9/11gate, "AA77" FDR numerology Options

[tumetuestumefais...]

I was looking into the "AA77" FDR record to find out how the Lat/Lon coordinates were shifted by Mr. Stutt and Legge to get the plane on the runway. So I've chosen the map closest to 2001 and I've plotted the last "AA77" landing, taxiing in, standing at the gate, taxiing out and the last takeoff:
(IMG:http://xmarinx.sweb.cz/situation1.png)

(The numbers are numbers of subframes in the FDR and they can also serve as a timing, because their step is one second. So for example when you've frame number 145840 and frame number 145860 it means they're 20 seconds from each other. Only point when it is interrupted is when the plane stands, then the FDR is not recording - in our case at the subframe count 146180. The needed data were provided to me by Mr. Warren Stutt)

Everybody sees at the situation picture that the coordinates taken from the FDR are off.
How much off they are?
I was looking what a reference I can find for landing and I've found the point where the plane sharply turned from the runway to the taxi circuit.

From the logic of the landing, the overal visible shift and the trajectory pattern is absolutely clear where it was:
(IMG:http://xmarinx.sweb.cz/turn.png)

Then I've got a strange idea and I've decided to measure the distance and angle to the position where the plane quite clearly parked to and departed from the gate:
(IMG:http://xmarinx.sweb.cz/1666.66.png)

From the distance number is clear that we keep up with the perps at least numerologically... (IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/rolleyes.gif)

Let's have a break and have a look what number had the gate where the "AA77" was boarded and departed. We easily find it in the Wikipedia:

"The flight boarded through Gate D26, in Midfueld Concourse D at Dulles."

or here:

"In 2001, American Airlines Flight 77, a Boeing 757, left gate D26 at Dulles en route to Los Angeles International Airport, but it was hijacked and deliberately crashed into the Pentagon as part of the September 11 attacks."

Let's yet have look into govt. documents...yep, it is there (page 29):

"Flight 77 pushed back from Dulles Gate D-26 at 8:09 A.M."

Boring. Let's go back to our little petty plots.

Now we need to measure the same distance and the same angle from the point where the plane sharply turned to the taxi circuit:
(IMG:http://xmarinx.sweb.cz/turn-gate.png)

And where the line ends?
Here:
(IMG:http://xmarinx.sweb.cz/gate-gate.png)

Lets look what number the gate has:
(IMG:http://xmarinx.sweb.cz/IAD-ConcourseD.png)
SOURCE

It's not completely clear what a number the gate has - we have there two gates:
9 and 11.

[Bruce Sinclair]

Just a couple of points to add to the discussion:

When you call for push-back clearance, the normal phraseology is "American 77, push (or push back) at your discretion" not "American 77 cleared for push". This is quite important, as the lead hand on the headset and the Captain ultimately determine if it is safe to push the aircraft off the gate. So normally you are never "cleared" as this implies a clearance or that the controller is accepting the responsibility for the safety of the push back. They always throw it back in the Captain's court with the phrase "at your discretion". At least, this has always been my experience.

In regards to engine starts on the push, this is entirely an airline by airline choice. I have worked for airlines that allow engine starts while the aircraft is being pushed back and others that don't. In the Boeing 737 you need to turn off the A hydraulic pumps for this exercise since there is no nose wheel steering lockout pin. On the Airbus A300 B4 that I flew, it has a lockout pin that remains installed until after the push back is complete. So in this case, the main concern is whether the tug is powerful enough and heavy enough to continue the push with the thrust of the idling engine(s).

I hope that the American Airlines pilots will respond to this and advise us whether AA allows engine starts on the push on the B757.

If my memory serves me well, the FDR starts on the ground as soon as it receives a signal of oil pressure from the first engine being started. At least, this is the way it works on the B-737-200. Once airborne, it will continue to record even if both engines are shut down since the air-ground sensor knows that the airplane is still airborne.

Fondest regards,

Bruce

[rob balsamo]

Just a couple of points to add to the discussion:

When you call for push-back clearance, the normal phraseology is "American 77, push (or push back) at your discretion" not "American 77 cleared for push".

I've heard both, including things like "After the 73 passes from left to right behind you, you're cleared to push..."

They always throw it back in the Captain's court with the phrase "at your discretion". At least, this has always been my experience.

If that were the case, then we would hear, "Takeoff at your discretion", or "Land at your discretion". (IMG:http://pilotsfor911truth.org/forum/style_emoticons/default/smile.gif)

Even though you get a clearance, the Capt has final authority for the safe operation of that aircraft and it's occupants. Just because a clearance is issued, does not absolve the Capt of his responsibilities.

"... at your discretion" usually implies "there is no one else pushing or entering gate... so push when you want".

In regards to engine starts on the push, this is entirely an airline by airline choice. I have worked for airlines that allow engine starts while the aircraft is being pushed back and others that don't. In the Boeing 737 you need to turn off the A hydraulic pumps for this exercise since there is no nose wheel steering lockout pin. On the Airbus A300 B4 that I flew, it has a lockout pin that remains installed until after the push back is complete. So in this case, the main concern is whether the tug is powerful enough and heavy enough to continue the push with the thrust of the idling engine(s).

I hope that the American Airlines pilots will respond to this and advise us whether AA allows engine starts on the push on the B757.

Rampers confirm engine start is not initiated until after they are clear.

http://htmlimg4.scribdassets.com/9n4uho52z...e5050ec/000.jpg

It seems he started after push, but before all clear.

If we start while in push, the rampers will stop the push and leave the tug till the engine is shut down.

The only time an engine start is allowed at the gate, is when ground power or an air start is required and prior arrangements are made with the ground crew.

If the above aircraft pushed from the South of the Concourse, that engine was started at the gate, not "during the push".

But we already know it mostly looks like a push from the North of the concourse, and then engine start after the push. This conflicts with AA77 push from D26.

With that said, i'll double check with Ralph, but i pretty much know what he is going to say... especially with those large suckers hanging well below the wing to suck in anything floating (or walking) around the gate area.