Another Question For Warren Stutt, concerning altitude Options

[rob balsamo]

Warren,

You calculated the margin for error in Groundpseed with groundspeed.

When you calculate the margin of error in altitude, you use altimeter setting?

Not only is that apples and oranges, but its completely and utterly intellectually dishonest Warren and I surprised you even attempted to correlate the two. Do you have an agenda? What is your objective? Truth? Or trying to sell the govt story to yourself and perhaps others. Maybe your correlation of groundspeed to altimeter setting might work with those who blindly support the govt story, but every single one of our pilots will laugh if they heard of such an absurd correlation. The list grows.

Basically, you are trying to say the static pressure at the static port was 29.98, by using a possible (read: not proven) margin for error in groundspeed. Thats absurd. Not only that, but your "margin for error" in groundspeed has the aircraft more than 70 feet underground! And if the static pressure at the port was in error due to high speed, we are back again with the Mackey argument of Mcrit and compressiblity. Do you now think Mcrit for the 757 is .70-72M? Remember, the ADC also starts to make adjustments above .55M that were calibrated during flight testing (according to apathoid, we still have not seen proof of this).

Try correlating apples to apples next time.

For example, 174' is the True altitude as determined by your decode.

40' MSL is required.

Thats an error of almost 77%! Not 0.78%

Conversely,

174 * 0.78% = 1.36 feet.

Warren, your margin of error in groundspeed equates to less than 2 feet in altitude.

What exactly are you trying to pull here?

Shame shame Warren, i expected more from you. Now i really question that new decode of yours. This whole discussion is moot if your decode is inaccurate, or worse, calculated with an agenda.

Warren, again, 3 independent data sets match each other. Airport, FMS and Pitot-Static. The Pitot-Static system was operating flawlessly.

At this point, it appears feasible to me that since the aircraft was overspeed, that the static pressure could have had small errors that would be larger than when the aircraft is flying at normal speeds. However I don't see a way of proving that this was the case.

Warren.

Proving your case is exactly what is required, especially if you want to grab a gun and start killing people in another land over it. All else is an argument based on your beliefs. An argument from incredulity, and is a logical fallacy.

[JFK]

Warren,

You calculated the margin for error in Groundpseed with groundspeed. <snip >

Actually from what I see in the code it is a straight read straight from the FDR file in Binary Coded Decimal format...

CODE

            Add(new Parameter("GROUNDSPEED ^", "(KNOTS)",
                new ParameterColumn("CAPT", new BCDParameterRow(94, 0, 0, 12, 2, 0.0, 1.0, 1))
                //,
                //new ParameterColumn("F/O", new BCDParameterRow(207, 0, 0, 12, 2, 0.0, 1.0, 1))
                ));

// BCDParameterRow(int aWordNum, int aSubFrameNumber, int aSuperFrameNumber, int aMSB, int aLSB, double aOffset, double aScalar, int aDecimalPlaces)

Word 94, all frames and superframes, bits 2-12, no offset, multiply by 1, 1 decimal place.

Of course if he wanted to be "sneaky" he could have done something during the decompression phase of the FDR file, but I do not see any evidence of that.


What I am finding curious is the Angle of Attack numbers throughout the entire final flight... As they always remain negative.
( I have not yet compiled the entire history in regards to that parameter )

[rob balsamo]

What I am finding curious is the Angle of Attack numbers throughout the entire final flight... As they always remain negative.
( I have not yet compiled the entire history in regards to that parameter )

-15.6 or thereabout appears to be level AoA. Check take-off roll and level off's at altitude.

[JFK]

Appears being the key word.

I just tried cross referencing with the "Corrected AoA" in the 757_3b_1.txt file, and found those values in most cases being almost exactly double.

The weird thing is that in the D226A101-3G.pdf, that word and corresponding bits ( Word 210, Bits 3-12 ) are assigned to the surge tank sensors.

Anyways I put this together from another 757 manual I found online for a Chineese Airline ( whilst in my quest for ARINC 429 specs ) :

Attached thumbnail(s)

 

[rob balsamo]

The weird thing is that in the D226A101-3G.pdf, that word and corresponding bits ( Word 210, Bits 3-12 ) are assigned to the surge tank sensors.

That's not the only parameter which conflicts regarding generic and custom DFL's.

(IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/wink.gif)

[JFK]

Just adding.... In the D226A101G.PDF the tolarance for the AoA is +/- .25 degrees

I did a sort by the value and there are multiple instances of near 90 degree both + and - throughout the entire FDR history.

Attached thumbnail(s)

 

[JFK]

That's not the only parameter which conflicts regarding generic and custom DFL's.

(IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/wink.gif)

Heh, looks like I may have to dust off one of my old OCR programs and convert that .PDF to text.
( Why they did that .PDF in images is beyond me )

[rob balsamo]

I did a sort by the value and there are multiple instances of near 90 degree both + and - throughout the entire FDR history.

Cross check that with aircraft movement. When i cross checked it on last flight (IIRC), it was on taxi. Its expected.

Check google images to understand what an AOA vane looks like on the outside of the aircraft. This will give you a better understanding of the readings. Its basically a wind vane. You need some pretty good forward movement for the vane to center itself.

[JFK]

Yeah, I understand what it looks like and how it works. ( look at my first attachment on this page )

What is really confusing me is the negative numbers it is generating...

Maybe it is me who is screwed up but isn't a negative number for this parameter an indication of the nose being down ?

< Goes to watch the ITVV_Airtours_757 DVD again >
( BTW, they never left the flight deck from before engine start until after engine shutdown (IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/wink.gif) )

[rob balsamo]

Maybe it is me who is screwed up but isn't a negative number for this parameter an indication of the nose being down ?

Clearly not (as you will see below), but my best guess is that it depends on manufacturer, airframe and perhaps airline (in how they want it calibrated). "Angle of Incidence" and dihedral may have something to do with it as well...

Bottom line, you can get a "fix" on level AOA just by reading the trends in the data vs. pitch angles. "Level" AOA appears to be roughly -15.6 (IIRC).

This is why our pilots laugh at the highly touted "MIT Professor" Will Clinger as he tries to equate Flight Director pitch angles to aircraft attitude.

(pause for another big laugh)....


ahem...

as you were.. (IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/smile.gif)

[JFK]

Yeah, well normal cruise for a 757 is ~ +2.5°, so says this Captain on this DVD explaining the instrumentation.

I have followed the schematics and the ADI DOES get a portion of it's input from the AoA sensor ( via the ADC ).

I just find it strange that they would play sign games like that, as it would waste processor cycles. (IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/dunno.gif)

[rob balsamo]

Yeah, well normal cruise for a 757 is ~ +2.5°, so says this Captain on this DVD explaining the instrumentation.

Thats called "Deck Angle". This is due to thinner air at cruise.

I just find it strange that they would play sign games like that, as it would waste processor cycles. (IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/dunno.gif)

Its not "sign games". Its just the way its calibrated.

Let me make it clear that "Level" AOA does not mean level to the horizon. It means level to the aircraft longitudinal axis.

For example. If this were an F-16. You would see 0 pitch angle and -15.6 AOA on take off roll.

The F-16 then "pulls" hard to a climb, you then see both pitch and AOA move into a positive direction (AOA perhaps still showing negative, yet pitch positive).

Once the F-16 is established in a 90 degree vertical climb, you see the AOA return to "level" of -15.6 degrees. The "wind vane" of AOA is "level" with the fuselage, but the nose is pointed 90 degrees up.

Clear as mud? :-)

The above is an extreme example to understand how the system works. I think you'll get it.

Again, this is just one of the many reasons we laugh at Will Clinger and why he will never debate us directly and instead elects to libel us (mostly me personally) through the J.REF cesspool and his .edu page.

I've said too much.. (IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/wink.gif)

[JFK]

Well the limey's call it "normal cruise" apparantly. (IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/tongue.gif)

I understand what you are saying regarding the F-16, However I seriously doubt you will ever see a 757 in a 90° climb. (IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/laugh.gif)

< (IMG:http://209.85.62.24/18/3/0/e68529//e68529.gif) Wonders if one weighs less than 85,000 lbs. empty >

[tomk]

LMAO,

I figured you kids would find some way to censor dissenting opinions.

"Strip all posts to a different thread."

Deceptive, but minimally clever...

... if you're trying to make 100% certain that readers see no contrary opinions.

(IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/laughing1.gif) (IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/laughing1.gif) (IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/laughing1.gif)

This post has been edited by tomk: Jan 7 2010, 11:48 AM

[JFK]

LMAO,

I figured you kids would find some way to censor dissenting opinions.

"Strip all posts to a different thread."

Deceptive, but minimally clever...

... if you're trying to make 100% certain that readers see no contrary opinions.

(IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/laughing1.gif) (IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/laughing1.gif) (IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/laughing1.gif)

Or trying to keep the topic somewhat on topic.

[alanj]

I figured you kids would find some way to censor dissenting opinions.

"Strip all posts to a different thread."

Thanks Tom,
You've just shown me a great example of how your "spin" works.
I'll use this as a guide for reading your future posts.
All the best (IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/thumbsup.gif)
Alan

[rob balsamo]

Well the limey's call it "normal cruise" apparantly. (IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/tongue.gif)

I understand what you are saying regarding the F-16, However I seriously doubt you will ever see a 757 in a 90° climb. (IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/laugh.gif)

< (IMG:http://209.85.62.24/18/3/0/e68529//e68529.gif) Wonders if one weighs less than 85,000 lbs. empty >

lol... i hear ya.

I see AOA vanes at 90 degrees on taxi all the time. Examples -

Plane is being pushed back from gate, a gust of wind hits it, it goes 90 deg.

Another... two aircraft back-to-back on a taxiway, one powers up, the AOA vane on the other goes 90 deg up....or down (control surfaces do a nice dance as well if the pilot powering up is off in la-la land not realizing whats behind him and the other has their controls unlocked).

etc...

If you see a 90 deg data point in flight, please let us know. (IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/smile.gif)

Let me also make it clear that -15.6 does not mean "nose down". Its just what the data shows as an indication for "level" when cross checking it against other data points, such as pitch. -15.6 (or thereabouts), represents "level AOA" in the csv file. I just double checked it with Warren's decode as well, he has the same.

[wstutt]

Hi Rob,

Warren,

You calculated the margin for error in Groundpseed with groundspeed.

When you calculate the margin of error in altitude, you use altimeter setting?

I can now show a relationship between ground speed and true altitude. My aim is to calculate true altitude using values that do no rely on pitot-static data.

I will use the following values:
Wind Speed - 10 knots (from the DCA weather data you gave me)
Wind Direction - 330° (from the DCA weather data you gave me)
Course - 61.5° (from the adjusted last values from the FDR file I gave previously)
Ground Speed - 481.2 knots (from the adjusted last values from the FDR file I gave previously)
True Airspeed - 481.0 knots = 811.8 ft/s (calculated from the above values and which can be verified using the Heading, Ground Speed, And Wind Correction Angle section of the online calculator you linked to)
Total Pressure - 1441.25mB = 42.56 inHg (interpolated from the last two values from the FDR file to the beginning of the last subframe using the same method that I used for the other values)
Temperature - 23°C = 296.15K (from the DCA weather data you gave me)
Altimeter Setting - 30.22inHg (from the DCA weather data you gave me)

I will use formulas provided in this document. (mod edit: 86 page pdf in link)

Rearranging
P = ρRT from equation (5.6) gives me
P/ρ = RT

Substituting that in to
V_t² = (7P_a/ρ_a)(((P_T-P_a)/P_a + 1)^2/7 - 1) from equation (5.38) gives me
V_t² = 7RT_a(((P_T-P_a)/P_a + 1)^2/7 - 1) Solving for P_a gives me
P_a = P_T(V_t² /(7RT_a) + 1)^-7/2

Using the following values:
V_t = true airspeed = 811.8 ft/s
P_T = total pressure = 42.56inHg
R = 3089.8 ft²/K s² from the top of page 5.6
T_a = temperature = 296.15K

in that equation gives me
P_a = static pressure = 30.21 inHg

Solving
P_aSD/P_B = (1 + (L/T_B)(H - H_B))^-g/LR from equation (5.13) for H - H_B gives
H - H_B = -(T_B/L)(1 - (P_aSD/P_B)^-LR/g)

Using the following values:
T_B = temperature at sea level = 296.15K
L = temperature lapse rate = -0.0019812 K/ft from the bottom of page 5.9
P_aSD = P_a = 30.21inHg
P_B = pressure at sea level = altimeter setting = 30.22inHg
R = 3089.8 ft²/K s² from the top of page 5.6
g = 32.174 ft/s² towards the bottom of page 5.3

in that equation gives me
H - H_B = true altitude = 9 ft

Interpolating from the last two values for pressure altitude in the FDR file using the same method I used for other values gives me a value of -92 ft. Correcting this using the online calculator as in this post gives me a true altitude of 182 feet.
(IMG:http://www.warrenstutt.com/General%20Images/Altimeter%20Correction%202.jpg)

Clearly the two different true altitudes of 9 ft and 182 ft at the beginning of the last subframe calculated from the FDR file and DCA weather data using different methods are not the same. So what happened? Are my calculations wrong or is the data inconsistent? Was the real true altitude somewhere in between these two values?

<snip>

Warren, again, 3 independent data sets match each other. Airport, FMS and Pitot-Static. The Pitot-Static system was operating flawlessly.

Was it?

Proving your case is exactly what is required, especially if you want to grab a gun and start killing people in another land over it. ...

Unfortunately the wars have already been started. In my opinion, if the wars were started under false pretenses, then action will not be successful against those responsible without proof of their wrong doing.

Warren.

This post has been edited by rob balsamo: Jan 8 2010, 08:56 AM

[wstutt]

Hi JFK,

Appears being the key word.

I just tried cross referencing with the "Corrected AoA" in the 757_3b_1.txt file, and found those values in most cases being almost exactly double.

The weird thing is that in the D226A101-3G.pdf, that word and corresponding bits ( Word 210, Bits 3-12 ) are assigned to the surge tank sensors.

<snip>

I found that if I used the same conversion formula for CORRECTED AOA as is used for INDICATED AOA which produces angles in the range -90 to +90 (which in effect halves the corrected AOA values), then the CORRECTED AOA values are very close to the INDICATED AOA values as you said.

Because of this closeness, it is now my opinion that word 210 bits 3 to 12, contains the CORRECTED AOA parameter rather than the DENSITY L TANK, DENSITY R TANK, DENSITY C TANK and DENSITY S TANK parameters. I will change this in the next release.

Good work JFK! The NTSB decoded that word as the DENSITY TANK parameters as well.

Warren.

[rob balsamo]

Warren,

DCA weather values are not precise to the degree. I explained this to you above. Your initial input skews all the rest.

I will admit I dont have the time nor the desire to cross check your math. Also, if you are going to link an 86 page pdf, it might be nice to let readers know its a big pdf file before they click on it. Its just nice internet etiquette.

Bottom line...

You can spend hours upon hours attempting to fit the data to an impact, but this list will still grow with professionals who understand the big picture when reviewing the data and information. We have another update coming soon.

3 sets of independent data match. FMS, Airport and Pitot-Static. This is basic aeronautical knowledge and is why you dont see the Romper Room acting up over it, instead they are making fools of themselves over -15.6 AOA in which it appears the majority of them havent even looked at the parameter data in the files.. (I took a gander over at the cesspool tonight, what a mess...lol).

If you want to compare apples to apples further, try comparing envelopes and margins of error. Still, this would not be in your range for impact. Keep in mind, Airspeed errors are +/- 6 knots according to documents provided by apathoid. Altitude is +/-75 feet. Your correlation doesnt even start till you exceed those initial margins of error.

It would also be nice if you would inform the Romper Room regarding the fact that the data presented in your decode and the NTSB csv file has already underwent the conversion from raw data to "engineering units" using the DFL formula's. It appears apathoid is the only one who actually looked at the data in the files, found out it is in fact showing -15.6 deg for a "level AOA", decided to once again use the DFL conversion on data which has already been converted, and still got it wrong as the product would be a negative value...lol. Of course he also couldnt miss out on an opportunity to make another post loaded with personal attacks. You might want to bring some jelly over there when you inform them as Im sure they are getting tired of eating their shoe raw. Too funny.

For those interested. See attached for a clear picture of what we been talking about regarding AOA and pitch angles. (We've already had enough laughs at Will's expense. I suppose it's time to throw him a bone.. you're welcome Will, and thanks for all the laughs when you attempted to use FD Pitch for aircraft attitude).

Attached File(s)

 Pitch_aoa_altitude_airspeed.csv ( 327.03K ) Number of downloads: 26