New FDR Decode

Originally posted by tezzajw
Three fixed points on the aeroplane are necessary and sufficient to model the geometric orientation of the aeroplane's flight path. Of course, that still doesn't account for slight wing flexing, if two of the points are on the wing tips.

Better be careful, ATS member "tezzajw". You'll get in even further trouble with PFT since turbofan seems to think he can develop a simulation that mirrors *precisely* what the 757 did with regards to the light poles - without knowing those parameters you speak of.

Originally posted by turbofan

Originally posted by tomk52NOT ONE of which has ever previously performed a forensic crash analysis.

Stop the lies "TomK". Jeff Latas has signed off on many P4T papers and
FDR studies. His credentials can be verified. Here is a short list of what
he did/does...

reply to post by R_Mackey


There you go with the "lies" again. Your uncritical credulousness does NOT equate to my mendacity, TF.

But when you're right, you're right.

There are professionals with accident investigation experience at P4T. Shame on all of them for associating with such blatant technical incompetence.

Let's see if your first fellow's claims stand up to scrutiny.

My initial Google search returned 165 hits.

But, what do you know, as soon as I eliminated the 9/11 & AA77 references, the hit did NOT "keep on comin'!" They went to ZERO.

But you'll be happy to note that there were several references to the "Top Thai Porn Star music videos".

I obviously have to retract that sweeping comment.

And apply it instead to the ALL investigations of the Pfft analyses (AA77, AA11, UA175, & UA93) that I've seen.

The guys who I have seen that have performed and/or participated in PffT's airline crash "investigations".
David Ray Griffin
Rob Balsamo
Jeff Hill
Calum Douglas
Aldo Marquis
Craig Ranke

Funny. I could find NOT ONE single reference to any one of these people having any experience prior to 9/11 in airplane crash investigations.

Of course, you'll be able to refer us all to their previous crash report authorship, won't you?

Perhaps, some of those Thai "actresses" could lend their technical gravitas to your side of the argument. After all, you don't seem particularly embarrassed that you need to leverage Charlie Sheen, Jesse Ventura & Rosie O'Donnell...?!!
__

Next, let's take the guys that do claim to have accident investigation in their background.

Jeff Latas
George Nelson
Michael Harley
J. Randall Reinhardt
Hadi Rizvi

I'll leave out the obvious fact that "being involved with" or "signing off on" airline crash investigations is not the same as "being knowledgeable about their process or details". I've had lots of Engineering VPs, QC inspectors, Customer Service reps, and CEOs review and even sign off on my engineering reports without understanding the methods or fundamental concepts. They were interested only in the conclusions.

Nonetheless, SOME familiarity is better than the zero level of those "investigators" listed above.

Now, show me analyses PERFORMED by the bottom five guys.?

I must have missed them. They would, of course, be powerful supports to your arguments on PfffT's website.

Or are these the typical "Truthers"? Guys that have concluded that the greatest mass murder & treason that this country has ever experienced has just occurred, know that they possess the skills & experience to expose the murderers & traitors ...

... but instead, sit on their collective butts for 9 years, & refuse to contribute anything more than a few blog comments. But never miss an opportunity to claim that their "trutherism" stems from patriotism??!!!

ACCORDING TO THEIR OWN WORDS, what a bunch of lazy traitors.

TomK.

[edit on 25-11-2009 by tomk52]

relative

Originally posted by trebor451

Originally posted by tezzajw
Three fixed points on the aeroplane are necessary and sufficient to model the geometric orientation of the aeroplane's flight path. Of course, that still doesn't account for slight wing flexing, if two of the points are on the wing tips.

Better be careful, ATS member "tezzajw". You'll get in even further trouble with PFT since turbofan seems to think he can develop a simulation that mirrors *precisely* what the 757 did with regards to the light poles - without knowing those parameters you speak of.

I've got about three months left to get some serious research completed and the semi-final draft to the publisher. I take a break from time-to-time to check this thread because I sometimes find something useful. I might say in that regards I have found weedwacker an invaluable source on several items. The rest is just pure entertainment and a chance to give my brain a rest. Since last night though, it has been beyond silly with this "three fixed points" nonsense.

Why? Because "three fixed points" (x, y, z) are relative to something. So perhaps we can make the plane's cog the origin and throw out "three fixed points" based on that reference system. My suggestion for the pole scenario is simply to use the point-of-contact between the VDOT camera pole and starboard wing. Why?

1) There is pretty solid photographic evidence (Ingersoll) that the encounter occurred (mark on pole and missing rung at that point).

2) Singed treetop nearby corresponds to where the starboard engine would have been relative to the point.

3) VDOT employees assert that the pole was hit hard enough to knock the camera loose in its housing at the top of the pole and disabled the camera.

4) The DCA ASR (closest radar, within 2 nautical miles) track projected is consistent with the encounter.

5) The FDR INS data once aligned with the IAD ASR is also very consistent with the encounter.

6) Multiple eyewitnesses suggest that the encounter occurred with the poles at that point, including Wallace who even drew a sketch of the pole encounter and a taxi cab driver who claims at least one segment of one pole went through his windshield, almost hitting him.

That is a pretty solid case for the encounter (eyewitness, radar, FDR, eyewitness testimony, physical, photographic). Now that is not tezzajw's probability = 1 threshold (which does not exist in the real world), but it is definitely within my p = 0.997 threshold.

So what are we going around in circles about? "Three fixed points" in space. Sounds like that 'disinformation' I was telling Craig about years ago has had its desired effect, degraded the debate into silliness

[edit on 25-11-2009 by 911files]

Originally posted by 911files

1) There is pretty solid photographic evidence (Ingersoll) that the encounter occurred (mark on pole and missing rung at that point).

2) Singed treetop nearby corresponds to where the starboard engine would have been relative to the point.

3) VDOT employees assert that the pole was hit hard enough to knock the camera loose in its housing at the top of the pole and disabled the camera.

4) The DCA ASR (closest radar, within 2 nautical miles) track projected is consistent with the encounter.

5) The FDR INS data once aligned with the IAD ASR is also very consistent with the encounter.

6) Multiple eyewitnesses suggest that the encounter occurred with the poles at that point, including Wallace who even drew a sketch of the pole encounter and a taxi cab driver who claims at least one segment of one pole went through his windshield, almost hitting him.

Here are 6 of the reasons why PFT and CIT try to discredit the work 911Files has completed. While searching for the truth, he found it. PFT and CIT didn't like the answers.

John, do you have a publish date yet?

Originally posted by ImAPepper
John, do you have a publish date yet?

Manuscript deadline is March, 2010 and release scheduled for Fall 2010/Winter 2011. I asked the publisher for August/September 2010, but a lot of that has to do when the 're-writes' are done and the printer's schedule.

It will be the most exhaustive NWO manual on the flight that I can come up with, chocked full of NWO 'disinformation'.

Originally posted by 911files

Originally posted by ImAPepper
John, do you have a publish date yet?

Manuscript deadline is March, 2010 and release scheduled for Fall 2010/Winter 2011. I asked the publisher for August/September 2010, but a lot of that has to do when the 're-writes' are done and the printer's schedule.

It will be the most exhaustive NWO manual on the flight that I can come up with, chocked full of NWO 'disinformation'.

Congratulations John! I for one will be looking for a signed copy.... Are you accepting the NWO Credit Cards for payment?

Originally posted by cesura
That would be true if we were modelling a video game or
alternative Truther universe in which aircraft can fly
sideways or otherwise perpendicular to the direction in
which they are pointed.

This must be a "truther" world or alternate universe.



No, it's just a crosswind approach and landing attempt at Hamburg.


It's called a crab angle. Aircraft fly "sideways" all the time.

Also, the data from the FDR shows this as well, of course not as extreme, but the winds were a direct crosswind. The nose is not pointed in the direction the aircraft is traveling. tezzajw is right. You are wrong, as usual Will.

Just more examples of the lack of understanding of flight dynamics by those who make excuse for the govt story.

Originally posted by cesura
When you or your fellow agents of disinformation think
you have scored a major point by saying the plane could
have been flying sideways, there is indeed little hope
for a sensible thread.

Will

Here is more "disinformation" from an "alternate universe", according to Will.



Will, you haven't a clue what or who you debate. This is why you refuse to bring your BS directly to P4T.

[edit on 25-11-2009 by R_Mackey]

double post - deleted

[edit on 25-11-2009 by R_Mackey]

Cesura,

I enjoy your posts. Thanks.

A couple of observations about the flight data.

1. Best INDEX for everything is vertical acceleration. 8 Hz = finest resolution. NOT accuracy. RESOLUTION. It may still be off by fractions of a second.

2. The radar data is clearly on the tail end of the data stream. Confirmed by the last data point. During the last second, there was 53 ft/sec descent rate (57' to 4') . If the radar data had been at the beginning of that frame, then the plane would have crashed 4/53rds of a second into the frame. It didn't. We don't know how long after the End of Data until impact, it does not appear to be very long.

3. PA lag errors do not seem to be a problem. From the charts of the two, the PA curve actually leads the radar offset by about 1 second. Most likely due to data skew. It looks like PA is taken at the start of a frame & radar altitude at the end.

4. You can use the radar height to get the best possible INDEX of all data, since it is provided at 8 Hz. Match it to the terrain. Do a "filter" on the terrain data to see how it would look to a 1 second sampling rate (in 1/8th second offsets. Pick the best data & match to PA - radar.) Look at slopes & select "best fit". Note that this eliminates "PA offset errors".

5. You can calculate the second by second vertical velocity by using "difference methods" on the Pressure Altitude (PA). I'd use six data points for each second's results. The two data points between which you are modeling, plus two points on either side. Do a 3rd order polynomial interpolation for that second's worth of data, and interpolate at each 1/8th second. Much better than a linear interpolation for the reasons that follow in the next point.

6. As I mentioned above, a polynomial fit to the "difference method approximation" of Vertical velocity is much better than a linear interpolation. If you use a linear interpolation, then you FORCE a constant velocity between data points. This is unrealistic considering the jerking around on the control yoke that Hanjour was doing. (You can see this by plotting "Vertical accel - 1" (to normalize for gravity) vs. time. Over the last 20 seconds or so, Hanjour put the plane into 2 1/2 cycles of PIO, with about a 6 second period.

Hanjour's PIOs

But what you can do is to use the "difference method" calculated vertical velocity (from PA) and the measured air speed to calculate the descent angle at each second. (ø = arcsin[Vertical velocity / Air speed)], once you've got the right units). That would then allow you to construct a true flight profile, right up to the End of Data. You can either calculate the ground track at 1 second intervals, using (Airspeed ft/sec)*(1 sec)*cos[ø] and then plot the altitude vs. ground location. Or you could simply do Velocity vector addition, knowing airspeed & descent angle, and working backwards from the End of Data.

I used the first method to plot the Flight Profile. Getting the aspect ratio to 1:1 gives a true picture of the profile.

AA77 Flight Profile

You'll note that all those circle & hyperbolic profile assumptions are wrong. As is the assumption that the plane had to EVER "level off". It appears that it did not.

TomK

PS
1. The angle of attack can be a quite large angle, depending on the maneuver that you executing. At the terminal speeds of AA77, tho, you are right that it'll be small.

2. The equations for banked flight that were ID'd in Wikipedia are only true for "coordinated flight". Hanjour was NOT very good with the rudders.


[edit on 25-11-2009 by tomk52]

reply to post by tezzajw

It's good to see you and 911files being honest about not knowing if the vertical acceleration is with respect to the aeroplane's axis or not.

Thank you so much for your concern, tezza. However, I'm afraid you have misinterpreted my post. Aloow me to once again claify, please:

There is NO DOUBT, nor confusion as to an acceleration value along the airplane's viertical axis. You are mistaken if you think that was part of my explanation. You may be forgiven for being in error.

Here's a two-dimensional comparison --- an automobile, on level surface. Always experiences a steady perpindicular one-G 'feeling' of accelerqation due to gravity. That is a constant, unmutable (ignoring the extremely minor, very small variations that occur due to slight localized gravitational fluctuations on the Earth's surface, due to latitude and elevation above sea level).

Take that same auto, and step on the pedal to move forward. NOW, we've introduced a horizontal acceleration component. You could graph that in a vector diagram, if you wished.

The feeling of your weight-shift is in the opposite direction to the motion of acceleration. Your mass is the same, but your effect on a scale (were it to be measured) would indicate a variation from your steady-state weight, and will vary along various axes, depending on where measured. Agree?

Now, take the auto at high speed into a banked turn, such as at a racetrack, to simulate an airplane in flight. In fact, the comparison works even better if you imagine yourself on a roller coaster, which I assume most have experienced at one time or another. The physics, and results are very similar to forces expereinced by airplanes in flight. At least, for demonstration purposes, for laypeople to relate.

Hope this helps clear up what, and what i am NOT unaware of.

Because, at NO TIME did I impl that I was "confused"...that was an unfortunate (and incorrect) interpretation. I alluded to the fact that, when it comes to all of the inner working intracacies of the SSFDR, I am not fully trained on the specific details of every aspect of its functions. It is not necessary in my training as a pilot, any more than it is necessary for a person to fully know how a television works in order to use it.

The myriad and complicated components of the SSFDR are left to the engineers and experts on the device...hence, the tongue-in-cheek reference made to it as a "Black Box". The term, for those not familiar with the idiom, means to convey a series of incredible and complex things that occur within, and mostly hidden from view to those who have not the comprehension to fully grasp the intracacies.

reply to post by R_Mackey


For the benefit of non-pilots, I shall attempt to explain why user "R_Mackey's" assertion here is not relevant in the discussion of AAL 77.

This I found whilst searching for the Aviation Weather information for the DCA area on 11 September, 2001...from a PfT post, 18 Sep 2009:

Local Weather Reports
Reagan National Airport

METAR KDCA 111251Z 35005KT 10SM CLR 21/14 A3021
SPECI KDCA 111341Z 33010KT 10SM CLR 23/14 A3022
METAR KDCA 111351Z 34009KT 10SM CLR 23/14 A3023
METAR KDCA 111451Z 32008KT 4SM HZ CLR 24/14 A3022
METAR KDCA 111551Z 33009G15KT 7SM CLR 26/14 A3021

To read it:

'METAR' is the ICAO standard term for weather reports. (Originally from French, it has no set pnemonic translation anymore...you could remember it as 'meteorological aerodrome report' if you wish...FAA in the AIM calls it 'aviation routine weather report'. Etc...

'SPECI' is short for 'Special' (Nowadays, most METAR are done automatically, hourly, by sophisticated weather observation stations and uploaded into the system for dissemination. At many airports today ATIS, taken from the METAR, is translated into synthesized speech for broadcast on the frequency pilts tune to for ATIS. A 'special' is made when conditions change significantly over the course of the hour).

'KDCA" is, of course, the ICAO identifier for Washington National Airport.

'111251Z' denotes the 11th of the month, at 1251Z, or GMT, or UTC...all mean the same thing. [Note the 'SPECI' issued at 1341Z...shortly after impact at the Pentagon, because someone in the Tower had the presence of mind to do so).

'33005KT' = Wind (from) 330 degrees at 5 knots.

'10SM' = TEN statute miles visibility. In the olden days in the US, Tower personnel used to report what they observed, using known landmarks to judge the visibility. Now, they use various devices (transmissometer, etc) but, gone are the days of '50 miles visibility' in official reports. 10SM is the default maximum, International standard. (Don't know why it's not Nautical miles, or Kilometers...don't ask me, it's a hodgepodge system that has developed over time...subject to International compromise of standards setting)

'CLR' = should be self-explanatory. In other countries' METARs you will see 'CAVOK'...."Clear and Visibility OK"...is how I've always interpreted that. Some pilots will say 'CAVU' for "unlimited"...things change...

'21/14' = the temperature/dewpoint in degrees Celsius

'A3021' = the altimeter setting to adjust your Kollsman window to compensate for 'non-standard' air pressures at your location. '3021' equates to 30.21 inches of mercury (Hg). Internationally, they use millibars, as too meteorologists in their weather reports and forecasting.
Altimeters have both scales handy for setting purposes.


OK...lesson finished.

We see that at the time just after impact, ~1341, the wind velocity read 10 KT, and 50 minutes earlier, at 1251, it was 5 KT. Still, very, very light winds, mostly steady in direction, mildly variable as to velocity.

So, yes, "Mackey" is correct, there was a crosswind...however, I just do not see how as little as ten knots has anywhere near the effect as shown in those YouTube videos of crosswind landings.

I went to calculate a WCA (wind correction angle) using figures approximated from the AAL 77 case.

Because of the high TAS (true airspeed, I used 462 KT) the WCA for the roughly 10 KT crosswind was just one degree left. I based that on the magnetic course of the airplanes path of 062 degrees. That was from memory, not sure if it's exact, but should be ballpark. (You may use other figures to refine the values...).

Comparing those conditions to another fictional airplane, landing as shown in the videos above, on a course of 062 degrees, ten knots of Xwind, but at a TAS of 140KT (more typical for an approach speed) the WCA is four degrees. Still, while slightly more, is quite insignificant.

FWIW, the extreme examples shown of high velocity crosswind landings represent unusual and undesirable circumstances...usually short-lived in duration, as local weather conditions change. Airports, when planned and constructed, are oriented to align with known, historically repeatable wind direction patterns. If there is a generous amount of land, then you may see additional runways at different angles. This is a luxury afforded some, but of course not all.

But, aviation being dynamic by its nature, one must learn to cope, hence crosswinds are encountered, and techniques learned by pilots. One should not have to stay on the ground, or divert to an alternate, simply because the winds are undesirable. Of course, there are airframe limits, published for each airplane type, to be aware of. They are, in large Transport Category jets called 'demonstrated crosswind ability' limits, or similar terms. We endeavor not to knowingly exceed those in normal operations. We can 'hold', if arriving and have enough fuel, and no appropriate runways are available; we can divert to an Alternate; or, we can excersize 'Captain's Emergency Authority' and just do the paperwork afterward.

Also, technique-wise, crosswind landings are preferably made using what's called the 'cross-control' technique, which is a way to keep the upwind wing banked slightly, while using opposite rudder to keep the fuselage lined with your direction of motion over the ground, intent is to make a smoother landing, since the wheels will be aligned when they contact the runway. However, in extreme crosswinds, as shown in those videos, there is a limit to how much bank angle you can use at touchdown, lest you scrape an engine nacelle or any other low-hanging component.

In that case, a slight crab at touchdown is appropriate. If uncomfortable. But, the airplnaes are very strong, and can handle it. In fact, the B-747 center gear is designed with a slight amount of 'swivel' capacity (as is the B-52) because of the limits to a wing-low landing, and the inboard engines.

To illustrate how strong the gear, and its mountings are, here is a video of the B-777 flight testing where they demonstrate the most severe conditions, as proof of concept (there's a B-747SP thrown in for good measure, too):



(Music is nice, too...)

weedwhacker,

The purpose for my reply to Will is to once again demonstrate the lack of knowledge of flight dynamics shown by those who claim to have all types of superior expertise and ridicule others based on it, when in fact they are completely wrong. In other words, as you agree, aircraft fly sideways all the time, it doesn't have to happen in an alternate universe.

Will reminds me of the posters out there who ridicule others for their typos because they cannot debate the topic, yet misspell every other word in their reply.

Now for the significance.

A 1 degree difference equates to a more than 2 foot "swing" difference in wing tip position. Even more for the tail. The crab is actually closer to 2.4 degrees IIRC, based on the data.

This must be taken into account when attempting precise measurements such as a 757 wingtip "scuff" on half of a pole which perhaps has a 6 inch diameter.

This is why tezzajw has been emphasizing the aircraft position in space, while Will has been incorrectly refuting such a notion as Will thinks all aircraft travel in the direction which the nose is pointed and therefore any single point on the airframe can be used for such a measurement. Will is wrong. The icing on the cake is when Will attempts to ridicule others from his pompous perch while being so wrong.

Also, for those who claim the "singed" tree was sucked into the right engine, please let us know where this is reflected in engine parameters.

Once again, no one here has provided any proof for the impact theory claims.



[edit on 25-11-2009 by R_Mackey]

I'd like to add something else, since we're on about the FDR Decode and such --- that is the claims of "impossible" speeds for AAL 77 that have been bandied about.

I guess those claims may finally be subsiding, as the FDR data is shown more and more to be reliable.

However, just for a re-cap, the most critical aspect of high-speed flight is the MAch Number, or percentage of the Speed of Sound. SoS in air is affected by temperature (and insignificantly by humidity, but we can ignore that).

The published Aircraft Limitation Mach speed for the B-757 is M.86

Much hay has been made for the 462 knots speed of AAL 77...terms such as 'equivalent airspeed' cropped up, and are simply diversions, and sorts of red herrings meant to distract.

The ability of an airplane like a B-757/767 to accelerate so far above 'normal' speed limits is possible only with the added affect of gravity...going 'downhill' with high power settings will allow the speed to increase well beyond 'limits'. In fact, in my experience in the airplanes, even with thrust at idle power, it is easy to reach the maximum speeds in a gliding descent, and it does not require any unusually low pitch attitudes to do it, nothing out of the ordinary, and would not seem "steep" to most passengers.

At near sea level, as in the case of AAL 77, Mach Limit isn't even an issue...in fact, the 'Mach number', using the 462 knots TAS, is about M.70
Well below the maximum of M.86

Will the airplane "fly apart"?

Well, this video of the Airbus A380 in flight testing may answer that. It is unnecessarily 'dramatic', not so much a documentary as an exagerrated commercial for Airbus...and it is specifically to test for 'flutter' tendencies...(which, of course, had already been thoroughly investigated in wind tunnels and computer-based eengineering profiles, but real, live flight tests still have to be performed satisfactorily).

You will see the test pilots take the airplane up to M.96 as part of their requirement to meet standards. Airbus advertises the airplane's MMo (Mach Max operating) at M.89, by the way. Just to compare to the Boeings.

A thought, as you watch this: IF it is such a 'dangerous' test flight, then why are there so many onboard??? Really, there need only be the two pilots, in case the worst happened, and they had to evacuate. Monitoring devices could record the data. See what I meant, overly dramatic?


(best bits at about 5:00 onward...)



Enjoy.

reply to post by R_Mackey

A 1 degree difference equates to a more than 2 foot "swing" difference in wing tip position. Even more for the tail. The crab is actually closer to 2.4 degrees IIRC, based on the data.

Yes, although I don't have the math equations to verify, nor calculate, the exact amounts, it is true that a swept-wing will seem to 'lengthen' as the leading edge is presented more amd more perpindicular to the relative wind. However, we are referencing fixed points on the ground, so the RW is not pertinent, just a mental image to help people visualize the concept.

So, actually, using your 2.4 degrees 'crab' angle, and the result increase in wing length of the downwind wing (the right in this case) and IF the precise, down to feet or even inches, location of the airplane along every point in the ground track can be determined, then it will be useful to be as precise as possible. Inasmuch as we wish to determine as exactly as possible the sequence of every strike on a light pole, or other ground objects along the ground track, and at what point along the leading edge of the wing they occured, then this will be information that must be incorporated.

I wonder, though, if that level of precision is possible, or if it is even necessary?

This must be taken into account when attempting precise measurements such as a 757 wingtip "scuff" on half of a pole which perhaps has a 6 inch diameter.

Well, as said, perhaps that question will be answered, in due course.

...as Will thinks all aircraft travel in the direction which the nose is pointed and therefore any single point on the airframe can be used for such a measurement.

Can't speak for 'Will'. It would, I think though, be premature to dismiss his understanding of the concept out-of-hand. Fair to say, isn't it, that regardless of the airplane attitude, the CG should be focused on firstly, as an indicator of overall motion and location, then the variables can be built around it to the proper dimensions. A daunting task I would think.

Also, for those who claim the "singed" tree was sucked into the right engine, please let us know where this is reflected in engine parameters.

I do not believe all are making that assertion. I have seen a photo of a tree that was 'lopped off', appeared to be cleanly sliced near the top, but I thought it was quite near the Pentagon, therefore not a candidate for this 'sucked into engine' hypothesis. However, that is a minor detail, that may be incorporated eventually into a full examination.

I am uncertain as to the veracity of the 'smoking engine' reports, anyway. There are other things that resemble 'white smoke' when released into a high speed airstream. Fuel, for example. But, there may be FDR data to support, or discount, that possibility. Again, that is not the focus, as such, of plotting the trajectory.

Once again, no one here has provided any proof for the impact theory claims.

I don't see that as a logical assumption, based on what's been discussed.

I did see someone mention final acceleration values that exceeded the recording limits, which circumstantially point to a sudden deceleration, which would thus indicate an impact.

Originally posted by weedwhacker
So, actually, using your 2.4 degrees 'crab' angle, and the result increase in wing length of the downwind wing (the right in this case) and IF the precise, down to feet or even inches, location of the airplane along every point in the ground track can be determined, then it will be useful to be as precise as possible. Inasmuch as we wish to determine as exactly as possible the sequence of every strike on a light pole, or other ground objects along the ground track, and at what point along the leading edge of the wing they occured, then this will be information that must be incorporated.

I wonder, though, if that level of precision is possible, or if it is even necessary?

No, it is not from the FDR data. Only the physical evidence (forensics) obtained from the poles can even come close to telling that story. As I mentioned before, there is one subframe per second covering at 450 knots, 0.125 nautical miles. The distance traveled by the plane in the pole encounters would be at most 0.12 nautical miles, which most likely is captured by segments of two subframes (overlap). There only 4 recorded values for long acc per subframe and chance that a particular value of any one being captured at the exact moment of impact with a pole rather slim.

I'm not going to take the time to do it, but someone might want to calculate the kinetic energy of a Boeing 757 moving at 450 knots and compare it with the break-away force given for the pole. I suspect that once compared the acceleration component of the break-away force would not be significant enough to even move the 'needle' 0.001 g's. The 'normal' variation for the final minute is ~0.06 g's, so unless the acc component is greater than 0.03 g's, it might not even register as an anomaly.

[edit on 25-11-2009 by 911files]

Originally posted by weedwhacker
Yes, although I don't have the math equations to verify, nor calculate, the exact amounts,

It's simple trig weedwhacker. Sin 1 = o/h. Wingspan is 124, divided by 2 = 62. Sin 1 = o/62. Sin 1(62) = o. Double it and this is the amount of "swing" in the wing for a 1 degree crab.

it is true that a swept-wing will seem to 'lengthen' as the leading edge is presented more amd more perpindicular to the relative wind.

The effective wingspan/wing length along a course will never increase when the aircraft is askew as compared to a course with zero wind. The effective wing length with repect to the damage path will decrease with any crab angle. The right wing might be more forward, but the left wing will be further back. For example and for illustration purpose and ignoring the fuselage, if the wingspan were 90 degrees to the damage path, the effective wing length for damage would be the width/chord of the wing.

To keep it simple, the area in which the wingspan will cover over the ground for damage will decrease with increased crab angle.

Take one of your model planes. Get two pens, one touching each wing tip. Twist the airplane a few degrees as in a crab and push it through the two pens. The tips will no longer touch both pens.

I'll let the supposed "Math PhD's" figure out the decrease in effective wing length for the damage path due to crab.

[edit on 25-11-2009 by R_Mackey]

Originally posted by cesura
I noted that the plane's "velocity vector implies the
approximate direction in which the plane is pointing",
but tezzajw apparently does not understand the meaning
of the word "approximate". He also does not understand
that, to a first approximation, fixed wing aircraft can
only fly forward:

Casual readers to the thread, witness how a PhD in Mathematics can be wrong and not admit it or even know it.

I claimed that three fixed coordinate points are needed to define the spatial flight path of the aeroplane.

cesura denounced this, stating that only one fixed point and a velocity vector are needed.

Example A:
Stand up. Face a doorway. Hold your arms out by your side. The fixed point will be the tip of your nose. Walk towards the doorway. Your arms will collide at a certain spot on the door frame. At all times your nose's position was being traced, as it bobbed up and down, and the velocity of your nose was known.

Example B:
Stand up. Face a doorway. Hold your arms out by your side, but now lower your left arm by maybe 20 degrees and raise your right arm by 20 degrees. Walk towards the doorway. Your arms will collide in a different spot on the side of the door frame. At all times your nose's position was being traced, as it bobbed up and down, and the velocity of your nose was known.

In Example A and Example B, your nose has the same 'flight path' and velocity vector. So what's different? Your arms hit a different spot on the door frame.

cesura, will not be able to tell where your arms hit, because he only knows your nose's position and its velocity. He has no clue about what your arms are doing.

We need to know what path our nose is taking. We also need to know the paths that our middle finger tips are doing. If we do, then it is abundantly clear that we know where our middle fingers collide in both Example A and B.

cesura must also know the pitch, roll and yaw values, which will provide the location of any point on our body, relative to our nose. Hence, generating three coordinate points, like I stated.

Here's some extra credit that you missed out on, cesura. Why is it wrong when I stated that any three fixed points on the aeroplane are needed? I'll tell you the answer in case you can't figure it out. We can't use three collinear points, as we won't know the roll value around the defined axis.

Any three fixed, non-collinear points on the aeroplane will define its flight path. I would use the nose cone, left and right wing tips. Noting that the wing tips do flex in flight and would generate a minor amount of error, unless the FDR can also read the angle of flex in the wing.

Originally posted by tezzajw
Noting that the wing tips do flex in flight and would generate a minor amount of error, unless the FDR can also read the angle of flex in the wing.

Good point tezz. I believe someone figured the numbers awhile ago regarding dihedral alone with respect to the VDOT "scuff". If the right wing tip made the scuff, the engines should have been dragging the ground, sucking in Lloyd and his cab along the way, and the wing should have also taken out the Highway sign between the VDOT and pole 1, due to dihedral only, no flex was calculated. Incorporate flex and it's worse. The engine is under the bridge.

Originally posted by tezzajw

Originally posted by cesura
I noted that the plane's "velocity vector implies the
approximate direction in which the plane is pointing",
but tezzajw apparently does not understand the meaning
of the word "approximate". He also does not understand
that, to a first approximation, fixed wing aircraft can
only fly forward:

Casual readers to the thread, witness how a PhD in Mathematics can be wrong and not admit it or even know it.

Casual readers to the thread, witness how someone can twist words into something not said.

Cesura qualified his statement with "approximate" and "approximation". Like me, he has stated over-and-over that we deal with the plane as a point-source and reference from the center-of-gravity (since in physics terms any object will obey the same Newtonian principles). "Forward" is relative to cog, not fuselage orientation. Capt Bob knows I may not be a pilot, but I have flown solo. I am very familiar with a runway looking like it is at an angle to the plane's orientation (windage), but that of course is why the words such as "approximate" come into play, especially talking spatial orientation relative to the flight path.

Originally posted by 911files
Why? Because "three fixed points" (x, y, z) are relative to something.

Which is why I stated that you can fix an origin where ever you like. You can fix an origin to be the door handle of your house, but it won't be as relevant as fixing an origin to be something like the base of a light pole or the base of the VDOT tower.

Originally posted by 911files
That is a pretty solid case for the encounter (eyewitness, radar, FDR, eyewitness testimony, physical, photographic). Now that is not tezzajw's probability = 1 threshold (which does not exist in the real world), but it is definitely within my p = 0.997 threshold.

The real world states that your analysis has no room for error. If you claim that the five light poles were struck, then the alleged FDR data must show this to be demonstrably true.

Any room for error will not validate your claim that the five light poles were struck by the aeroplane.

I don't know why this is such a sticking point for you?

If you're not going to be 100% confident in your results, then you can claim that the aeroplane might have struck the light poles. In which case your analysis proves nothing, but will be accurate to within your stated confidence interval.

Originally posted by 911files
So what are we going around in circles about? "Three fixed points" in space. Sounds like that 'disinformation' I was telling Craig about years ago has had its desired effect, degraded the debate into silliness

Well, if you follow cesura's lead and only model the aeroplane as a single point and a velocity vector, then you'll be in big trouble. You know it too. There will be now way for you to know how the wings are skewed. Skewed wings could fly over light poles with ease. Some witnesses on the scene reported that the aeroplane appeared to banking.

You have to nail the flight path to show that some part of the aeroplane hit those five light poles. Take your time.