Originally posted by N-ONE
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UPS Cargo Jet Crashes Near Birmingham Shuttlesworth International Airport
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Evan, regarding the maths:
Assuming that the GS aerial is 1000ft down the runway, which is typical, and if I made no mistakes in the calculations:
Again, this is for the hypothetical case that there was an ILS, which was not the case.
It would be nice to depict the terrain profile below that 3.24 GS slope.
--- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
--- Defend what you say with arguments, not by imposing your credentials ---
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Originally posted by Gabriel View PostEvan, regarding the maths:
Assuming that the GS aerial is 1000ft down the runway, which is typical, and if I made no mistakes in the calculations:
Again, this is for the hypothetical case that there was an ILS, which was not the case.
It would be nice to depict the terrain profile below that 3.24 GS slope.
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Originally posted by Evan...It doesn't seem very forgiving...
You can do math all day long...
But one might paint a broad stroke that the final stages of an approach is always kind of critical and that deviating a little bit below "the glidepath" (regardless of whatever is defining that glide path) (or the minimum altitude) has caused lots of crashes in the past, is certainly part of this crash (even though we don't know the exact mechanism of this deviation)- and will probably cause crashes in the future.
Anyway- so what if it's 50 feet or 100 feet of buffer...a predawn, non-precision approach is a fairly critical operation, and yeah, they didn't have a long drawn out "stabilized" period, and whether they 'struggled' to 'level off' (Evan's theory) or sort of just sagged a little low without having the runway or PAPI in sight (Gabe's theory)...the differences here are a bit subtle.
PS- Gabirel- I think I did see a symbol on an approach chart that coded for a PAPI...and wow- PM me if you want to talk about the approach plates- Flyboy raked me over the coals a couple years back over "Radar Required"....it was after a statement that ALL approaches begin with an IAF...sort of like always intercepting the glide slope from below
OH AND ANOTHER POST SCRIPT....Has anyone considered that the airliner with the Polish president might have sagged below the minimum altitudes on a non-precision approach in hard IMC conditions and hit trees?Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.
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I've already deleted the Excel file.
For the "aiming point" I used 1000ft down the runway instead of 500ft. Just displace the above chart 500ft and what you get is about 300ft for the 3.24 slope and -19ft for 1 dot low, so yes, it matches your figures.
--- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
--- Defend what you say with arguments, not by imposing your credentials ---
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Hi Evan,
With cockpit indications giving an unstable approach down to minimums, including a Ground Prox Warning at the last, why would an experienced crew not perform a go-around?
Hind sight is a wonderful thing for us all, but there is more yet to this puzzle. There always is.
RIP
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Originally posted by Gabriel View PostCan someone please explain those approach charts?
What are the different MDAs?
What are the numbers in parenthesis?
What does "radar required" mean and the several times "radar" is written along the vertical profile? Does it mean "radio altimeter"?
http://155.178.201.160/d-tpp/1308/00050R18.PDF
MDA's also vary by the accuracy of the navigation signals, vary by the quality of the weather- some airports (without ASOS, if you have to get the altimiter setting from 20 miles away- have a higher MDA).
The numbers in the parenthesis are just the MDA rounded up to the nearest 100 feet (which is about the accuracy of your altimiter). I imagine Flyboy can point out some particular FAR on whether you can round off, or try to go do to the true minimum altitude)
Radar required means ATC radar- and it means you do not have to have an IAF.
I think the word "Radar" by itself is that the Radar guy should be double checking that you are at the right DME fixes....
For the record, I never really understood the IAF/FAF business....sort of makes sense for an NDB- you NEED a starting point before you go shooting out to "join the approach course", but with a VOR or LOC.....not sure why you can't simply 'join' them- they're pretty darn accurate! (Actually, I'm pretty sure you do simply join them in a radar environment, but for some outlying airport without a TRACON or tower- the approaches tend to call for a "good IAF" to nail down your location)
Don't know if Flyboy lurks here, but I can see him rolling his eyes and uttering 3BS at these explanations- I'm probably glossing over a million important nuances, and have some misunderstandings (Bobby? Snyder?)Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.
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[QUOTE=3WE;612061]OH AND ANOTHER POST SCRIPT....Has anyone considered that the airliner with the Polish president might have sagged below the minimum altitudes on a non-precision approach in hard IMC conditions and hit trees?
--- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
--- Defend what you say with arguments, not by imposing your credentials ---
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Originally posted by Gabriel View PostAnd what are the numbers next to each MDA (1, or 1 1/2, etc...)
I have 10 hours of instrument time- I'm a big-time Parlour talking ass-hatLes règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.
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Originally posted by Gabriel View PostBelieve it or not, I nearly (but decided against) posted that this accident looked more like the Polish AF-1 than Asiana, and that it would be good to have Northwester to run all the numbers (approach vs terrain profile, measurement of distances, altitudes, elevations and all sort of tools to visualize the evolution of the airplane through the 4D space).Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.
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Originally posted by 3WE View PostVisibility in NM.
I have 10 hours of instrument time- I'm a big-time Parlour talking ass-hat
--- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
--- Defend what you say with arguments, not by imposing your credentials ---
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Ok, IMTOY is a fix that helps you be more accurate...
If you can do the approach and get a fix for the IMTOY waypoint then you can descend to lower minimums....
If you are unable to get the fix for IMTOY then higher minimums...
...and I'll furthe speculate that this is because the terrain is a bit more critical than your 'average approach'.
I do not know what "S18" means.
Oh yeah on the runway diagram, note the letter P with a circle drawn around it located right around the TDZE....Me think that stands for PAPI.
I do know that the classic airline pilot job interview is "read this approach plate" and tell us about every last bit of info that's on there and then answer our additional questions.
After this discussion, I'm about ready to change my signature to 3BS, Chief Instructor, Sweet Monkey River Flight School Del Norte. (But we only offer lessons on how to fly MSFS).Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.
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Originally posted by Gabriel View PostBelieve it or not, I nearly (but decided against) posted that this accident looked more like the Polish AF-1 than Asiana, and that it would be good to have Northwester to run all the numbers (approach vs terrain profile, measurement of distances, altitudes, elevations and all sort of tools to visualize the evolution of the airplane through the 4D space).
But that Russian mind control ray might have some serious range...
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Originally posted by N-ONE View PostHi Evan,
With cockpit indications giving an unstable approach down to minimums, including a Ground Prox Warning at the last, why would an experienced crew not perform a go-around?
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