 feet of lost altitude, at near stall speed. At normal approach speed for that Cessna, the loss should be hardly noticeable. We were sight seeing at about 70 Knots and 10 degrees of flaps, when I had my adventure, showing off the plant where I worked part of the time. We also crossed at a diagonal, making the time above or in the plume longer than the actual width of the plume.
Unfortunately, I think she was ducking a bit to get under the cloud layer, and was simply too low, too soon, and moving too fast to react in time to pull up, if she did see the stack at all.
Higher and slower would have been a better path, but in instrument conditions, many ad a little extra speed for a safety margin, which makes actually landing that much harder. I have noticed that tendency in other instrument pilots that I have flown with in actual conditions.
Such small lapses remove pilots from life in the early hours of developing the experience and judgement that makes flying safer. Very sad when it happens.
I flew a Cessna 172 what I expected to be across, 20 or 30 feet above the two plumes from a power plant,, about half a mile down wind from the plant. Each was plume the product of a generator operating at 500,000,000 watts. What I did not allow for was the heat transfer from the visible plume of combustion exhaust, into the air above it. Passing over the first plume, in the 100 feet of flight in air hotter than 500 degrees, lift was reduced, and I descended about 30 feet.
The next plume itself was hit, and had no oxygen in it, the engine cut off, but continued to turn, just idle speed. We dropped another 30 feet, and the gasses entering through the vents was extremely hot, and devoid of oxygen. A moment later, back in clean air, engine back to the same power as before entering, and we opened the windows to clear the fumes.
Passing through those small plumes of steam from stacks a couple of feet in diameter might cause as much as 5 or 10 feet of lost altitude, at near stall speed. At normal approach speed for that Cessna, the loss should be hardly noticeable. We were sight seeing at about 70 Knots and 10 degrees of flaps, when I had my adventure, showing off the plant where I worked part of the time. We also crossed at a diagonal, making the time above or in the plume longer than the actual width of the plume.
Unfortunately, I think she was ducking a bit to get under the cloud layer, and was simply too low, too soon, and moving too fast to react in time to pull up, if she did see the stack at all.
Higher and slower would have been a better path, but in instrument conditions, many ad a little extra speed for a safety margin, which makes actually landing that much harder. I have noticed that tendency in other instrument pilots that I have flown with in actual conditions.
Such small lapses remove pilots from life in the early hours of developing the experience and judgement that makes flying safer. Very sad when it happens.
martym
Pre-takeoff checklist
Your OAT gauge goes up to 500F? If not, by what means did you measure the temperature of the 'plume?'
Last edited:
martym
Pre-takeoff checklist
P3 compressor air in a PT6 engine is ~550F? Would the engine even notice? A few hundred feet in 3 sec would ~6000 fpm rate of descent. The POH would have to contain a warning note about flying through steam if that were the case.
455 Bravo Uniform
Final Approach
It’s not so simple. What happens to the air around that rising plume of hot air/vapor/steam/exhaust? The surrounding air is displaced in 3 dimensions, plus it’s moving if there is any wind at all.
You missed that I worked in that plant. 500 degrees is the plant technology records, not anything that I could measure. Each boiler burned a railway car of coal per hour, to give you an idea how large that gas stream from each stack was. The lack of oxygen mentioned is the result of controlling air and fuel precisely, to prevent high temperature oxygen from causing accelerated deterioration in the induced draft fans, electrostatic precipitators and stack.
Today, flying that low over a power plant close to Washington DC might cause a visit from Federal Officials, from one department or another, there are 4 that claim one interest or another in security of power production. Before I quit working there, I had to get a Secret Clearance, in order to go inside the fence. That clearance was renewed annually.
A good Youtube statement here. From someone who has spent a lot of time flying in winter conditions and totally misled one time to almost land on a field parallel to a runway, I agree that this is a possibility....
Bobby Hubbard
2 months ago (edited)
I wonder if she mistook that long flat grey roof in that mist and blowing snow as a runway... Seems easy to do if she fixated outside looking for the runway and not cross checking her position on the g1000.
That may not be the exact scenario, maybe the roof had snow on it(or maybe not). but an illusion would explain exactly why someone would be so low.
Either way....beware of illusions. And if you have to make a sudden, large change in flight path in marginal conditions, does it really make sense?
Bobby Hubbard
2 months ago (edited)
I wonder if she mistook that long flat grey roof in that mist and blowing snow as a runway... Seems easy to do if she fixated outside looking for the runway and not cross checking her position on the g1000.
That may not be the exact scenario, maybe the roof had snow on it(or maybe not). but an illusion would explain exactly why someone would be so low.
Either way....beware of illusions. And if you have to make a sudden, large change in flight path in marginal conditions, does it really make sense?